University of Iowa
Iowa Research Online
Theses and Dissertations
2006
Systematics of late Cambrian (Sunwaptian)
trilobites from the St. Charles Formation,
southeastern Idaho
Thomas Arthur Hegna
University of Iowa
Copyright 2006 Thomas Arthur Hegna
This thesis is available at Iowa Research Online: http://ir.uiowa.edu/etd/45
Recommended Citation
Hegna, Thomas Arthur. "Systematics of late Cambrian (Sunwaptian) trilobites from the St. Charles Formation, southeastern Idaho."
MS (Master of Science) thesis, University of Iowa, 2006.
http://ir.uiowa.edu/etd/45.
Follow this and additional works at: http://ir.uiowa.edu/etd
Part of the Geology Commons
SYSTEMATICS OF LATE CAMBRIAN (SUNWAPTAN) TRILOBITES FROM THE
ST. CHARLES FORMATION, SOUTHEASTERN IDAHO
by
Thomas Arthur Hegna
A thesis submitted in partial fulfillment
of the requirements for the Master of
Science degree in Geoscience
in the Graduate College of
The University of Iowa
December 2006
Thesis Supervisor: Associate Professor Jonathan M. Adrain
Copyright by
THOMAS ARTHUR HEGNA
2006
All Rights Reserved
Graduate College
The University of Iowa
Iowa City, Iowa
CERTIFICATE OF APPROVAL
_______________________
MASTER'S THESIS
_______________
This is to certify that the Master's thesis of
Thomas Arthur Hegna
has been approved by the Examining Committee
for the thesis requirement for the Master of Science
degree in Geoscience at the December 2006 graduation.
Thesis Committee: ___________________________________
Jonathan M. Adrain, Thesis Supervisor
___________________________________
Christopher A. Brochu
___________________________________
Ann F. Budd
To my family, for their support and encouragement
ii
ACKNOWLEDGMENTS
There are many people to which I owe much. I owe a great debt to my wife,
Megan, for her encouragement and support. How she endures my constant talk of
trilobites, I will never know. Likewise, my parents, Robert and Ellamae, encouraged me
from an early age to follow my passions, and always supported me when I did so. It is to
these three people that I dedicate this thesis.
Completion of this thesis is in no small part due to the guidance and advice of my
advisor, Jonathan Adrain. Willingly offering an undergraduate a research project and a
lab assistantship, and then tolerating that same student for almost six more years is a
heroic deed—and one for which I am very grateful. There is no one better to learn about
trilobites from than him, and I feel privileged to have participated in his research
program. And, though not officially involved in my thesis, I must also thank Steve
Westrop (University of Oklahoma), who helped relocate the Franklin Basin section,
collect the samples, and also willingly offered advice on Cambrian trilobites.
I have been privileged to be a part of the paleontological milieu at Iowa. The
faculty, in particular my committee members Chris Brochu and Nancy Budd, were
always willing to interact with myself and other students. In fact, all three of my
committee members mentored honors designation projects that I undertook as an
undergraduate—all of whom helped shape my intellectual development. I am grateful for
the presence of other budding trilobitologists, Chuck, Talia, and Tin-Wai, all of whom
were an excellent sounding board and always willing to help out. The same is true of the
other paleontology students at Iowa who were there throughout my tenure—truly, this
thesis would not be the document it is without their discussions over pizza at the Airliner.
iii
ABSTRACT
Previously unreported silicified trilobite faunas occur in a narrow stratigraphic
interval of the Upper Cambrian (Sunwaptan) St. Charles Formation in the Bear River
Range of southeastern Idaho. The faunas occur in four closely spaced rudstones and
trilobite packstones indicating deposition in a shallow subtidal setting above storm wave
base. At least 23 species are represented, included two undescribed genera and several
undescribed species. The faunas are notable for their high trilobite abundance and
pervasive silicification. Most coeval faunas have been described on the basis of small
numbers of "crack-out" specimens, and the new material reveals many details of
anatomy, including knowledge of most exoskeletal sclerites. The four trilobite-yielding
beds contain markedly different taxon-abundance profiles, yet most species are shared
between them. This suggests multiple, taphonomically-controlled samples of a similar
underlying distribution, though true ecological variation cannot be discounted.
iv
TABLE OF CONTENTS
INTRODUCTION .......................................................................................................... 1
MATERIALS AND METHODS..................................................................................... 3
Introduction .................................................................................................. 3
Preparation and Analytical Techniques ......................................................... 5
GEOLOGICAL BACKGROUND................................................................................... 6
Regional Geology ......................................................................................... 6
The Nounan Formation .......................................................................... 7
The Garden City Formation ................................................................... 7
The St. Charles Formation ..................................................................... 8
PALEOECOLOGY....................................................................................................... 17
Environments ............................................................................................. 17
Taphonomy ................................................................................................ 19
Diversity..................................................................................................... 23
Correlation.................................................................................................. 25
SYSTEMATIC PALEONTOLOGY ............................................................................. 27
Genus PSEUDAGNOSTUS Jaekel, 1909 ................................................... 29
Genus LITAGNOSTUS Rasetti, 1944......................................................... 34
Genus PTYCHASPIS Hall, 1863 ................................................................ 39
Genus IDIOMESUS Raymond, 1924.......................................................... 45
Ptychaspidine sp. ........................................................................................ 46
Genus Indeterminate ................................................................................... 47
Macronodine sp. ......................................................................................... 49
Genus KATHRYNIA Westrop, 1986a ........................................................ 49
Genus IDAHOIA Walcott, 1924a ............................................................... 50
Genus SARATOGIA Walcott, 1916 ........................................................... 53
Genus WILBERNIA Walcott, 1924a .......................................................... 56
Genus NAUSTIA Ludvigsen, 1982............................................................. 61
Genus ELLIPSOCEPHALOIDES Kobayashi, 1935a.................................. 63
Genus TRIARTHROPSIS Ulrich, in Bridge, 1931...................................... 66
Genus TAENICEPHALUS Ulrich and Resser, in Walcott, 1924a ............... 67
Genus New Genus A .................................................................................. 68
Genus DRUMASPIS Resser, 1942 ............................................................. 71
Dokimocephalidid sp. ................................................................................. 77
Genus New Genus B................................................................................... 78
Genus MALADIA Walcott, 1924a.............................................................. 82
Unassigned cranidium type A ..................................................................... 90
Unassigned pygidia type A ......................................................................... 90
Unassigned pygidium type B ...................................................................... 91
Unassigned pygidia type C.......................................................................... 92
Unassigned pygidium type D ...................................................................... 93
Unassigned pygidium type E....................................................................... 93
Unassigned pygidia type F .......................................................................... 94
Unassigned pygidia type G ......................................................................... 94
v
Unassigned librigenae type A ..................................................................... 95
Unassigned librigena type B ....................................................................... 95
Unassigned hypostomes and thoracic segments........................................... 96
Unassigned meraspid trilobite..................................................................... 97
CONCLUSIONS........................................................................................................... 99
APPENDIX A............................................................................................................. 101
APPENDIX B ............................................................................................................. 196
REFERENCES ........................................................................................................... 221
vi
LIST OF TABLES
Table
B1: Net weight of processed rock, by horizon and number of species identified
therein. ............................................................................................................... 197
B2: Sclerite counts from horizon 9.6 (crackout)........................................................... 198
B3: Sclerite counts from horizon 9.6 (silicified). ......................................................... 199
B4: Sclerite counts from horizon 10.1-10.2 (crackout)................................................. 200
B5: Sclerite counts from horizon 10.1-10.2 (silicified). ............................................... 201
B6: Sclerite counts from horizon 10.6-10.72 (crackout)............................................... 202
B7: Sclerite counts from horizon 10.6-10.72 (silicified)............................................... 203
B8: Sclerite counts from horizon 11.2-11.3 (crackout)................................................. 204
B9: Sclerite counts from horizon 11.2-11.3 (silicified). ............................................... 205
B10: Sclerite counts from the original silicified sample from Franklin Basin............... 206
B11: Spearman rank correlation coefficients comparing crackout and silicified
collections from the same horizon....................................................................... 207
B12: Spearman rank correlation coefficients comparing each silicified collection to
each other silicified collection and each crackout collection to each other
crackout collection.. ........................................................................................... 208
B13: Euptychaspidid character matrix.. ....................................................................... 209
B14: Taxa and sources for ptychaspidid analysis ......................................................... 210
B15: Characters and character states used in the ptychaspidid phylogenetic
anaylsis. ............................................................................................................. 212
B16: Ptychaspidid phylogenetic analysis character codings.. ....................................... 215
B17: Character state changes for the phylogenetic tree in figure A44 under
ACCTRAN. See table B15 for character states. ................................................. 217
vii
LIST OF FIGURES
Figure
A1: Correlation chart................................................................................................... 102
A2: Locality maps. ...................................................................................................... 104
A3: Stratigraphic column and rock samples................................................................. 106
A4: Images from Franklin Basin, Idaho....................................................................... 108
A5: Images displaying the character of the silicification as preserved in silicified
blocks.................................................................................................................. 111
A6: Thin section images of lithic specimens preserved from Franklin Basin................ 114
A7: Pseudagnostus new species 1. .............................................................................. 116
A8: Pseudagnostus new species 1. .............................................................................. 118
A9: Litagnostus new species 2, Idiomesus new species A, Euptychaspidine new
species F, ?Kathrynia sp. ..................................................................................... 120
A10: Litagnostus new species 2................................................................................... 122
A11: Ptychaspis new species 3. ................................................................................... 124
A12: Ptychaspis new species 3, Ptychaspidine sp., and Macronodine sp...................... 126
A13: Ptychaspis n. sp. 3 pygidia.................................................................................. 128
A14: Unassigned cranidium type A, unasigned pygidia type G., dokimocephalid
sp., and unassigned pygidia................................................................................ 130
A15: Trilobites from Franklin Basin............................................................................ 132
A16: New genus A and new species 6.. ....................................................................... 134
A17: New genus A and new species 6.. ....................................................................... 136
A18: Drumaspis sp. and Drumaspis af. D. walcotti. .................................................... 138
A19: Drumaspis af. D. walcotti cranidia...................................................................... 141
A20: Drumaspis af. D. walcotti cranidia...................................................................... 143
A21: Drumaspis af. D. walcotti librigenae................................................................... 145
A22: Drumaspis af. D. walcotti and Drumaspis sp. pygidia......................................... 147
viii
A23: Triarthropsis sp.. Ellipsocephaloides cf. E. nitela? and E. monsensis cranidia
and pygidia. ....................................................................................................... 149
A24: Idahoia n. sp. B. ................................................................................................. 152
A25: Wilbernia n. sp. 4................................................................................................ 154
A26: Wilbernia sp., Wilbernia n. sp. 4, and Wilbernia? cf. W. expansa cranidia and
librigenae........................................................................................................... 156
A27: Wilbernia n. sp. 4 and unidentified pygidia......................................................... 159
A28: Maladia n. sp. 8 cranidia. ................................................................................... 161
A29: Maladia n. sp. 8 cranidia. ................................................................................... 163
A30: Maladia n. sp. 8 librigenae ................................................................................. 165
A31: Maladia n. sp. 8 pygidia. .................................................................................... 167
A32: Maladia n. sp. 9 cranidia and pygidia ................................................................. 169
A33: Naustia n. sp. 5 cranidia...................................................................................... 171
A34: Naustia n. sp. 5 pygidia. ..................................................................................... 173
A35: Saratogia n. sp. C, Saratogia sp., and Idahoia n. sp. B cranidia. ......................... 175
A36: Misc. librigenae.. ................................................................................................ 177
A37: New Genus B and new species 7 cranidia. .......................................................... 180
A38: New Genus B and new species 7 cranidia.. ......................................................... 182
A39: Hypostomes........................................................................................................ 184
A40: Hypostomes and thoracic segments..................................................................... 186
A41: Relative diversity................................................................................................ 188
A42: Phylogenetic tree of the Euptychaspidinae and Macronodinae. ........................... 190
A43: Phylogenetic tree of the Ptychaspididiae. ............................................................ 192
A44: One of the 408 MPTs with branches numbered................................................... 194
ix
1
INTRODUCTION
The Cambrian trilobite faunas of Great Basin area of Nevada, Utah and Idaho
have been studied for over 125 years and the geographic expanse and exposure of
Cambrian-age rocks there make it a very attractive area for research (Palmer, 1971).
However, despite the rich trilobite record, studies of trilobite evolution in the Cambrian
have generally suffered two major problems: phylogeny largely determined by
stratigraphy and incomplete morphological data.
I seek to address these issues via a study of new silicified trilobite material from
the Upper Cambrian (lower Sunwaptan) St. Charles Formation, Franklin Basin, Idaho
(figures A1-A4). The fossiliferous horizons were collected in bulk during the fall of
2004 from four discrete trilobite-bearing horizons. These horizons varied from rudstones
to trilobite packstones, indicating a shallow, subtidal environment above storm wave
base. Just over 224 kg of rock were digested and over 4,900 identifiable sclerites were
recovered (see tables B1-B10). Lochman and Hu (1959) documented a trilobite fauna
from the St. Charles Formation at a locality near Mink Creek, Idaho. They documented
fourteen trilobite species from manually prepared (‘crackout’) material. Trilobites from
the St. Charles Formation seem to exhibit a relatively high level of regional variation—
there is little species-level overlap between this study and Lochman and Hu’s (additional
material examined from the St. Charles Formation at Two Mile Canyon reinforces this
conclusion). The goals of this study are to 1) consider the environmental and taphonomic
factors involved (figures A5-A6), 2) present a systematic description of the taxa (figures
A7-A40), and 3) document the faunal pattern created by the recovery of silicified fossils
versus conventional manual sampling (figure A41; tables B11-B12). Completion of these
three goals will enrich our picture of lower Sunwaptan trilobite diversity and help to
elucidate some of the factors driving diversity signals.
2
In the fossil record, morphology is the record of how evolution proceeded. It,
therefore, is obvious that incomplete morphological data will make it more difficult to
discern the pattern. As discussed by Adrain and Westrop (2004a, 2005), the potential of
silicified faunas to contribute morphologic and ontogenetic information to studies of
Cambrian trilobite evolution has been underexploited until recently. Already, silicified
Cambrian trilobite faunas have contributed significantly to our knowledge of trilobite
evolution via the discovery of previously unknown morphologic features (e.g. the pleural
‘pockets’ of pygidia belonging to species of Macronoda Lochman, 1964; see Adrain and
Westrop, 2005) hold much potential for the elucidation of higher-level phylogenetic
affinities.
3
MATERIALS AND METHODS
Introduction
Species recognition has long been problematic in biology; the necessary
restriction to fossil material in paleontology makes species recognition even more
difficult. The approach to species recognition used herein follows closely the “phena”
concept laid out by Smith (1994). A “phenon” is a minimum morphological unit (group)
that is consistently diagnosable by meaningful characteristics (Smith, 1994, p. 19).
Several pygidial types, not previously recognized within Upper Cambrian
trilobites assemblages are described herein. Their postulated association with previously
documented cranidia highlights the problem of association when dealing with
disarticulated remains. Trilobites have a complex, multisclerite body; associating
different body part to a species, when disarticulated, can be a non-trivial task. However,
solely basing taxonomy and phylogenetic inferences on data derived from one body part
(e.g. the cranidia) is obviously insufficient. Another option—associating sclerites with
too little or inappropriate evidence—is just as undesirable as it could potentially create
evolutionary chimeras. Upper Cambrian trilobites are perhaps more vulnerable to
misassociation of sclerites than younger trilobites because there are relatively few
examples of articulated Upper Cambrian trilobites known (for important exceptions see
Chatterton and Ludvigsen, 1998; Stitt, 1983). Many trilobite workers prior to 1980 did
not state the criteria used to associate cranidia and pygidia where articulated specimens
were absent, with most opting not to explain their associations in detail. It is
recommended that workers pay particular attention to the associations in their work and
detail the criteria by which they arrived at their conclusions.
There are three main ways by which one can make species body part associations
with trilobites, and they are discussed below in order of decreasing confidence.
Articulated trilobites are the easiest to assess, as all of the information pertaining to the
4
body part associations is preserved. This information can be used to then assess the
sclerite associations of related groups—for example articulated specimens of Elvinia
roemeri (Shumard, 1861) and Irvingella major Ulrich and Resser, in Walcott, 1924a
figured by Chatterton and Ludvigsen (1998) and Irvingella nuneatonensis (Sharman,
1886) figured by Rushton (1967) support the cranidia-librigenae-pygidia association of
the related species Drumaspis. Morphology can also be used to assess trilobite sclerite
associations. Associations involving cranidia and librigenae are perhaps the easiest to
assess in this way, as they need to physically fit together. Associating pygidia with
cranidia is more difficult solely using morphology because a) dorsal sculpture, while
often similar on cranidia and pygidia, can vary in the degree of expression along the A-P
axis, and b) they do not articulate directly together. This latter point has an important
counterexample—trilobite enrollment. For trilobites to enroll, the cranidium and
pygidium necessarily need to have some contact. The amount of contact varies, with
some species possessing elaborate coaptive structures (morphological features ensuring
an interlocking fit of the head and tail, see Clarkson and Whittington, in Whittington et
al., 1997). However, well-documented examples of enrolled trilobites from the
Cambrian are comparatively rare (Stitt, 1983), when much better documented examples
from the post-Cambrian are considered (Chatterton and Campbell, 1993; Henry and
Clarkson, 1975; Lespérance, 1991). Because trilobite cranidia and pygidia do not have a
set ratio of relative size to one another, it is an inappropriate to use size alone as a
morphological criterion for making species sclerite associations. Co-occurrence may
have historically been the most widely used criteria for Upper Cambrian trilobites (not
necessarily the only criterion used), but it is also the most subject to physical taphonomy.
As work by Adrain and Westrop (2004b) has shown, taphonomic sorting in shallow
subtidal environments can cause cranidia:pygidia ratios to deviate wildly from the
expected ration of 1:1. Thus, constant co-occurrence could indicate a similarity in
hydrodynamic behavior rather than a biological association.
5
Preparation and Analytical Techniques
The section studied herein is located at Franklin Basin, in the Bear River Range of
southeastern Idaho (figures A1, A2, A3.1, A4.1). Bulk samples were collected from four,
trilobite-bearing horizons in Franklin Basin, ID, with additional talus collections from
Two Mile Canyon (figure A2.2). Silicified specimens were freed from the surrounding
matrix using hydrochloric acid until reaction ceased; crackout specimens were prepared
with an air hammer. For photography, silicified specimens were blackened with either
dilute India ink or photographic opaque, mounted on blackened toothpicks with gum of
tragacanth, and whitened with ammonium chloride. Crackout specimens were blackened
and whitened using the same methods. Photographs were taken using a digital camera
mounted on a Leitz Aristophot macrophotography system. The digital images were
processed using GraphicConverter and Adobe Photoshop. Spearman rank correlation
coefficients were calculated using software made freely available by Wessa (2006).
Cladistic analyses were conducted using MacClade and PAUP* 4.0b10 (Maddison and
Maddison, 2005; Swofford, 2002). This material was summarized by Hegna et al.
(2006).
6
GEOLOGICAL BACKGROUND
Regional Geology
In the Late Cambrian, the paleocontinent of Laurentia was positioned in the
tropics. According to several studies, the equator ran approximately from modern-day
Ellesmere Island in the east to the modern-day location of the state of Georgia in the west
(Cocks and Torsvik, 2002; Hartz and Torsvik, 2002; Torsvik, 2001). A transect of the
area beginning at the equator would have found the exposed craton and a passive margin
shoreline nearest the equator, with ocean depth increasing northward (westward in the
modern-day orientation, see Lochman-Balk, 1971; Palmer, 1971). Subsidence allowed
for the accumulation of the thick sedimentary sequences (Hintze, 1973) that are observed
today in the Great Basin area.
Palmer (1960, 1971) synthesized the regional geology of the Great Basin by
observing that the Cambrian deposits can be classified into three broad categories: 1)
inner and 2) outer detrital belts separated from one another by a 3) medial carbonate belt.
A crude interpretation of this pattern is one of environmental change along a depth
gradient; detailed analyses show that the broad pattern holds true though the details are
much more complex (Kepper, 1972, 1976; Koepnick, 1976; McBride, 1976). Much of
the change through time in the distribution of these three categories geographically can
be thought of as a product of a change in sea level, which, in the Upper Cambrian, most
current workers attribute to eustacy (e.g. Palmer, 1981; Saltzman et al., 2004) rather than
regional uplift (e.g. Hanson, 1953; Shiveler, 1986). Stratigraphy in the southern Idahonorthern Utah area has been studied by Biek (1999), Coulter (1956), Deiss (1938, 1941),
Ervin (1982), Hanson (1953), Harlick, (1989), Haynie (1957), Hintze (1973), Howell et
al. (1944), Landing (1981), Lochman-Balk (1956, 1972), Mansfield (1927), Nielson
(1983), Palmer (1956, 1971), Richardson (1913), Ross (1949), Saltzman et al., (2004),
Shiveler (1986), Taylor and Landing (1982), Taylor et al. (1981), Taylor and Repetski
7
(1985), Wakeley (1975), Walcott (1908), Williams (1948), and Williams and Maxey
(1941).
The Nounan Formation
The general geologic context for the St. Charles Formation is provided by a
consideration of the units above and below (figure A1). Below the St. Charles is the
Nounan Formation (Walcott, 1908)—a series (≈270-360m) of ridge- and ledge-forming
thin-bedded dolomites and limestones (Palmer, 1971). The Nounan Formation is roughly
correlative with the Orr Formation of western Utah (Lochman-Balk, 1972), but unlike the
Orr Formation, it has been not been studied in detail (e.g. Hintze and Palmer, 1976).
Biostratigraphic evidence from trilobites suggests that it contains the MarjumanSteptoean stage boundary. Saltzman et al. (2004) reported fossils from the
Crepicephalus (upper Marjuman) through Dunderbergia (upper Steptoean) Zones. This
agrees with the findings of Williams and Maxey (1941) (it is also most likely consistent
with Ervin’s (1982) vague identification of Dresbachian (≈upper Marjuman)
‘marjumiids’). It has even been suggested that the lower portion of the Nounan
Formation may be as old as the upper Middle Cambrian (Cedaria Zone; see Hanson,
1953; Williams and Maxey, 1941). The Nounan Formation is conformably overlain,
grading from sand-free, ribbon limestones into the relatively pure sandstones of the
lowest member of the St. Charles Formation, the Worm Creek Quartzite (Saltzman et al.,
2004).
The Garden City Formation
Above the St. Charles Formation is the Garden City Formation (figure A1;
Richardson, 1913). The Garden City Formation, well known for its silicified trilobite
faunas (Adrain et al., 2003; Lee and Chatterton, 1997a, 1997b, 1997c; Ross, 1951, 1951a,
1953), is a series of evenly bedded bioclastic grainstones to micrites with
intraformational limestone conglomerates (Taylor and Landing, 1982). Its base is
8
equivalent to the Symphysurina Zone in the early Ibexian Series (Taylor and Landing,
1982), and is approximately correlative with the House and Fillmore Formations of
Western Utah (Hintze, 1973). The contact between the Garden City and the underlying
St. Charles is a sharp disconformity with at least twelve meters of erosional relief
(Landing, 1981; evidence of subaerial exposure is discussed by Taylor and Repetski,
1985, p. 240). The Cambro-Ordovician boundary was tentatively thought to occur at this
disconformity, more as a matter of convenience due to the lack of biostratigraphic
constraint (Mansfield, 1927; Ross, 1949, 1951; Williams and Maxey, 1941). However,
work in the early 1980s, utilizing conodont biostratigraphy, has shown that the equivalent
of the Ibexian Missisquoia typicalis Subzone and possibly the lowest part of the
Symphysurina brevispicata Subzone occur in the upper part of the St. Charles (figure
A1), and that the boundary between the two formations is a diachronous disconformity
representing a gap comprising most of the Symphysurina Zone (Landing, 1981; Taylor
and Landing, 1982). These two subzones are likely is no lower than fourteen meters
from the St. Charles-Garden City disconformity (Taylor and Landing, 1982).
The St. Charles Formation
The St. Charles Formation (Walcott, 1908) occurs between these two
aforementioned units (figure A1). Regionally, it extends at least from the Portneuf Range
in the north to the south side of the Great Salt Lake in the Lakeside Mountainsin the
south and averages between 225-315 meters thick (Palmer, 1971). It has been treated as
being composed of two to three members, though only the lowest member, the Worm
Creek Quartzite, is formally named (Palmer, 1971). Informal names for the other two
members will be used for brevity herein; they are the trilobitic member (oldest) and the
sucrosic member (youngest). Work on the St. Charles by Harlick (1989) in the Lakeside
Mountains of Utah and by Ervin (1982) in Copenhagen Canyon, Idaho, suggests that this
bipartite division of the unnamed upper portion of the St. Charles may be of only regional
9
significance as pervasive dolomitization (the characteristic used to identify the sucrosic
member in Franklin Basin) in those localities has affected the entire upper portion
(trilobitic and sucrosic members) of the St. Charles. Until the dolomitization of the St.
Charles is better understood, that caveat will need to be kept in mind. The following
sections dominantly deal with description of the lithofacies; paleoecological
interpretation and correlation will be dealt with later on.
Worm Creek Quartzite
The Worm Creek Quartzite (Richardson, 1913) is a dominantly siliciclastic
(quartzitic to feldspathic) unit with interbeds of sandy limestone (described in detail by
Haynie, 1957; see figure A4.5). It varies widely in thickness (2-270 meters), thinning to
the south (Coulter, 1956; Hanson, 1953; Haynie, 1957; Palmer, 1971)—this variance is
largely responsible for the variance observed in the average thickness of the St. Charles
Formation as a whole (Shiveler, 1986). However, the gradation nature of the upper and
lower boundaries of the Worm Creek (Harlick, 1989) allow for differences of opinion as
to the magnitude of this regional trend (see Wakeley, 1975). The Lemhi Arch (or Salmon
River Arch; see Rowell et al., 1979) in central Idaho is the presumed source for the
sediment (Hanson, 1953; Shiveler, 1986), as it is for the Middle Cambrian siliciclastics of
northern Utah and southern Idaho (Palmer, 1971). This assessment is supported by the
observation that sand grains within the Worm Creek are smaller and better sorted to the
south in the sections studied by Shiveler (1986). If it is the source of the siliciclastics, the
thickness of the Worm Creek varies inversely with the distance from the source.
Saltzman et al. (2004) have interpreted the Worm Creek as containing the Sauk
II-Sauk III boundary—a continent scale regression occurring during the Dunderbergia
Zone (upper Steptoan, Upper Cambrian). In the Worm Creek, the boundary represents
only a lowstand of sealevel. However unlike the succession of rock present in Idaho,
several cratonal successions have no record of Dunderbergia Zone fossils—the direct
10
result of a depositional hiatus presumably caused by the Sauk II-Sauk III regression
(Palmer, 1981; Saltzman, et al., 2004). Runkel et al. (1998) have estimated the
magnitude of this regression in the Upper Mississippi Valley to have been, at most, a few
tens of meters. Saltzman et al. (2004) described the Worm Creek in two halves, with the
lower half coarsening upward and the upper half fining upward. The symmetrical
division between the two was interpreted therein to be the Sauk II-Sauk III boundary.
The fact that the Worm Creek is generally reported to contain either Dunderbergia Zone
or Elvinia Zone fossils matches the expectations one would have for a unit representing a
nearshore environment at the Sauk II-Sauk III boundary. Howell et al. (1944) reported
Elvinia Zone fossils while Saltzman et al. (2004) reported Dunderbergia Zone fossils
below the Worm Creek and Elvinia Zone fossils above. Coulter (1956) reported
Crepicephalus in his broad study of the geology of the Preston Quadrangle, but without
illustration, it is impossible to evaluate. The transition between the Worm Creek and the
trilobitic member is gradational, though poorly exposed (Ervin, 1982). Regionally, the
unit is roughly correlative with the Corset Spring Shale (Hintze, 1973).
The Trilobitic Member
The informally-named trilobitic member of the St. Charles Formation is of the
greatest interest herein, as it is the unit containing the fossiliferous limestones (figures
A3.1-6, A4.1, 3, 7). They are thin-bedded and estimated by Palmer (1971) to include
roughly 100 m (Franklin Basin seems to contain only about 30 m). No distinct boundary
between the two informal members is recognized—the interval in Franklin Basin is
poorly exposed (figures A4.3, 7). Non-trilobite members of the silicified shelly fauna
include: brachiopods (?Billingsella Hall and Clarke, 1892 see figure A5.3), conodonts
(see Landing, 1981), echinoderm debris, gastropod steinkerns (Pelagiella Matthew, 1895
and Anconochilus Knight, 1947), sponge spicules (and possible sponge body fossils
derived from the insoluble residue), and tuberculate plates of an unknown affinity (near
11
the top edge of figure A5.3) 1. There are also several odd silicified elements bearing
superficial resemblance to the conodont Clavohamulus Furnish,1938 (elements figured
by Furnish, not Lehnert et al., 1997), and to specimens referred to New Genus A of
Ethington et al., 1986. The figured stratigraphic column shows the four sampled
horizons in relation to one another, in the context of about 15m of stratigraphic section
immediately above the Worm Creek Quartzite (figure A3.1).
Acid digestion failed to dissolve most samples completely; substantial blocks of
densely silicified fossil fragments and chert remained after reaction had ceased (figures
A3.6, A5.1-5, 7). Silicification of fossil material seemed to be relatively homogeneous
within these blocks—when sawed in half the undigested blocks still contained limestone
that was previously prevented from reacting with the acid due to the dense silicification.
When these nodules are bisected (figure A3.6), calcareous material is found to still
remain in the center; the density of the silicified material is such that acid was unable to
penetrate completely. The chert occurs in small nodules, not in beds or layers. Blocks
created by this dense silicification were more commonly to be found in the residue from
the horizons FBSC 10.1-10.2m and FBSC 10.6-10.72m, and less commonly from the
FBSC 9.6m and FBSC 11.2-11.3m (perhaps related to the density of bioclastic material;
the prefix FBSC specifies Franklin Basin, St. Charles, which will be dropped henceforth).
Large (whole or fragments of) trilobite sclerites were observed in situ; they tended to lie
1 One other ‘arthropod’ has been identificd from the St. Charles Formation, though none
were found in the course of this study. Walcott (1924b) described what he identified as a new
monospecific genus of notostracan crustacean, Ozomia Walcott, 1924 from the St. Charles
Formation, Blacksmith Fork Canyon, Utah. He did not figure any specimens from the St.
Charles, but figured specimens of Ozomia from other localities suggest that it is not a notostracan.
The types and only species , Ozomia lucan Walcott, 1924b, was informally recombined in the
Paleobiology Database by P. Wagner as Ribieria lucans (http://paleodb.org/cgibin/bridge.pl?action=displayTaxonomicNamesAndOpinions&reference_no=9042I)—implying an
identify as a rostroconch mollusk. From the figured specimens, an interpretation as an early
bivalved arthropod is still consistant as well, though without restudy neither hypothesis carries
much weight.
12
parallel to bedding—consistent with, though not indicative of, hydrodynamic sorting
(figures A5.1, 5, 7).
Hand specimens were preserved for study from each of the four horizons; all are
dark grey, highly crystalline bioclastic limestones (figures A3.2-5). Lithologically, these
can be divided into three lithofacies: 1) a matrix-supported intrarudite (with a grainstone
matrix), 2) a clast-supported intrarudite (with a micritic matrix), and 3) a bioclastic
grainstone. Weathered surfaces of each display silica fragments protruding, weathering
more slowly than the surrounding carbonate, whereas flat calcareous pebbles (where
present) weather out preferentially. These siliceous fragments include primarily siliceous
bioclastic material (e.g. sponge spicules), secondarily siliceous bioclastic material (e.g.
trilobite sclerites), and small chert nodules. Each of these three lithologies are discussed
individually below.
Lithology 1, the matrix-supported intrarudite (flat-pebble conglomerate,
intraclastic limestone conglomerate), occurred in horizons 9.6 and 10.6-10.72m (figures
A3.3, 5). Dominantly a grey, highly crystalline, bioclastic calcirudite, the flat-pebble
clasts are micritic (likely fecal, see figure A6.1), some with possible laminations. In size,
the clasts are larger than those in lithology 2—up to 9 cm long and 0.7 cm thick—and are
mostly arranged sub-horizontally (max inclination ≈ 40°). Irregular, anastomosing seams
are common (especially in horizon 10.6-10.72m) with prominent flat pebble truncations
on both upper and lower (figures A3.3d-e) surfaces of the pebbles as well as occasional
orange colored rinds on the seams, making the interpretation of them as stylolites and
clay seams more convincing. The lower surface pebble truncations support a nonerosional origin for at least some of the seams.
Wanless (1979) discussed the different responses of limestone to stress; the
structures observed herein seem to reflect what he referred to as sutured-seam solution
(common stylolites; found in rocks with structural resistance to stress, i.e. grainsupported beds, skeletal material, etc) and non-sutured seam solution (typified by the
13
presence of clay seams, which was indicated by the presence of thin, undulating,
insoluble flakes of clay in the acidized residue). The dominantly horizontal stylolites
most likely result from stress related to overburden (figures A3.2-4; Wanless, 1979). The
expected result of the stylolite formation would be a concentration in insoluble material
in irregular laminae or layers. This may partially explain the large, welded masses of
semi-layered silicified material that remained in the insoluble residues after acid
digestion—though the pressure would need to still be low enough to prevent the silica
from going into solution.
The association of stylolites and dense concentrations of silicified material raises
an interesting question: could the stylolites be, in part, responsible for the concentration
of silicified material? If the silicification was a late diagenetic event, the silicification
may have preferentially occurred around stylolites. Similar patterns of silicification
localized around faults have been discussed by Adrain and Fortey (1997), and localized
silicification is known to occur in the St. Charles Formation (Harlick, 1989). The pattern
of dense silicification (figure A3.6, A5.1-4) and sparse silicification (figure A6.1-6) in the
same horizon are consistant with this interpretation. If silicification occurred in this way,
one may be able to find trilobite sclerites truncated along stylolites and then subsequently
silicified.
Both horizons 9.6m and 10.6-10.72m are representatives of lithology 1, but differ
in several ways. Horizon 9.6m is less densely packed with bioclastic material (both in
terms of crackout material and insoluble acid residue) and has a less coarsely crystalline
matrix than 10.6-10.72m. However, proportionally horizon 9.6m contains a significant
number of large crackout specimens (Wilbernia cranidia ≈ 4 cm long; figures A25 and
A26)—possibly indicating less torturous predepositional sorting than the other horizons.
Horizon 10.6-10.72m lacks the same proportion of large crackout specimens.
14
Lithology 2, the clast-supported intrarudite, only occurs in the bottom 3 cm of
horizon 10.1-10.2m (figure A3.4). The polished slab is deceptive in the fact that this
lithology was not readily separated from the bioclastic grainstone above in most
instances. As a result, the two lithologies within the same bed were processed together.
Some of lithology 2 was successfully separated from the rest of horizon 10.1-10.2m
(which was comprised of lithology 3) and processed separately from it—lithology 2
proved to be very poor in silicified material. However, what was present was similar to
what was found in the upper portion of horizon 10.1-10.2m. The lower edge of the
boundary between lithology 2 and lithology 3 (figures A3.4g-h) has a thin rind (1 mm) of
orange discoloration (hematite?), with a larger irregular zone of tan discoloration below
that (up to 8 mm). One possible truncated flat pebble was observed (figure A3.4h),
though its upper edge is indistinct due to the tan discoloration. The rock above this
boundary is indistinguishable from the rest of the upper lithology—no discolorations or
rinds. This boundary is consistant with an interpretion as a local surface of nondeposition and erosion.
Lithology 3, the bioclastic grainstone, occurs in horizons 10.1-10.2m and 11.211.3m (figures A3.2, 4). It is very similar to lithology 1, save that it lacks flat pebbles.
In horizon 10.1-10.2m, it is a mostly homogeneous dark grey bioclastic grainstone (≈10
cm thick) that has been very heavily silicified. Irregular, anastomosing seams, which
may be stylolites, run through it, though no unequivocal evidence of grain truncation was
observed at these seams. 11.2-11.3m most closely resembles 10.1-10.2m, but is less
homogeneous. The bottom 1.7 cm of horizon 11.2-11.3m are more micritic while there is
a concentration of orange matrix along a crack (3 cm from bottom) in the hand specimen
(a weakness from a stylolite?). From the thin section made from this horizon (figures
A6.5-6), the orange material is known to contain small dolomite rhombs.
Regional heterogeneity in the St. Charles Formation and the small section studied
herein prevent a detailed comparison with other previously studied sections. Two of the
15
study localities of Shiveler (1986) provide rough analogs for the trilobitic member; she
documented a recrystallized, intraclastic, fossiliferous dolowackestones and
dolopackstones near Petticoat Peak and Malad City. Unfortunately, no detailed fossil
data were recorded. Harlick (1989) and Shiveler (1986) identified nearshore
environments—oolites, and algal structures—that have no recognized analog in the
trilobitic member. Comparisons with other sections (those studied by Ervin, 1982;
Harlick, 1989; as well as the Fish Haven section of Shiveler, 1986) are more difficult as
the dolomitization is too pervasive to permit the identification of body fossils. No clear
pattern to this pervasive dolomitization exists when the localities are examined in the
context of their arrangement on a modern map, unlike the late Ordovician-early Silurian
strata of the central United States (Amsden and Barrick, 1986).
Several talus samples were recovered from Two Mile Canyon, near Malad City,
ID (figure A2). Nielson (1983) studied this area in detail by (albeit the south side of the
canyon—collections discussed herein were derived from the north side of the canyon).
He documented over 100 meters of fossiliferous limestone from which these samples
could be derived from. Without more detailed information it is impossible to precisely
relate these trilobite-bearing rocks and our samples to the trilobitic member in Franklin
Basin, but the trilobites found there are at least broadly comparable to those found in the
St. Charles elsewhere in Idaho (this study; Lochman and Hu, 1959).
The Sucrosic Member
The informally-named sucrosic member of the St. Charles Formation is a series of
massive cherty dolomites. They have a sugary texture and are light grey with wavy
bioturbated bedding and thin chert horizons. Taylor and Landing (1982) observed highrelief stromatolites, thrombolites, oncolites, and rare parallel laminated fabrics they
suggested may be algal in origin. The member contains few body fossils; Taylor and
Repetski (1985) reported finding gastropods and specimens of the early mollusc,
16
Matthevia Walcott, 1885. Conodont biostratigraphy was studied by Landing (1981), and
placed the upper part of the St. Charles in the middle (possibly upper) Cordylodus
proavus Zone (Clavohamulus elongatus to, possibly, C. hintzei Subzones—equivalent to
the Missisquoia or perhaps lower Symphysurina trilobite zones) Silicified trace fossil are
frequently visible weathering out on the surface (figures A4.2, 4, 6, 8, 9; see Harlick,
1989). The variation encompassed by sucrosic member of Franklin Basin is very close to
the descriptions given by Ervin (1982) and Harlick (1989) for the entire upper portion of
the St. Charles, which was heavily dolomitized, in their respective study areas.
17
PALEOECOLOGY
Environments
The depositional environment of the trilobite bearing horizons studied herein from
the St. Charles Formation is obvious relevance for both understanding the habitat
occupied by this fauna and for also understanding the conditions and biases that may
have effected its preservation. Broadly, the St. Charles Formation contains what has been
interpreted to be the boundary between the inner detrital (Worm Creek Quartzite
Member) and medial carbonate belt (the upper carbonate portion of the St. Charles, the
informal trilobitic and sucrosic members) described by Palmer (1960). Much of the
primary environmental signature has been obliterated by secondary dolomitization in
several areas of the St. Charles that have been previously studied (Ervin, 1982; Harlick,
1989; Shiveler, 1986)—making paleoenvironmental interpretations more difficult.
Despite this, a several carbonate environments have been identified. At Copenhagen
Canyon (one of the northernmost sections that have been studied), dolomitized
equivalents of exposed, low-energy intertidal, and supratidal facies have been identified,
agreeing well with its suggested proximity to shore (Ervin, 1982). More southern
localities identified paleoenvironments ranging from shelf lagoon to open shelf
environments interspersed with migrating algal mudbanks in the undolomitized units
(Harlick, 1989; Nielson, 1983; Shiveler, 1986).
The beds studied herein fit well within the previous interpretations for the
carbonate portion of the St. Charles Formation; all three lithologies from the four
sampled beds likely represent a shallow subtidal shelf environment. Scant outcrop of this
interval in the Franklin Basin area prevents a detailed analysis of stratigraphic patterns, so
conclusions are necessarily restricted to the four horizons sampled for trilobites. The
presence of trilobites and echinoderms is held to be indicative of open marine
environments (Heckel, 1972). The absence of crossbeds, or other prominent current or
18
wave structures suggests an environment below normal wave base, while the presence of
grainstone and intraclasts precludes (with an exception made for allochthonous basinal
deposits, i.e. turbidites, see Cook and Taylor, 1977) an interpretation as a basinal
environment.
The presence of intrarudites, or more specifically, flat-pebble conglomerates (FPC
hereafter), is relevant to the Franklin Basin study section as nearly all horizons studied
contained flat pebbles (lithologies 1 and 2 in horizons 9.6m, 10.1-10.2m, and 10.610.72m; figures A3.3, 3.5). Deposits containing flat pebbles remain enigmatic despite
several notable contributions on their temporal distribution and genesis (Kwon et al.,
2002; Myrow et al., 2004; Pratt, 2002; Sepkoski, 1982; Wilson, 1985). Chief among the
enigmas are two questions: why are FPCs common in the Cambrian and Ordovician but
not today, and what process is responsible for their deposition. The former question has
been addressed by Sepkoski (1982) and Wilson (1985) and will not be treated further.
The latter, however, is relevant for understanding the environmental context of the
trilobite-bearing beds.
FPCs (or limestone conglomerates in general) have been postulated to represent
several different environments: intertidal (Lochman-Balk, 1970; Roehl, 1967), lagoonal
(Sepkoski, 1982), above and below fair weather wave base (Myrow et al., 2004), and
basinal turbidites (Cook and Taylor, 1977). The abundance of interpretations is not
simply for lack of consensus, rather, FPCs seem to occur in a variety of environments due
to a variety of reasons (as indicated by depositional environment indicators besides the
flat pebbles themselves). As with the depositional environments, FPCs are though to be
caused by a variety of mechanisms: storms and hurricanes (‘tempestites’; Kreisa, 1981;
Sepkoski, 1982), tidal currents (‘tidalites’; Wilson, 1985), diagenesis (Kwon et al., 2002),
tsunamis (‘tsunamites’; Pratt, 2002), or mass flow (‘turbidites’) caused by storms or
seismic waves occurring either on the shelf (Myrow et al., 2004) or on the continental
slope (Cook and Taylor, 1977).
19
The FPCs beds from Franklin Basin may represent some form of tempestite
deposit. Criteria for the identification of tempestite deposits were set out by Aigner
(1982) and Kreisa (1981), and, as observed by both sources, they closely resemble the
properties of an idealized Bouma sequence (graded bedding) due to the fact that both
result from deposition under conditions of waning energy. Grading in the FPC beds in
Franklin Basin was weak (10.6-10.72m) to indiscernible (9.6m, 10.1-10.2m). Criteria for
identifying tempestites from turbidites (limited lateral extent and variable in thickness,
pot and gutter casts, etc.; see Ensele and Seilacher, 1991; Kreisa, 1981) were not
observed due to the limited outcrop exposed. However, due to the suggested bathymetric
position of the St. Charles Formation on the Cambrian shelf (Lochman-Balk, 1971), a
shallow subtidal tempestite origin seems more likely than basinal turbidite or intertidal
tidalite. The evidence is consistent with this interpretation, but is by no means indicative
of it. If this interpretation is correct, however, then the fauna of the St. Charles
Formation can be interpreted as essentially autochthonous. Intraclasts, in general, are
likely not to have been transported far, creating lag deposits—behavior consistent with
the action of modern shells during storms (Kreisa, 1981). Furthermore, the flat pebbles
were not observed to contain any fossils, either in thin section or in hand sample; so any
contamination by faunal mixing would have likely been minimal at best.
Taphonomy
There are several times at which a taphonomic bias can be introduced into a fossil
assemblage. This bias can be either directional (skewing the observed diversity by
selectively removing certain fossils from the fossil record) or non-directional (essentially
randomly removing fossils from the fossil record with no net effect on relative
abundance). Directional taphonomic bias is best typified by aragonite dissolution, which
selectively removes aragonitic shells from the fossil record (Cherns and Wright, 2000),
while processes like shell breakage due to compaction are thought of as non-directional
20
(affecting all bioclasts with a roughly equal probability). In the following paragraphs,
several types of taphonomic effects that may have impacted the observed diversity of the
St. Charles Formation will be discussed.
Hydodynamic sorting of trilobite sclerites is an important control on relative
abundance (Westrop, 1986b) and potentially a directional taphonomic bias. Only one
actualistic study on the hydrodynamic behavior of trilobite sclerites has been conducted
(Lask, 1993), and since this study was only concerned with one species of trilobite, it is
impossible to draw broader conclusions from it about the interaction between size and
shape within different hydrodynamic conditions. Additionally, certain structural
morphologies (the doublure, the presence of arches, see Wilmot, 1990) may make a
sclerite more resistant to breakage during the hydrodynamic sorting, but the relative
importance of these features remains to be studied. As a null hypothesis, a silicified
assemblage of trilobite that has undergone no hydrodynamic sorting should contain
roughly equal proportions of cranidia to pygidia (Adrain and Westrop, 2004b).
A cursory glance at the observed cranidia: pygidia abundances (tables B2-12)
demonstrates that this is rarely the case. Certain taxa exhibit anomalous ratios—for
example, Drumaspis in horizons 10.1-10.2m and 11.2-11.3m, and both Maladia and
Ptychaspis in horizon 10.1-10.2m, all with overabundant cranidia. Why these taxa in
particular should be affected is not entirely clear—it may be that with a higher
abundance, the bias is more apparent. The fact that horizons varied more in the relative
abundance of particular taxa rather than their specific composition is suggestive of the
kind of taphonomic situation documented by Westrop (1986), which was shown to be a
size-sorting taphonomic phenomenon. Though a detailed size analysis was not
undertaken, it is observed that high abundance of the small trilobite, new genus B, in
certain horizons could drive the results toward implicating size sorting.
Silicification, as a process, is poorly understood. At least four different models
for silica replacement have been discussed in the literature (Carson, 1991; Maliva and
21
Siever, 1988). Two of the models deal with the local environmental conditions, while the
other two deal with the geochemistry of replacement—making these models not
necessarily mutually exclusive. The environmental models involve either 1)
microenvironmental conditions created by decaying organic matter (Carson, 1991), or 2)
environmental conditions created by the mixing of marine and meteoric water (Knauth,
1979). Geochemically, replacement by silica is thought to have either 1) involved a
calcium silicate precursor (see Carson, 1991) or have been 2) controlled by force of
crystallization along thin solution films (Maliva and Siever, 1988). In general, it is
thought to be very similar to the formation of nodular chert—the two are often studied
together (Carson, 1987). The silica involved in the process is thought to come from
biogenic silica (Carson, 1991), with the silicification happening relatively quickly after
deposition. Silicification may happen prior to the complete lithification of the
surrounding sediment (Jacka, 1974) and as shallowly as 5-10m below the sediment
surface (Clayton, 1984). Silicification is not always a wide-ranging phenomenon2.
Harlick (1989) documented some very localized silicification (about a meter in diameter)
of trace fossils, presumably governed by local fluid diffusion. The stylolites observed in
Franklin Basin (figures A3.3d-e) may have provided a conduit for silicification.
The pattern that silicification creates (both in terms of microstructure and
taxonomic selectivity) has been only incompletely documented. Much of the work has
concerned silicified brachiopods (Brown et al., 1969; Daley and Boyd, 1996; Holdaway
and Clayton, 1982; Newell et al., 1953). A few silicified sclerites (figures A6.2-3, 5-6),
exhibited what can be interpreted to be the early stages of silicification of the inner and
outer edges of trilobite bioclasts. This pattern is very similar to the partial trilobite
silicification documented by Maliva and Siever (1988; their figure 1A)—the small quartz
2 Another locality of the St. Charles Formation in Blacksmith Fork Canyon, Utah, was
found to contain no silicified trilobite sclerites, though possible silicified internal molds of genal
spines were identified (material collected by S. R. Westrop and processed by the author).
22
crystals can be discerned from the calcite by the difference in relief. Silicified sclerites
exhibiting a two-layer silicification (e.g. figures A5.5, A7.9, A12.28, A21.19, etc.) occur
throughout the sampled horizons. This same sort of silicification (i.e. outer edges of the
sclerite silicified first) has been reported elsewhere (Reinhardt, 1977; the ‘silica
envelopes’ of Nielsen, 1983). Putative examples of “liesegang” diffusion structures
(concentric rings of silica formed by fluid diffusion) are also present (e.g. figures A7.11,
A8.17-18, A10.3), though without detailed petrographic analysis, they could be
interpreted as possible sites of encrustation (though the positive relief of the structures
would seem to rule this out as a possibility)3. Positive-relief ridges were also observed
(e.g. figure A18.20), which may share a common genesis with the “liesegang”-type
structures. Silicified internal and external molds (figures A24.1-2, 6, etc.) were also
discovered in the acid-digested residue. Thin sections of material from the St. Charles
seem to indicate that these molds were the result of drusy quartz growing on the (inner or
outer) surface of the sclerite rather than replacing it (figures A6.7-8; see the discussion of
Idahoia below). The thin sections failed to capture the other main mode of silicification,
namely, complete replacement of the sclerite by silica.
Many taphonomic biases are treated as non-directional. Certain groups of
brachiopods have been found to exhibit different patterns of silicification and because of
that have differential preservation potentials as silicified fossils (Brown et al., 1969;
Carson, 1991; Newell et al., 1953)—a directional taphonomic bias. Examples of nonsilicified trilobites were found, both in thin section and in crackout material (figure
A6.4)—but there is no evidence for selective silicification among trilobites. Specimens
of Wilbernia were always more abundant in crackout material, which is suggestive of a
3 They resemble beekite rings, which have been documented by Carson (1987) in
brachiopods and are also present in the material described by Öpik (1967) and Adrain (1997).
23
possible directional silicification bias. However, there is an equally plausible explanation
involving recovery taphonomy, which is detailed below.
Recovery taphonomy encompasses anything that happens to a specimen during
collection and preparation. Though human selectivity can play a role—potentially
providing a directional bias toward, for example, complete specimens—it is one that with
diligence, one can work to minimize, and will not be considered further here. Depending
on the method of preparation utilized, different factors can influence the number and type
of specimens recovered. Crackout, or manual preparation, is governed by the physical
properties of the rock and how it breaks. Cracks in rocks often begin at and propagate
along heterogeneities—during manual preparation, one wants fossils to be these
heterogeneities so that the crack reveals a fossil. However, it is easier for the crack to
break around a larger, less convex, or smooth specimen than it is for it to break neatly
around a small, highly convex, or sculpturally complex specimen. This is essentially the
same observation made by Adrain and Fortey (1997) in their paper on the trilobites of the
Tourmakeady Limestone. The end result is that crackout sampling will de-emphasize
smaller, highly convex, or sculpturally complex specimens. Numerical comparisons
between the crackout and silicified collections are detailed below.
Diversity
The four horizons sampled at Franklin Basin can be roughly divided into two
biofacies (according to the relative abundances derived from the silicified material): a
new genus B -dominated biofacies and a Drumaspis-dominated biofacies. The new
genus B biofacies exclusively occurs in the matrix-supported intrarudite (lithology 1);
while the Drumaspis biofacies occurs in the bioclastic grainstone (lithology 3;
presumably it also occurs in the clast-supported intrarudite, lithology 2). A comparison
of the pie diagrams on figure A41 suggests that the original field sample from Franklin
Basin was originally derived from horizon 10.1-10.2m, due to it faunal similarity. The
24
number of species identified in each horizon seems to be uncorrelated with the amount of
rock sampled (see table B1, though note that approximately one quarter of the material
from horizon 10.1-10.2m was reposited in the University of Iowa Paleontology
Repository and not used in this study)—with horizon 10.6-10.72m yielding the greatest
number of species (see tables B2-10). The total number of species (from silicified
material) identified at each horizon varied between 10-19 species—within the range for
Late Cambrian shallow subtidal within-habitat (alpha) diversity documented by Westrop
and Adrain (1998).
The volume of silicified material sampled is orders of magnitude larger than that
sampled manually. Therefore, the conclusions drawn from a comparison of the relative
abundances must be considered tentative suggestions of overall patterns. Spearman rank
correlation coefficients (r) were calculated comparing the taxonomic rank abundance (of
maximum number of individuals for the 11 most abundant taxa) of each silicified and
crackout collections at each horizon. Additionally, each silicified collection was
compared with each other silicified collection, and the same for the crackout collections.
With the samples being drawn, effectively, from the same pool (i.e. the horizon of their
origin), one would expect a positive correlation between the diversity sampled using acid
digestion and crackout preparation. If there were no different in the observed diversities
for each method, a perfect correlation of r=1.0 would be found; no correlation would be
indicated by r=0.0.
Most comparisons yielded no siginificant comparisons (at p < 0.05). Only
Spearman rank correlation coefficients (r) for crackout and silicified collections from
horizons 9.6m and 11.2-11.3m were significant—with a moderate positive correlation
(table B11). Crackout and silicified collections from horizons 10.1-10.2m and 10.610.72m were not significantly correlated. It should be noted that the horizons with the
largest sample sizes were also the horizons which lacked significant correlation; the only
comparisons to yield statistically significant results (p <0 .05) were the horizons with the
25
smallest disparity between the silicified and crackout sample size and smallest net sample
size. Given the observed lithologic and taxonomic differences between the horizons, one
would expect that the silicified and crackout collections from any one horizon would be
more strongly correlated with each other than to any other silicified or crackout collection
(respectively; table B12). These values are included for comparison to the Spearman
rank correlation coefficient from the silicified and crackout collections for each single
horizon, however none were statistically significant (at p < 0.05).
The data at hand conform to expectations expressed above about how silicified
and crackout samples might differ. The small trilobite genera—new genus B and
Triarthropsis—were absent (or nearly so) in crackout collections, but abundant in certain
silicified horizons. Likewise, tuberculate and highly convex species of Ptychaspis and
Saratogia were nearly absent from crackout material, but comparatively much more
prominent in the silicified samples. The low-convexity and large species of Wilbernia
made up a relatively large percentage of the crackout diversity, but were much more rare
in the silicified samples. More quantitative data on this subject is needed.
Correlation
The St. Charles Formation is uncontroversially regarded as Late Cambrian (mid
Sunwaptan) in age (figure A1). Conodont data (Landing, 1981) has shown that the upper
part of the St. Charles extends temporally into the early Ibexian. Few other occurrences
of trilobites from the St. Charles Formation have been reported aside from the systematic
work of Lochman and Hu (1959), Resser (1942), and Walcott (1924a, 1925). However,
prior to the publication of her systematic treatment of trilobites from the St. Charles,
Lochman-Balk (1956) gave a brief list of trilobite genera from the St. Charles, notably
including Elvinia Walcott, 1924a, Iddingsia Walcott, 1924, Irvingella Ulrich and Resser,
in Walcott, 1924a, Pterocephalia Roemer, 1849, and Maladia Walcott, 1924a—all
genera which were not identified or discussed in her later paper. Lochman and Hu (1959)
26
described the fauna as being within the Ptychaspis subzone (within what is today the
Sunwaptan). However, that subzone nomenclature is based on the nearshore clastic
sediments of the upper Mississippi Valley (Bell et al., 1952; Berg, 1953; Bell et al., 1956;
Grant, 1962). This is problematic because it has been demonstrated that trilobite
assemblages in the Upper Cambrian track lithologies (Westrop, 1996). While the
trilobite fauna from the St. Charles Formation may be approximately correlative with the
Ptychaspis subzone, using the upper Mississippi Valley nomenclature would require
shoehorning and special pleading. A better alternative is to attempt to construct a
separate nomenclature for different facies (Ludvigsen and Westrop, 1983a). Among
subtidal carbonates, the St. Charles is roughly coeval with Ellipsocephaloides zone in
Alberta, Canada, of Westrop (1986). This is supported at the generic level by the cooccurrence of eight genera. Additionally, both localities would have been situated on
what was the northern margin of the Laurentian continent.
27
SYSTEMATIC PALEONTOLOGY
Descriptive terminology follows Whittington and Kelly (1997). Use of the term
‘flange’ in reference to the agnostoid doublure follows Bruton and Nakrem (2005). The
term ‘extremal rim’ is introduced to refer to the ridge produced by the meeting of the
anterior (cephalic) or posterior (pygidial) border with the doublure encircling the nonarticulating edges of agnostoid cephala and pygidia (indicated on a Pseudagnostus
cephalon, figure A7.8). Materials figured herein are reposited at the Paleontology
Repository, Department of Geoscience, University of Iowa, Iowa City, Iowa, with
specimen numbers prefixed SUI. Ratios are given in percentages; angles presented in
degrees. Measurements given in the following descriptions take the form average
(range; n=number of specimens)% and are based only off of the illustrated specimens
that preserve the relevant dimension. New species which will warrant new specific
names in the eventual publication will be designated by numbers—Genus new species 1.
New species which are too fragmentary or too poorly known to warrant new specific
names will be designated by letters—Genus new species A
Phylum ARTHROPODA von Siebold and Stannius 1845
Class UNCERTAIN
Discussion.—The debate over the phylogenetic placement of agnostids is
particularly contentious, and as such, the agnostids discussed herein will be classified as
‘Class Uncertain.’ The traditional view interprets agnostids as derived eodiscinids within
Trilobita (Cotton and Fortey, 2005; Fortey and Theron, 1994), and the countervailing
view interprets agnostids as stem group crustaceans (Bergström, 1992; Hou and
Bergström, 1997; Shergold, 1988, 1991a; Stein et al., 2005; Walossek and Müller, 1990).
Unfortunately, both sides to the debate largely rest their claims on different sets of
data—the traditional view relying on morphological data derived from the dorsal
exoskeleton (Cotton and Fortey, 2005) and countervailing view utilizing soft-part
28
morphology obtained from lagertätten like the ‘Orsten’ deposits of Sweden (Müller and
Walossek, 1987). The most recent work on the topic (Stein et al., 2005) suggests that the
characteristics used previously to support the agnostids-as-trilobites view (Naimark,
2006) are synpleisiomorphies of Euarthropoda or Arthropoda sensu stricto (Maas et al.,
2004).
Order AGNOSTIDA Salter, 1864
Suborder AGNOSTINA Salter, 1864
Family AGNOSTIDAE M’Coy, 1849
Subfamily PSEUDAGNOSTINAE Whitehouse, 1936
Discussion.—The Pseudagnostinae are in need of a comprehensive revision using
modern morphometric methods to parse apart the shape variation that has been so
difficult to quantify. Shergold’s (1977) revision was ambitious in scope—treating 88
species—but though it provided a framework for classification, it also introduced a level
of taxonomic essentialism into pseudagnostine classification. His broad divisions were
based on single characters dealing with the position of the axial glabellar node
(spectaculate verses papilionate). While is may simplify classification to have divisions
based on single characters, we must have some assurance that the single characters being
used reflect a deeper phylogenetic signal. Specimens from Franklin Basin suggest that
this may not be the case with the axial glabellar node. A comparison of figures A7.9
(x8.56) and A7.10 (x 17.12) shows that the axial glabellar node appears to move forward
through ontogeny (the axial node is between the indentations for F2 in specimen A7.10,
but in front of them in specimen A7.9). A similar criticism was made by Peng and
Robison (2000), while both Westrop (1986a) and Pratt (1992) questioned whether or not
the criteria used by Shergold introduced taxonomic artificiality. This tentative
ontogenetic evidence does not invalidate Shergold’s (1977) scheme for classification per
se, but it does give reason to reexamine the evidence.
29
Genus PSEUDAGNOSTUS Jaekel, 1909
Type species.—Agnotstus cyclopyge Tullberg, 1880 from the Upper Cambrian
rocks of Sweden (by original designation). As the original type material is missing
(though not necessarily lost, personal communication from J. Bergström cited by
Shergold, 1977), topotype material was designated by Shergold (1997) from material
collected from the type locality at Andrarum, Sweden by Westergård (1922, cephalon, pl.
1.7, Lund University Lo 3066t and pygidium, pl. 1.8, Lo 3067t).
Diagnosis.—See Shergold (1977).
Discussion.—Peng and Robison (2000), in their monograph on agnostoid
biostratigraphy in China, suggested that Litagnostus Rasetti, 1944, Plethagnostus Clark,
1923, Pseudagnostina Palmer, 1962, Rhaptagnostus Whitehouse, 1936, Sulcatagnostus
Kobayashi, 1937, and Xestagnostus Öpik, 1967, are all junior subjective synonyms of
Pseudagnostus. Plethagnostus has not been in use since Kobayashi (1935b) and its
suppression by Shergold (1977) is considered uncontroversial. As for the remaining taxa,
this claim seems premature without quantitative analysis. However, until sense can be
made of these characteristics and their value in pseudagnostine systematics established,
most genera listed above, following the suggestion of Paterson and Laurie (2004), will be
maintained herein. Pseudagnostus n. sp. 1 possesses a mixture of features associated
with Pseudagnostus and Rhaptagnostus. Pseudagnostus-like features include the firmly
impressed axial furrows and the rounded pygidium; Rhaptagnostus-like features include
the weak glabellar furrows and position of the axial glabellar node. Because of this,
Pseudagnostus is considered to be a senior subjective synonym of Rhaptagnostus herein.
Peng and Robison (2000) also bring a large number of species into synonymy—of
particular interest is Pseudagnostus josepha Hall, 1863 and P. prolongus (Hall and
Whitfield, 1877). Their species concept seems to be motivated by a desire to subsume
what they interpret as an entire morphocline into a single species. The question of
whether or not their synonymy does, in fact, capture an entire morphocline (or
30
morphoclines) is moot—morphoclines are hypotheses based on observed character
distributions, and in the modern biological usage they are hypothetical entities distinct
from that of a species (e.g. Caris et al., 2006). What the relation of a morphocline is to a
species is not entirely clear (published example of morphoclines include both withinspecies and between-species morphoclines), but it can perhaps best be thought of as a
morphologically-based lineage or transformation series. Using a morphocline in place of
a species concept would therefore conflate pattern (the organisms) with process (the
course of evolution)—Peng and Robison’s approach is avoided herein.
Moreover, the type and topotype material (illustrated by Bell et al., 1952; Nelson,
1951; Shergold, 1977) are preserved as molds in the sand and siltstones of the Franconia
Formation, from the Upper Mississippi Valley of North America. As observed by
Westrop (1986a), preservation of this type makes recognition of exoskeletal detail
difficult. Small and/or complex specimens from the Franconia Formation suffer most due
to the ‘low resolution’ preservation of the silt and sandstones—making it difficult to
impossible to discern fine morphological detail. Further complicating matters is the fact
that testate (no testate specimens are known from the Franconia Formation) and
exfoliated specimens of the same species can appear morphologically different,
especially with regard to characteristics like effacement. Because of this, it seems
inappropriate to base a wide-ranging species, like P. josepha off of such material. It is
recommended here that the species P. josepha be restricted to the type locality.
New specimens referred to P. josepha (illustrated by Peng and Robison) differ
fairly obviously in outline with the cephala and pygidia of the Chinese specimens being
more ovaline and elongate medially than the type material illustrated by Shergold (1977;
his figures 15.9-10). The only unexfoilated cranidium illustrated therein (Peng and
Robison, 2000, their figure 10.7) appears to have a distinctive autapomorphy—small, low
nodes abutting the anterior margin of the glabella on either side of the median
preglabellar furrow. New specimens of P. prolongus illustrated therein are a similar
31
case—all are strongly deliquiate, unlike the cotype specimens illustrated by Palmer
(1955). These two cases suggest that Peng and Robison’s (2000) synonymies should be
treated with caution. Ignoring differences like these will make the task of parsing out any
putative morphocline, biogeographic pattern, or phylogenetic relationship that much
more difficult.
Pseudagnostus new species 1
Figures A7.1-21; A8.1-25
Diagnosis.—A species of Pseudagnostus with a circular cephalon wider than
long; shallow but distinct median preglabellar and axial furrows on the cephalon;
cephalic axial furrow widens posteriorly, glabellar furrows only represented by weak
notches; pygidium subcircular, roughly as long as wide; weak posterolateral spines,
posterior border furrow on pygidium shallows medially; pygidial S1 absent, trispinose.
Description.—Cephalon subcircular, wider than long, widest point lateral to F2,
max. length 96.7 (93.6-99.0; n=5)% of max. width, max. acrolobe length 90.5 (88.0-91.7;
n=5)% of max length; border longest medially, in dorsal view appears to pinch out lateral
to fused M1-M2, in lateral border thins posteriorly, slightly overhung by genal field near
genal angle, border rounded, sloping downward, in anterior view ventral edge of border is
slightly arched dorsally, in lateral view ventral edge of border has slight inflection lateral
to anterior edge of glabella making anterior portion of border hang slightly lower than
posterior portion; extremal rim thin, less prominent posteriorly; posterolateral corner in
lateral view rounded; border furrow weak, manifest by change in slope; posterior border
furrow deeply impressed, ends at intersection with axial furrow at posterior margin, angle
from horizontal 26.1 (23.5-30; n=5)°, angle smaller in larger specimens; small cephalic
posteriorlateral spine present, manifest as small prominent node dorsally, part of
dorsolateral folding of posterior margin in posterior view; posterior margin in posterior
view subrectangular; cephalthoracic aperture half-ellipse, 16.8 (n=1)% of max cephalic
width; axial furrow weakly impressed, widens posterior to axial node with basal lobes
32
appearing to create its widest part; basal lobes abut posterior margin, low in convexity,
triangular in outline; basal furrow narrow; glabellar length 68.2 (66.5-69.7; n=5)% of
max cephalic length, glabellar width 34.6 (32.8-37.3; n=5)% of max cephalic width,
glabella longer than wide, 52.4 (50.5-55.3; n=5)% as wide as long; posterior margin of
glabella slightly pointed, terminates in a weak node, abuts cephalothoracic aperture, F1
absent; M1 and M2 fused, M1+M2 widest part of glabella; weak ridge extending from
axial node to glabellar terminus; F2 and F3 weak, manifest as slight notches as axial
furrow; M3 with rounded lateral edge, nearly as wide as M1+M2; axial node narrow and
elongate, highest elevation on cephalon; M4 short and rounded, sloping to genal field;
median preglabellar furrow uniform in width; genal field weakly scrobiculate in small
specimens, smooth in larger specimens; impressions of minor posterior, major posterior,
and oblique lateral scars of the posterior lobe faintly visible on crackout specimens
(figure A7.18); doublure is widest medially, pinches out at genal angle, thin flange
present on inner edge of doublure.
Pygidium subcircular, max length 96.1 (93.2-101.9; n=6)% of max width; max
acrolobe length 77.9 (77.0-79.4; n=6)% of max length; border smoothly curved in dorsal
view, steeply declines to edge; extremal rim thin, well-defined anteriorventrally; tiny
posterolateral spines present as nodes laterally in advance of the posterior edge of the
acrolobe (measurement not including articulating half ring), border widest at small
posterolateral spines, tapers anteriorly to intersection with anterior border, ends anteriorly
in right angle; posterior border furrow weakly impressed, visible as change in slope from
acrolobe to border, non-deliquate, border furrow slightly wider next to posterolateral
spines and at end of faint posterolaterally directed axial furrows (accessory furrows);
articulating facet subquadrilateral, slight recess situated under slight anterolateral nodes,
facet nearly vertical, slopes slightly vetrolaterally; anterior margin trapezoidal in anterior
view, anteriorlateral nodes present at dorsolateral corners; anterior border furrow deepest
at facets; anterior border widest at anterolateral nodes, tapers to articulating half ring and
33
posterior border; articulating half ring semielliptical, dorsally convex, nearly as wide as
axis; F0 tapers laterally, widest and shallowest medially; axial furrow slightly sinuous,
variably impressed; axis subpentagonal, widest at M1, M1 40.1 (39.1-40.8; n=6)% as
wide as max width, axis longest medially, 28.6 (27.7-29.9; n=6)% as long as max length;
M1 manifest as slight bulge in axial furrow; F1 faint trace from axial furrow to axial
node, axial furrow insertion roughly lateral to anterior edge of axial furrow; F2 deep as
axial furrow, weakly expressed in larger specimens, connects axial furrow and posterior
extent of axial node, axial furrow insertion of F2 slightly in front of posterior edge of
axial node; axial node prominent, oval in outline, highest point on pygidium; posterior
axial furrow traces (accessory furrows) weak to effaced behind F2; posterior lobe poorly
define laterally, merges with pleural field; small median posterior node present next to
posterior border on posterior lobe; doublure tapers anteriorly, thin flange present on
interior edge of doublure.
Figured material.—Five silicified cranidia (SUI 00000-00000), two crackout
cranidia (SUI 00000-00000), and eight silicified pygidia (SUI 00000-00000).
Occurrence.—Present in all horizons sampled in Franklin Basin. Specimens are
most common at horizon 10.1-10.2 and least common at horizon 10.6-10.72.
Provisionally identified in material collected from Two Mile Canyon.
Discussion.—P. n. sp. 1 contains a mix of features not observed in any one
species of Pseudagnostus, and rather than broadening the concept for an existing species,
it is preferable to construct a new species. Lochman and Hu (1959) identified two
species of Pseudagnostus in their material from the St. Charles Formation at Mink Creek,
Idaho. Specimens assigned to P. prolongus by Lochman and Hu (1959) have stronger
glabellar furrows and wider pygidia. Incidentally, specimens assigned therein to P.
convergens (Palmer, 1959) have a strong transverse F3 furrow, something lacked by the
specimens originally illustrated by Palmer. That character, plus moderately impressed
posterior portions of the pygidial axial furrow (“accessory furrow”) suggest that the
34
specimens would be better assigned to P. communis (Hall and Whitfield, 1877). P.
convergens differs in its more elliptical pygidium and is more distinct glabellar furrows.
Specimens belonging to P. pseudocyclopyge Ivshin, 1956 figured by Ludvigsen et al.,
(1989) present some similarities to P. n. sp. 1. The smallest cephalon figured herein
(figure A7.10) is very similar to one figured by Ludvigsen et al. (1989, his figure 2.18).
Both specimens are weakly scrobiculate, with P. pseudocyclopyge having a longer
anterior glabellar lobe. However, Ludvigsen et al.’s specimen is roughly twice the size
of the Franklin Basin specimen, suggesting that the scrobiculae were maintained until
adult size was reached in the former, whereas they were lost in the latter.
Genus LITAGNOSTUS Rasetti, 1944
Type species.—Litagnostus levisensis Rasetti, 1944 from the Upper Cambrian
Levi Formation, Quebec, Canada (by original designation).
Diagnosis.—See Ludvigsen et al.’s (1989) discussion of Litagnostus (p. 13-14).
Discussion.— Shergold’s (1977) revision of Pseudagnostus did not treat
Litagnostus, remarking only that it was difficult to assess this effaced form. Ludvigsen et
al. (1989) studied the original type material Rasetti (1944) used in creating Litagnostus
while studying other species present in the Shallow Bay Formation of Newfoundland,
Canada. They concluded that there is a coherent group of Sunwaptan species from
Laurentia forming the core of Litagnostus: L. levisensis Rasetti, 1944; L. parilis Hall,
1863 (see Westrop, 1986a); L. planulatus (Raymond, 1924); L. clarki (Kobayashi,
1935b); L. expansus Palmer, 1955; and L. laevis (Palmer, 1955) defined by wide cephalic
and pygidial borders (though weakly defined on the cephalon), a non-elongate pygidium,
and an undefined posterior axial lobe on the pygidia (deuterolobe). With the possible
exception of the poorly known L. clarki (discussed below), they seem to represent a welldefined core group by which to evaluate other putative Litagnostus species. Use of this
suite of characters will prevent the use of Litagnostus as a form taxon for effaced
35
pseudagnotines. There are other potential synapomorphies of Litagnostus: for example,
all Litagnostus species have weak to absent posterolateral pygidial spines. Additionally,
the character of the doublure and the nature of the cephalic and pygidial thoracic
articulations are documented here for the first time—providing more potential sources of
additional character support. The remainder of Shergold’s (1977) clarki group, assigned
to Litagnostus by Ludvigsen et al. (1989) was not evaluated herein.
Litagnostus new species 2
Figures A9.1-10; A10.1-21
Diagnosis.—A species of Litagnostus with well-defined rectangular genal corners
orthogonal to sagittal line; anterior border visible around entire cephalic margin; distinct
pygidial posteriorlateral spines; uniformly deep posterior border furrow at articulating
half-ring.
Description.—Cephalon subcircular, wider than long, max length (sag.) 91.0
(89.9-92.0; n=3)% of max width, max acrolobe length 91.9 (90.6-92.9; n=3)% of max
length; anterior border smoothly rounded in dorsal view, appears to taper posteriorly due
to slight overhang by genal field, anterior border in anterior view arched slightly dorsally
to horizontal, anterior border in lateral view horizontal to inflected slightly; genal angle
smoothly rounded; extremal ridge thin, most prominent at genal angle; posterior border in
dorsal view distinctly rectangular, defined by posterior border furrow which shallows
medially; glabellar and preglabellar furrows all but effaced, faint trace of axial furrow
adjacent to position normally occupied by basal lobes present; glabellar axial node small
and nearly effaced; rounded node present at posterior terminus of glabella, set slightly
anterior to posterior border.
Pygidium subcircular, wider than long, max length 91.0 (89.2-92.8; n=5)% of
max width, max acrolobe length (excluding articulating half ring) 83.1 (81.4-83.8; n=5)%
of max length; posterior border defined weakly by change in slope, widest at
posterolateral spines, tapers anteriorly in dorsal view; posterolateral spines small nodes,
36
laterally in advance of posterior edge of acrolobe; articulating facet tapered at posterior
border, wider and slightly recessed under anterior prongs, shape oblong, slightly curved
anteriorly in lateral view; anterior prongs weak; anterior margin trapezoidal in anterior
view; articulating half ring low in convexity, F0 uniformly deep and long; weak axial
furrows extend from F0 to roughly lateral to axial node; M1 weakly defined as slightly
outward bulge in axial furrows; F2 weakly defined ventrally; axial node circular to
ovaline, highest elevation on pygidia; doublure lunate with distinct inner flange.
Figured material.—Four silicified cranidia (SUI 00000-00000) and six silicified
pygidia (SUI 00000-00000).
Occurrence.—Litagnostus n. sp. 2 is present in horizons 9.6, 10.1-10.2 and 11.211.3 at Franklin Basin, Idaho as well as in samples from Two Mile Canyon, Idaho.
Discussion.—The poorly known L. expansus Palmer, 1955, may prove to be a
senior subjective synonym of L. n. sp. 2, but the small illustration of only one pygidium
makes it difficult to assess. L. expansus seems to possess a more distinct pygidial border
than L. n. sp. 2. L. clarki (Kobayashi, 1935b) is in a similar state—but with the condition
of the available material (Shergold, 1977, his figures 15.14-15) it is impossible to tell for
certain. In fact, L. clarki’s status within Litagnostus seems far from certain, as it lacks the
wide cephalic and pygidial borders attributed to Litagnostus by Ludvigsen et al., (1989).
L. parilis (Hall, 1863) as illustrated by Westrop (1986a) has a pygidial axis wider than
the articulating half-ring and a shorter pygidium—both features L. n. sp. 2 lacks.
Class TRILOBITA Walch, 1771
Family PTYCHASPIDAE Raymond, 1924
Discussion.—Adrain and Westrop (2001) constructed a phylogeny of the late
Sunwaptan ptychaspidid subfamilies Euptychaspidinae and Marcronodinae. Their results
are an intellectual starting point for the analysis conducted herein—a phylogenetic
analysis of Ptychaspididae. There are several questions that this analysis attempts to
address: what are the sistergroups to the three ptychaspidid subfamilies, is the
37
Ptychaspidinae monophyletic, and what is the relationship of Asian ptychaspidids
(Asioptychaspis Kobayashi, 1933; Changia Sun, 1924; Quadraticephalus Sun, 1924) to
the North American ptychaspidids? This analysis is a preliminary examination of
ptychaspidid phylogeny, and as such, all findings must be thought of as prescriptions for
future study. As such, the traditional usage of the subfamily Ptychaspidinae was retained
with question.
Since the analysis of Adrain and Westrop (2001), two new species of
Euptychaspis Ulrich, in Bridge, 1931 (E. dougali Adrain and Westrop. 2004a and E.
lawsonensis Adrain and Westrop, 2005), one new species of Sunwaptia Westrop, 1986c
(S. plutoi Adrain and Westrop 2004a), and one new species of Macronoda Lochman,
1964 (M. notchpeakensis Adrain and Westrop, 2005) have been published. As a step in
elucidating the phylogeny of the ptychaspidids, these new species were integrated into
the analysis of Adrain and Westrop (table B13). The analysis was conducted using a
branch-and-bound search on PAUP* 4.0b10. Unsurprisingly, the trees were nearly
congruent (figure A42). Both Euptychaspis and Macronoda remained monophyletic;
Sunwaptia resolved in a polytomy with the Macronoda clade.
To address the question of how both Euptychaspidinae and Macronodinae are
related to other ptychaspidids, a larger cladistic analysis was constructed. For this, 58
taxa (table B14) were evaluated and coded for 47 characters (table B15-B16). This
matrix was analyzed using PAUP* with a 500 random replicate heuristic search
(Hoytaspis speciosa (Walcott, 1879), a dikelocephalid sensu Jell and Adrain (2003) was
used as an outgroup). 408 most-parsimonious trees with a length of 311 steps were
recovered. The strict consensus tree for these 408 trees is shown in figure A43 (the
characters are optimized for one of the 408 MPTs displayed in figure A44 and listed in
table B17). Clades recovered in the expanded analysis of Adrain and Westrop’s (2001)
matrix were recovered (though differing slightly in resolution/structure). Tree scores and
bootstrap values are low (see figure A43).
38
The Ptychaspidinae is a relatively heterogeneous collection of genera—with
morphologies ranging from small, blind Idiomesus Raymond, 1924, to the larger
Proricephalus Westrop, 1986c with an elongated preglabellar field. One of the novel
results of this analysis was the suggestion that the Ptychaspidinae is paraphyletic. Two of
the stalwart genera within Ptychaspidinae, Idiomesus and Ptychaspis Hall, 1863 proved
to be more closely related to separate subfamilies (Macronodinae and Euptychaspidinae,
respectively) than with each other. A paraphyletic group of Asian species of Ptychaspis
are, according to this analysis, more closely related to the Euptychaspidinae than to the
North American species of Ptychaspis. Though this presents a bit of a biogeographic
conundrum (no Asian species belonging to the Euptychaspidinae are known), the species
which is most closely related to the Euptychaspidinae, the poorly-known Ptychaspis sp.
nov. of Sohn and Choi (2005) is a plausible sistertaxon to it. Ptychaspis sp. nov. has a
wide glabella, wide palpebral lobes, and a short spike-like occipital node—all features
which could be interpreted to suggest Euptychaspidinae affinities. However, no pygidia
or librigenae for Ptychaspis sp. nov. are known. The rest of the Asian species of
Ptychaspis all prove to be more closely related to each other than to any other species of
Ptychaspis. Prior to Zhang and Jell (1987), these three species each belonged to a
separate genus, Asioptychaspis Kobayashi, 1933; the resurrection of Asioptychaspis
should be evaluated further in light of these results.
Two main clades of Ptychaspis species are present (with exceptions made for the
poorly-known P. arcolensis Nelson, 1951 and Eoptychaspis cylindricus Nelson, 1951
which were excluded from the analysis). P. miniscaensis (Owen, 1852) and P. striata
Whitfield, 1878 form a monophyletic group more closely related to Asioptychaspis +
Euptychaspidinae than to a clade composed of P. cacus Walcott, 1905, P. n. sp. 3 new
species, P. granulosa (Owen, 1852), P. tuberosa Feniak in Bell, Feniak, and Kurtz, 1952.
P. bullasa Lochman and Hu, 1959 is the sistertaxon to the clade including the
Euptychaspidinae + previous mentioned species of Ptychaspis.
39
Idiomesus has a monophyletic core including the types species. This
monophyletic core—I. tantillus Raymond, 1924, and I. ultimus Ludvigsen and Westrop,
1986—are the sistergroup to a polytomy including the Macronodinae, I. intermedius
Rasetti, 1959, I. levisensis Rasetti 1944. The paraphyletic collection of species of
Idiomesus basal to the clade including the Macronodinae + the aforementioned species of
Idiomesus exhibit a plausible set of trends toward effacement and blindness. Several of
these species have zero-length branches and may plausibly be interpreted as ‘lineage.’
However, they are all poorly known (in particular I. greggi, I. granti, and the species
from Two Mile Canyon and Franklin Basin), and are in need of further evaluation.
No one has suggested the possibility of another subfamily-level clade of
ptychaspidid trilobites—and herein, this suggestion is regarded as the most tentative of
the results from this analysis. With use of a different outgroup (Prosaukia oldyelleri
Adrain and Westrop, 2004a) the clade indicated by an arrow on figure A43 no longer
retained its monophyly. With that outgroup, Imerella Loch and Taylor, 2004 became the
sistergroup of the Euptychaspidinae + Macronodinae (+ Ptychaspis and Idiomesus). The
rest of the clade indicated by the arrow in figure A43 was no longer monophyetic under
this senario. Furthermore, the status of Changia (and thereby Quadraticephalus) as a
member of the Ptychaspididae (see Jell and Adrain, 2003) is not universally accepted
(Westrop, 1986a). The monophyly of Keithia Raymond, 1924, Proricephalus, and
Changia seems reasonable, but their relationship to one another and to the rest of the
ptychaspidids is a subject for further study.
Subfamily ?PTYCHASPIDINAE Raymond, 1924
Discussion.—See the above discussion.
Genus PTYCHASPIS Hall, 1863
Type species.—Dikelocephalus miniscaensis Owen, 1852, from the Upper
Cambrian (Sunwaptan, Ptychaspis-Saukia Zone, Prosaukia Subzone, P. miniscaensis
40
Faunule) Franconia Formation of Minnesota, USA (subsequent designation by Miller,
1889; see Bell, Feniak, and Kurtz, 1952).
Diagnosis.—See Westrop (1986a).
Discussion.—Several species of Ptychaspis originally based on material from the
Upper Mississippi Valley have been subsequently identified elsewhere (Bell and
Ellinwood, 1962; Grant, 1965; Hu, 1971; Lochman and Hu, 1959; Ludvigsen and
Westrop, 1986; Stitt, 1977; Stitt and Metcalf Straatmann, 1997; Westrop, 1986a). The
problem, as discussed above, is that the material from the Upper Mississippi Valley is
coarse and preserves relatively little detail. If the situation were reversed, and species of
Ptychaspis were described from other areas prior to the Upper Mississippi Valley, one
would not assign any specimens from the Upper Mississippi Valley to other species-level
taxa. It should, therefore, be considered that the species from there be restricted to that
area (including P. arcolensis, P. granulosa, P. miniscaensis, P. striata, and P. tuberosa),
and their documented occurrences from elsewhere be considered on their own.
Ptychaspis new species 3
Figures A11.1-25; A12.1-8, 25-28; A13.1-22
Diagnosis.—A species of Ptychaspis with prominent ‘buttressing tubercles’ on
the adaxial edge of the axial furrow, parallel-sided glabella, deep and wide S1, weak S2
and S3, tubercle-free alae present, anterior margin rounded either bare or with transverse
striations, large eyes (roughly 40% of max cranidial length).
Description.—Cranidium sub-trapezoidal in outline, max length 67.6 (66.3-68.8;
n=2)% of max width across palpebral lobes; margin of anterior area rounded in anterior
view, sculpture varies from faint pitting to 1-3 weakly expressed striations; fixigenae
convex, in anterior view slopes toward axial furrow, tuberculate posterior to eye ridge,
tubercles on abaxial portions of fixigenae lower and subdued, a slightly curved (convex
posteromedially, subparallel to sag. plane) row of 4-5 large spike-like tubercles buttress
glabella extends adjacent to L2-3, fixigenal buttressing tubercles more pronounced in
41
larger specimens, project nearly horizontally toward glabella overhanging axial furrow,
slight tubercle asymmetry and size variation within individual specimens; posteromedial
corner of fixigena with effaced bacculae, larger specimens have slight exsag. furrow
separating it from fixigenal field, more pronounced in larger specimens; eyes long, free
of tuberculation, one slender continuous striation runs entire length of eye on adaxial
edge next to palpebral furrow, palpebral furrow wide and of uniform depth, eye (_-e)
length 39.4 (36.1-43.2; n=5)% of max cranidial length, max eye width 18.0 (13.3-20.8;
n=6)% eye (_-e) length, width across _ 81.9 (76.7-84.4; n=4)% of width across e, eye
nears glabellar elevation in larger specimens, 2-3 small tubercles along facial suture
anterior to _; posterior border furrow long and shallow, shortest at abaxial termination,
longest posterior to eyes, anterior margin of furrow slopes shallowly to fixigenal field,
posterior margin of furrow slopes steeply to posterior border; posterior border longest
abaxially, narrowest at insertion to occipital ring, as many as four subdued tubercles in a
row parallel to posterior border; occipital ring smooth with occipital tubercle located
medially, longest abaxially, abaxial ends of occipital furrow lobate with weak notch-like
furrows at occipital furrow, max occipital ring length 21.4 (18.7-23.9; n=8)% of max
occipital width, max occipital width 39.2 (38.2-40.2; n=4)% of max cranidial width
across palpebral lobes, max occipital length 13.8 (12.4-16.0; n=5)% of max sag cranidial
length; doublure present under occipital ring, manifest as striated curved flap, longest
medially, shortest at axial articulating process; occipital furrow longest and deepest at
insertion with axial furrow, shallow medially, deepens and curves anteriorly at occipital
notches; glabella parallel sided, subrectangular, large flat tubercles with central pores
medially, smaller and more convex near axial furrow, conical and projecting horizontally
at axial furrow and along distal margins of S1, max glabellar width across L1, max
glabellar width 83.1 (74.3-88.7; n=8)% of max glabellar length, max glabellar width 37.8
(35.6-39.1; n=4)% of max cranidial width across palpebral lobes, max glabellar length
72.4 (71.6-73.0; n=5)% max cranidial length; L1 coarsely tuberculate in small specimens,
42
increasingly effaced in larger specimens with effacement beginning at posterolateral
corners of L1, longest distally, distal portions of L1 sublobate with weak exsag. furrows
demarcating them, 1-3 spike-like tubercles directed anteriorly on anterior edge of distal
portions of L1, max sag length of L1 16.8 (14.1-21.4; n=8)% of max L1 width, L1 medial
length 14.1 (11.3-16.0; n=9)% of total glabellar length, L1 width proportionally longer on
smaller specimens; S1 wide, perpendicular to sagittal line medially, curved anteriorly at
axial furrow, shallowest medially, medial length of S1 6.9 (3.8-10.1; n=9)% of total
glabellar length, longer in larger specimens; L2 less pronounced in larger specimens,
spike-like tubercles usually present on L2 margins adjacent to axial furrow or S1,
approximate medial length of L2 24.4 (22.6-29.1; n=9)% of max glabellar length; S2
manifest weakly viable dorsally as tubercle-free line, ventrally it is apparent that S2 is
discontinuous, shallowing to obsolescence medially; L2 almost indistinguishable from
frontal lobe of glabella dorsally, defined in larger specimens by a weak S3; S3 narrow
tubercle-free line, ventrally S3 very narrow, manifest only immediately adjacent to axial
furrow; frontal area rounded, steeply inclined to anterior margin, angle formed at meeting
of glabella and anterior margin 148.3 (136.1-167; n=5)°; axial furrow deep adjacent to
L2-3, shallows posteriorly.
Librigena with lateral border with curved striations visible laterally; triangular
genal spine, convex dorsally, concave ventrally.
?Pygidium elliptical with raised rim; roughly twice as wide as long (size estimates
drawn from reconstructed pygidium, figure A34.8); axis nearly as long as pygidium, max
axial length ≈89.8% (n=1) of max pygidial length, max axial width ≈29.2% (n=1) of max
pygidial width, max axial width ≈65.7% (n=1) of max axial length; articulating half-ring
lunate, max length of articulating half-ring ≈9.0 (n=1) of max pygidial length; axis
contains four axial rings plus terminal axial piece, axial rings each have prominent
anastomozing striations on their surfaces, anterior two rings have weak exsagital furrows
near lateral margins of rings; pseudo-articulating half-ring present, subelliptical in shape,
43
weakly defined anteriorly; terminal axial piece higher than posterior border, slopes
smoothly into border; axial furrows defined by change in elevation from pleural field to
axis, form ≈10.5° (n=1) angle with sagittal line; border recumbent save at contact with
terminal axial piece and anterior margin, border width at lateral-most point ≈5.8% (n=1)
of max pygidial width, rounded external margin, inner (posterolateral) margin concave,
covered with subparallel striations, in posterior view border has weak inverted ‘v’-shape,
border appears ‘folded over’ at anteriormost extent—smoothing out into anterior margin;
pygidial doublure short sagittally, lengthens toward anterolateral corner; anterior margin
slightly curved (convex anteriorly); pleura field with rare striations (figure A13.4),
pleural and interpleural furrows weakly defined (esp. posterolaterally).
Figured material.—Ten cranidia (SUI 00000-00000), three librigenae (SUI
00000-00000), and one crackout pygidium (SUI 00000), and eight silicified pygidial
fragments (SUI 00000-00000).
Occurrence.—Cranidia and librigenae occur only in horizon FBSC 10.1-10.2 of
the Upper Cambrian (lower Sunwaptan) St. Charles Formation, Franklin Basin, but
pygidial fragments are known from horizons 10.1-10.2, 10.6-10.72, and 11.2-11.3 m.
Discussion.—This species possesses many unique features for a species of
Ptychaspis, making close comparisons difficult. Close comparisons are also difficult for
the poor preservation of many of the other species of Ptychaspis as discussed above. The
S2 furrow is increasingly lost thru ontogeny; other species from the St. Charles
Formation (Ptychaspis bullasa Lochman and Hu, 1959) seem to exhibit the opposite
trend. The glabella is similar is shape to that of Ptychaspis miniscaensis (Owen, 1852; as
illustrated by Westrop, 1986, as P. cf. miniscaensis; glabellae are similar in that they are
widest at L1, taper anteriorly, have visible bacculae, and have shallow S2 medially). The
two differ prominently in their sculpture, with P. cf. miniscaensis covered in striations.
The pygidial association is made with question for two reasons: the pygidial fragments
are typically larger than cranidial fragments, and the pygidial fragments occur in more
44
horizons than the crandial fragments. Otherwise, the pygidia are fairly similar to those
illustrated by Westrop (1986a) as belonging to P. cf. miniscaensis.
Ptychaspis sp.
Figures A15.18, 21, 25
Description.—Librigena with stout spine, spine curves slightly adaxially;
striations run laterally on inner and outer edges of spine, meet in posteriorly pointing ‘v’
shape dorsally; posterior border furrow weakly impressed on librigena; ventrally
recessed, subdued punctate sculpture near base of genal spine.
Figured material.—One partial librigena (SUI 00000).
Occurrence.—Horizon 10.6-10.72 of the Upper Cambrian (lower Sunwaptan) St.
Charles Formation at Franklin Basin, Idaho.
Discussion.—Ptychaspidid librigenae seem to be widely variable between closely
related genera—librigenae belonging to Idiomesus (see Idiomesus cf. I. intermedius
Rasetti, 1959, as figured in Adrain and Westrop, 2005) are effaced, while unfigured
Ptychaspis librigenae from Two Mile Canyon, Idaho, have subparallel striations along
the border and genal spine and tubercles on the librigenal field. The librigena figured
here is very similar to an unfigured one from Two Mile Canyon that belongs to a
Ptychaspis-like species with a partially effaced cranidium. The subdued punctate
sculpture, though not discernable on specimens from the Upper Mississippi River Valley
(i.e. see Bell et al., 1952), it is present on Ptychaspis cf. miniscaensis figured by Westrop
(1986a) and may be a more general feature of Ptychaspis. The librigena figured here and
the similar one from Two Mile Canyon differ from the typical Ptychaspis librigenae in
that typical librigenae have distinct lateral and posterior borders, and striated or
tuberculate librigenal fields (see Bell et al., 1952 and Westrop, 1986a).
45
Genus IDIOMESUS Raymond, 1924
Type species.— Idiomesus tantillus Raymond, 1924, from the upper zone of the
Gorge Formation (upper Sunwaptan), Highgate Gorge, Vermont, USA (by original
designation).
Diagnosis.—See Ludvigsen and Westrop (1986).
Discussion.—See the discussion under Ptychaspididae
Idiomesus new species A
Figures A9.11-12, 15-16, 19-20
Diagnosis.—A blind species of Idiomesus roughly half as long as wide, strong,
persistent but short S1, S2 and S3 furrows manifest very weakly, glabella narrows
anteriorly, narrow axial furrows, weak posteromedial pitting on the fixigenae, weak
preglabellar furrow. Pygidium with raised striated posterior border, roughly as long as
wide, with an axis about one-third of the pygidial width, small pockets present at distal
pleual tips under posterior border, three axial rings and pleura.
Description.— Cranidium: Small and blind, cranidium subtrapezoidal in outline,
finely granulose over most of the dorsal surface, max length 54.8% (n=1) of maximum
width; anterior margin with straight anterior edge; facial suture curves dorsally in lateral
view to vestigial position of eye laterally equivalent to S3, width across eye indentation
56.3% (n=1) of max cranidial width; anterior margin arched dorsally slightly; fixigenal
field with weak granules and weak pitting in posteromedial corner; posterior border
longest distally, shortest at axial furrow; posterior border doublure mirrors expression of
posterior border; posterior border furrow long and deep, max length of posterior border
furrow 9.4% (n=1) of max cranidial length; occipital ring nearly semicircular with
straight anterior margin and rounded posterior margin, occipital node set next to occipital
furrow, occipital ring width 28.5% (n=1) of max cranidial width, max occipital ring
length 17.7% (n=1) of max cranidial length; semicircular occipital doublure under
occipital ring; occipital furrow of uniform length and depth; glabella tapered and bullet
46
shaped, widest at L2, max glabellar width 63.5% (n=1) of max glabellar length, max
glabellar width 25.2% (n=1) of max cranidial width, max glabellar length 72.2% (n=1) of
max cranidial length, defined laterally by axial furrows which taper anteriorly, defined
anteriorly by weak preglabellar furrow; L1 isolated by pervasive S1, longest medially, L1
width 24.1% (n=1) of max cranidial width, medial L1 length 10.9% (n=1) of max
cranidial length; S1 of uniform depth and length; L2 weakly defined anteriorly by weak
S2, L2 longer than L1; S2 and S3 weakly defined, visible ventrally only as very slight
swelling near axial furrow.
Figured material.—One cranidium (SUI 00000).
Occurrence.— Horizon FBSC 10.1-10.2 of the Upper Cambrian (lower
Sunwaptan) St. Charles Formation, Franklin Basin, southeastern Idaho, USA.
Discussion.—Idiomesus n. sp. A fits well into the phylogenetic trend toward
effacement and blinding documented by Ludvigsen and Westrop (1986). Tails for
Idiomesus new sp. have not yet been identified from material belong to the same horizon
as the cranidium. Idiomesus n. sp. A is most similar to I. greggi Ludvigsen and Westrop,
1986—which it differs from in that it is has a weak S2 furrow and apparently narrower
cranidial axial furrows.
Ptychaspidine sp.
Figures A12.9-11, 18
Description.— Pygidium small, elliptical in outline, max length 48.4 (47.0-49.7;
n=4)% of max width; posterior border raised with striations, smoothly curved, posterior
border 10.9 (10.2-11.4; n=3)% of max length; axial nearly as wide as long, narrowly
separated from posterior border, max axial width 97.5 (87.4-1.06; n=3)% of max axial
length (excluding articulating half ring), max axial width 33.2 (31.0-35.7; n=4)% of max
pygidial width, max axial length (excluding articulating half ring) 70.6 (67.1-75.5; n=3)%
of max pygidial length; three axial rings present, distinct inter-ring furrows with pleated
47
appearance, decrease in length posteriorly, anteriormost axial ring with tuberculate
sculpture developed; three pleura present, widen abaxially, terminate in small pockets at
posterior border, weak striations developed on anterior edge of pleura; articulating halfring low and short.
Figured material.—Four pygidia (SUI 00000-00000).
Occurrence.—Horizon 10.6-10.72 of the Upper Cambrian (lower Sunwaptan) St.
Charles Formation, at Franklin Basin, Idaho.
Discussion.—The resemblance of pygidia assigned herein to Ptychaspidine sp. to
that assigned to I. greggi is rather striking. However, assigning these tails to Idiomesus
would present a problem—in that only one Idiomesus cranidium has been identified from
Franklin Basin, and there are comparatively many small Ptychaspidine sp. tails residing
in the unpicked smaller size fractions. It is therefore considered prudent to leave these
tails unassigned at the subfamily level until more is known about the species of Idiomesus
from Franklin Basin, as well as the other ptychaspidids from the same area.
Subfamily EUPTYCHASPIDINAE Hupé, 1953
Genus Indeterminate
Discussion.—The occipital spine with ridges is a fairly diagnostic feature of
euptychaspidines—the least controversial representatives of which are Euptychaspis
Ulrich, in Bridge, 1931 and Kathleenella Ludvigsen, 1982. The specimen described here
differs prominently from other species of Kathleenella in the lack of a narrow anterior
border. Its absence appears to be genuine and not a preservational artifact, but this
assertion is made with some reservation. If its absence is, indeed, genuine, it would add
to the list of Euptychaspis–like features it possesses. Furrows on the occipital spine,
poorly defined eye ridge, and the weak almost dash-like striations on the preglabellar
field are other features it shares with Euptychaspis (the closest species of Euptychaspis is
likely E. dougali Adrain and Westrop, 2004a). The rows of granules present on the
48
fixigenae and the ‘striations’ mentioned previously may represent an intermediate stage
in dorsal sculpture development between tubercles and striations (see Westrop, 1986a, pl.
8.9-10 for a specimen of Ptychapis which seems to exhibit the same pattern with larger
tubercles). The paucity of material assignable to this taxon makes unambiguous
determination of its generic affiliations impossible.
Euptychaspidine new species F
Figures A9.13-14, 17-18, 21-22, 28
Description.—Cranidium semicircular in outline; anterior cranidial margin with
irregular striations; eyes small, fixigenae raised between eyes with eye ridge defined
weakly by small granules; granules on fixigenae appear to radiate outward from eye in
rays; weak bacculae present; posterior border furrow long abaxially, narrows adaxially;
posterior border weakly granulose; occipital ring with stout spine; occipital spine steeply
inclined and flanked laterally by narrow grooves; occipital furrow uniform in depth,
weakly granulose on posterior wall; glabella tapered; S1 wide and pit-like abaxially,
weakly persistent across glabella; S2 and S3 narrow and distinct, deep at axial furrow.
Figured material.—Two fragmentary cranidia (SUI 00000-00000).
Occurrence.—Horizon 11.2-11.3m of the Upper Cambrian (lower Sunwaptan) St.
Charles Formation at Franklin Basin, Idaho.
Discussion.—The closest comparison is likely with specimens assigned to K.
subula by Westrop (1995) . Specimens illustrated by Westrop have much wider fixigenal
areas and anteriorly wider axial furrows than specimens illustrated by Ludvigsen (1982)
and likely represent an undescribed species. Features shared by Westrop’s K. subula
include the rounded shape of the cranidium, weak eye ridges, and tapered glabella. It
differs from Kathleenella new species in its anteriorly widened axial furrows, its
possession of a triangular anterior border, and the higher degree of tuberculation.
Subfamily MACRONODINAE Westrop, 1986c
49
Macronodine sp.
Figures A12.12-17, 19-24
Description.—Pygidium with axis parallel sided; 5 pleural ribs, 4 axial rings with
position of the fifth posterior ring melded with the raised pygidial border, small pits
present in transverse row along axial rings; short inter-ring furrows; pleural ribs pleated
with the anterior edge one rib ‘folded over’ the next anterior rib’s posterior edge, pleated
edge forms a raised ridge which connects with the pygidial border, row of small pits
present on anterior edge of pleurae, each pleural rib ends in discrete rounded pocket
which the lateral border overhangs, pockets visible ventrally as rounded edges which
would have likely been completely hidden by the doublure; flattened pygidial border
striated and long; small pit present on border where pleural ridge intersects.
Figured material.—Four pygidial fragments (SUI 00000-00000)
Occurrence.—Horizon 10.1-10.2 m of the Upper Cambrian (lower Sunwaptan) St.
Charles Formation at Franklin Basin, Idaho.
Discussion.—The deep pleural pits and long, flattened posterior border suggest
macronodine affinities. However, specimens assigned herein to macronodine sp. have
terminal axial pieces which merge with the posterior border and lack swollen
protuberances which overhang the pleural pits in both two of the best-known
macronodines: Sunwaptia plutoi Adrain and Westrop, 2004a and Macronoda
notchpeakensis Adrian and Westrop, 2005. The assessment of macronodine affinities for
these pygidial fragments must therefore be considered tentative, at best.
Family ENTOMASPIDIAE Ulrich, in Bridge, 1931
Genus KATHRYNIA Westrop, 1986a
Type species.—Kathrynia limbata Westrop, 1986a from the Upper Cambrian
(Sunwaptan; Proricephalus wilcoxensis Fauna) Mistaya Formation, southern Alberta,
Canada.
50
Diagnosis.—See Westrop (1986).
Kathrynia? sp.
Figures A9.23-27
Description.—Deep recessed anterior border furrow; anterior border striated,
widest medially; preglabellar field with low tubercles; distinct eye ridge; smooth glabella
with distinct S1.
Figured material.—One fragmentary cranidium, (SUI 00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—The weakly prow-like anterior border is suggestive of an affinity
with Kathrynia, but by no means indicative. The shorter length of the anterior border
when compared to the length of the frontal area (sag) can be compared with Bowmania
Walcott, 1925. However, the shape of the anterior border suggests that the suture with
the librigenae would have been marginal only medially and dorsal abaxially. This is
contrasted with the well-preserved specimens of B. lassieae Adrain and Westrop, 2004a,
which have a marginal suture for the entire length of the anterior cranidial border. This is
somewhat similar to the condition possessed by Heterocaryon Raymond, 1937 (e.g.
Heterocaryon vargum Westrop, 1986a), which lacks the longer and flatter preglabellar
field shared by this specimen and other specimens of Kathrynia and Bowmania.
Family IDAHOIIDAE Lochman, 1956
Genus IDAHOIA Walcott, 1924a
Type species.—Idahoia serapio Walcott, 1924a from the Upper Cambrian
(Sunwaptan) St. Charles Formation (Walcott’s Ovid Formation, see Ulrich and Cooper,
1938), Two Mile Canyon, Idaho (by original designation).
51
Diagnosis.—Drawn from Ludvigsen and Westrop (1983b): An idahoiid with a
broad, flattened anterior border, prominent anterior pits, smooth or weakly furrowed
glabella and a pygidium with a short axis and flattened posterior border.
Discussion.—Ludvigsen and Westrop (1983; Westrop, 1986) have done much to
clear up the relationship between Idahoia and Saratogia. Still, the group is in need of
phylogenetic revision. The subgeneric concepts used by Ludvigsen and Westrop are reelevated to the generic level herein—the newly documented diversity makes such a reelevation tenable. Minimally, Idahoia as used herein includes Idahoia serapio, Idahoia
maladensis Walcott, 1924a, Idahoia wisconsinensis (Owen, 1852) and the new species
documented here. Several other specimens assigned to I. serapio and I. wisconsinensis
may ultimately prove to represent new species when larger samples are studied. How,
exactly, some of the less well-known idahoiid genera (i.e. Merria Frederickson, 1949,
and Psalaspis Resser, 1937) are related is an open question.
Idahoia new species B
Figures A24.1-20; 35.24
Description.—Cranidium with broad frontal area; anterior border broad and flat
with anastomozing striations, convex in anterior view, anterior edge curved inverted ‘v’shape; anterior border bounded by long shallow anterior border furrow, mirrors course of
anterior border, over half as long as anterior border, uniform in length, posterior edge of
anterior border furrow inclined posteriorly such that preglabellar field is set higher than
anterior border, bounded posteriorly by row of raised tubercles, course of row of
tubercles mirrors shape of anterior border; eyes large and ‘c’-shaped, bordered by distinct
palpebral furrow, set close to glabella, lower in elevation than glabella; glabella tapered,
subquadrate; occipital furrow narrow and uniform in length; occipital ring longest
medially with stout occipital spine projecting posteriorly.
?Librigena with rounded lateral border and curved librigenal spine.
52
Figured material.—Fragmentary or mold material from 8 cranidia (SUI 0000000000) and one librigena (SUI 00000).
Occurrence.—Horizons 9.6, 10.1-10.2, 10.6-10.72, and 11.2-11.3m of the Upper
Cambrian (lower Sunwaptan) St. Charles Formation at Franklin Basin, Idaho.
Discussion.—Material belonging to Idahoia was dominantly represented by
silicified internal or external molds. Silicified molds were counted along with silicified
sclerites to produce the diversity counts—observations from silicified residues and thin
sections (figures A6.7-8) suggests that risk of ‘double counting’ is low because sclerite
silicification and mold silicification do not occur together. If they did, the silicified mass
containing both the mold and sclerite would be unlikely to be sampled. Why there should
have been so much more mold material is a mystery—easier fragmentation of the thin
sclerite compared to the presumed durability of the mold material could be a partial
explanation. However, it does suggest that there may be a directional bias in the
taxonomic composition of the silicified sclerites recovered. Whether or nor this bias
would still exist when silicified mold material like this is taken into account is unknown.
The fragmentary nature of the material illustrated herein as belonging to Idahoia
makes detailed comparisons impossible—indeed, the association of the fragments is not
without question. However, the specimen illustrated as figure A24.3, 7-8, 12 has a very
distinctive autapomorphy—the long anterior border furrow situated anteriorly to the
dorsal row of raised tubercles. Comparison is closed with I. serapio Walcott, 1924a and
I. maladensis Walcott, 1925, which both share the quadrate glabella, preglabellar field
with caecae, and long anterior border. Idahoia new sp. B differs in that it has a long
anterior border furrow anterior to the row of tubercles situated on the anterior portion of
its preglabellar field. Because of this distinct autapomorphy, it is suggested that the
specimens illustrated herein represent at least one new species, but verification will
necessarily need to await the discovery of more and better material.
53
Genus SARATOGIA Walcott, 1916
Type species.—Conocephalites calciferous Walcott, 1879 from the Upper
Cambrian Hoyt Limestone, New York State (by original designation).
Diagnosis.—Drawn from Ludvigsen and Westrop (1983). A species of
Idahoiidae with curved anterior border; anterior border furrow with steepest edge
anteriorly located; anterior facial suture branches divergent; preglabellar field sloped
downward, tapered subtrapezoidal glabella; glabellar furrows convex anteriorly;
palpebral lobes wide and band-like, abuts glabella anteriorly, close to glabella posteriorly,
medial point of palpebral lobe located lateral to glabellar midlength; wide occipital
furrow, usually with occipital spine, pygidium with long axis in contact with rim-like
pygidial border, striations present on pygidial rim and axis.
Discussion.—As discussed above under Idahoia, herein the subgeneric concept of
Saratogia and Idahoia according to Ludvigsen and Westrop (1983) is elevated to generic
status.
Saratogia new species C
Figures A35.1-13, 15-16, 18-19, 22-23; A36.1, 3, 6, 8-9, 13
Description.—Cranidium densely covered by large tubercles, low in convexity;
max width across palpebral lobes 90.5 (86.9-94.9; n=1)% of max cranidial length;
anterior border tuberculate, longest medially, tapered abaxially, anterior margin forms
obtuse medial prow, posterior margin of anterior border slightly flexed anteriorly, thin in
anterior view, max anterior border length 13.0 (12.0-14.0; n=3)% of max anterior border
width, max anterior border length 7.6 (6.6-8.3; n=3)% of max cranidial length, max
anterior border width 64.5 (63.0-66.7; n=3)% of max width across palpebral lobes;
preglabellar field tuberculate, preglabellar field tubercles exhibit a weak radiating pattern
parallel to facial suture, longer exsagittally than sagittally, max width across preglabellar
field wider than anterior border but narrower than max distance across palpebral lobes, ;
anterior portion of facial suture divergently trending, length along anterior portion of
54
facial suture 20.3 (19.1-21.1; n=3)% of max cranidial length, distance across _ 60.0
(59.0-61.1; n=4)% of width across palpebral lobes; eyes large and ‘c’-shaped, prominent
tubercle row along outer margin with about 15 tubercles, anterior edge of eye abuts S3,
posterior edge of eye set slightly abaxially from L1; palpebral furrow distinct, deepest
anteriorly and posteriorly; palpebral area lower than eye, tuberculate, eye width (at _)
20.8 (18.9-23.6; n=4)% of max eye length (_- _), max eye length 40.7 (39.4-41.7; n=3)%
of max cranidial length, max eye width 9.4 (8.9-10.4; n=4)% of width across palpebral
lobes; posterolateral projection tuberculate with deep posterior border furrow; occipital
ring tapered abaxially, anterior and posterior occipital ring margins convex posteriorly,
short medial spine present, max occipital ring length (excluding spine) 25.1% (n=1) of
max occipital ring width, max occipital ring length 12.3 (11-9-13.1; n=3)% of max
cranidial length, max occipital width 58.4% (n=1) of max width across palpebral lobes,
weakly bounded laterally by shallow extension of axial furrow; occipital ring doublure
lunate and longest medially, shorter than occipital ring; S0 shallow and wide, narrower
abaxially; glabella anteriorly tapered and bullet shaped, max glabellar width 82.9 (79.388.8; n=4)% of max glabellar length, max glabellar width 52.1 (47.1-54.9; n=4)% of max
width across palpebral lobes, max glabellar length 57.8 (57.3-58.4; n=3)% of max
cranidial length, covered in large tubercles; axial furrows deep and uniform, continuous
with preglabellar furrow, forms 9.3 (8.0-10.3; n=4)° angle with sagittal line, S1 deeper
abaxially, separated slightly from axial furrow, forms 53.6 (51.6-57.5; n=3)° angle with
sagittal line; S2 deep, reaches axial furrows, narrower and less inclined than S1; S3 weak,
isolated from axial furrow, subhorizontal; S4 very weak, discernable ventrally on some
specimens (figure A35.2).
?Librigenae with librigenal field with small tubercles arrayed in loose radiating
pattern; eyes large and ‘c’-shaped, palpebral furrow distinct with weakly defined eye
socle, eye closest to lateral border at anterior facial suture; lateral border with either
tubercles dorsally and subparallel striations laterally (figures A36.1, 3, 6, 13) or
55
subparallel striations both dorsally and laterally (figures A36.8-9), tubular in shape with
short genal spine; lateral border furrow deepest anteriorly, shallowest in genal corner;
posterior border covered with small tubercles, shortest abaxially; posterior border furrow
weakest at genal corner.
Figured material.—Eight silicified cranidia (SUI 00000-00000) and three
silicified librigenae (SUI 00000-00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—The specimens assigned to Saratogia n. sp. C clearly represent a
new species, but without positively identified pygidial material, I decline to name a new
species. S. calcifera (Walcott, 1879), which was re-illustrated by Ludvigsen and Westrop
(1983) is the only real relevant comparison. It differs from Saratogia n. sp. C in that it
has finer, denser tuberculation, no tubercles on the palpebral lobe, and a longer occipital
spine. The librigenae assigned herein to Saratogia n. sp. C are only tentatively assigned,
as they appear to have a slightly finer pattern of tubercles in general.
Saratogia sp.
Figure A35.14, 17, 20, 21
Figured material.—Four silicified cranidia (SUI 00000-00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—The cranidia referred to herein as Saratogia sp. share a suite of
features which are lacking in Saratogia n. sp. C. However, due to the partial nature of
the material, not single specimen possesses the entire suite of features. The list includes
having a stout occipital spine insertion, fine tuberculation, closely set S1 furrows, S2
furrows that are not continuous with axial furrows, and a slight preoccipital glabellar
expansion. The status of these specimens can only be answered with the discovery of
more material.
56
Genus WILBERNIA Walcott, 1924a
Type species.— Ptychoparia pero Walcott, 1890, from the Upper Cambrian
Wilberns Formation, Texas, USA (by original designation).
Diagnosis.—See Westrop (1986a).
Discussion.—Wilbernia, as presently understood, is comprised of five species
which have been identified all across Laurentia (W. diademata Hall, 1863; W. expansa
Frederickson, 1949; W. explanata Whitfield, 1880; W. halli Resser, 1937; and W. pero),
and four less well-represented species (W. hudsonensis Resser, 1937; W. hunterensis
Kobayashi, 1938; W.? minuta Wilson, 1951; W. walcotti Resser, 1937; excluding material
assigned to Wilbernia as sp. indet.). The quality of the illustrated material (or the
illustrations) for the latter four species makes evaluation of their status difficult.
Published illustrations of the former five species suggest that there may be more than one
species lurking within each. For example, examples of W. pero illustrated by Lochman
and Hu (1959) differs from the holotype and topotype material illustrated by Bell and
Ellinwood (1962) in that they have more convex glabellae and anterior borders which are
low with respect to the palpebral plane. Specimens of W. pero illustrated by Westrop
(1986a) have shorter, more convex anterior borders, and longer occipital rings than Bell
and Ellinwood’s material. This suggests the presents of more species-level diversity than
is currently recognize, though confirmation of this will rely on new collections and a
restudy of figured specimens.
Wilbernia new species 4
Figures A5.1, 5; A25.1-15; A26.4-5, 7-20; A27.1-18, 22, 26
Diagnosis.—A species of Wilbernia with a wide, uniformly long anterior border
with medial depression, short to no preglabellar field, rectangular glabella, broad flat
pygidia with weak postaxial ridges.
Description.—Cranidium with broad anterior border virtually lacking preglabellar
field; max anterior border width nearly equal max width across posterior border
57
(measurements may be estimated by using a plane of symmetry); max length 91.6%
(figure A24.25) of max width across posterior border, max width across anterior border
95.5 (88.6-106.8; n=4)% of max length, max width across palpebral lobes 85.0 (79.888.7; n=5)% of max length; anterior border nearly abuts glabella, long, roughly uniform
in length sag. and exsag., dorsally convex save slight anteriorly sloping wide medial
furrow, medial length of anterior border 25.0 (21.9-26.1; n=4)% of max width of anterior
border, medial length of anterior border 24.1 (23.0-25.4; n=5)% of max cranidial length;
anterior border furrow wide and shallow, row of fine pits in anterior border furrow;
preglabellar field absent (figure A25. 2) to minimal (figure A25.15); anterior portions of
facial suture highly divergent, facial suture creates ≈ 46.2 (35.2-53; n=5)° angle with
sagittal line; narrow weak eye ridge; eyes set close to glabella, weakly ‘c’-shaped, set
posteriorly, anterior edge of eyes laterally equivalent to S2, max eye width 22.2 (18.530.7; n=5)% of max distance across eye, max eye width 6.3 (4.9-9.6; n=5)% of distance
between palpebral lobes, max distance across eyes 22.6 (21.1-24.8; n=5)% of max
cranidial length, anterior edge of eye set closer to glabella than posterior edge, distance
across _ 94.0 (91.1-97.0; n=2)% of distance across _, distance across _ 79.8 (76.3-83.2;
n=6)% of max width across palpebral lobes; posterior fixigenal area short rectangular
projection; posterior border furrow wide, shallowest at axial furrow; occipital ring wider
than glabella, max occipital ring length 23.2 (21.1-25.0; n=6)% of max occipital ring
width, max occipital ring length 12.4 (11.7-13.6; n=5)% of max cranidial length, max
occipital ring width 63.3 (61.4-65.0; n=6)% of max width between palpebral lobes weak
posterolaterally directed furrow present near distal edge of occipital ring, forms weak
laterally projecting lobes; glabella roughly parallel-sided, rectangular to slightly medially
waisted, usually widest anteriorly, posterior glabellar width 97.0 (91.7-105.0; n=8)% of
anterior glabellar width, anterior glabellar width 80.3 (74.3-84.3; n=8)% of medial
glabellar length, anterior glabellar width 58.9 (55.8-65.7; n=7)% of width between
58
palpebral lobes, medial glabellar length 61.2 (59.8-61.9; n=5)% of max cranidial length,
S1 and S2 long shallow depressions roughly parallel to one another.
Librigena flat and broad, covered with fine anastomozing striations; lateral border
flattened dorsally, gently rounded ventrally, narrows posteriorly; lateral border furrow
shallow anteriorly, deeper posteriorly but shallows abruptly anterior to librigenal spine;
weak line on dorsal surface reflects adaxially extent of doublure ventrally (figures A26.7,
16-17); lateral and posterior borders never intersect; posterior border furrow narrow,
continuous for short distance on genal spine, shallows to obsolescence on genal spine;
genal spine narrow and rounded; librigenal field bare; eye prominent; doublure with
striations parallel to lateral and posterior border, striations form near right angle at
librigenal corner.
Pygidium broad and flat, oval shaped, max medial length 54.1 (52.6-55.4; n=3)%
of max width; axis tapered posterior with narrow axial ridge continuous to posterior
border, defined by abrupt change in elevation, terminal axial piece grades into axial ridge,
two distinct axial rings (ant) plus one weakly defined axial ring (post); articulating halfring lower than anteriormost axial ring, longest medially; pseudo-articulating half-ring
short; axial furrow (along anterior three axial rings) at 9.6 (8.8-11; n=3)° angle with
sagittal line, medial length across anterior three axial rings 82.1 (80.7-84.6; n=3)% of
max axial width, medial length across anterior three axial rings 39.3 (37.5-41.4; n=3)% of
max medial pygidial length, max axial width 25.8 (25.2-27.1; n=3)% of max pygidial
width; posterior border poorly defined, low striations along edge of pygidium; two
distinct pleurae, curved posterolaterally; doublure long and flat, tapered laterally,
doublure ≈42.2% (figure A27.5) of length medially, covered with striations, doublure
tucked into axial recess medially.
Figured material.—Eight cranidia (SUI 00000-00000), nine librigenal fragments
(SUI 00000-00000), and nine pygidia (SUI 00000-00000).
59
Occurrence.—Horizons 9.6m to 11.2-11.3m of the Upper Cambrian (lower
Sunwaptan) St. Charles Formation at Franklin Basin, Idaho. One possible cranidium
observed in sample TMC SCP 2.579 from Two Mile Canyon.
Discussion.—The most plausible sister species to W. n. sp. 4 is W. pero, but as
discussed above, W. pero as presently understood is a rather variable species. All
specimens of W. pero share rectangular, weakly waisted glabellae and broadly curved
anterior borders set near the glabella with W. n. sp. 4. W. n. sp. 4 is distinct from W. pero
(sensu Bell and Ellinwood, 1962) in that its anterior border does not become shorter
laterally. W. n. sp. 4 has a higher anterior border and less convex glabella than W. pero
(sensu Lochman and Hu, 1959), and it differs from W. pero (sensu Westrop, 1986a) in
that the anterior border is much longer (sag. and exsag.) and flatter with a weak medial
depression and lacks an occipital node. The shape of the cranidium is broadly compatible
with W. hunterensis Kobayashi, 1938, but with the poor quality of the original
illustration, it is impossible to say anything more than that. Pygidial and librigenal
material is poorly known from other species of Wilbernia, so comparison is difficult.
Wilbernia pygidia and librigenae were assigned to W. n. sp. 4, but it is conceivable that
fragments belonging to one of the less well-know species of Wilbernia from Franklin
Basin were included.
Wilbernia sp.?
Figures A15.11; A26.1
Figured material.—One cranidium, SUI 00000.
Occurrence.—Horizon 9.6m of the Upper Cambrian (lower Sunwaptan) St.
Charles Formation at Franklin Basin, Idaho.
Discussion.—Wilbernia sp.? is most similar to a specimen illustrated by Bell and
Ellinwood (1962) as W. expansa (their plate 54.12). It shares the broad anterior border
adjacent to the glabella and tapered glabella. Wilbernia sp.? however, is prominently
waisted at S1. When compared to other species from Franklin Basin, it differs from
60
Wilbernia n. sp. 4 in the shape of the glabella; the glabella of Wilbernia sp.? is waisted
posterior at S1, has a more prominent S1, and is tapered anteriorly. The condition of the
specimen is poor, and it may yet prove to be a member of W. n. sp. 4 as the two both have
long and broad anterior borders. Wilbernia sp.? shares a tapered glabella with Wilbernia?
cf. W. expansa, but the anterior border of Wilbernia? cf. W. expansa is much longer and
flatter.
Wilbernia? cf. W. expansa Frederickson, 1949
Figure A26.2-3, 6
Figured material.—One cranidium and two cranidial fragments (cranidial
fragments are questionably assigned), SUI 00000-000000.
Occurrence.—The cranidium is from horizon 9.6 m of the Upper Cambrian
(lower Sunwaptan) St. Charles Formation at Franklin Basin, Idaho. The two cranidial
fragments are from horizon 10.6-10.72m.
Discussion.— This cranidium does not seem to be conspecific with either
Wilbernia n. sp. 4 or Wilbernia sp.?; it differs in the shape of it anterior border,
posteromedial glabellar inflation, and possession of a prominent occipital node. Its
anterior border is of particular note as it is dorsally concave with a shallow furrow
running the width of it. A concave border and occipital node are also possessed by
Wilbernia cf. W. expansa as illustrated by Westrop (1995), though its anterior border is
much longer than that belonging to W.? cf. W. expansa. The slight curvature and short
length of the anterior border plus the presence of a prominent occipital node are
suggestive of affinities with Noelaspis Ludvigsen and Westrop, in Ludvigsen et al., 1989.
The diagnosis of Noelaspis as given in Ludvigsen et al. (1989) emphasizes pygidial
characteristics as well as the possession of a short preglabellar field and convex anterior
border—all features that are absent or unknown in these specimens.
Family REMOPLEURIDIDAE Raymond, 1924
61
Discussion.—Remopleurididae is used in the broad sense of Jell and Adrain
(2003), subsuming Richardsonellidae Raymond, 1924. Elucidating exactly how the
Richardsonellidae (sensu Ludvigsen et al., 1989) are related to the rest of the
remopleuridids is beyond the scope of this work. However, it does seem likely that
Richardsonellidae, as previously conceived, would be paraphyletic with respect to the
Remopleurididae.
Genus NAUSTIA Ludvigsen, 1982
Type species.—Naustia papilio Ludvigsen, 1982 from the Upper Cambrian
Rabbitkettle Formation, Broken Skull River, Mackenzie Mountains (by original
designation).
Diagnosis.—See Ludvigsen, 1982. Emended to include up to eight pairs of
pygidial spines.
Naustia new species 5
Figures A5.8; A33.1-22; A34.1-15; A36.2, 4-5, 7, 10-11
Diagnosis.—A species of Naustia with a short preglabellar field, shallow glabellar
furrows, librigenal border and genal spine form right angle with posterior librigenal
border, pygidium with up to eight pairs of spines, pygidial spines not sharply curved
posteriorly, three axial rings with prominent pseudo-articulating half-ring.
Description.—Cranidium low in convexity, weakly granulose over much of
surface; max width across palpebral lobes 98.2% (n=1) of max cranidial length; anterior
border lunate, thin in anterior view, max anterior border length 86.0% (n=1) of max
cranidial length; preglabellar field longer exsagittally than sagittally, covered with very
low caecal ridges, preglabellar field medial length 13.9% (n=1) of max cranidial length;
anterior portion of facial suture divergent, forms 19° (n=1) angle with sagittal line;
distance across _ 62.9% (n=1) of distance across palpebral lobes; eyes large and
semicircular, anterior and posterior edges of eye abut glabella, palpebral furrow distinct,
62
short furrow weak furrow parallel to palpebral furrow present within palpebral lobe,
width of palpebral lobe (at _) 23.8 (21.5-26.0; n=2)% of eye length (_- _), width of
palpebral lobe 10.4 (9.8-11.0; n=2)% of max width across palpebral lobes (one
measurement was derived from measuring to a plane of symmetry and doubling the
measurement), max eye length 41.4% (n=1) of max cranidial length; posterolateral
projection short with deep posterior border furrow; occipital ring longer sagittally than
exsagittally, lower in elevation than glabella, max occipital ring length 14.8% (n=1) of
max cranidial length, weak occipital node located medially; S0 narrow and pervasive to
axial furrows; glabella subrectangular to weakly tapered anteriorly, widest near S0, weak
preoccipital glabellar expansion present (more pronounced in smaller specimens), S1 and
S2 manifest ventrally, anterior width across glabella 80.8 (77.3-84.3; n=2)% of max
glabellar length, anterior glabellar width 86.0% (n=1) of max glabellar width.
Librigena with weak caecal ridges; librigenal field narrow with eye set close to
lateral border; cylindrical lateral border continuous with cylindrical librigenal spine; eye
socle prominent bounded by distinct furrows; ventral doublure mirrors width of lateral
and posterior borders.
Pygidium with spinose margin and weak striations on most surfaces, eight pairs of
straight conical border spines, occasional small triangular medial postaxial spine present;
axis subrectangular highly elevated, three distinct axial rings, terminal axial piece divided
into two lobes, prominent pseudo-articulating half-ring present; broad interpleural
furrows present on pleural field; doublure covered with anastomozing striations, flexed
anterodorsally into cavity created by axis, longer exsagittally than sagittally.
Figured material.—Seven silicified cranidia (SUI 00000-00000), one crackout
cranidia (SUI 00000), five silicified librigenae (SUI 00000-00000), eight silicified
pygidial fragments (SUI 00000-00000), and two crackout pygidia (SUI 00000-00000).
63
Occurrence.—Horizons 9.6, 10.1-10.2, and 10.6-10.72m of the Upper Cambrian
(lower Sunwaptan) St. Charles Formation at Franklin Basin, Idaho. Cranidia are only
known from horizon 10.6-10.72m.
Discussion.—Ludvigsen’s (1982) concept of Naustia circumscribed a welldefined group of species, including the Laurentian representatives N. papilio and N.
tyboensis (Taylor, 1976). If the cranidia / pygidia association is correct, the inclusion of
N. n. sp. 5 will require broadening the concept of Naustia with particular regards to the
pygidium. N. n. sp. 5 has a tail that has a comparatively shorter axis with fewer (though
well-defined) axial rings. Both N. papilio and N. tyboensis have terminal axial pieces
which seem to possess very short post-axial ridges, and seem to lack significant pseudoarticulating half-rings.
Family ELLIPSOCEPHALOIDIDAE Hupé, 1955
Genus ELLIPSOCEPHALOIDES Kobayashi, 1935a
Type species.—Ellipsocephaloides curtus Whitfield, 1878 from the Upper
Cambrian Lone Rock Formation of Wisconsin (by original designation).
Diagnosis.—See Westrop (1986a).
Discussion.—Higher-level affinities of Ellipsocephaloides (assigned to the
monogeneric family Ellipsocephaloididae) remain obscure. Westrop (1986a) compared
them to members the Remopleurididae and to the Olenidae. Biogeographically, the
former suggestion makes more sense, as the olenid genera he compares
Ellipsocephaloides to are not present on Laurentia. As no articulated specimens have yet
been found, the cranidia-pygidia associations must be considered provisional.
Ellipsocephaloides monsensis Resser, 1942
Figures A23.24, 27, 32-33
1942
Ellipsocephaloides monsensis Resser, p. 66, pl.12.4-6.
1942
Ellipsocephaloides montis Resser, p.65, pl. 11.4-5.
64
1942
Ellipsocephaloides declevis Resser, p. 67, pl. 12.10-13.
?1952 Ellipsocephaloides gracilis Feniak, in Bell et al., p. 188, pl. 34.3.
1959
Ellipsocephaloides monsensis Resser, Harrington, et al., p. O517, pl.
410.5a-b
1962
Ellipsocephaloides monsensis Resser, Greggs, p. 149, pl. 18.16-18.
1986
Ellipsocephaloides monsensis Resser, Westrop, p. 56, fig. 36B, pl. 25.1-
17,
Diagnosis.—See Westrop (1986a).
Description.—Cranidium with parallel sided glabella, rounded corners anteriorly;
glabellar furrows pit-like, do not connect with axial furrow; S1 deepest, v-shaped with
bottom of v pointing medially, faintly continuous across glabella; S2 linear, angled
slightly anterolaterally; S3 faint; occipital furrow uniformly deep; interoccular fixigenae
narrow and low; eyes large and long, subparallel to glabella posterior to S2, angled
toward anterolateral glabellar corner anterior to S2.
Holotype.—A cranidium (USNM 108752a) from the Bison Creek Formation,
southern Alberta, illustrated by Resser (1942, his plate 12.4) and by Westrop (1986a, his
plate 25.17).
Figured material.—One crackout cranidium (SUI 00000).
Occurrence.—Horizon 9.6m of the Upper Cambrian (lower Sunwaptan) St.
Charles Formation at Franklin Basin, Idaho.
Discussion.—Variation in the anterior border (presence and character of the
medial ridge) suggests that E. monsensis (sensu Westrop, 1986a) may be a species
complex; however, the amount of material available and published photographs of other
specimens prevent a comprehensive revision of this species. Specimens assigned to E.
butleri Resser, 1942 by Resser (1942) as well as by Berg and Ross (1959) are too poorly
preserved to be meaningfully compared, and hence, E. butleri had best be considered
nomen dubia rather than junior subjective synonym of E. monsensis (see Westrop,
65
1986a). No pygidia similar to those previously illustrated as belonging to E. monsensis
were identified, and as the pygidia assigned herein to E. cf. E. nitela Resser, 1942
occurred in a different horizon, an association between the two is considered unlikely.
Ellipsocephaloides cf. E. nitela? Resser, 1942
Figures A23.19-20, 22-26, 28-31, 34-35
Description.—Pygidium rimmed with eight short flat triangular pleural tips;
medial length 54.5% (n=1) of max width; pleural field low creating flat posterior margin;
anteriormost pleural furrow most distinct, pleural furrows more distinct than interpleural
furrows, furrows weak posteriorly and distally but remain visible; pleural tips roughly
equal in size; axis short and distinct from pleural field, roughly as long as wide, max axial
width 103.6 (88.8-117.1; n=4)% of max axial length including articulating half ring; three
axial rings present with distinct paired nodes; anteriormost axial ring short medially with
prominent pseudo-articulating half-ring; distance between paired nodes decrease
posteriorly; articulating half-ring semicircular, accounts for 21.8 (18.5-27.4; n=4)% of
axial length; doublure with curved interior margin, roughly equal in length sag. and
exsag., covered with terrace lines, medial doublure length 21.6 (19.3-23.9; n=2)% of
medial pygidial length.
Figured material.—Five pygidia (SUI 00000-00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—The pygidia illustrated here as E. cf. E. nitela? are almost
indistinguishable from those illustrated by Resser (1942; his plate 12.2-3). Specimens
illustrated herein do not have an as distinct anteriormost pleural and interpleural furrow
as E. nitela. E. nitela has been treated as a junior subjective synonym of E. silvestris
Resser, 1942 (see Westrop, 1986a). The cranidia are difficult to distinguish (the holotype
of E. nitela has a wider glabella and eyes set slightly more posteriorly than E. silvestris),
but the pygidial differences between the two are real. As the pygidia figured by Resser
66
(1942) are at roughly the same magnification, the difference is unlikely to be ontogenetic.
More collections need to be made from the Honey Creek Limestone in Oklahoma, where
both species were first identified (though different localities), to settle the matter. Until
then, E. nitela is cautiously treated as a species distinct from E. silvestris.
Resser (1942) identified one species of Ellipsocephaloides, E. bearensis Resser,
1942, from the St. Charles Formation (near St. Charles, Idaho). The type specimen is a
poorly preserved fragmentary cranidium with no associated pygidium (Resser, 1942; his
plate 11.12). No similar cranidia were identified from Franklin Basin. Westrop (1986a)
synonymized it with question into E. curtus (Whitfield, 1878); however, the state of the
figured material suggests that until new collections can be made from the type locality, E.
bearensis should be regarded as a nomen nuda.
Family CATILLICEPHALIDAE Raymond, 1937
Genus TRIARTHROPSIS Ulrich, in Bridge, 1931
Type species.—Triarthropsis nitida Ulrich, in Bridge, 1931 from the Upper
Cambrian Eminence Dolomite of southern Missouri (by original designation).
Triarthropsis sp.
Figures A23.1-18, 21
Description.—Cranidium subtrapezoidal; max length 89.3 (84.5-94.1; n=2)% of
max width between palpebral lobes; anterior margin without defined anterior border,
steeply declined anteriorly, in lateral view convex downward coming to slight point
medially, faint striations visible in some specimens (figure A23.9); eyes small, slightly
lunate; eye ridges weak and low; distal fixigenal area triangular not rectangular, posterior
border furrow deep; posterior border longest distally, narrowest adjacent to occipital ring;
occipital ring lower than glabella, max occipital ring length 28.8 (22.7-35.9; n=3)% of
max occipital ring width, max occipital ring length 16.0 (11.6-19.9; n=5)% of max
cranidial length, weak occipital node set next to occipital furrow; glabella parallel sided
67
to slightly tapered, max glabellar width 79.6 (70.5-85.4; n=5)% of max glabellar length,
max glabellar width 55.3 (51.8-58.7; n=2)% of max width between palpebral lobes, max
glabellar length 76.9 (72.6-80.3; n=5)% of max cranidial length, decrease in glabellar
width between S1 furrows to S2 furrows is 92.6 (86.9-97.3; N=4)%; S1 straight in larger
specimens, curved sharply toward occipital ring in smaller specimens, S1 never persistent
across glabella, confluent or nearly so with axial furrow; S2 straight, parallel to S1,
narrower and weaker than S1; S3 present as short weak trace.
Figured material.—Nine cranidia (SUI 00000-00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—Triarthropsis sp. is most similar to T. nitida (for additional figured
specimens, see Westrop, 1986a), but has a more quadrate glabella and narrower
interoccular fixigenal areas. Additionally, the F1 furrow of T. sp. is subhorizontal,
whereas most other species of Triarthropsis have furrows that are horizontal near the
axial furrow and sharply posteriorly directed adaxially.
Family PARABOLINOIDIDAE Lochman, 1956
Genus TAENICEPHALUS Ulrich and Resser, in Walcott,
1924a
Type species.—Conocephalites shumardi Hall, 1863 from the Upper Cambrian
Lone Rock Formation of Wisconsin (by original designation).
Diagnosis.—See Westrop (1986a).
Taenicephalus sp.
Figures A15.1, 4
Description.—Cranidium with entire surface granulose, granules smaller in
furrows; glabella low in convexity, tapered anteriorly, anterior glabellar margin slightly
bowed posteriorly; glabella well-defined by axial and preglabellar furrows, furrows
68
deepest at anterolateral corners of glabella; glabellar furrows narrow anteriorly, slit-like
in character; eyes higher in elevation than glabella, beginning anteriorly equivalent to
anterior margin of glabella; anterior border furrow short and uniform, bowed posteriorly
medially; anterior border widest medially, nearly isosceles triangle in shape with rounded
anterior tip; anterior tip in anterior view low giving m-shaped profile to anterior border
ventrally.
Figured material.—One partial cranidium (SUI 00000).
Occurrence.—Horizon 10.1-10.2m of the Upper Cambrian (lower Sunwaptan) St.
Charles Formation at Franklin Basin, Idaho.
Discussion.—Resser (1942) erected a number of species of Taenicephalus,
including one from the St. Charles Formation (Taenicephalus libertyensis Resser, 1942
from a locality near Liberty, Idaho). Though also from the St. Charles Formation, T.
libertyensis and Taenicephalus sp. are not conspecific—Resser’s specimens lack the
slightly concave anterior glabellar margin, and posteriorly bowed anterior border furrow.
In shape, it is similar to specimens illustrated by Westrop (1986) as Taenicephalus
nasutus (Hall, 1863), but Taenicephalus sp. differs markedly in its sculpture (granules
verses pits). Characters preserved in this small fragment are suggestive of it belonging to
a new species, but more material would be needed to ascertain its status for certain.
Genus New Genus A
Discussion.—This species, represented only by cranidia and librigenae, seems to
clearly represent a new genus of trilobite. It is fairly clearly a parabolinoidid—with
small, flap-like palpebral lobes set forward. This particular taxon is unique in that both
its palpebral lobes and anterior border abut the glabella and it possesses a weak S3 furrow
in the middle of a weakly protuberant composite L3 & L4 lobe. Proportionally, it is
similarity to Parabolinoides Frederickson, 1949.
New genus A and new species 6
69
Figures A16.1-27; A17.1-22
Description.—Cranidium tapered anteriorly with proportionately long
posterolateral fixigenal projections; max cranidial length 82.5 (75.3-89.7; n=2)% of max
cranidial width (max width estimated from specimens with only one posterolateral
fixigenal projection preserved), max cranidial length 122.7 (115.7-128.9; n=3)% of max
width across palpebral lobes, width across palpebral lobes 68.9 (65.1-72.6; n=2)% of max
cranidial width; anterior border slightly lunate with subparallel striations, longest
medially, max anterior border length 22.7 (20.7-24.8; n=2)% of max anterior border
width, max anterior border length 13.8 (13.1-15.0; n=4)% of max cranidial length, max
anterior border width 52.6 (45.6-59.6; n=2)% of max cranidial width, anterior margin of
anterior border is straight to low ‘m’ shape in anterior view (figures A16.14, 21),
elevation of anterior border highest medially, posterior margin of anterior border nearly
straight and perpendicular to sag. line with slight medial bulge manifest rarely (figure
A15.10); anterior portion of facial suture (_-b) divergent; preoccular field small; eyes
small, anterior edge of eye at or just behind anterior edge of glabella (figures A16.16,
17), palpebral lobe asymmetrical with apex of curve set posteriorly, distance across eye
(_-_) 26.7 (23.8-29.1; n=3)% of max cranidial length, proximal edge of palpebral lobe
abuts axial furrow forming a pit-like widening of the furrow laterally equivalent to S2;
width across anteriormost point of eye (_-_) 85.0 (83.3-86.9; n=3)% of width across
posteriormost point of eye (_- _); posterior fixigenal area subrectangular, nearly bisected
diagonally by posterior border furrow from posteromedial to anterolateral corners, in
anterior view posterior fixigenal area declined abaxially; posterior border furrow not
continuous to lateral fixigenal margin, shortest at axial furrow, wide and shallow
abaxially; posterior border lengthens abaxially, min posterior border length 23.9 (17.630.1; n=2)% of max posterior border length; fixigenal doublure longest at lateral
fixigenal margin, thins to obsolescence before reaching axial furrow; occipital ring
subrectangular to lunate, tapered laterally, max occipital ring length 25% (n=1) of max
70
occipital width, max occipital ring length 13.8 (12.6-15.0; n=4)% of max cranidial length,
max occipital ring width 45.3% (n=1) of max crandidial width; occipital ring doublure
lunate, max length nearly equal to that of occipital ring; glabella tapered anteriorly with
large specimens possessing slightly expanded frontal lobes deviating from tapered trend,
equal in elevation to palpebral lobes, bounded by straight axial furrows which are slightly
curved outward anteriorly in larger specimens, axial furrows form 11.5 (10.5-12.9; n=5)°
angle with sag. line, max glabellar width.96.8 (93.0-103.7; n=3)% of max glabellar length
(larger specimens tend to have glabellae wider than long); max glabellar length 63.9
(61.8-66.7; n=4)% of max cranidial length, max glabellar width 75.5 (67.0-81.3; n=3)%
of max width across palpebral lobes, width across frontal lobe 70.0 (68.3-72.8; n=3)% of
max glabellar width, anterior glabellar margin has slight median furrow creating bilobate
appearance to frontal lobe in some specimens (figure A16.10); axial furrows distinct,
deepest lateral to palpebral lobes; preglabellar furrow short and distinct, preglabellar field
short; glabellar furrows lateral notches, weaken anteriorly; S1 straight, uniformly deep,
forms 46.7 (42.5-50.5; n=5)° angle with sag. line, not contiguous with axial furrows; S2
deepest glabellar furrow, deepens abaxially, subparallel to S1, narrower than S1,
contiguous with axial furrows; S3 weak to absent on weakly protuberant composite L3 &
L4, narrow, set in from axial furrows; S4 stronger than S3 where present, site of slight
glabellar constriction in larger specimens, contiguous with axial furrows, directed
anteromedially from axial furrows.
Librigena flat with small eye; eye with distinct thick socle, eye socle width (at _)
27.3 (22.7-29.5; n=6)% of distance across eye (_-_), anterior portion of facial suture
short and straight; posterior portion of facial suture long, straight until posterior border,
after intersection with posterior border curves sharply posterolaterally; distance along
anterior portion of facial suture (_-_) 25.6 (25.1-26.4; n=3)% of distance along posterior
portion of facial suture (_-_); librigenal field low, devoid of ornamentation; genal corner
rhomboid with short spine at corner, distance from genal spine to _ 31.4 (28.5-36.9;
71
n=4)% of distance along posterior portion of facial suture; subparallel striations run
length of lateral border and culminate at tip of genal spine; lateral border flat posterior,
more convex and defined anteriorly, anterior width of lateral border 13.1 (11.7-14.2;
n=3)% of distance across librigenal field (_-_); distance across eye 30.3 (29.1-31.4;
n=3)% of distance across librigenal field; doublure broad and flat at genal corner; lateral
border doublure has ventral ridge the length of librigena, inner edge of doublure inclines
sharply to ventral side of librigenal field.
Ontogeny.—Only a few relatively late meraspid specimens were photographed
(figures A17.1-2, 6-8). Consequently, little information can be provided about the
ontogeny of the new genus A aside from a few apparent trends in late meraspid-holaspid
development. The glabella appears to grow at a relatively faster rate than the preoccular
and palpebral fixigenal fields as these areas are comparatively much larger in smaller
specimens and nearly disappear by time maximum size is reached. Glabellar furrows, on
the other hand, seem to be a relatively late addition in ontogeny. The shape of the
glabella changes as well, from being much narrower in smaller specimens, to being
slightly wider than long in larger specimens.
Figured material.—Eleven cranidia (SUI 00000-00000) and eleven librigenae
(SUI 00000-00000).
Occurrence.—Horizons 9.6, 10.1-10.2, and 10.6-10.72m of the Upper Cambrian
(lower Sunwaptan) St. Charles Formation at Franklin Basin, Idaho.
Discussion.—See the discussion above.
Family ELVINIIDAE Kobayashi, 1935a
Genus DRUMASPIS Resser, 1942
Type species.— Drumaspis walcotti Resser, 1942, from the Upper Cambrian
(lower Sunwaptan) St. Charles Formation, Two Mile Canyon (locs. 4y, 5e), Wasatch
Mountains, Idaho, USA (by original designation).
72
Diagnosis.—See Westrop (1986a).
Discussion.—Resser (1942) erected the genus Drumaspis along with fourteen
species belonging to it. Subsequent taxonomic work has synonymized many of his
original species (and those erected in Grant, 1962) into just three species: Drumaspis
walcotti Resser, 1942; Drumaspis idahoensis Resser, 1942; Drumaspis texana Resser,
1942. Longacre (1970) discussed the reasoning; D. texana has disconnected S1 furrows
and is always stratigraphically below D. idahoensis (which has connected S1 furrows).
The holotype and paratype of D. walcotti were suggested by Longacre (1970) to be
different species (possibly one to the idahoensis group and the other to the texana group).
Longacre’s reliance on the single characteristic of the pervasiveness of S1 may explain
her inclusion of Drumaspis in Ptychaspididae—all of which have pervasive S1 furrows.
However, a perusal of the original figures of Resser suggests that this combining of taxa
may have been premature—significant variation exists in many other characters (e.g.
relative size of the eyes, length of preglabellar field, character of S3, relative size of
frontal glabellar lobe, sculpture, etc.). Further complicating matters is the fact that the
holotype for the type species of the genus, D. walcotti, is missing from the collections of
the U.S.N.M. (see Westrop, 1986a). Drumaspis is in need of a comprehensive revision,
involving a restudy of Resser’s (1942) types and a morphometric analysis, which is
beyond the scope of this study.
Drumaspis af. D. walcotti Resser, 1942
Figures A5.3-4, 6-7; A18.1-22; A19.1-26; A20.1-22, 26-28; A21.1-20; A22.1-33
Diagnosis.—The assignment to D. walcotti is provisional—the state of Drumaspis
taxonomy does not allow for the construction of a coherent species-level diagnosis at this
juncture.
Description.—Cranidia: Subtrapezoidal outline; weakly granulous in small
specimens, larger specimens have slight ‘wrinkled’ appearance (figure A19.10), weak
striations present on anterior and posterior border; max cranidial length 67.9 (62.5-72.0;
73
n=8)%) of max cranidial width (the measurement ‘max cranidial width’ includes
specimens for which only one fixigena was preserved; the measurement was taken from
the distal fixigenal corner to the median occipital node and then doubled), max width (tr.)
across palpebral lobes 89.7 (86.1-93.1; n=3)% of max cranidial width (tr.); anterior
border triangular (isosceles), anteriormost point of border squared off, curved downward
in profile, anterior border 14.9 (12.0-18.1; n=10)% as long (sag.) as wide (tr.), max
anterior border width (tr.) 38.0 (31.5-42.1; n=7)% of max cranidial width (tr.), anterior
border length 8.6 (7.6-10.7; n=13)% of max cranidial length, distal ends of anterior
border curve posteriorly, in anterior view weakly ‘M’-shaped ventral edge, dorsal edge
smoothly curved, anterolateral edges of anterior border roughly line up with anterior
portion of facial suture forming apparent continuous flat edge; anterior border furrow
short, uniform in length to slightly longer medially; no preglabellar field; preoccular
fixigenal area short and narrow; eyes large and “C”-shaped; palpebral lobe uniform in
width on anterior portion of eye (_- _), slightly narrower to pointed posterior termination,
posterior termination hooked slightly posterolaterally in dorsal view, in lateral view
posterior termination narrower and declines sharply to postoccular fixigenal field,
anterior termination inclines sharply downward to preoccular fixigenal field, width of
palpebral lobe (taken palpebral lobe’s point of greatest curvature: _) 11.8 (8.7-14.8;
n=11)% of max distance across eye (_- _), max distance across eye (_- _) 58.6 (52.664.8; n=10)% of max cranidial length, width of palpebral lobe 4.4 (3.8-5.3; n=7)% of
max cranidial width; palpebral furrow distinct, uniform width, deepest near posterior
termination of palpebral lobe; interoccular fixigenal area below elevation of glabella,
declines smoothly; postoccular fixigenal area declines ventrally sharply abaxially to
palpebral lobe; width across anteriormost point of eyes (_) 57.8 (53.3-63.4; n=6)% of
width across posteriormost point of eyes (_); posterior border longest abaxially, medial
posterior border length 47.5 (36.2-55.6; n=6)% of max posterior border length (exsag.),
border appears to insert under posterior corner of L0; posterior border furrow shallow and
74
long abaxially, shorter and deeper adaxially; L0 long, max L0 length 23.7 (20.4-25.4;
n=10)% of max L0 width, max L0 length 16.2 (13.9-18; n=13)% of max cranidial length
(sag.), max L0 width 47.8 (46.2-49.5; n=4)% of max cranidial width, posterior edge
slightly lunate, anterior edge weak ‘w’-shape, small node near middle point of anterior
edge of L0; S0 shallowest medially, deepens abaxially, mirrors weak ‘w’-shape of
anterior edge of L0, does not intersect axial furrow; glabella is weakly tapered, parallelsided to weakly trapezoidal, max glabellar width approximately 100 (90.9-108.6; n=16)%
of medial glabellar length (sag); medial glabellar length (sag) 66.1(62.8-68.8; n=13)% of
max cranidial length, max glabellar width 45.1 (38.1-49.5; n=8)% of max cranidial width,
anterior edge of glabella perpendicular to sagittal line with a slight indentation medially,
glabella overhangs preglabellar furrow slightly save at anterior indentation; axially
furrows deepen anteriorly, form 4.8 (3.5-7; n=16)° angle with sagittal line; glabellar
furrows never continuous to axial furrow; S1 two distinct straight to slightly curved
furrows, variable in length, longest portion can be either medial or distal edge, often
connected medially by a long shallow furrow perpendicular to sag. line, anterolateral
portion forms 68.4 (61.2-73.9; n=16)° angle with sagittal line; S2 shallower than S1,
nearly parallel to anterolateral portion of S1; S3 very weak, roughly horizontal, convex
anteriorly, inset from axial furrow.
Librigena with large eye set close to lateral border; slight wrinkled sculpture to
librigenal field; eye length (_ to _) slightly over one third of max librigenal length (tip of
librigenal spine to _; value estimated using specimen in figure A21.17), eye length 66.6
(62.7-71.2; n=9)% of max distance along librigenal field (inner edge of genal corner to
_); eye socle low even rim; anterior branch of facial suture short and linear, slightly
longer than shortest eye-to-lateral-border distance; shortest distance between eye and
lateral border is one quarter of eye’s length from anterior branch of facial suture;
librigenal field wider posterior, slopes downward; posterior branch of facial suture
weakly sinuous from eye to intersection with posterior border furrow, facial suture linear
75
and posteriorly directed across posterior border; distance along anterior branch of facial
suture 40.6 (35.4-48.8; n=9)% of distance along posterior branch of facial suture
(excluding distance across posterior border); posterior border furrow shallow and broad,
longer adaxially; posterior border wider adaxially, weak striations present posteriorly,
posteromedial corner acute and flared out; lateral border rounded with subparallel
striations for entire length, widest medially; lateral border furrow poorly defined
posteriorly; lateral border width at _ 20.8 (16.0-22.3; n=9)% of eye length; librigenal
spine conical, straight and tapered, striations more dense than on lateral border; doublure
striated and rounded, along lateral border corresponds in width in thickness, along
posterior border doublure tapers slightly adaxially
Pygidium elliptical; sagittal length 46.2 (43.5-47.8; n=5)% of max width; axis
semicircular in anterior view, highly convex, max axial length 93.5 (88.6-99.4; n=5)% of
max axial width, max axial length 81.2 (77.4-84.3; n=5)% of sag pygidial length, max
axial width 40.3 (36.8-42.3; n=6)% of max pygidial width; articulating half-ring lunate,
near horizontal in lateral view, articulating half-ring 14.6 (9.2-18.7; n=5)% of max
pygidial length, separated from axis by uniformly deep and wide furrow; axis comprised
of two well-defined axial rings plus terminal axial piece of two poorly defined rings; axis
defined by axial furrow which are shallower posteriorly, axial furrows form a 17.9 (14.420.5; n=6)° with sag. line; anteriormost axial ring widest of axial rings, anterior margin
straight, posterior margin bowed anteriorly at pseudo-articulating half-ring; inter-ring
furrow between first and second rings deep exsag., shallow and wide medially forming
pseudo-articulating half-ring; terminal axial piece longer than either of axial rings, weak
medial low spot manifestation of incipient inter-ring furrow; distance between axis and
posterior border short; pleural field with poorly defined pleura; pleural furrows weak and
shallow, two defined anteriorly; one interpleural furrow occasionally visible in larger
specimens; at anterior margin site of ring socket set slightly lower than pleural field,
socket elliptical; posterior border poorly defined by shallow posterior border furrow,
76
border covered with subparallel striations, border flattened slightly dorsally and rounded
ventrally as doublure; doublure longest exsag, shortest medially; in posterior view ventral
edge of pygidium arched upward medially in weak upside-down ‘v’ shape.
Ontogeny.—Small specimens from Two Mile Canyon were illustrated for
comparative purposes. Beginning with Longacre (1970) many workers relied on the
nature of the S1 glabellar furrow to tell apart the three recognized species of Drumaspis.
The couple of specimens (all from one sample) from Two Mile Canyon suggest that the
development of the glabellar furrows is variable during ontogeny. Whether or not the
two specimens from Two Mile Canyon are conspecific is moot—the point is that the
depth of the glabellar furrows can vary through ontogeny. This would compromise its
utility, and confirm Westrop’s (1986a) suggestion that it is a poor basis for species
delimitation. Two immature cranidial fragments from Franklin Basin are
illustrated—one (figure A18.8) overlain (at the same magnification) over a greyed out
image of a complete immature cranidium from Two Mile Canyon for comparison. It
should be noted that though the shape is identical, the expression of the glabellar furrows
differs markedly.
Few meaningful trends can be commented upon with such a dearth of material.
The position of the posteriormost edge of the palpebral lobe varies between specimens
from Two Mile Canyon and Franklin Basin (compare figures A18.4, 6, 11). Through
ontogeny, both the anterior border and the occipital node become smaller relative to the
rest of the cranidium—trends also observed in another immature Drumaspis cranidium
illustrated from eastern Alaska (Palmer, 1968; his plate 13.4).
Holotype.—U.S.N.M. no. 108670a from the Upper Cambrian St. Charles
Formation, Two Mile Canyon, Idaho (by original designation). The holotype cannot be
located in the U.S.N.M. collections (see Westrop, 1986a).
Figured material.—Twenty-seven cranidia (SUI 00000-00000), sixteen librigenae
(SUI 00000-00000), eight pygidia (SUI 00000-00000).
77
Occurrence.—Horizons 9.6, 10.1-10.2, 10.6-10.72, and 11.2-11.3m of the Upper
Cambrian (lower Sunwaptan) St. Charles Formation at Franklin Basin, Idaho. Possibly
conspecific juvenile material illustrated from Two Mile Canyon, Idaho (TMC SCO
1.015; figure A17.1-7) as well as a teratological pygidium from Two Mile Canyon, Idaho
(TMC SC2 3.957; figures A20.21-22, 26-29).
Discussion.—See above discussion on the Drumaspis species group. The
pygidium figured in figures A22.21, 22, 26-29 from Two Mile Canyon is deformed on
the left side—segmentation appears disrupted on the left side resulting in partial release
forward of a thoracic segment from the pygidium.
Drumaspis sp.
Figure A20.24-26, 29-30
Figured material.—Two partial cranidia (SUI 00000-00000).
Occurrence.—Horizon 10.1-10.2 m of the Upper Cambrian (lower Sunwaptan) St.
Charles Formation at Franklin Basin, Idaho.
Discussion.—The apparently longer and narrower glabellae of these two
specimens warranted their separation from D. af D. walcotti.
Family DOKIMOCEPHALIDAE Kobayashi, 1935a
Dokimocephalidid sp.
Figures A14.13-16
Description.—Cranidium densely granulose; anterior border rounded in lateral
view, covered with striations, arched dorsally in anterior view, anterior border 10.5 (n=1)
of max cranidial length; anterior border furrow short, uniformly deep; preglabellar field
short, steeply declined, preglabellar field 7.3% (n=1) of max cranidial length; axial
furrows and preglabellar furrow confluent and uniform in depth; glabella anteriorly
tapered, bullet-shaped, 90.5% as wide as long (n=1), max glabellar length 61.4% (n=1) of
max cranidial length; glabellar furrows not continuous across glabella, not confluent with
78
axial furrows, angled ≈50* anteriorly from sagittal line; S1 distinct, strongest glabellar
furrow; S2 narrower than S1, S3 faint; occipital ring longest medially, narrows abaxially,
max length 15.8% (n=1) of max cranidial length; palpebral lobes granulose, defined by
palpebral furrow.
Figured material.—One cranidium (SUI 00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.— The affinities of this cranidial fragment are difficult to establish
based on this one cranidial fragment. Similarity to the genera Kindbladia Frederickson,
1948; Berkeia Resser, 1937; Dellea Wilson, 1949 is noted.
Family UNCERTAIN
Genus New Genus B
Type species.—New genus B new species 7 from the lower Sunwaptan trilobitic
member of the St. Charles Formation, Franklin Basin, Idaho.
Diagnosis.—Small trilobite with near-marginal facial suture, small to absent eyes,
pit-like S1 and S2 furrows, librigenae with a wide flat doublure, flat genal fields,
indistinct lateral borders and shove-shaped articulation with medial suture.
Discussion.—This distinctive and diminutive trilobite is of uncertain affinities.
There are a host of diminutive, small-eyed trilobites in the Upper Cambrian, and until
more is known about the morphology of new genus B, each must be considered as a
possible sistergroup. A relationship with the ‘entomaspidids’ (a likely paraphyletic group
of early harpetid trilobites; Entomaspididae Ulrich, in Bridge, 1930) is possible because
of the glabellar similarity between new genus B and, for example, Bowmania Walcott,
1924a. However, this relationship is considered unlikely because all ‘entomaspidids’
have wide, curved anterior borders and distinct lateral librigenal borders—features that
new genus B lacks. A relationship with the Shumardiidae Lake, 1907 is considered
79
unlikely for the following reasons: shumardiids typically have a glabella that is wider
anteriorly and either merges with the preglabellar area (i.e. Oculishumardia Peng et al.,
2003) or anteromedially pointed with a narrow preglabellar furrow separating it from the
preglabellar field (i.e. Shumardia cf. exophthalma Ross, 1967). Among the
ptychaspidids, a close relationship to Idiomesus is another possibility. New genus B has
a suite of characters that are possessed by at least some of the species of Idiomesus; these
include a pointed anterior prow, marginal suture, and librigenae lacking distinct lateral
borders. Additionally, there are several characteristics that most Idiomesus species have
that new genus B lacks: a shallow preglabellar furrow, continuous S1 furrows, notch-like
S2 and S3 furrows.
Alsataspididae Turner, 1940 is herein considered the most likely family to which
new genus B may belong. It shares the two narrow incised glabellar furrows, ocular
ridges, and small to absent palpebral lobes. Skljarella lidiae Petrunina, 1973 is of
particular note—S. lidiae (see Fortey and Owens, 1991) in particular has a very similarly
shaped cranidium to new genus B, and its glabella is less pyriform / lozenge-shaped than
other alsataspidids.
New genus B new species 7
Figures A36.12, 14-28; A37.1-28; A38.1-30;
Diagnosis.—A species of new genus B with a pointed anterior prow, weak alae,
no palpebral lobes and granulose sculpture.
Description.—Cranidium semicircular in outline, covered with small granules;
max length 67.0 (65.6-71.8; n=10)% of max width, max width across ocular inflection on
facial suture 68.9 (65.1-71.7; n=6) of max cranidial width; no anterior border; anterior
margin with prominent medial prow in anterior view, steeply inclined downward
anteriorly, medial length of anterior area 17.3 (14.5-21.0; n=12)% of max cranidial
length; anterior portion of facial suture convex anterolaterally; eye ridges low and
persistent across fixigenal area, in dorsal view ridges swept slightly posteriorly; palpebral
80
lobes absent, facial suture with prominent ocular inflection at lateral edge of eye ridges;
posterior portion of facial suture linear; fixigenal field triangular, inflated posterior to eye
ridges, lowest at baccular area; weak bacculae present in some specimens, lateral to L1;
posterior border furrow deep and long, longest laterally, not continuous to lateral margin,
shallower near axial furrows; posterior border longest near lateral margin, narrowest at
axial furrow, min posterior border length 41.9 (32.6-50.0; n=12)% of max posterior
border length, max posterior border length 15.9 (13.7-18.6; n=10)% of max cranidial
length; occipital ring with lunate rear margin, anterior margin perpendicular to sagittal
line, max occipital length 29.3 (24.7-35.2; n=13)% of max occipital ring width, max
occipital ring length 15.7 (12.4-18.7; n=12)% of max cranidial length, max occipital
width 39.8 (35.0-55.0; n=12)% of max cranidial width, large occipital node located
medially near S0; occipital doublure as long as occipital ring medially, shorter than
abaxially; glabella subquadrate to ovaline, widest near S2, rounded to squared-off
anteriorly, highest elevation on cranidium, max glabellar width 78.1 (63.1-85.0; n=14)%
of max glabellar length, min glabellar width (across L1) 96.2 (88.6-101.4; n=13)% of
max glabellar width, max glabellar width 35.8 (30.8-50.8; n=12)% of max cranidial
width, max glabellar length 63.4 (60.4-68.1; n=12)% of max cranidial length, glabellar
granules most distinct medially; S1 narrow, widest medially, pit-like and not confluent
with axial furrows, angled slightly anterolaterally; S2 similar to S1 except narrower; axial
furrows widest posteriorly, narrow groove anteriorly.
Librigena with bare to weakly granulose librigenal field, granules clustered
toward lateral border; roughly elliptical in dorsal view; in lateral view librigenal highly
convex; lateral border slightly sinuous in dorsal view, indistinct from librigenal field,
possesses marginal striations, anterior to librigenal field lateral border flattens and
becomes shovel-shaped at medial suture; short conical genal spine present; facial suture
strongly sinuous in dorsal view, slight depression present in posterior-most inflection of
facial suture curve; doublure flat, widest posterolaterally, shortest anteriorly.
81
Figured material.—Seventeen cranidia (SUI 00000-00000) and six librigenae
(SUI 00000-00000).
Occurrence.—Horizons 9.6, 10.1-10.2, 10.6-10.72, 11.2-11.3m of the Upper
Cambrian (lower Sunwaptan) St. Charles Formation at Franklin Basin, Idaho.
Discussion.—See the above generic discussion.
new genus B? new species D
Figures A15.2-3, 5-6, 8-9, 12-14
Description.—Cranidium semicircular in outline; no anterior border; anterior
margin smoothly curved in dorsal and anterior views, at least three striations present
there; max length 69.5 (68.6-70.3; n=2)% of max width; max width across posteriormost
point of palpebral lobe 87.8 (85.7-89.9; n=2)% of max width; eye ridges low and
persistent across fixigenal area, forms a 23.5 (21.8-259; n=3)° posterolaterally with a
transverse line; palpebral lobes linear and thin dorsally, elevated above fixigenal field,
defined by a shallow palpebral furrow which is deeper posteriorly; fixigenal field
triangular in shape, sparse low tubercles present; posterolateral corners rounded; posterior
border furrow deep and long, not continuous to lateral margin, shallower near axial
furrows; posterior border rounded, longest near lateral margin, narrowest at axial furrow;
occipital ring lunate, equal in elevation to glabella, max occipital ring length 28.5 (25.233.0; n=3)% of max occipital ring width, max occipital ring length 14.3 (13.1-15.5;
n=2)% of max cranidial length; max occipital width 33.0 (32.3-33.8; n=2)% of max
cranidial width, almost entire occipital ring covered by doublure ventrally; glabella
highest elevation of cranidium, rounded anterior profile, subparallel lateral sides, widest
at S2, max glabellar width 73.7 (71.3-76.0; n=2)% of max glabellar length; max glabellar
width 35.3 (35.0-35.5; n=2)% of max cranidial width; max glabellar length 69.0 (66.471.7; n=2)% of max cranidial length; rounded anterior margin; S1 strong notches,
directed posteromedially from axial furrow; S2 weaker than S1, horizontal in orientation.
Figured material.—Three cranidia (SUI 00000-00000).
82
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—Known from few specimens, the affinities of this trilobite are hard
to discern. Though it lacks the prominent anterior prow of new genus B new species
7and has small palpebral lobes, its general shape and narrow glabellar furrows suggest
that it may be another species of new genus B.
Genus MALADIA Walcott, 1924a
Types species.— Maladia americana Walcott, 1924a, from the Upper Cambrian
(Sunwaptan) St. Charles Formation (Walcott’s Ovid Formation, see Ulrich and Cooper,
1938), Idaho, USA.
Diagnosis.—A trilobite with a subquadrate glabella, steeply sloping anterior
border, anterior border highly convex, glabellar furrows weak, eyes large and
semicircular with weak to absent palpebral furrows, librigenae with striated lateral
borders, lateral borders round in section, pygidia with distinctive recumbent ‘rolled’
borders, weak pleural furrows.
Species included.—Maladia americana Walcott, 1924a; M. carinata (Rasetti,
1945); M. n. sp. 8; and M. n. sp. 9. M. carinata was originally described as being a new
genus, Resseraspis Rasetti, 1945, which is herein suppressed as a junior subjective
synonym of Maladia.
Discussion.—The higher-level affinities of Maladia have been unclear since
Walcott first named it. The general consensus was that it represented an early eurekiid.
This assessment was largely based on the shape of the cranidium and the spinose
pygidium assigned by Walcott to M. americana (previously the only known species).
New material from Franklin Basin, however, suggests that Walcott’s pygidial assignment
was incorrect. Instead of a spinose pygidium, Maladia possesses a distinctive pygidium
with a recumbent posterior border. This new association itself poses several problems
83
that must be discussed with before affinities can be discussed: how was the cranidial /
pygidial association discerned, why haven’t recumbent borders been identified before,
and how does a recumbent border develop?
Two new species of Maladia co-occur in the Franklin Basin horizons, one of
which, M. n. sp. 8 is one of the more abundant trilobites. The Maladia-type cranidia
belonging to M. n. sp. 8 consistently co-occur with recumbent-border pygidia in
comparable abundances. Both the cranidia and pygidia have thick cuticles and are of
similar sizes. Furthermore, the second species of Maladia, M. n. sp. 9, is completely
absent (or nearly so) from some horizons where M. n. sp. 8 is very common. Few
examples of recumbent borders are present in the literature—an odd observation when it
is noted that three separate tails with recumbent borders were identified in this study (P.
n. sp. 3, M. n. sp. 8, and M. n. sp. 9). It is likely that the silicified preservation allowed
for the recover of the recumbent tail morphology. Very few Upper Cambrian silicified
faunas are known (e.g. Adrain and Westrop, 2004; Ludvigsen, 1982); leaving few
opportunities to potentially recover this morphology. Furthermore, when recumbent tails
were isolated in crackout material, the border inevitably broke off (figures A13.1-2;
A31.28; A32.10). This would suggest that other species with pygidia possessing
recumbent borders are out there, they are difficult to identify as such. Indeed, one other
such tail has been identified and correctly assigned, belonging to M. carinata. The
recumbent border is a very distinctive morphology; understanding how it forms is critical
for understanding the higher-level systematic affinities of Maladia. Unfortunately, no
ontogenetic material belonging to Maladia has been identified from Franklin Basin, so
this question will remain unanswered for the time being.
The higher-level affinities of Maladia are unclear. A close relationship with
eurekiids is now unlikely given the new tail assignment. The cranidia of Maladia are
similar in shape and convexity to both Tatonaspis Kobayashi, 1935a and to Yukonaspis
Kobayashi, 1936. Though assigned to separate families in Jell and Adrain (2003;
84
Tatonaspis in the Illaenuridae Vogdes, 1890 and Yukonaspis in the Catillicephalidae
Raymond, 1938), Tatonaspis and Yukonaspis have a previously unappreciated level of
cranidial similarity; both have large, inflated, rectangular glabellae; large, flap-like
palpebral lobes; divergent anterior facial suture branches; and short, convex anterior
borders which are nearly overhung by the glabella. All of these features are also
possessed by Maladia, but how these similarities pertain to the systematic position of
Maladia is not yet clear.
Maladia new species 8
Figures A28.1-23; A29.1-27; A30.1-19; A31.1-28
Diagnosis.—A species of Maladia with a short to absent preglabellar field, very
large eyes, highly convex, anterior border convex with weak ‘m’ shape in anterior view,
weak occipital node, pygidial axis abuts recumbent border, medial notch in pygidial
doublure.
Description.—Highly convex with large, prominent eyes; small diffuse pits over
entire dorsal surface; max cranidial length (sag) 59.8 (56.1-63.8; n=4)% of max cranidial
width (some width measurements are estimates derived from measuring half the
cranidium to a plane of symmetry and doubling the measurement), max cranidial length
(sag.) 83.7 (76.0-91.9; n=13)% of max width across palpebral lobes; anterior border
longest medially, max anterior border length 14.6 (11.1-18.3; n=9)% of max anterior
border width, max anterior border length 10.1 (7.5-13.0; n=11)% of max cranidial length,
max anterior border width 57.8 (53.0-65.4; n=10)% of max width between palpebral
lobes, tapers anteriorly, anterior border narrower or equal in width to max glabellar width
(tr.), lunate in anterior view with slight ‘M’ shape to the ventral edge; preglabellar field
short in anterior view, absent in dorsal view, preglabellar field not overhung by glabella
in lateral profile; anterior portion of facial suture (_- _) bowed laterally slightly, weakly
divergent in front of eyes, weakly convergent proximal to anterior border, anterior
portion of facial suture 38.6 (34.3-44.8; n=11)% of max cranidial length; preoccular area
85
narrow posteriorly, widest anteriorly, width across anterior border less than that across
anterior edge of eyes _, _ laterally equivalent to slightly in front of anterior edge of
glabella, width across _ 87.4 (84.6-90.9; n=11)% of width across _, width across _ 68.2
(64.9-74.1; n=11)% of width across palpebral lobes; palpebral lobes large half-circles, _
roughly laterally equivalent to S1, _ set posterior to midpoint of line connecting _- _, max
eye length (_- _) 40.5 (33.5-45.5; n=13)% of max cranidial length, palpebral furrow
manifest as slight increase in elevation abaxially with curvature less exaggerated than on
palpebral suture, palpebral lobe flat not bulbous in profile, width of palpebral lobe at _
26.1 (21.1-32.2; n=13)% of max eye length (_- _), width of palpebral lobe at _ 8.8 (7.011.1; n=13)% of max width across palpebral lobes; elevation of fixigenal field sharply
lower posterior to palpebral lobe, course of posterior portion of facial suture roughly
perpendicular to sagittal line, posterior portion of facial suture 99.7 (86.9-107.4; n=3)%
of anterior portion of facial suture; posterior border slightly longer midway between axial
furrow and distal-most point, posterior border narrower at axial furrow, appears to insert
behind occipital ring; occipital ring longest medially, 16.6 (14.5-19.0; n=13)% of max
cranidial length, max occipital ring length 22.5 (21.5-24.3; n=7)% of max occipital ring
width, max occipital ring width 63.4 (58.3-68.5; n=7)% of max width between palpebral
lobes, occipital ring margin convex posteriorly, weak medial tubercle present nearer to S0
than to posterior margin; occipital doublure lunate with weak striations; S0 perpendicular
to sagittal line medially, curved sharply anteriorly at point roughly equivalent to anterior
corner of glabella, at inflection S0 bifurcates slightly to posterior, bifurcated branch
terminates less than halfway across occipital ring (exsag); glabella broad and
subrectangular, widest at S0, max glabellar width 95.8 (89.5-102.6; n=12)% of max
glabellar length (sag), max glabellar width 58.8 (52.2-67.8; n=12)% of max width
between palpebral lobes, max glabellar length 73.7 (70.9-76.0; n=13)% of max cranidial
length, smoothly rounded in profile, S1 weakly manifest, S2 and S3 only visible in some
86
specimens; axial furrows uniform in depth and width, form 8.9 (5.5-11, n=13)° with
sagittal line, equal in depth and width to preglabellar furrow.
Librigena highly convex; eye long with distinct eye socle, length across eye 39.0
(35.7-43.0; n=4)% of linear distance between _ and intersection of lateral border furrow
with anterior portion of facial suture, facial suture branches nearly linear along librigenal
field, posterior portion of facial suture bent slightly anteriorly at posterior edge of eye,
bent sharply at intersection with border furrows, anterior portion of facial suture (from
eye to intersection with border furrow) 57.2 (54.7-60.4; n=4)% of linear distance along
posterior portion of facial suture (posterior edge of eye to _), length of anterior portion of
facial suture (from eye to intersection with border furrow) 34.7 (24.9-38.0; n=8)% of
linear distance between _ and intersection of lateral border furrow with anterior portion
of facial suture, posterior portion of facial suture 63.0 (62.0-64.8; n=4)% of linear
distance between _ and intersection of lateral border furrow with anterior portion of facial
suture; lateral border furrow deepest anteriorly, shallower posteriorly; posterior border
furrow weak; lateral border rounded and narrow anteriorly, flattened and wide
posteriorly, covered with subparallel striations, lateral border width at _ 10.9 (8.9-13.4;
n=8)% of linear distance between _ and intersection of lateral border furrow with
anterior portion of facial suture; librigenal corner weakly delineated from librigenal field,
short to moderately sized genal spine present; posterior border flat; posterior border
doublure shorter than posterior border; lateral border doublure approximately equal in
width to lateral border, striations on doublure curve around genal corner.
Pygidium semicircular, max length 52.7 (50.4-58.0; n=5)% of max width; anterior
margin of pleural field deflected slightly anterolaterally; articulating socket prominent,
set lower than pleural field; axis short and convex, max axial length 86.6 (83.0-93.9;
n=5)% of max axial width, max axial length 66.7 (63.5-69.3; n=5)% of max pygidial
length, max axial width 40.5 (39.4-41.7; n=6)% of max pygidial width, two distinct axial
rings present plus terminal axial piece each with weak striations, articulating half-ring
87
short and convex in lateral view; first (anteriormost) axial ring wider laterally, rounded in
lateral view, bounded by pseudo-articulating half-ring posteriorly; second axial ring
uniform in length; terminal axial piece longer than axial rings, occasionally contains
poorly defined axial ring (figure A30.14); axial furrows defined by change in elevation,
form 17.6 (16.9-18.3; n=5)° angle with sagittal line; pleural field low with indistinct
pleurae, deep groove at posterior edge of pleural field obscured by posterior border
(figure A30.28), behind axis postaxial field depressed, confluence of postaxial depression
and marginal groove compresses posteromedial corners of pleural field into short ridges;
posterior border highly convex and covered with dense subparallel striations, border
recumbent over posterior margin of pleural field, interior edge of posterior border ‘s’shaped in cross section (figures A30.24, 27), recumbent aspect of posterior border curved
slightly anteromedially at anterolateral pygidial corners; doublure with slight notch
medially, widest adjacent to posterior edges of axial furrows, tapered anteriorly.
Figured material.—13 silicified cranidia (SUI 00000-00000), one crackout
cranidium (SUI 00000), 15 silicified librigenae (SUI 00000-00000), one crackout
librigena (SUI 00000), one crackout pygidium (SUI 00000), and six silicified pygidia
(SUI 00000-000000).
Occurrence.—Horizons 9.6, 10.1-10.2, 10.6-10.72, and 11.2-11.3m of the Upper
Cambrian (lower Sunwaptan) St. Charles Formation at Franklin Basin, Idaho.
Discussion.—M. n. sp. 8 is much more convex and has a shorter preglabellar field
than any other species of Maladia. Parsing out differences among the librigenae is more
difficult—the librigenae assigned to M. n. sp. 8 here may possibly be a mix of M. n. sp. 8
and M. n. sp. 9 librigenae. A possible injury is present on the left anterior facial suture
branch of the specimen figured on figures A28.1-2, 4-5, 7-8.
Maladia new species 8
Figures A32.1-27
88
Diagnosis.—A species of Maladia with a short preglabellar field, short and
narrow anterior border, weak eye ridges, semicircular pygidium with a short postaxial
ridge connecting the axis to the recumbent posterior border, prominent ventral notch in
doublure continuous with ventral trace of the postaxial ridge.
Description.—Cranidium roughly as wide across palpebral lobes as long (109.8%;
n=1; some width measurements estimated by doubling the measurement over a plane of
symmetry); ventral margin of anterior border nearly straight (figure A32.12) to dorsally
flexed (figures A32.3, 9), weak ‘m’-shape in anterior view (medial apex pointed
ventrally) and in dorsal view (medial apex pointed posteriorly), longest medially, tapered
abaxially, max anterior border length 15.6 (15.3-15.8; n=2)% of max anterior border
width, max anterior border width 57.1% (n=1) of max width between palpebral lobes,
max anterior border length 9.9 (9.6-10.1; n=2)% of max cranidial length; preglabellar
field convex, short; anterior portion of facial (_- _) suture divergent, anterior portion of
facial suture 30.7 (30.4-30.9; n=2)% of max cranidial length; eye ridge weak (figure
A32.7) to absent; eyes large and semicircular, set laterally equivalent to middle of
glabella, palpebral furrow weak but distinct, palpebral lobe lunate, widest medially, max
eye width (at _) 26.5 (25.6-27.5; n=2)% of max distance across eye (_- _), eye length
35.0% (n=1) of max cranidial length, max eye width 8.8% (n=1) of max width across
palpebral lobes; posterior margin of occipital ring convex posteriorly, tapered abaxially,
max occipital ring length 32.8% (n=1) of max occipital ring width, max occipital ring
length 14.4 (12.9-15.8; n=2)% max cranidial length; occipital node small and weak; S0
distinct and straight medially, shallow and anterolaterally curved abaxially; glabella
trapezoidal, tapered anteriorly, widest next to S0, max glabellar length 98.2 (97.8-98.6;
n=2)% of max glabellar width, max glabellar length 67.4 (65.4-69.4; n=2)% of max
cranidial length, max glabellar width 60.4% (n=1) of max width across palpebral lobes;
S1 and S2 weak when visible, form ≈47° angle with sagittal line (figure A32.2); axial
89
furrows uniform, wider than preglabellar furrow, axial furrow forms 9.2 (8.5-9.7; N=3)°
angle with sagittal line.
Pygidium semicircular to subtriangular, max length 62.3 (61.4-63.0; n=4)% of
max width; anterolateral margin directed slightly anterolaterally from perpendicular to
sagittal line; prominent articulating socket present at anterior edge of axial furrow;
articulating half ring semicircular, tapered distally, sloped slightly anteroventrally in
lateral view; axis wide with prominent but narrow postaxial ridge, max axial width 80.4
(77.3-88.1; n=5)% of max axial length (including articulating half-ring), max axial length
76.5 (74.5-81.8; n=5)% of max pygidial length, max axial width 38.0 (36.1-40.4; n=4)%
of max pygidial width; two to three distinct axial rings with dorsal striations;
anteriormost ring short medially, longer abaxially, bounded posteriorly by pseudoarticulating half-ring; second axial ring (from anteriormost ring) with incipient pseudoarticulating half-ring posteriorly; third axial ring weakly separated from terminal axial
piece by shallow axial furrow; terminal axial piece broad with weak furrow separating
third and forth axial rings, fourth axial ring divided into two lobes by the insertion of the
postaxial ridge; axial furrows defined by change in elevation between pleural field and
axis, form 10.3 (7.5-12.0; n=5)° angle with sagittal line; postaxial ridge narrow, equal in
elevation to posterior border; posterior border high and covered with dense subparallel
striations, max length of the posterior border 13.2 (11.3-14.5; n=5)% of max pygidial
length, border recumbent over edge of pleural field save at postaxial ridge and at
anterolateral pygidial corners, recumbent portion of posterior border curved slightly
anteromedially at anterior corners, doublure and border together form rounded tube-like
border; doublure longest exsagittally, medial indentation in doublure continuous with
ventral trace of postaxial ridge; pleural field low with indistinct pleurae, posterior edge of
pleural field has low groove which posterior border fits into (figure A32.10).
Figured material.—Three silicified cranidia (SUI 00000-00000), two crackout
cranidia (SUI 00000-00000), and six pygidia (SUI 00000-00000).
90
Occurrence.—Horizons 10.1-10,2, 10.6-10.72, and 11.2-11.3m of the Upper
Cambrian (lower Sunwaptan) St. Charles Formation at Franklin Basin, Idaho.
Discussion.—M. n. sp. 9 is most similar to M. carinata. Both possess weak
glabellar furrows, short preglabellar fields, and thin postaxial ridges on the pygidia. The
proportions of each are also similar to the cranidium assigned to M. americana by
Walcott; M. americana differs from them in possessing thin, distinct ocular ridges.
Unassigned sclerites
Unassigned cranidium type A
Figures A14.1-2
Description.—Cranidium with weakly striated surface; weak occipital node;
palpebral lobes abut glabella; flap-like, eyes asymmetrical in shape, widest lateral to S1;
palpebral furrow weak, glabella tapered with weak S1.
Figured material.—One cranidium (SUI 00000).
Occurrence.—Horizon 10.1-10.2m of the Upper Cambrian (lower Sunwaptan) St.
Charles Formation at Franklin Basin, Idaho.
Discussion.—This cranidial fragment is very difficult to assess; superficially, it
bears some resemblance to Monocheilus or Bayfieldia.
Unassigned pygidia type A
Figures A14.19-20, 23-25
Description.—Pygidium circular; axis small, estimated to comprise less than one
third of the dorsal surface area, roughly half as long (excluding postaxial ridge) as max
pygidial length, tapers posteriorly, three axial rings visible, gradually weaker in
expression posteriorly, axis strongly elevated from pleural field; postaxial ridge steeply
elevated from pleural field, arched slightly ventrally; pleura weakly expressed only
immediately adjacent to axis, pleural field broad with terrace ridge, pleural fields slope
downward away from axis; pleural margin with three weak nodes; doublure broad.
91
Figured material.—Two pygidia (SUI 00000-00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—Pygidia that have both postaxial ridges and few axial rings are not
common in the Upper Cambrian. The tail discussed here is nearly identical to ones
illustrated as belonging to Drumaspis texana Resser, 1942 and D. deckeri Resser, 1942
by Bell and Ellinwood (1962). However, as articulated specimens of other species
belonging to the Elviniidae have been described (e.g. Chatterton and Ludvigsen, 1998), it
becomes more and more likely that those pygidia were misattributed to
Drumaspis—belonging instead to another species (tails assigned therein to Taenicephalus
appear likely). The cranidia-pygidia association attributed to Drumaspis herein is
supported not only by morphological evidence from other articulated elviniids, but also
by shear abundance—both heads and tails are numerous and co-occurring. Ludvigsen et
al., (1989) attributes a similar tail to Pseudosaukia sesostris (Billings, 1865), save that P.
sesostris has a scalloped posterior margin rather than a rounded one. Rasetti (1961)
figured an unassigned pygidium (unidentified pygidium no. 5; his plate 25.16) that
appears very close in character to the one figured herein. Trilobites from Franklin Basin
which lack pygidial association (and are also of a similar size/abundance) include the
new genus A, Taenicephalus sp., and dokimocephalid sp.
Unassigned pygidium type B
Figures A14.21-22, 26-28
Description.— Pygidium with curved posterior margin; prominent striations on
posterior border, distinctly raised from pleural field posterolaterally, merges with pleural
field anterolaterally; posterior border narrower than doublure; pleural field at most two
thirds of max width; pleural field lacks well-defined pleural ribs, prominent striation
radiate from anterolateral corner of pygidium across pleural field, near axis striations
92
parallel axial rings, striations not present posterior to axis; axis with four axial rings, axial
rings defined by lateral striations.
Figured material.—One pygidium (SUI 00000).
Occurrence.—Horizon 10.1-10.2m of the Upper Cambrian (lower Sunwaptan) St.
Charles Formation at Franklin Basin, Idaho.
Discussion.—Striations of this nature are virtually unknown. The tail is most
similar to the unassigned pygidium no. 7 illustrated by Rasetti (1945; his plate 62.29-30).
Because of how the specimen illustrated herein in broken, it is impossible to tell the
precise proportions of the axial width to the max width, but it is at least consistent with
the relatively wide axis possessed by Rasetti’s unassigned pygidium no. 7. Rasetti’s
pygidium, however, is much more convex than the Franklin Basin specimen. A
pygidium figured as belonging to Kendellina? crassitesta Westrop, 1986a has pleural
field striations, but the similarities end there. K? crassitesta is proportionately much
wider, has faintly defined pleural ribs on the pleural field, and a recessed posterior
border. The pygidium is also not entirely dissimilar to that of Plethopeltis acutus
(Rasetti, 1944) figured by Ludvigsen et al. (1989). Unfortunately, none of these
comparisons shed any light on what this pygidium may belong to in the Franklin Basin
fauna.
Unassigned pygidia type C
Figures A15.10, 15-16
Figured material.—Three pygidia (SUI 00000-00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—These three pygidia are too small to describe properly herein. They
all share deep pleural furrows, but are not necessarily conspecific. They may represent
immature representatives of species previously discussed.
93
Unassigned pygidium type D
Figures A27.19-21
Description.—Pygidium highly convex with straight posterior margin in dorsal
view; axis v-shaped with four axial rings; prominent pseudo-articulating half-ring
present; axial furrows weak; pleural field steeply declined posteriorly; interpleural
furrows faint, pleural furrows more distinct than interpleural furrows, both pleural and
interpleural furrows weaken posteriorly and abaxially; posterior margin arched dorsally
in posterior view.
Figured material.—One pygidium (SUI 00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—The affinities of this pygidium are unclear, but it is very similar to
another pygidium illustrated by Adrain and Westrop (2004a; their plate 17.31, 38, 43).
Unassigned pygidium type E
Figure A27.23
Description.—Pygidium semicircular; axis rounded; short articulating and
pseudo-articulating half-rings; four axial rings present; anteriormost interpleural furrow
deep, terminates shy of pygidial margin curving sharply posteriorly, interpleural furrows
weak posteriorly; anteriormost pleural furrow distinct, terminates shy of pygidial margin
in small pit, pleural furrow fade posteriorly; pygidial margin with striations.
Figured material.—One pygidium (SUI 00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—The rarity and fragmentary nature of the specimen prevents detailed
comparisons. It is at least broadly similar to a pygidium belonging to Taenicephalina
glabra Ludvigsen and Westrop in Ludvigsen et al., 1989 (his plate 15.3).
94
Unassigned pygidia type F
Figures A27.24-25
Description.—Pygidium elliptical; axis narrow and long; axial rings rectangular
with axial nodes, roughly four discernable axial rings; interpleural furrows deep and long,
end shy of pygidial margin, at least four interpleural furrows visible; pleural furrows
short and deep, persistent to pygidial margin, at least four visible; pleural tips pointed,
curved posteriorly.
Figured material.—Two pygidia (SUI 00000-00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—Both pygidia are obviously not from mature individuals, but neither
clearly belongs to any other identified species from Franklin Basin. Closest comparison
may be with Triarthropsis—pygidia illustrated by Rasetti (1959) share a conical-shaped
axis and distinct pleural and interpleural furrows with the specimens illustrated herein.
Unassigned pygidia type G
Figures A14.3-12, 17-18
Description.—Pygidium elliptical; possesses four pairs of short round marginal
spines and one small medial spine, spines decrease in size medially, have striations
leading to tips, trend poserolaterally, curved slightly posteriorly; pleural furrows deep and
wide, terminate shy of spine tip; interpleural furrows thin, strongest distally; distinct
rounded axis with two axial rings, axis parallel-sided; posterior ring longest (terminal
axial piece), terminal axial piece almost divided into two lateral lobes (figure A14.12);
articulating half-ring as long as axial rings; pseudo-articulating half-ring wide and
distinct; fulcrum set near axis (figure A14.9); doublure striated, medially as long as
postaxial field.
Figured material.—Six pygidia (SUI 00000-00000).
95
Occurrence.—Horizons 9.6, 10.1-10.2, and 10.6-10.72m of the Upper Cambrian
(lower Sunwaptan) St. Charles Formation at Franklin Basin, Idaho.
Discussion.—The affinities of these pygidia are unclear. Comparisons can be
made with eurekiids with regards to the elliptical shape, short axis, and short marginal
spines. However, most eurekiids have two axial rings and axes that extend much closer
to the spinose pygidial margin. Without a cranidial association, little more can be said
about the affinities of these pygidia.
Unassigned librigenae type A
Figure A15.7
Figured material.—One librigena (SUI 00000).
Occurrence.—Horizon 10.1-10.2m of the Upper Cambrian (lower Sunwaptan) St.
Charles Formation at Franklin Basin, Idaho.
Discussion.—This fragment is likely a part of a librigena belonging to as yet
unidentified (or unassigned) trilobite, though an identity as a broken tip of a thoracic
segment cannot be ruled out. Comparison can be made with a librigena illustrated as
Symphysurina sp. indet, by Westrop (1986a; his plate 32.13), though no nileid trilobites
were observed in material from the Franklin Basin locality.
Unassigned librigena type B
Figures A15.13, 17, 19-20, 22-24
Description.—Librigena with quarter-circle librigenal field; lateral border low,
rounded in lateral view; lateral border furrow weak, absent at genal corner; distance along
anterior portion of facial suture roughly equal to distance along posterior portion;
posterior border of librigena juts out in sharp point; posterior border furrow narrow; genal
spine straight, appears to originate from posterolateral corner of librigenal field and
extend over posterior border producing a slight swelling of posterolateral corner of
librigenal field (figure A13.19); eye small, highly curved.
96
Figured material.—Three librigena (SUI 00000-00000).
Occurrence.—Horizons 9.6 and 10.6-10.72m of the Upper Cambrian (lower
Sunwaptan) St. Charles Formation at Franklin Basin, Idaho.
Discussion.—Librigenae type B may actually represent two species. The
specimen from 9.6m (figure A15.13) has a much larger eye and the angle formed
between the posterior border and the posterior portion of the facial suture is much more
obtuse any of the specimens from 10.6-10.72m (figures A15.17, 19-20, 22-24).
However, the lone specimen from horizon 9.6m is also the smaller of the specimens, so
ontogenetic change cannot be ruled out as a cause of the differences. The overall shape
and origin of the genal spine high on the lateral border is similar to the librigenae
illustrated by Ludvigsen (1982) as belonging to Yukonaspis sp.
Unassigned hypostomes and thoracic segments
Figures A39.1-13; A40.1-22
Figured material.—Six silicified thoracic segments (SUI 00000-00000) and
fourteen silicified hypostomes (SUI 00000-00000; one partial etched).
Occurrence.—Horizons 9.6, 10.1-10.2, and 10.6-10.72m of the Upper Cambrian
(lower Sunwaptan) St. Charles Formation at Franklin Basin, Idaho.
Discussion.—There is a dearth of truly reliable hypostome and thoracic segment
associations in the Upper Cambrian—little can be added here aside from the
documentation of additional hypostomal types. The size of the hypostome illustrated in
figures A39.1-4 makes it likely that it belongs to one of the larger taxa described
herein—Wilbernia or Idahoia. A hypostome attributed to Wilbernia pero by Westrop
(1986) is very similar to the illustrated here in its subquadrate posterior
margin—increasing the circumstantial evidence for its assignment to Wilbernia n. sp. 4.
Hypostomes that have been attributed to Ptychaspis (illustrated by Lochman and Hu,
1959 and Westrop, 1986) are characterized by distinct and long middle furrows
97
subparallel to the sagittally plane. By those criteria, it is unlikely that any of the
hypostomes illustrated herein belong to Ptychaspis n. sp. 3. Unassigned hypostomes
illustrated by Ludvigsen and Westrop (1983b) are similar to several illustrated here
(figures A40.1, 2, 4, 5, 8, 13, 17, 18). This, unfortunately, does not help narrow down
possible taxic associations any, as three subfamilies and one genus are in common
between the two study localities (Dokimocephalinae, Elviniinae, Ptychaspidinae, and
Saratogia).
The thoracic segments with short axial spines (figures A40. 3, 6, 9, 10, 12, 14, 16)
are most distinctive of those illustrated and could be conspecific. They would most
plausibly belong to a taxon with spines either on its occipital ring or axial ring—making
Saratogia and Idahoia plausible candidates. Thoracic segments are well known for
several species of elviniid (Chatterton and Ludvigsen, 1998)—segments figured in
figures A40. 11 and 21 could conceivably belong to the elviniid present in the St. Charles
(Drumaspis).
Unassigned meraspid trilobite
Figures A33.13, 15
Figured material.—One cranidium (SUI 00000) attached to the underside of a
Naustia n. sp. 5 cranidium (SUI 00000).
Occurrence.—Horizon 10.6-10.72m of the Upper Cambrian (lower Sunwaptan)
St. Charles Formation at Franklin Basin, Idaho.
Discussion.—Cambrian trilobite ontogenies remain poorly known. The quality of
the photograph of this particular specimen was restricted by its location—attached to the
underside of a Naustia n. sp. 5 cranidium amongst other silicified debris. Little can be
said about it other than it has a tapered glabella and is relatively low in convexity. In
those regards, it resembles specimens illustrated by Hu as Parabolinoides moustonus Hu,
1970 (Hu, 1986; his plate 19.11-12; a parabolinoidid), Apomodocia conica Hu, 1971 (Hu,
98
1971; his plate 9.9-11; a parabolinoidid), and Housia ovata, Palmer 1965 (Hu, 1980; his
plate 45.13; a pterocephaliid). The suggestion of parabolinoidid affinities is consistent
with the presence of at least two species of parabolinoidids represented in the material
from Franklin Basin: Taenicephalus sp. and the new genus A and new species 6.
99
CONCLUSIONS
This project has added new information on several fronts to our knowledge of
Cambrian trilobites and their evolution. This study documented the occurrence of about
twenty-three species (at least eight of which are new) belonging to nineteen genera (at
least two of which are new). This contrasts with the fourteen species belonging to ten
genera documented by Lochman and Hu (1959) in their study of trilobites from a
different locality of the St. Charles Formation. Of those, only two species and seven of
the genera are common to both faunas. This comparison only serves to reinforce the
somewhat trivial conclusion that there is still much to be learned from further studies of
previously studied formations in the Great Basin.
Recovery of three-dimensional, silicified remains has the potential to contribute
much to our understanding of trilobite evolution. The very unique pygidia belonging to
Maladia, documented here for the first time, suggest that previous assessments of
Maladia as a member of the Eurekiidae were incorrect. What Maladia will eventually
prove to be is not yet clear—but complete, detailed morphological documentation of its
morphology will only aid in this endeavor.
The ptychaspidid phylogeny presented here suggests, if only tentatively, some
provocative ideas about the evolution of the Ptychaspididae. Chief among these is the
paraphyly of the Ptychaspidinae—its traditional membership encompassing instead a
stem group to the Euptychaspidinae and the Macronodinae. Additionally, the suggestion
of another subfamily-level clade within the Ptychaspididae is novel, and will require
further evaluation involving the restudy of several poorly known North American and
Asian species.
Lastly, the abundance data for all of the sampled horizons give us reason to think
carefully about our sampling methods and how they affect our picture of diversity. In
particular, when collections of trilobites derived from the same horizon (sampled by both
100
crackout and acid digestion) were compared, the correlations between them were not as
striking as one may have supposed. In fact, half showed no significant correlation of the
relative diversity between the crackout and silicified samples derived from the same
horizon. This suggests that the sampling method utilized may exhibit a significant
control on the observed relative abundance.
101
APPENDIX A
FIGURES AND PHOTOGRAPHIC PLATES
102
Figure A1: Correlation chart.
Trilobite zonation follows Shergold and Geyer (2003) with a modification to their
Ellipsocephaloides zone following Westrop (1986) and to their series and stage
nomenclature following Miller et al. (2006). Approximate correlation of biomere
boundaries and the old North American state nomenclature drawn from Hintze (1973)
and Palmer (1979).
103
104
Figure A2: Locality maps.
1. Regional map of northern Utah-southern Idaho with white boxes representing
the two localities where samples were derived from. Mountain ranges shown in grey.
2. Topographic map showing where the talus collections from Two Mile Canyon
(TMC) were derived from.
3. Topographic map showing where the measured section of the St. Charles
Formation in Franklin Basin (FBSC) was located.
105
106
Figure A3: Stratigraphic column and rock samples.
Hand samples are in stratigraphic order with depositional ‘up’ corresponding to
up on the page. Lower case letters used to denote close up photos of hand samples.
Hand samples at x.4.28; close up hand sample images at x.856. Solid lines indicate likely
stylolites; dashed lines encircle other structures of interest (flat pebbles, truncated
bioclasts).
1. Stratigraphic column with key. Sampled horizons are marked with asterisks
and labeled. Section measured by J. M. Adrain, E. Landing, and S. R. Westrop.
2. Polished hand sample from 11.2-11.3 m showing lithofacies 3. Images (a) and
(b) show possible stylolites with likely clay seams. They also correspond to cracks in the
rock. Image (c) shows a truncated bioclast on an indistinct stylolite.
3. Polished hand sample from 10.6-10.72 m showing lithofacies 2. Images (d)
and (e) show stylolites truncating flat pebbles on upper and lower surfaces.
4. Polished hand sample from 10.1-10.2 m showing lithofacies 2 and 3. Image
(f) shows the orientation of the bioclasts in lithofacies 3. Images (g) and (h) show the
boundary (possibly erosional) between lithofacies 2 and 3 with possible pebble
truncation.
5. Bisected hand sample from 9.6 m showing lithofacies 1. Flat pebbles are
outlined; they show preferential weathering on the weathered right side of the sample.
6. Bisected block from 10.1-10.2 m after acid digestion showing the undigested
core that was prevented from reacting with the HCl by the dense silicification. An acid
test confirmed the presence of calcite in the middle. Image (i) shows the boundary
between acidized and unacidized rock with a faint rusty stain.
107
108
Figure A4: Images from Franklin Basin, Idaho.
Items used for scale: yellow fieldbook (black divisions on the edge are 1 cm
apiece), green pen (15.1 cm), and penny (1.9 cm). All photos taken by the author except
for images A5.4, A5.6, and A5.8 (taken by S. R. Westrop).
1. A photomosaic panoramic photograph of Franklin Basin. The photo is taken
looking west from approximately the 7,835 ft elevation mark near the center of the
topographic map in Figure 2c.
2. Silicified burrows, likely referable to Palaeophycus Hall, 1847 (see Harlick,
1989), present on the weathered bedding surface of a rock from the sucrosic member of
the St. Charles Formation. The black string-like traces associated with the burrow on the
left are of an unknown origin (fecal?).
3. In situ outcrop of the trilobitic member of the St. Charles Formation, looking
approximately east.
4. Silicified ?Palaeophycus burrows present on the weathered bedding surface of
a rock from the sucrosic member of the St. Charles Formation. Note the echinoderm
ossicle present approximately 4 cm from the penny to the right.
5) Talus block of the Worm Creek Quartzite Member of the St. Charles
Formation. Note the hematite staining and the planer and crossbeds.
6. Silicified ?Palaeophycus burrows present on the weathered surface of a rock
from the sucrosic member of the St. Charles Formation.
7. In situ outcrop of the trilobitic member of the St. Charles Formation, facing
approximately south.
8. Silicified ?Palaeophycus burrows present on the weathered bedding surface of
a rock from the sucrosic member of the St. Charles Formation.
109
Figure A4—continued.
9. Silicified ?Palaeophycus burrows present on the weathered bedding surface of
a rock from the sucrosic member of the St. Charles Formation.
110
111
Figure A5: Images displaying the character of the silicification as preserved in silicified
blocks.
Images were all taken from blocks from horizons at Franklin Basin recovered
after reaction with HCl had ceased except for images A5.6 and A5.8, which were etched
with HCl on the surface for a brief period of time. Horizon and magnification are
specified as (horizon; magnification).
1. Large fragment of an anterior border (Wilbernia n. sp. 4) protruding from the
surface (parallel to bedding) of a silica-welded block (10.1-10.2; x2.14).
2. A surface perpendicular to bedding on an insoluble block (10.1-10.2; x2.14).
Note the difference in fragment orientation when compared to bedding-parallel
photographs.
3. A surface parallel to bedding on a welded block (10.1-10.2; x2.14).
Identifiable fragments include a billingsellid brachiopod, indeterminate librigenal
borders, trilobite thoracic fragments, tuberculate plates, and a Drumaspis af. D. walcotti
tail in the lower right.
4. An oblique photograph of a welded block (10.1-10.2; x2.14). A Drumaspis af.
D. walcotti cranidium in exhibited in anterior view in the lower portion of the image.
5. A large Wilbernia n. sp. 4 (?) librigena preserved parallel to bedding on a
welded block (11.2-11.3; x2.14.). The condition of the lateral border suggests incomplete
silicification and subsequent degradation during acid digestion.
6. An etched surface showing the silicified residue emerging from the rock (10.610.72 x3.424). A partial Drumaspis af. D. walcotti cranidium is in the center.
7. An insoluble fragment displaying the orientation of silicified fragments within
the rock (11.2-11.3; x2.14). Three partial Drumaspis af. D. walcotti cranidia are visible.
112
Figure A5—continued.
8. A large tail belonging to Naustia n. sp. 5, in an elevated posterior view, which
was partially etched by HCl (10.1-10.2; x1.5). The condition of the silicified cuticle
(right side) suggests silicification was partial.
113
114
Figure A6: Thin section images of lithic specimens preserved from Franklin Basin. All
images with crossed polarizers.
1. Image of a flat pebble magnified roughly x2 (horizon 9.6 m).
2. Image of a trilobite (?) bioclast with a micritic infilling, a thin rim of quartz (?)
on the lower internal edge, and a thin external micritic envelope (horizon 9.6 m).
3. A more magnified image of a trilobite fragment illustrated in the upper left
corner of image 6 showing small (quartz) crystals growing on the external surface
(horizon 10.1-10.2 m).
4. An unsilicified trilobite fragment with a micritic envelope in calcite cement.
Possible echinoderms also present (horizon 10.1-10.2 m).
5. An unsilicified trilobite fragment showing localized small quartz (?) crystals
on the external surface and small euhedral dolomite rhombs on the right side of the image
(horizon 10.1-10.2 m). The dolomitic areas correspond to the areas of the hand samples
that are orange and fine grained (see fig. A3.2)
6. Trilobite fragments with thin quartz (?) rims and micritic envelopes in a
euhedral dolomite matrix (horizon 10.1-10.2 m).
7. Drusy quartz growing in between and on the surface of trilobite fragments,
showing that the some silicified internal and external molds may have formed as quartz
void fillings (horizon 10.6-10.72 m).
8. Drusy quartz growing on the surface of trilobite (?) bioclastic fragments.
Bioclastic fragments have an unidentified replacement structure (horizon 10.6-10.72 m).
115
116
Figure A7: Pseudagnostus new species 1. Specimens silicified unless otherwise noted.
1, 2, 4, 5, 8. Cephalon from 10.1-10.2m, SUI 00000, dorsal, ventral, left lateral,
posterior, and anterior views, x12.84. The arrow associated with figure A7.8 points to
the feature herein referred to as the extremal ridge.
3, 6, 7. Cephalon from 10.1-10.2m, SUI 00000, dorsal, right lateral, and anterior
views, x8.56.
9, 12, 14. Cephalon from 10.1-10.2m SUI 00000, dorsal, left lateral, and anterior
views, x8.56. Two-layer silicification can be observed.
10. 13, 15. Cephalon from 10.1-10.2m, SUI 00000, dorsal, left lateral, and
anterior views, x17.12.
11, 16, 17. Cephalon from 10.1-10.2m, SUI 00000, dorsal, right lateral, and
anterior views, x12.84. Possible beekite-type structure or encrustation scar present.
18-20. Crackout cephalon from 10.1-10.2, SUI 00000, dorsal, left lateral, and
anterior views, x8.56.
21. Crackout cephalon from 9.6m, SUI 00000, dorsal view, x4.28.
117
118
Figure A8: Pseudagnostus new species 1. All specimens silicified.
1, 5, 9, 13. Pygidium from 10.1-10.2m, SUI 00000, dorsal, left lateral, posterior,
and oblique anterior views, x12.84.
2, 6, 10. Pygidium from 10.1-10.2m, SUI 00000, dorsal, left lateral, and posterior
views, x12.84.
3, 7, 11, 14, 15. Pygidium from 10.1-10.2m, SUI 00000, dorsal, left lateral,
posterior, anterior, and ventral views, x8.56.
4, 8, 12. Pygidium from 10.1-10.2m, SUI 00000, dorsal, left lateral, and posterior
views, x8.56.
16. Immature pygidium from 10.1-10.2m, SUI 00000, dorsal view, x17.12.
17, 20, 23. Pygidium from the original Franklin Basin sample, SUI 00000, dorsal,
right lateral, and posterior views, x10.272. Possible beekite-type structure or encrustation
scar present.
18, 21, 24. Pygidium from 10.1-10,2m, SUI 00000, dorsal, right lateral and
posterior views, x12.84. Possible beekite-type structure or encrustation scar present.
19, 22, 25. Pygidium from 11.2-11.3m, SUI 00000, dorsal, right lateral and
posterior views, x 12.84.
119
120
Figure A9: Litagnostus new species 2, Idiomesus new species A, Euptychaspidine new
species F, ?Kathrynia sp. All specimens are silicified.
1, 4, 6. L. n. sp. 2 cephalon from Two Mile Canyon Sample TMC SCM 1.373,
SUI 00000, dorsal, left lateral, and anterior views, x 10.272.
2, 5, 7. L. n. sp. 2 cephalon from the original Franklin Basin sample, SUI 00000,
dorsal, left lateral, and anterior views, x8.56.
3. L. n. sp. 2 cephalon from 10.1-10.2m attached to a fragment of the anterior
portion of the librigenal doublure from Wilbernia sp., SUI 00000, dorsal view, x10.272.
8-10. L. n. sp. 2 cephalon from 10.1-10.2m, SUI 00000, left lateral, anterior and
dorsal views, x6.42.
11, 12, 15, 16, 19, 20. Idiomesus new species A from 10.1-10.2m, SUI 00000,
dorsal, left oblique, anterior, ventral, left lateral, and posterior views, x17.12. Preexisting
cracks resulting in the loss of a portion of the specimen between dorsal and ventral
photography.
13, 17. Composite images of Euptychaspidine n sp. F, reconstructed using
specimen SUI 00000 and Photoshop, anterior and dorsal views, x4.28.
14, 18, 21, 22. Euptychaspidine n sp. F partial cranidium from 11.2-11.3m, SUI
00000, anterior, right lateral, right oblique, and dorsal views, x10.272.
23-26. Kathrynia? sp. partial cranidium from 10.6-10.72m, SUI 00000, anterior,
right lateral, dorsal, and left oblique views, x17.12.
27. Composite image of Kathrynia? sp., reconstructed using specimen SUI 00000
and Photoshop, dorsal view, x8.56.
28. Euptychaspidine n sp. F partial cranidium from 11.2-11.3m, SUI 00000,
dorsal view, x12.84.
121
122
Figure A10: Litagnostus new species 2. All specimens are silicified.
1, 2, 4, 7. Pygidium from 10.1-10.2m, SUI 00000, dorsal, ventral, right lateral,
and posterior views, x8.56. Damage to specimen A10.2 occurred between dorsal and
ventral photography.
3, 6, 10. Pygidium from 10.1-10.2m, SUI 00000, dorsal, left lateral, and posterior
views, x10.272. Possible beekite-type structure or encrustation scar present.
5, 8, 9. Pygidium from the original Franklin Basin sample, SUI 00000, dorsal,
left lateral, and posterior views, x8.56.
11-13, 15, 16. Pygidium from 10.1-10.2m, SUI 00000, dorsal, left lateral, ventral,
posterior, and anterior views, x8.56.
14, 17, 21. Pygidium from 10.1-10.2m, SUI 00000, dorsal, left lateral, and
posterior views, x8.56.
18-20. Pygidium from 10.1-10.2m, SUI 00000, dorsal, left lateral, and posterior
views, x8.56.
123
124
Figure A11: Ptychaspis new species 3. All specimens are silicified.
1, 4, 6, 9, 12. Cranidium from 10.1-10.2m, SUI 00000, dorsal, anterior, posterior,
ventral, and left lateral views, x6.42.
2, 5, 7, 10, 13. Cranidium from 10.1-10.2m, SUI 00000, dorsal, anterior
posterior, ventral and right lateral views, x8.56. Two-layer silicification can be observed.
3. Cranidium from 10.1-10.2m, SUI 00000, dorsal view, x8.56.
8. Cranidium from 10.1-10.2m, SUI 00000, dorsal view, x6.42.
11, 15, 21, 25. Cranidium from 10.1-10.2m, SUI 00000, right lateral right oblique,
anterior, and dorsal views, x6.42. Two-layer silicification can be observed.
14, 20, 23, 24. Cranidium from 10.1-10.2m, SUI 00000, left oblique, anterior, left
lateral, and dorsal views, x8.56. Two-layer silicification can be observed.
16, 19, 20, 22. Cranidium from 10.1-10.2m, SUI 00000, left oblique, anterior left
lateral, and dorsal views, x12.84.
17, 18. Cranidium from 10.1-10.2m, SUI 00000, anterior and dorsal views,
x6.42.
125
126
Figure A12: Ptychaspis new species 3, Ptychaspidine sp., and Macronodine sp. All
specimens are silicified.
1, 2, 5, 6. Immature cranidium of P. n. sp. 3 from 10.1-10.2m, SUI 00000, dorsal,
left lateral, anterior, and left oblique views, x17.12.
3, 4, 7, 8. Immature cranidium of P. n. sp. 3 from 10.1-10.2m, SUI 00000, right
oblique, dorsal, right lateral, and anterior views, x12.84.
9-11, 18. Ptychaspidine sp. pygidia from 10.6-10.72m, SUI 00000-00000, dorsal
view, x17.12.
12, 13, 16, 17. Pygidial fragment of Macronodine sp. from the original Franklin
Basin sample, SUI 00000, posterior, left lateral, dorsal, and left oblique views, x10.272.
Two-layer silicification can be observed.
14, 19, 20. Pygidial fragment of Macronodine sp. from 10.1-10.2m, SUI 00000,
posterior, dorsal, and ventral views, x12.84.
15. Pygidial fragment of Macronodine sp. from 10.1-10.6m, SUI 00000, dorsal
view, x15.
21-24. Pygidial fragment of Macronodine sp. from 10.1-10.2m, SUI 00000,
posterior, left lateral, dorsal, and left oblique views, x17.12.
25. Left librigenal fragment of P. n. sp. 3 from 10.1-10.2m, SUI 000000, dorsal
view, x17.12.
26, 27. Left librigenal fragment of P. n. sp. 3 from 10.1-10.2m, SUI 000000, left
lateral and ventral views, x17.12.
28. Right librigenal fragment of P. n. sp. 3 from 10.1-10.2m, SUI 000000, dorsal
view, x17.12. Two-layer silicification can be observed with only a tiny portion of the
upper (dorsal) layer remaining near the insertion of the genal spine.
127
128
Figure A13: Ptychaspis n. sp. 3 pygidia. All specimens are silicified unless otherwise
noted.
1, 2. Crackout pygidium from 10.6-10.72m, SUI 00000, dorsal and lateral views,
x2.568.
3, 7. Pygidium from 11.2-11.3m, SUI 00000, right lateral and dorsal views,
x6.42.
4. Pygidium from 11.2-11.3m, SUI 00000, dorsal view, x6.42.
5, 6. Pygidium from 10.1-10.2m, SUI 00000, dorsal and ventral views, x6.42.
8. Composite pygidium reconstructed using specimens SUI 00000-00000
(A34.11 and A34.19) with photomerge in Photoshop, x1.712.
9, 12. Pygidium from 10.1-10.2m, SUI 00000, dorsal and right lateral views,
x4.28.
10, 13, 17. Pygidium from 10.1-10.2m, SUI 00000, dorsal, posterior, and right
lateral views, x4.28. Indeterminate tail attached to the posterior portion of the axis.
11. Pygidium from 10.1-10.2m, SUI 00000, dorsal view, x6.42.
14. Pygidium from the original Franklin Basin sample, SUI 00000, dorsal view,
x4.28.
15, 16, 19, 20. Pygidium from 10.1-10.2m, SUI 000000, left lateral, posterior,
dorsal, and ventral views, x4.28
18, 21, 22. Pygidium from 10.6-10.72m, SUI 000000, left lateral, dorsal,
posterior views, x12.84.
129
130
Figure A14: Unassigned cranidium type A, unasigned pygidia type G., dokimocephalid
sp., and unassigned pygidia. All sclerites are silicified.
1. Unassigned cranidium type A from 10.1-10.2m, SUI 00000, dorsal views,
x8.56
2. Reconstructed composite cranidium of unassigned cranidium type A
reconstructed using specimen SUI 00000 and Photoshop, dorsal view, x4.28.
3, 5, 6, 10. Unassigned pygidia type G from 10.1-10.2m, SUI 00000, posterior,
left lateral, dorsal, and ventral views, x17.12.
4, 7. Unasigned pygidia type G from 9.6m, SUI 00000, posterior and dorsal
views, x12.84.
8. Unasigned pygidia type G from 10.6-10.72m, SUI 00000, dorsal view, x17.12.
9. Unasigned pygidia type G from 10.6-10.72m, SUI 00000, dorsal view, x17.12.
11, 12, 18. Unasigned pygidia type G from 10.6-10.72m, SUI 00000, posterior,
dorsal, and left lateral views, x17.12.
13-16. Dokimocephalid sp. cranidium from 10.6-10.72, SUI 00000, anterior,
dorsal, right oblique, and right lateral views, x13.696.
17. Unasigned pygidia type G from 10.6-10.72m, SUI 00000, dorsal view,
x15.408.
19, 23, 24. Unassigned pygidium type A from 10.6-10.72m, SUI 00000, dorsal,
posterior, and right lateral views, x6.42.
20, 25. Unassigned pygidium type A from 10.6-10.72m, SUI 00000, dorsal and
right lateral views, x12.84.
21, 22, 26-28. Unassigned pygidium type B from 10.1-10.2m, SUI 00000,
anterior, posterior, right lateral, ventral, and dorsal views, x12.84.
131
132
Figure A15: Trilobites from Franklin Basin. All specimens are silicified.
1,4. Taenicephalus sp. from 10.1-10.2m, SUI 00000, dorsal and anterior views,
x10.272.
2, 3, 5, 6, 8, 12. New Genus B? sp. from 10.6-10.72m, SUI 00000, dorsal,
ventral, anterior, posterior, right oblique, and right lateral views, x10.272.
7. Librigenal fragment(?) type A of an indeterminate trilobite from 10.1-10.2m,
SUI 00000, dorsal view, x10.272. Two-layer silicification can be observed with the
dorsal layer flaking off.
9. New Genus B? sp. from 10.6-10.72m, SUI 00000, dorsal view, x17.12.
10. Indeterminate pygidium type C from 10.6-10.72m on the occipital ring of a
dokimocephalid sp. (fig. A12.13-16), SUI 00000, dorsal view, x17.12.
11. Partial Wilbernia sp. from 10.6-10.72m, SUI 00000, dorsal view, x8.56.
13. Indeterminate librigena type B from 9.6m, SUI 00000, dorsal view, x17.12.
14. New Genus B? sp. from 10.6-10.72m, SUI 00000, dorsal view, x8.56.
15. Indeterminate pygidium type C from 10.6-10.72m, SUI 00000, dorsal view,
x17.12.
16. Indeterminate pygidium type C from 10.6-10.72m on the anterior border of a
Wilbernia? sp. (Fig. 13.11), SUI 00000, dorsal view, x17.12.
17, 20, 24. Indeterminate librigena type B from 9.6m, SUI 00000, left lateral,
right lateral, and dorsal views, x12.84.
18, 21, 25. Ptychaspis sp. librigena from 10.6-10.72m, SUI 00000, ventral,
dorsal, and right lateral views, x12.84.
19, 22, 23. Indeterminate librigena type B from 9.6m, SUI 00000, dorsal,
posterior, and right lateral views, x10.272.
133
134
Figure A16: New genus A and new species 6. All specimens are silicified.
1, 2, 5, 8. Cranidium from 10.1-10.2m, SUI 00000, dorsal, right oblique, anterior,
and left lateral views, x10.272.
3, 4, 6, 7. Cranidium from 10.1-10.2m, SUI 00000, dorsal, anterior, left lateral,
and left oblique views, x8.56.
9, 14, 16. Cranidium from 10.6-10.72m, SUI 00000, right lateral, anterior and
dorsal views, x17.12.
10-12. Cranidium from 10.1-10.2m, SUI 00000, dorsal, right lateral, and anterior
views, x8.56.
13, 15, 19, 20, 23, 24. Cranidium from 10.1-10.2m, SUI 00000, right lateral, right
oblique, anterior, posterior, ventral, and dorsal views, x17.12.
17, 18, 21. Cranidium from 10.1-10.2m, SUI 00000, dorsal, left lateral, and
anterior views, x12.84.
22, 25-27. Cranidium from 10.1-10.2m, SUI 00000, ventral, left lateral, anterior,
and dorsal views, x17.12.
135
136
Figure A17: New genus A and new species 6. All specimens are silicified.
1-3, 6. Immature cranidium from 10.6-10.72m, SUI 00000, dorsal, right oblique,
anterior, and right lateral views, x17.12.
4, 9, 12. Librigena from 10.6-10.72m, SUI 00000, ventral, dorsal and right lateral
views, x8.56.
5, 10. Cranidium from 10.6-10.72m, SUI 00000, dorsal and anterior views,
x17.12.
7, 8. Two cranidia from 10.6-10.72m, SUI 00000-00000, dorsal views, x17.12.
11. Librigena from 10.6-10.72m, SUI 00000, dorsal view, x10.272.
13. Librigena from 10.1-10.2m, SUI 00000, dorsal view, x8.56.
14, 15, 17. Librigenae from 10.1-10.2m, SUI 00000-000000, dorsal views,
x12.84.
16. Librigena from 10.1-10.2m, SUI 00000, dorsal view, x17.12.
18. Librigena from 10.1-10.2m, SUI 00000, dorsal view, x10.272.
19. Librigena from 10.1-10.2m attached to a Pseudagnostus n. sp. 1 pygidium,
SUI 00000, dorsal view, x12.84.
20, 22. Librigena from 10.6-10.72m, SUI 00000, dorsal and ventral views,
x10.272.
21. Librigena from the original Franklin Basin sample, SUI 00000, dorsal view,
x8.56.
137
138
Figure A18: Drumaspis sp. and Drumaspis af. D. walcotti. All specimens are silicified
unless otherwise noted.
1, 2, 5, 6. Immature Drumaspis sp. cranidium from Two Mile Canyon (sample
TMC SCO 1.015), SUI 00000, left oblique, anterior, left lateral, and dorsal views,
x17.12.
3, 4, 7. Immature Drumaspis? sp. cranidium from Two Mile Canyon (sample
TMC SCO 1.015), SUI 00000, left lateral, dorsal, and anterior views, x12.84.
8. Immature Drumaspis af. D. walcotti (?) cranidial fragment from 10.6-10.72m
superimposed over the outline of specimen figured above (fig. A16.4), SUI 00000, dorsal
view, both at x17.12. This demonstrates a rough correspondence in shape despite
differential degrees of expression for the lateral glabellar furrows.
9. Drumaspis af. D. walcotti cranidium from 10.6-10.72m, SUI 00000, dorsal
view, x12.84.
10. Drumaspis af. D. walcotti cranidium from 10.6-10.72m, SUI 00000, dorsal
view, x12.84.
11. Drumaspis af. D. walcotti cranidium from the original Franklin Basin sample,
SUI 00000, dorsal view, x17.12.
12, 13. Drumaspis af. D. walcotti cranidium from the original Franklin Basin
sample, SUI 00000, ventral and dorsal views, x4.28.
14, 17, 20. Drumaspis af. D. walcotti cranidium from 10.1-10.2m, SUI 00000,
right lateral, anterior, and dorsal views, x12.84.
15. Drumaspis af. D. walcotti. cranidium from 10.6-10.72m, SUI 00000, dorsal
view, x10.272.
16. Crackout Drumaspis af. D. walcotti cranidium from 9.6m, SUI 00000, dorsal
view, x6.42.
139
Figure A18—continued.
18, 21, 22. Drumaspis af. D. walcotti cranidium from 10.6-10.72m, SUI 00000,
anterior, right lateral, and dorsal views, x17.12.
19. Crackout Drumaspis af. D. walcotti cranidium from 10.1-10.2m, SUI 00000,
dorsal view, x4.28.
140
141
Figure A19: Drumaspis af. D. walcotti cranidia. All specimens are silicified.
1, 2, 5, 6. Cranidium from 10.1-10.2m, SUI 00000, anterior, right lateral, dorsal,
and right oblique views, x6.42.
3, 4, 7. Cranidium from the original Franklin Basin sample, SUI 00000, anterior,
dorsal, and right lateral views, x8.56.
8, 11, 13, 14. Cranidium from the original Franklin Basin sample, SUI 00000,
anterior, dorsal, right lateral, and right oblique views, x6.42
9, 10, 12, 15. Cranidium from 10.1-10.2m, SUI 00000, right lateral, dorsal,
anterior, and right oblique views, x8.56. Two-layer silicification can be observed.
16, 17, 21, 22. Cranidium from 11.2-11.3m, SUI 00000, right oblique, left lateral,
dorsal, and anterior views, x5.136.
18-20, 26. Cranidium from 10.6-10.72m, SUI 00000, dorsal, anterior, left lateral,
and left oblique views, x6.42.
23-25. Cranidium from 10.1-10.2m, SUI 00000, dorsal, anterior, and left lateral
views, x8.56.
142
143
Figure A20: Drumaspis af. D. walcotti cranidia. All specimens are silicified.
1, 4, 5. Cranidium from 10.1-10.2m, SUI 00000, dorsal, anterior, and right lateral
views, x4.28.
2, 3, 9, 13, 16, 20. Cranidium from 10.1-10.2m, SUI 00000, left oblique, dorsal,
anterior, ventral, posterior, and left lateral views, x10.272.
6-8, 12. Cranidium from 10.1-10.2m, SUI 00000, dorsal, anterior, left lateral, and
left oblique views, x4.28.
10, 11, 15, 19. Cranidium from 10.6-10.72m, SUI 00000, anterior, left lateral,
dorsal, and left oblique views, x6.42.
14, 17, 18. Cranidium from 10.1-10.2m, SUI 00000, anterior, dorsal, and left
lateral views, x4.28.
21-23, 27, 28. Cranidium from 10.1-10.2m, SUI 00000, dorsal, posterior, right
lateral, anterior, and ventral views, x6.42.
24, 29. Cranidium from 10.1-10.2m, SUI 00000, anterior and dorsal views,
x6.42.
25, 26, 30. Cranidium from 10.1-10.2m, SUI 00000, anterior, dorsal, and left
lateral views, x6.42.
144
145
Figure A21: Drumaspis af. D. walcotti librigenae. All specimens are silicified.
1, 2. Right librigena from 10.6-10.72m, SUI 00000, ventral and dorsal views,
x10.272.
3, 4. Left librigena from 10.6-10.72m, SUI 00000, dorsal and ventral views,
x12.84.
5, 7. Right librigena from 10.1-10.2m, SUI 00000, right lateral and dorsal views,
x8.56.
6, 8. Left librigena from 10.1-10.2m, SUI 00000, ventral and dorsal views,
x10.272.
9. Right librigena from 10.1-10.2m, SUI 00000, dorsal view, x12.84.
10, 12. Left librigenae from 10.1-10.2m, SUI 00000, dorsal views, x8.56.
11, 18. Left librigenae from 10.6-10.72m, SUI 00000, dorsal views, x10.272.
13, 14. Left librigenae from the original Franklin Basin sample, SUI 00000,
dorsal views, x8.56.
15. Right librigena from the original Franklin Basin sample, SUI 00000, dorsal
view, x10.272.
16, 17. Right librigenae from the original Franklin Basin sample, SUI 00000,
dorsal views, x10.
19. Left librigena from the original Franklin Basin sample, SUI 00000, dorsal
view, x12.84.
20. Right librigena from 10.1-10.2m, SUI 00000, dorsal view, x8.56.
146
147
Figure A22: Drumaspis af. D. walcotti and Drumaspis sp. pygidia. All specimens are
silicified.
1, 2, 4, 5, 8, 9. Pygidium from 10.6-10.72m, SUI 00000, posterior, anterior,
dorsal, ventral, right lateral, and right oblique views, x8.56.
3, 6, 10. . Pygidium from 11.2-11.3m, SUI 00000, dorsal, posterior, and left
lateral views, x17.12.
7, 12, 13. . Pygidium from 10.6-10.72m, SUI 00000, posterior, dorsal, and right
lateral views, x12.84.
11, 14, 19, 25. . Pygidium from 10.6-10.72m, SUI 00000, right lateral, ventral,
posterior, and dorsal views, x10.272.
15-18, 20. . Pygidium from 10.6-10.72m, SUI 00000, right lateral, dorsal, ventral,
anterior, and posterior views, x5.136.
21, 22, 26-29. . Teratological pygidium belonging to Drumaspis sp. from Two
Mile Canyon (sample TMC SC2 3.957), SUI 00000, posterior, left lateral, dorsal,
anterior, right lateral, left oblique views, x12.84.
23, 30, 31. . Pygidium from 10.1-10.2m, SUI 00000, right lateral, dorsal and
posterior views, x10.
24, 32, 33. . Pygidium from 10.1-10.2m, SUI 00000, left lateral, posterior and
dorsal views, x8.56.
148
149
Figure A23: Triarthropsis sp.. Ellipsocephaloides cf. E. nitela? and E. monsensis
cranidia and pygidia. All specimens are silicified unless otherwise noted.
1, 6, 17, 18. Cranidium of Triarthropsis sp. from 10.6-10.72m, SUI 00000,
dorsal, anterior, left lateral, and left oblique views, x17.12.
2, 7, 11. Cranidium of Triarthropsis sp. from 10.6-10.72m, SUI 00000, dorsal,
right lateral, and anterior views, x17.12.
3, 8. Cranidium of Triarthropsis sp. from 10.6-10.72m, SUI 00000, anterior and
dorsal views, x17.12.
4, 9. Cranidium of Triarthropsis sp. from 10.6-10.72m, SUI 00000, anterior and
dorsal views, x17.12.
5, 10, 15, 16. Cranidium of Triarthropsis sp. from 10.6-10.72m, SUI 00000,
dorsal , anterior, left lateral, and left oblique views, x17.12.
12-14, 21. Cranidia of Triarthropsis sp. from 10.6-10.72m, SUI 00000, dorsal
views, x17.12. Specimen SUI 00000 (no. 21) assigned to Triarthropsis sp. with question.
19, 20, 24. Pygidia of E. cf. E. nitela? from 10.6-10.72m, SUI 00000, dorsal
views, x17.12.
22, 26, 27, 32, 36. Pygidium of E. cf. E. nitela? from 10.6-10.72m, SUI 00000,
left lateral, anterior, ventral, posterior, and dorsal views, x12.84.
23, 28, 34. Crackout cranidium of E. monsensis Resser, 1942 from 9.6m, SUI
00000, anterior, dorsal, and left oblique views, x8.56. Specimen is the same as that
illustrated in fig. A21.33; it broke free of the limestone matrix during preparation.
25, 29-31, 35. Pygidium of E. cf. E. nitela? from 10.6-10.72m, SUI 00000,
ventral, right lateral, left lateral, posterior, and dorsal views, x17.12.
150
Figure A23—continued.
33. Crackout cranidium of E. monsensis Resser, 1942 from 9.6m, SUI 00000,
anterior view, x4.28. Originally, the specimen was on the same block of a Wilbernia sp.
cranidium (figure A25.15 upper right corner), but chipped off during preparation.
151
152
Figure A24: Idahoia n. sp. B. Specimens are silicified unless otherwise noted.
1, 2, 6. Cranidial mold from 9.6m, SUI 00000, dorsal, anterior, and left lateral
views, x6.42.
3, 7, 8. Cranidial fragment from 10.1-10.2, SUI 00000, dorsal, left lateral, and
anterior views, x4.28.
4. Librigenal fragment (internal mold) from 11.2-11.3m, SUI 00000, dorsal view,
x4.28.
5. Cranidial fragment from the original Franklin Basin sample, SUI 00000,
ventral view, x2.14.
9, 10, 14. Cranidial mold from 11.2-11.3m, SUI 00000, dorsal, anterior, and right
lateral views, x2.14.
11. Silicified cranidium from 11.2-11.3m, SUI 00000, dorsal view, x4.28.
12. Reconstructed composite cranidium using specimen SUI 000000 and
Photoshop, dorsal view, x2.14.
13. Cranidial mold fragment from 11.2-11.3m, SUI 00000, dorsal view, x1.712.
15, 18, 20. Cranidial mold from 10.6-10.72m, SUI 00000, anterior, left lateral,
and dorsal views, x1.712.
16, 17, 19. Cranidial mold from 10.6-10.72m, SUI 00000, dorsal, anterior, and
left lateral views, x1.712.
153
154
Figure A25: Wilbernia n. sp. 4. All specimens are crackout unless otherwise noted.
1, 4, 8. Partially exfoliated cranidium from 10.1-10.2m, SUI 00000, dorsal,
anterior, and left oblique views, x1.712. Image 23.1 created using photomerge in
Photoshop.
2, 5. Partially exfoliated cranidium from 10.1-10.2m, SUI 00000, dorsal and
anterior views, x2.568.
3, 6, 7, 10. Silicified cranidium from 11.2-11.3m, SUI 00000, dorsal, anterior,
right lateral, and right oblique views, x2.568. Note the dominantly horizontal orientation
of the other silicified bioclastic fragments,
9, 12, 14. Partially exfoliated cranidium from 9.6m, SUI 00000, left lateral,
anterior, and dorsal views, x4.28.
11, 13. Partially exfoliated cranidium from 9.6m, SUI 00000, anterior and dorsal
views, x1.712.
15. Partially exfoliated cranidium from 9.6m, SUI 00000, image created using
photomerge in Photoshop, dorsal view, x1.712.
155
156
Figure A26: Wilbernia sp., Wilbernia n. sp. 4, and Wilbernia? cf. W. expansa cranidia
and librigenae. Specimens are crackout unless otherwise noted.
1. W. sp. cranidium from 9.6m, SUI 00000, image created using photomerge in
Photoshop, dorsal view, x1.284. Maladia head visible near anterior border; W. n. sp. 4
tail figured in fig. A27.22 on the left margin.
2. W.? cf. W. expansa cranidium from 9.6m, SUI 00000, dorsal view, x7.704.
3. W.? cf. W. expansa? cranidium from 10.6-10.72m, SUI 00000, dorsal view,
x2.568.
4, 5, 9. Exfoliated W. n. sp. 4 from 10.1-10.2m, SUI 00000, dorsal, anterior, and
right lateral views, x1.284. Figure A24.4 created using photomerge in Photoshop.
6. Silicified internal mold of a W.? cf. W. expansa? cranidium from 10.6-10.72m,
SUI 00000, dorsal view, x2.568.
7. W. n. sp. 4 librigena from 9.6m showing part of the doublure anteriorly, SUI
00000, image creating using photomerge in Photoshop, ventral view, x1.712.
8. Partially exfoliated W. n. sp. 4 cranidium from 9.6m, SUI 00000, image
created using photomerge in Photoshop, dorsal view, x1.712.
10. Silicified left librigena belonging to W. n. sp. 4 from 10.1-10.2m, SUI 00000,
dorsal view, x12.84.
11, 18. Silicified left librigenae belonging to W. n. sp. 4 from 10.1-10.2m, SUI
00000-00000, dorsal views, x6.42.
12. Silicified left librigena belonging to W. n. sp. 4 from 10.1-10.2m, SUI 00000,
dorsal view, x8.56.
13. Silicified right librigena belonging to W. n. sp. 4 from 10.1-10.2m, SUI
00000, dorsal view, x8.56.
157
Figure A26—continued.
14. Crackout right librigena belonging to W. n. sp. 4 from 10.6-10.72m, SUI
00000, dorsal view, x1.712
15. End on view of the broken genal spine of SUI 000000 (fig. 24. 14) showing
the cuticle and infilling, x2.568.
16, 17. Silicified left librigena belonging to W. n. sp. 4 from 10.1-10.2m, SUI
00000, dorsal and ventral views, x4.28.
19. Silicified right librigena belonging to W. n. sp. 4 from 11.2-11.3m, SUI
00000, dorsal view, x2.14.
20. Silicified left librigena belonging to W. n. sp. 4 from 10.1-10.2m, SUI 00000,
ventral view, x2.14.
158
159
Figure A27: Wilbernia n. sp. 4 and unidentified pygidia. All specimens silicified unless
otherwise noted.
1. Crackout W. n. sp. 4 pygidium from 11.2-11.3m, SUI 00000, dorsal view,
x4.28.
2, 3, 8. W. n. sp. 4 pygidium from 10.1-10.2m, SUI 00000, dorsal, posterior, and
left lateral views, x17.12.
4, 5, 11, 16, 17. W. n. sp. 4 pygidium from 10.1-10.2m, SUI 00000, anterior,
ventral, dorsal, posterior, and right lateral views, x12.84.
6, 9. W. n. sp. 4 pygidium from 10.1-10.2m, SUI 00000, dorsal and right lateral
views, x6.42.
7, 10, 15. W. n. sp. 4 pygidium from 10.1-10.2m, SUI 00000, right lateral, dorsal,
and posterior views, x17.12.
12-14. W. n. sp. 4 pygidium from 9.6m, SUI 000000, posterior, dorsal, and right
lateral views, x12.84
18. Crackout W. n. sp. 4 pygidium from 9.6m, SUI 00000, dorsal view, x2.14.
19-21. Unidentified pygidium (type D) from 10.6-10.72m, SUI 00000, dorsal,
left lateral, and posterior views, x17.12. Partial pygidium (type G) attached anteriorly.
22. Crackout W. n. sp. 4 pygidium from 9.6m, SUI 00000, dorsal view, x1.712.
23. Unidentified pygidium (type E) from 10.6-10.72m, SUI 00000, dorsal view,
x17.12.
24, 25. Unidentified pygidia (type F) from 10.6-10.72m, SUI 00000-00000,
dorsal views, x17.12.
26. Crackout W. n. sp. 4 pygidium from 9.6m, SUI 00000, dorsal view, x2.14.
160
161
Figure A28: Maladia n. sp. 8 cranidia. All specimens are silicified.
1, 2, 4, 5, 7, 8. Cranidium from 10.1-10.2m, SUI 00000, dorsal, ventral, anterior,
left lateral, left oblique, and posterior views, x6.42.
3, 6, 9, 15. Cranidium from 10.1-10.2m, SUI 00000, dorsal, anterior, ventral, and
left lateral views, x6.42.
10-13, 16. Cranidium from 10.6-10.72m, SUI 00000, dorsal, anterior, detail of
anterior border (x5), right lateral, and right oblique views, x2.568.
14, 18, 19, 22, 23. Cranidium from 10.1-10.2m, SUI 00000, right lateral, anterior,
posterior, dorsal, and ventral views, x6.42.
17, 20, 21. Cranidium from 10.1-10.2m, SUI 00000, dorsal, right lateral, and
anterior views, x8.56.
162
163
Figure A29: Maladia n. sp. 8 cranidia. All are silicified unless otherwise noted.
1, 6. Crackout cranidium from 11.2-11.3m, SUI 00000, dorsal and anterior views,
x1.712.
2, 4, 7. Cranidium from 9.6m, SUI 00000, dorsal, left lateral, and anterior views,
x10.272.
3, 5, 9. Immature cranidium from 10.1-10.2m, SUI 00000, right lateral, dorsal,
and anterior views, x13.696.
8, 14, 15. Cranidium from 9.6m, SUI 00000, anterior, right lateral, and dorsal
views, x8.56.
10-12. Cranidium from 10.6-10.72m, SUI 00000, dorsal, anterior, and left lateral
views, x2.568.
13, 17, 20. Cranidium from 10.1-10.2m, SUI 00000, dorsal, anterior, and left
lateral views, x8.56.
16, 19, 22-25. Immature cranidium from 10.1-10.2m, SUI 00000, right lateral,
right oblique, dorsal, posterior, ventral, and anterior views, x13.696.
18. Cranidium from the original Franklin Basin sample, SUI 00000, dorsal view,
x4.28.
21, 26, 27. Cranidium from 11.2-11.3m, SUI 00000, left lateral, anterior, and
dorsal views, x6.42.
164
165
Figure A30: Maladia n. sp. 8 librigenae. All specimens are silicified unless otherwise
noted.
1, 2. Left librigena from 10.1-10.2m, SUI 00000, dorsal and ventral views, x8.56.
3, 6. Right librigena from 10.1-10.2m, SUI 00000, dorsal and ventral views,
x12.84.
4. Left librigena from 9.6m, SUI 00000, dorsal view, x12.84.
5, 9, 14. Right librigena from the original Franklin Basin sample, SUI 00000,
dorsal views, x10.272.
7. Right librigena from 10.6-10.72m, SUI 00000, dorsal view, x4.28.
8, 11. Right librigena from 9.6m, SUI 00000, right lateral and dorsal views,
x12.84.
10. Left librigena from 10.6-10.72m, SUI 00000, dorsal view, x10.272.
12, 17. Right librigenae from 10.1-10.2m, SUI 00000, dorsal views, x10.272.
13, 16. Right librigena from the original Franklin Basin sample, SUI 00000,
dorsal and right lateral views, x8.56.
15. Right librigena from 10.6-10.72m, SUI 00000, dorsal view, x8.56.
18. Left librigenae from 10.1-10.2m, SUI 00000, dorsal views, x10.272.
19. Crackout right librigena from 10.1-10.2m, SUI 00000, dorsal view, x2.568.
A small Drumaspis cranidial internal mold is visible anteriorly.
166
167
Figure A31: Maladia n. sp. 8 pygidia. All specimens are silicified unless otherwise
noted.
1, 2, 4, 5, 7. Pygidium from 10.6-10.72m, SUI 00000, posterior, anterior, dorsal,
ventral, and left lateral views, x12.84.
3, 6, 10, 15, 19. Pygidium from 9.6m, SUI 00000, posterior, dorsal, ventral, and
anterior views, x8.56.
8, 9, 11-14. Pygidium from 9.6m, SUI 00000, right lateral, anterior (dorsal),
anterior (ventral), posterior, ventral, and dorsal views, x8.56.
16. Pygidium from the original Franklin Basin sample, SUI 00000, dorsal view,
x8.56.
17, 18, 20, 22, 23. Pygidium from 10.1-10.2m, SUI 00000, anterior, left lateral,
posterior, ventral and dorsal views, x12.84.
21. Pygidium from 10.1-10.2m, SUI 00000, dorsal view, x8.56.
24-27. Partial pygidial border with magnified insets from 11.2-11.3m, SUI
00000, fig. 24 is the left edge of the pygidial border (dorsal to the left, x12.84), fig. 25 is
the pygidial border (x6.42), fig. 26 is the medial portion of the border ventrally (x12.84),
fig. 27 is the right edge of the pygidial border (ventral up, x12.84).
28. Crackout pygidium with the posterior border broken off from 9.6m, SUI
00000, dorsal view, x2.568.
168
169
Figure A32: Maladia n. sp. 9 cranidia and pygidia. All specimens are silicified unless
otherwise noted.
1. Crackout cranidium from 10.1-10.2m, SUI 00000, dorsal view, x4.28.
2, 3. Crackout cranidium from 10.1-10.2m, SUI 00000, dorsal and anterior views,
x4.28.
4, 6. Pygidium from 10.6-10.72m, SUI 00000, ventral and dorsal views, x8.56.
5. Cranidium from 11.2-11.3m, SUI 00000, dorsal view, x6.42.
7, 8, 12, 13. Cranidium from 10.6-10.72m, SUI 00000, dorsal, right lateral,
anterior, and right oblique views, x12.84. A small Drumaspis cranidium is attached
ventral side up to the anterior portion of the glabella.
9. 14, 15. Cranidium from 10.6-10.72m, SUI 00000, anterior, left lateral and
dorsal views, x6.42.
10. Crackout pygidium without border from 10.6-10.72m, SUI 00000, dorsal
view, x2.568.
11, 16, 17. Pygidium from 10.1-10.2m, SUI 00000, posterior, dorsal, and right
lateral views, x12.84.
18-21. Pygidium from 11.2-11.3m, SUI 00000, dorsal, ventral, posterior, and
right lateral views, x8.56.
22-24. Pygidium from 10.6-10.72m, SUI 00000, right lateral, posterior, and
dorsal views, x8.56.
25-27. Pygidium from 11.2-11.3m, SUI 00000, left lateral, dorsal, and posterior
views, x6.42.
170
171
Figure A33: Naustia n. sp. 5 cranidia. All are silicified unless otherwise noted.
1, 2, 7, 8, 10. Cranidium from 10.6-10.72m, SUI 00000, dorsal, ventral, anterior,
right oblique, and right lateral views, x12.84.
3. Reconstructed composite cranidium created using Photoshop and SUI 00000
(fig. A31.1), x4.28.
4, 5. Cranidia from 10.6-10.72m, SUI 00000-00000, dorsal views, x12.84.
6, 9, 12. Cranidium from 10.6-10.72m, SUI 00000, right lateral, anterior, and
dorsal views, x12.84.
11, 16. Cranidium from 10.6-10.72m, SUI 00000, dorsal and left lateral views,
x15.
13. Unidentified juvenile cranidium associated with the specimen in fig. A31.1415 from 10.6-10.72m, SUI 00000, dorsal view, x12.84.
14, 15, 17. Cranidium from 10.6-10.72m, SUI 00000, right lateral, anterior, and
dorsal views, x8.56.
18-20. Cranidium from 10.6-10.72m, SUI 00000, left lateral, anterior, and dorsal
views, x4.28.
22. Crackout cranidium from 10.6-10.72m, SUI 00000, dorsal view, x2.568.
172
173
Figure A34: Naustia n. sp. 5 pygidia. Specimens are silicified unless otherwise noted.
1, 2. Pygidium from 10.1-10.2m, SUI 00000, anterior and ventral views, x1.712.
Fig. 32.2 was created using photomerge in Photoshop.
3, 7. Silicified internal molds of pygidia from 10.6-10.72m, SUI 00000-00000,
dorsal views, x2.568.
4-6. Pygidium from 10.1-10.2m, SUI 00000, ventral, dorsal, and posterior views,
x2.14.
8. Crackout pygidium from 10.6-10.72m, SUI 00000, ventral view, x2.14.
9. Pygidium from 9.6m, SUI 00000, dorsal view, x10.272.
10. Pygidium from 10.1-10.2m, SUI 00000, ventral view, x8.56.
11, 13. Pygidium from 10.1-10.2m, SUI 00000-00000, dorsal view, x6.42.
12. Pygidium from 10.1-10.2m, SUI 00000, dorsal view, x2.568.
14, 15. Crackout pygidium from 10.1-10.2m, SUI 00000, posterior and dorsal
views, x1.712. Images were constructed using photomerge in Photoshop.
174
175
Figure A35: Saratogia n. sp. C, Saratogia sp., and Idahoia n. sp. B cranidia. All
specimens are silicified unless otherwise noted.
1-4, 7. Saratogia n. sp. C cranidium from 10.6-10.72, SUI 00000, dorsal, ventral,
left lateral, left oblique, and anterior views, x12.84.
5, 6, 11, 12, 15. Saratogia n. sp. C cranidium from 10.6-10.72, SUI 00000,
anterior, dorsal, left oblique, ventral, and right lateral views, x12.84.
8-10, 13. Saratogia n. sp. C cranidium from 10.6-10.72, SUI 00000, anterior,
right oblique, dorsal, and right lateral views, x12.84.
14. Saratogia sp. cranidium from 10.6-10.72, SUI 00000, dorsal view, x6.42.
16. Saratogia n. sp. C cranidium from 10.6-10.72, SUI 00000, dorsal view,
x17.12.
17. Saratogia sp. cranidium from 10.6-10.72, SUI 00000, dorsal view, x8.56.
18, 19, 23. Saratogia n. sp. C cranidium from 10.6-10.72, SUI 00000, anterior,
right lateral, and dorsal views, x10.272.
20. Saratogia sp. cranidium from 10.6-10.72, SUI 00000, dorsal view, x17.12.
21. Saratogia sp. cranidium from 10.6-10.72, SUI 00000, dorsal view, x12.84.
22. Saratogia n. sp. C cranidium from 10.6-10.72, SUI 00000, dorsal view,
x17.12.
24. Idahoia n. sp. B cranidium from 10.6-10.72, SUI 00000, ventral view,
x12.84.
176
177
Figure A36: Misc. librigenae. All specimens are silicified.
1, 3, 6. Saratogia n. sp. C librigena from 10.6-10.72m, SUI 00000, dorsal, right
and left lateral views, x12.84.
2. Naustia n. sp. 5 librigena from 10.1-10.2m, SUI 00000, dorsal view, x13.696.
4. Naustia n. sp. 5 librigena from 10.6-10.72m, SUI 00000, dorsal view, x17.12.
5. Naustia n. sp. 5 librigena from 10.1-10.2m, SUI 00000, dorsal view, x13.696.
7, 11. Naustia n. sp. 5 librigena from 10.6-10.72m, SUI 00000, dorsal and ventral
views, x12.84.
8, 9. Saratogia n. sp. C librigena from 10.6-10.72m, SUI 00000, left lateral and
dorsal views, x8.56.
10. Naustia n. sp. 5 librigena from 10.1-10.2m, SUI 00000, dorsal view, x13.696.
12, 16, 17. New Genus B and new species 7 librigena from 10.6-10.72m, SUI
00000, anterior, dorsal, and left lateral views, x12.84.
13. Saratogia n. sp. C librigena from 10.6-10.72m, SUI 00000, dorsal view,
x8.56.
14. New Genus B and new species 7 librigena attached to an unidentified
librigena from 10.1-10.2m, SUI 00000, dorsal view, x12.84.
15. New Genus B and new species 7 librigena from 10.6-10.72m, SUI 00000,
dorsal view, x17.12.
18, 22-25. New Genus B and new species 7 librigena from 10.1-10.2m, SUI
00000, right lateral left lateral, dorsal, ventral, and anterior views, x17.12.
19. New Genus B and new species 7 librigena from 10.6-10.72m, SUI 00000,
dorsal view, x17.12.
20, 21, 27. New Genus B and new species 7 librigena from 10.6-10.72m, SUI
00000, ventral, right lateral (ventral), and dorsal views, x12.84.
178
Figure A36—continued.
26, 28. New Genus B and new species 7 librigena from 10.6-10.72m, SUI 00000,
ventral and dorsal views, x12.84.
179
180
Figure A37: New Genus B and new species 7 cranidia. All specimens are silicified.
1, 2, 5, 6. Cranidium from 10.6-10.72m, SUI 00000, dorsal, left lateral, left
oblique, and anterior views, x12.84.
3, 4, 8, 9, 13. Cranidium from 10.6-10.72m, SUI 00000, right lateral, anterior,
right oblique, dorsal, and ventral views, x17.12.
7, 10-12. Cranidium from 10.6-10.72m, SUI 00000, anterior, dorsal, left oblique,
and left lateral views, x12.84.
14, 15, 20. Cranidium from 9.6m, SUI 00000, dorsal, right lateral, and anterior
views, x12.84.
16-19. Cranidium from 10.6-10.72m, SUI 00000, left oblique, left lateral, dorsal,
and anterior views, x17.12.
21, 22, 25, 26. Cranidium (attached to a second New Genus B and new species 7
cranidium) from 10.6-10.72m, SUI 00000, dorsal, right oblique, anterior, and left lateral
views, x17.12.
23, 24, 27, 28. Cranidium from 10.1-10.2m, SUI 00000, left lateral, dorsal, left
oblique, and anterior views, x12.84.
181
182
Figure A38: New Genus B and new species 7 cranidia. All specimens are silicified.
1, 2, 5, 6, 9. Cranidium from 10.6-10.72m, SUI 00000, dorsal, ventral, anterior,
left lateral, and left oblique views, x17.12.
3, 4, 7, 8. Cranidium from 10.6-10.72m, SUI 00000, dorsal, left oblique, anterior,
and left lateral views, x17.12.
10, 11, 15, 16. Cranidium from the original Franklin Basin sample, SUI 00000,
dorsal, ventral, right lateral, right oblique, and anterior views, x17.12.
12-14, 17. Cranidium from 10.1-10.2m, SUI 00000, left lateral, anterior, dorsal,
and left oblique views, x12.84.
18, 20, 23-25, 27. Cranidium from 10.1-10.2m, SUI 00000, dorsal, right lateral,
anterior, ventral, left lateral, and posterior views, x17.12.
19. Cranidium from 10.1-10.2m, SUI 00000, dorsal view, x17.12.
21. Cranidium from 10.6-10.72m, SUI 00000, dorsal view, x1.12.
22, 26, 28, 29. Cranidium from 11.2-11.3m, SUI 00000, right oblique, dorsal,
anterior, and right lateral views, x17.12.
30. Cranidium partial etched from a block of limestone from horizon 10.610.72m, SUI 00000, dorsal view, x6.42.
183
184
Figure A39: Hypostomes. Specimens are silicified unless otherwise noted.
1-4. Hypostome from 10.1-10.2m, SUI 00000, dorsal, ventral, right lateral, and
posterior views, x4.28.
5, 6, 8. Hypostome from 10.9-10.72m, SUI 00000, dorsal, posterior, and right
lateral views, x8.56.
7. Silicified internal mold of a hypostome from 9.6m, SUI 00000, dorsal view,
x12.84.
9. Hypostome from 10.9-10.72m, SUI 00000, dorsal view, x10.272.
10. Hypostome from 10.9-10.72m, SUI 00000, dorsal view, x6.848.
11. Hypostome from 10.9-10.72m, SUI 00000, dorsal view, x12.272.
12. Hypostome from 10.9-10.72m, SUI 00000, dorsal view, x17.12.
13. Hypostome etched from a block of limestone from 11.2-11.3m, SUI 00000,
dorsal view, x10.272. Visible in the broken median body is a New Genus B and new
species 7 cranidium and a ?ptychaspidid pygidium.
185
186
Figure A40: Hypostomes and thoracic segments. All specimens are silicified.
1, 2, 4, 5. Hypostome from 10.6-10.72m, SUI 00000, dorsal, posterior, left
lateral, and anterior views, x17.12.
3, 10. Thoracic segment from 10.6-10.72m, SUI 00000, dorsal and right lateral
views, x8.56.
6. Thoracic segment from 10.6-10.72m, SUI 00000, dorsal view, x8.56.
7. Hypostome from 10.1-10.2m, SUI 00000, dorsal view, x17.12.
8. Hypostome from 10.6-10.72m, SUI 00000, dorsal view, x17.12.
9. Thoracic segment from 10.6-10.72m, SUI 00000, dorsal view, x8.56.
11. Thoracic segment from 10.1-10.2m, SUI 00000, dorsal view, x8.56.
12, 14, 16. Thoracic segment from the original Franklin Basin sample, SUI
00000, dorsal, posterior, and anterior views, x12.84.
13. Hypostome from 10.1-10.2m, SUI 00000, dorsal view, x17.12.
15, 19, 20, 22. Hypostome from 10.1-10.2m, SUI 00000, left lateral, dorsal,
posterior, and anterior views, x12.84.
17, 18. Hypostome from 10.1-10.2m, SUI 00000, dorsal and posterior views,
x17.12.
21. Thoracic segment from the original Franklin Basin sample, SUI 00000, dorsal
views, x12.84.
187
188
Figure A41: Relative diversity.
Relative diversity shown for each horizon, divided up into silicified and crackout
samples where relevant. Numbers on the pie charts reflect the minimum number of
individuals (the largest number of any one sclerite type). Genera with multiple species
assigned in open nomenclature are grouped together.
189
190
Figure A42: Phylogenetic tree of the Euptychaspidinae and Macronodinae.
The phylogenetic tree shows the relationships between the Euptychaspidinae
(green) and the Macronodinae (blue) trilobites. This analysis is essentially that of Adrain
and Westrop (2001), with their character #23 corrected and four new species from Adrain
and Westrop (2004a, 2005) added. The analysis used a branch-and-bound search, and
resulted in three MPTs. The strict consensus of those three trees (which is identical to the
semi-strict and Adam’s consensus trees) is shown below. Bootstrap values above 50%
are given above the branches—bootstrap values were found by running 100 bootstrap
replicates. See table B13 for the character codings.
191
192
Figure A43: Phylogenetic tree of the Ptychaspididiae.
Sources for character information are given in table B14. The list of characters
and character states is given in table B15, and the character codings are given in table
B16. The tree is the strict consensus (identical to the semistrict consensus) tree of the
408 MPTs resulting from a 500 random replicate heuristic search. Bootstrap values
above 50% are given above the branches—bootstrap values were found by running 100
bootstrap replicates. A bootstrap value of 76 was achieved for a clade containing all
species of Macronoda, which was not resolved on this tree. The traditionally defined
Euptychaspidinae are in green and the traditionally defined Macronodinae are in blue.
The polyphyletic core of Ptychaspidinae are shown in red.
193
194
Figure A44: One of the 408 MPTs with branches numbered—character state
transformations on numbered branches listed in table B17.
195
196
APPENDIX B
DATA TABLES
197
Table B1: Net weight of processed rock, by horizon and number of species identified
therein.
HORIZON
PROCESSED WEIGHT (kg)
TOTAL # OF SPECIES
9.527 kg.
12
FBSC 10.1-10.2
112.814 kg
15
FBSC 10.6-10.72
55.233 kg
18
FBSC 11.2-11.3
46.775 kg
10
Total:
224.349 kg
23
FBSC 9.6
198
Table B2: Sclerite counts from horizon 9.6 (crackout).
FBSC 9.6
Maladia n. sp. 8
Wilbernia (2)
Drumaspis
Pseudagnostus
New Genus B
New genus A
Ellipsocephaloides
Naustia
Unidentified cranidium
Total
Heads Tails
9
1
6
3
3
1
2
2
2
1
1
1
1
25
8
Lib.
2
3
1
Max Ind
9
6
3
2
2
1
1
1
1
Total Sclerites
12
12
5
4
2
1
1
1
1
6
26
39
199
Table B3: Sclerite counts from horizon 9.6 (silicified).
FBSC 9.6
New genus B
Drumaspis
Maladia n. sp. 8
Pseudagnostus
New genus A
Wilbernia
Naustia
Litagnostus
Idahoia
Unassigned pygidium G
Unidentified pygidium
Unidentified librigena
Agnostoid indet
Total
Heads Tails
75
4
19
17
23
15
7
10
2
Lib.
13
32
29
2
4
2
1
1
1
1
1
14
142
50
81
Max Ind
75
19
23
10
2
2
2
1
1
1
1
1
14
Total Sclerites
92
68
67
17
4
4
2
1
1
1
1
1
14
152
273
200
Table B4: Sclerite counts from horizon 10.1-10.2 (crackout).
FBSC 10.1-10.2
Wilbernia
Drumaspis
Maladia n. sp. 8
Pseudagnostus
Maladia n. sp. 9
Litagnostus
Naustia
Ptychaspis
Unidentified librigena
Total
Heads
3
6
2
1
2
Tails
Lib.
3
1
Max Ind
3
6
2
1
2
2
1
1
1
Total Sclerites
6
6
3
2
2
2
1
1
1
5
19
24
1
1
2
1
1
14
5
201
Table B5: Sclerite counts from horizon 10.1-10.2 (silicified).
FBSC 10.1-10.2
Drumaspis
Pseudagnostus
Maladia n. sp. 8
New genus B
Litagnostus
New genus A
Wilbernia
Ptychaspis
Macronodinae indet.
Idahoia
Naustia
Idiomesus
Taenicephalus
Maladia n. sp. 9
Unassigned pygidium G
Unidentified pygidium
Unidentified librigena
Total
Heads
281
201
158
67
40
18
6
32
Tails
180
177
60
Lib.
302
93
158
23
7
21
3
4
20
40
43
3
13
4
1
1
1
1
1
1
809
494
657
Max Ind
281
201
158
79
40
20
22
32
3
7
20
1
1
1
1
1
1
866
Total Sclerites
763
378
311
225
63
58
56
56
3
17
24
1
1
1
1
1
1
1960
202
Table B6: Sclerite counts from horizon 10.6-10.72 (crackout).
FBSC 10.6-10.72
Drumaspis
Maladia n. sp. 8
Idahoia
Naustia
Wilbernia
New genus A
Ptychaspis
Total
Heads
20
1
2
2
1
1
Tails
1
2
Lib.
1
Max Ind
20
2
2
2
1
1
1
Total Sclerites
22
3
2
4
1
1
1
1
29
34
2
1
27
6
203
Table B7: Sclerite counts from horizon 10.6-10.72 (silicified).
FBSC 10.6-10.72
New genus B
Drumaspis
New genus A
Saratogia
Naustia
Unassigned pygidia G
Maladia n. sp. 8
Wilbernia
Ellipsocephaloides?
Triarthropsis
Maladia n. sp. 9
Pseudagnostus
Kathrynia?
New genus B n. sp. D
Idahoia
Euptychaspidine n sp. F
Ptychaspididae indet.
Unidentified cranidia
Unidentified pygidia
Unidentified librigena
Ptychaspidinae indet
Ptychaspis
Dokimocephalidid sp.
Heads Tails
753
194
186
18
26
10
6
6
4
2
2
12
21
1
5
1
1
1
2
1
1
Total
1039
Lib.
320
304
34
4
19
12
10
1
3
6
1
3
8
1
232
705
Max Ind
753
194
18
26
10
6
6
5
12
21
5
1
1
2
1
1
1
3
6
1
3
8
1
Total Sclerites
1073
684
52
30
35
6
18
12
12
21
6
2
1
2
1
1
1
3
6
1
3
8
1
1074
1979
204
Table B8: Sclerite counts from horizon 11.2-11.3 (crackout).
FBSC 11.2-11.3
Maladia
Drumaspis
Wilbernia
Pseudagnostus
Litagnostus
Total
Heads
2
3
1
Tails
1
Lib.
1
1
1
1
6
3
2
Max Ind
2
3
1
1
1
Total Sclerites
4
3
2
1
1
8
11
205
Table B9: Sclerite counts from horizon 11.2-11.3 (silicified).
FBSC 11.2-11.3
Drumaspis
New genus B
Pseudagnostus
Wilbernia
Maladia n. sp. 9
Maladia n. sp. 8
Ptychaspis
Litagnostus
Idahoia
Euptychaspidine n sp. F
Unidentified pygidia
Total
Heads
43
13
6
1
1
1
1
4
2
Tails
24
Lib.
34
24
18
16
16
2
8
4
8
2
72
74
82
Max Ind
43
13
18
8
16
4
8
4
4
2
2
Total Sclerites
101
37
24
17
17
11
8
5
4
2
2
122
228
206
Table B10: Sclerite counts from the original silicified sample from Franklin Basin.
FBSC O
Drumaspis
Maladia n. sp. 8
New Genus B
Pseudagnostus
Litagnostus
New genus A
Wilbernia
Macronodinae indet.
Idahoia
Ptychaspis
Idiomesus
Unidentified pygidia
Unidentified librigenae
TOTAL
Heads
48
17
7
12
3
Tails
71
31
Lib
88
27
31
18
Max Ind
71
31
16
13
7
4
3
4
2
4
1
2
9
Total Sclerites
207
75
38
25
10
8
6
1
2
5
1
2
18
178
167
398
13
7
8
6
1
2
1
1
4
2
91
129
207
Table B11: Spearman rank correlation coefficients comparing crackout and silicified
collections from the same horizon. A value of 1 indicates a perfect positive
correlation; a value of -1 indicates a perfect negative correlation. A value of
zero indicates no correlation. P-values of 0.05 or smaller indicate that the
preceding value of Spearman rank correlation coefficient is statistically
significant; only two Spearman rank correlation coefficients are statistically
significant.
Horizon
Spearman’ P-value
s rank (r)
Qualitative evaluation
Difference in sample size
between silicified and crackout
collections (# of sclerites)
9.6m
0.827
0.009
Statistically significant
111
10.1-10.2m
0.352
0.263
Statistically insignificant
843
10.6-10.72m
0.445
0.159
Statistically insignificant
972
11.2-11.3m
0.759
0.016
Statistically significant
110
208
Table B12: Spearman rank correlation coefficients comparing each silicified collection
to each other silicified collection and each crackout collection to each other
crackout collection. Numbers highlighted in yellow are correlation
coefficients between crackout collections; numbers highlighted in blue are
correlation coefficients between silicified collections. P-values are in
parentheses behind the coefficient; only one value is significant at p < 0.05.
9.6m
10.1-10.2m
10.6-10.72m
11.2-11.3m
9.6m
XXXXXXX
0.477 (0.131)
0.273 (0.384)
0.277 (0.379)
10.1-10.2m
0.698 (0.027)
XXXXXXX
0.164 (0.603)
0.736 (0.020)
10.6-10.72m
0.505 (0.110)
0.202 (0.522)
XXXXXXX
-0.132 (0.674)
11.2-11.3m
0.202 (0.522)
0.489 (0.121)
0.070 (0.818)
XXXXXXX
209
Table B13: Euptychaspidid character matrix. Based on Adrain and Westrop (2001), with
the codings for character 23 corrected and new species added from Adrain and
Westrop (2004a, 2005). The ‘&’ symbol represents both states ‘0’ and ‘2’.
TAXA
Character codings
1
Keithiella depressa
Euptychaspis kirki
Euptychaspis typicalis
Euptychaspis jugalis
Euptychaspis lawsonensis
Euptychaspis dougali
Kathleenella subula
Kathleenella maritima
Kathleenella hamula
Larifugula triangulata
Leiobienvillia leonensis
Sunwaptia carinata
Sunwaptia plutoi
Wilcoxaspis bulbosa
Macronoda prima
Macronoda punctata
Macronoda notchpeakensis
10
20
25
0000000000000000000000000
20100101101002??000011210
2010010110100201000011110
20111101?01002??0100???10
2011110110110211000011010
2100100110100201000011110
0100111100110111000011100
0100101?001101110000????0
01011001001101110000???00
3101100100111111000010120
3101100100110111001001220
10211000001112201001???00
1021100000121000101020000
10011000011102200100???00
10211000002102??0001203?1
10&11000002102??000120311
1121100000220220100120301
210
Table B14: Taxa and sources for ptychaspidid analysis. See text.
Number
1
2
Taxa
Hoytaspis speciosa
Keithiella depressa
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Keithiella intermedia
Keithiella sp. nov.
Keithiella cylindrica
Keithiella patula
Keithiella scrupulosa
Keithia subclavata
Keithia schucherti
Keithia connexa
Keithia similis
Imlerella praecipita
Ptychaspis n. sp. 3
Ptychaspis cf. miniscaensis
Ptychaspis striata
Ptychaspis bullasa
Ptychaspis tuberosa
Ptychaspis granulosa
Ptychaspis sp.
Idiomesus levisensis
21
22
23
24
25
26
27
Idiomesus (TMC 1.373)
Idiomesus n. sp. A
Idiomesus (TMC 1.015)
Idiomesus intermedius
Idiomesus tantillus
Idiomesus infimus
Idiomesus granti
Source
Ludvigsen & Westrop, 1983b
Ludvigsen & Westrop, 1983b; Ludvigsen et
al., 1989
Westrop, 1986a
Adrain & Westrop, 2005
Ludvigsen et al., 1989
Winston & Nicholls, 1967
Bell & Ellinwood, 1962
Ludvigsen et al., 1989
Ludvigsen et al., 1989
Rasetti, 1945
Rasetti, 1944
Loch & Taylor, 2004
herein
Ludvigsen & Westrop, 1986; Westrop, 1986a
Westrop, 1986a
Lochman & Hu, 1959
Westrop, 1986a
Bell et al., 1952
Sohn & Choi, 2005
Ludvigsen & Westrop, 1986; Adrain &
Westrop, 2004a
Unpub. mat. from Two Mile Canyon, ID
herein
Unpub. mat. from Two Mile Canyon, ID
Ludvigsen, 1982
Ludvigsen, 1982; Ludvigsen & Westrop, 1986
Ludvigsen & Westrop, 1986
Ludvigsen & Westrop, 1986; Westrop, 1986a
211
Table B14—continued.
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Idiomesus greggi
Idiomesus ultimus
Macronoda notchpeakensis
Macronoda prima
Macronoda punctata
Sunwaptia plutoi
Sunwaptia carinata
Wilcoxaspis bulbosa
Euptychaspis typicalis
Euptychaspis lawsonensis
Euptychaspis dougali
Euptychaspis kirki
Euptychaspis jugalis
Kathleenella subula
Kathleenella hamulata
Kathleenella maritimata
Larifugula triangulata
Larifugula cf. leonensis
Larifugula leonensis
Proricephalus wilcoxensis
Proricephalus scapane
Alborsella stoecklini
Asioptychaspis subglobosa
Asioptychaspis asiaticus
Asioptychaspis ceto
Changia correcta
Changia cf. C. coreanicus
Changia planulatus
Changia walcotti
Changia manchuricus
Ptychaspis cacus
Ludvigsen & Westrop, 1986; Westrop, 1986a
Ludvigsen & Westrop, 1986
Adrain & Westrop, 2005
Lochman, 1964; Adrain & Westrop, 2005
Loch et al., 1993
Ludvigsen & Westrop, 1986; Westrop, 1986a
Ludvigsen & Westrop, 1986; Westrop, 1986a
Ludvigsen & Westrop, 1986; Westrop, 1986a
Ludvigsen, 1982
Adrain & Westrop, 2005
Adrain & Westrop, 2004a
Westrop, 1995
Winston & Nicholls, 1967
Ludvigsen, 1982
Ludvigsen, 1982
Ludvigsen et al., 1989
Ludvigsen, 1982
Ludvigsen et al., 1989
Ludvigsen, 1982
Westrop, 1986a, 1986c
Westrop, 1986a, 1986c
Kushan, 1973
Zhang & Jell, 1987; Zhu & Wittke, 1989
Zhang & Jell, 1987
Zhang & Jell, 1987
Shergold, 1991b
Shergold, 1991b
Kobayashi, 1957; Shergold et al., 1988
Kobayashi, 1933; Zhang & Jell, 1987
Kobayashi, 1933
Zhang & Jell, 1987
212
Table B15: Characters and character states used in the ptychaspidid phylogenetic
anaylsis.
Characters
Character States
1. Character of anterior margin in anterior view
0=straight; 1=pointed ventrally; 2=dorsally
convex
2. Anterior border
0=Present, band; 1=absent; 2=present, narrow
rim; 3=small medial triangle; 4=present,
medially very long; 5=long, narrow, flat and
rectangular
3. Anterior course of facial suture
0=convergent; 1=divergent
4. Anterior glabellar notch
0=absent; 1=present
5. Anterior border furrow
0=absent; 1=anterior to preglabellar furrow,
deep; 2=narrow, confluent with preglabellar
furrow; 3=discontinuous with preglabellar
furrows at anterior glabellar corners; 4=Very
wide, confluent with preglabellar furrow;
5=anterior to preglabellar furrow, shallow
6. Character of anterior lobe of glabella
0=subrectangular to rounded; 1=merges with
anterior field (preglabellar furrow shallows
medially); 2=suboval in front of S1; 3=suboval
in front of S2
7. Widest point of glabella
0=L1; 1= L2 or post-L2
8. Position of center of eye (or eye notch)
0=at L2; 1= S2 thru frontal lobe; 2=lateral to
anterior glabellar margin
9. Eye
0=present, lunate ; 1=present, flap-like;
2=absent, minute
10. Eye Ridge
0=absent, effaced; 1=present; 2=absent, eyes
abut glabella
11. Glabellar shape
0=parallel sided; 1=tapered; 2=anteriorly
inflated; 3=spindle shaped
12. Continuous S1
0=present; 1=absent
13. Character of S2
0=present, continuous; 1=weak or notch-like;
2=absent
14. Character of S3
0=present, weak; 1=present, strong notches;
2=absent
15. Bacculae (posterolateral fixigenal swelling)
0=present; 1=absent
16. Widened of axial furrow (shallowing of
fixigenal field)
0=absent; 1=present, posteriorly; 2=present,
anteriorly
213
Table B15—continued.
Characters
Character States
17. Cranidial length (minus occipital spine) /
width
0=between72.1-95%; 1=between 56.1-72%;
2=less than 56%; 3=greater than 95.1%
18. Max. glabellar width / interoccular cranidial
width
0=between 39.1-46%; 1= between 46.1-50%;
2=between 50.1-58%; 3=between 59-66%;
4=>66.1%; 5=<39%
19. Occipital spine
0=present; 1=absent
20. Posterior border wrapped around occipital
spine
0=absent; 1=present
21. Glabellar sculpture
0=tuberclate; 1= anastomosing ridges; 2= none;
3=pitted
22. Preglabellar field sculpture
0= none; 1=striations; 2=tubercles
23. Librigenal field sculpture
0=none; 1=striations; 2=tubercles
24. Defined lateral border on librigenae
0=absent; 1=present; 2=weakly; 3=posteriorly
only
25. Narrow dorsal ridge running length of genal
spine
0=absent; 1=present
26. Triangular depression under genal spine
0=present; 1=absent
27. Raised border on pygidium
0=present, marginal; 1=present, bounded
posteriorly by sloping field; 2=absent
28. Dorsally visible pygidial pleurae
0=more than 3; 1=3 or less
29. Pockets at pleural tips under pygidial border 0=absent; 1=present
30. Pleural rim with anastomosing ridges
0=absent; 1=present
31. Number of axial rings
0=5 or more axial rings; 1=less than 5 axial
rings
32. Plectrum
0=absent; 1=present
33. Lengthening of anterior border furrow
medially (see Kathleenella)
0=absent; 1=present
34. Facial suture
0=opisthoparian; 1=proparian
35. Weak sagital glabellar ridge(?) on exfoliated 0=absent; 1=present
surfaces
36. Broad, effaced, triangular fixigenae with
anterior apex at axial furrow
0=absent; 1=present
214
Table B15—continued.
Characters
Character States
37. Fixigenal sculpture
0=none; 1=tubercles; 2=anastomosing ridges;
3=pitting
38. Tubercles on posterior fixigenal border
0=absent; 1=present
39. Occipital node
0=present; 1=absent
40. Furrow inflected partially down genal spine 0=absent; 1=present
from proximal end (junction of lateral and
posterior border furrows continuing down genal
spine)
41. Elevation of fixigenal field
0=raised, subequal to glabella; 1=raised or
subequal only interoccularly; 2=low
42. Slope of preglabellar field in lateral view
(sag)
0=between ≈40-75°; 1=near horizontal to less
than 39°; 2=near vertical to overhung by
glabella
43. Preglabellar area length (sag) / sag. cranidial 0=Below 7.9%; 1=between 8-15.9%;
length
2=between 16-30%; 3=above 30.1%
44. Max glabellar width / glabellar sag length
0=below 67%; 1=between 67.1-79%; 2=above
79.1%
45. S4 furrow
0=absent; 1=present
46. Posterior border furrow
0=reaches cranidial margin; 1=isolated from
cranidial margin
47. Occipital furrow
0=strong; 1=weak
215
Table B16: Ptychaspidid phylogenetic analysis character codings. See Table B14 for
taxon numbers.
Taxon
Number
Character codings
1
5
10
15
20
25
30
35
40
45
47
1
2
3
4
0010500000000010111000210?20000000001?110012000
0010300001001010101000210?00100000001?000?11100
10103000010110001?10??????0100100000?00?0221100
5
00102001?10010001110?0?10?0?00?0000000012121100
6
?010200101001?000010???????????000000?0???21??0
7
?010400001101000?01000?????????000001?0?0?21??0
8
0010301001211000011000?????????0001010??2201000
9
0010301001211000111000????0000?00010100?2201000
00102001010110001010?0010?0110100000?0012121000
10
0010301001211000?2100??????????000101?0?22011?0
11
???0?010012110?01210???????????00010????2201??0
12
0110010101011212111030010??????00000001?0011001
13
0100000000001000101001??00001010000011010002010
14
0110000100101000121011111?000000000020010212000
15
0100000100000200121010110??????0000020110202000
16
0100000100000?00111001210?00101000001?010012000
17
?1?00001000002002010??????0010100000????0201000
18
?1000001010002?022100??20??????000001??10202000
19
?10000110?200010011011?????????00000200?0200000
20
11000111202011010210200001000000000030000010110
21
0100010121100200211000000??????0000010000012000
22
?100010120101011201020?????????00000300?0200010
23
0100000101100210211001210??????0000010000012000
24
11000112202012110310200001000010000000000010010
25
1100011220212211221020000??????0000000000210010
26
1101010220101111231020?????????000000?0??221??0
27
?100010221101??12010?0?????????0000010??02220?0
28
0100010221100011211020????0010100000??0?0210??0
216
Table B16—continued.
#
1
29
?100011?20212211011020?????????00000000?02100?0
30
220?2211202022112310200001001000000000100202010
31
??00?21120202211131020????001000?000001?0202010
32
??00?21120202211??102?????0?1000?000001??20?010
33
200022112120121212100001010010000000101011110?0
34
20002211212012?2211000?????????000001???1112010
35
2000221121201002121020?????????00000301?1201000
36
0201531010200011050131111?1101100000201?0011100
37
02115310102002101001310010110100000020100202000
38
020?5010100012121501111100110110000020100022000
39
???1?31010200010?10131101?1101000000??1002021?0
40
?211531110200211010111?????????000002?1???21000
41
1301100110011010050000231?110110000011100021000
42
1300100110011210050002230??????0100011100020000
43
?30011011000101011?????????????010000?????21000
44
0300521111211210100020030?210110000000100021001
45
?301121111211010130020?????????00000301?2022000
46
?300521110211210120?20????2000000000001?2122001
47
20104001011010?0301020?????0000100000?0?01300?0
48
14104000?11010023010?0?????????10000????0131100
49
001000000230111012102011??200010000?00112120100
50
010003110?200202121010?0??1100100000200?2200000
51
??00?3110?2002??11101???0??????0000?2?0??2020?0
52
010003110?20020211101?120??????000002?102201000
53
?510?00102111210141020????2000000001001?2121001
54
?510?00102311210141020020?210010000100112121001
55
?510?001123012101?1020020?2?00100001000?2112000
56
?510?001121????0141020020?????10000100??212????
57
58
?510?001?21112?01?1020??0?000010000100??21210?1
5
10
15
20
25
30
35
40
45
47
01?0?000000000201?1102?????????0000011??0202000
217
Table B17: Character state changes for the phylogenetic tree in figure A44 under
ACCTRAN. See table B15 for character states.
Branch
Number (see
figure B44)
Number of
Changes
Character State Changes
1.
1
17(0)
2.
1
45(0)
3
5
7(1); 11(2); 35(1); 41(2); 43(0)
4.
1
18(2)
5.
2
1(1); 28(1)
6.
2
12(1); 42(2)
7.
4
1(2); 8(1); 44(0); 45(0)
8.
2
2(4); 16(2)
9.
4
21(2); 32(1); 37(0); 43(3)
10.
4
1(1); 5(4); 11(1); 17(3)
11.
3
15(1); 29(1); 43(1)
12.
2
18(0); 31(0)
13.
5
5(3); 8(0); 37(1); 40(0); 41(0)
14.
2
23(2); 45(1)
15.
1
12(1)
16.
1
17(0)
17.
3
18(0); 28(1); 29(1)
18.
4
5(2); 14(0); 15(0); 39(0)
19.
1
31(0)
20.
2
9(0); 27(1)
21.
1
11(1)
22.
1
28(1)
23.
4
9(1); 39(0); 43(1); 44(2)
24.
2
12(1); 47(1)
25.
3
2(5); 18(4); 24(2)
26.
5
8(0); 14(1); 23(1); 44(0); 45(1)
27.
6
10(2); 11(3); 18(2); 21(2); 27(2); 36(1)
character (state)
218
Table B17—continued.
Branch
Number (see
figure B44
Number of
Changes
Character State Changes
28.
4
2(0); 41(2); 42(1); 43(2)
29.
5
6(1); 12(1); 16(2); 21(3); 47(1)
30.
4
13(1); 23(0); 38(0); 44(1)
31.
2
10(1); 44(1)
32.
6
18(2); 28(0); 30(0); 31(0); 41(2); 42(1)
33.
3
18(0); 27(2); 47(1)
34.
5
4(1); 10(1); 18(3); 37(3); 41(2)
35.
2
6(1); 12(0)
36.
3
4(1); 25(1); 33(0)
37.
3
14(2); 22(2); 44(0)
38.
3
17(0); 18(5); 37(1)
39.
7
6(0); 7(0); 11(0); 21(0); 33(1); 38(1); 44(1)
40.
4
1(1); 5(1); 14(0); 23(2)
41.
8
2(3); 6(2); 12(1); 21(2); 22(0); 23(0); 24(3); 37(0)
42.
2
18(0); 23(0)
43.
2
14(0); 45(1)
44.
4
24(0); 31(0); 42(2); 43(0)
45.
2
8(1); 21(1)
46.
5
3(0); 14(0); 18(5); 43(1); 45(1)
47.
3
16(1); 17(0); 44(1)
48.
5
3(1); 6(3); 13(0); 21(3); 25(1)
49.
3
11(0); 16(2); 18(5)
50.
3
4(1); 8(0); 20(1)
51.
8
2(2); 5(5); 9(1); 13(1); 19(0); 39(1); 42(0); 43(2)
52.
3
14(0); 17(0); 44(0)
53.
2
15(1); 30(1)
54.
2
18(2); 44(0)
55.
2
39(1); 44(1)
character (state)
219
Table B17—continued.
Branch
Number (see
figure B44)
Number of
Changes
Character State Changes
56.
1
24(2)
57.
5
6(3); 16(2); 22(0); 24(0); 41(2)
58.
5
7(1); 11(2); 27(1); 28(1); 40(0)
59.
6
3(1); 11(1); 13(1); 14(0); 25(1); 43(1)
60.
2
22(0); 39(1)
61.
2
18(2); 31(0)
62.
3
21(1); 29(0); 37(2)
63.
3
13(1); 42(0); 46(1)
64.
3
15(2); 20(1); 22(2)
65.
1
44(1)
66.
2
10(1); 18(2)
67.
1
17(2)
68.
2
8(0); 14(0)
69.
3
18(0); 24(2); 38(1)
70.
3
23(1); 42(2); 43(0)
71.
2
10(0); 15(0)
72.
4
11(1); 17(2); 26(1); 40(0)
73.
5
6(1); 9(2); 22(0); 23(0); 24(0)
74.
1
15(0)
75.
7
8(2); 14(0); 16(1); 21(2); 42(2); 44(0); 46(1)
76.
5
1(1); 13(1); 18(0); 31(0); 43(2)
77.
1
44(2)
78.
2
10(0); 37(0)
79.
3
8(1); 37(2); 43(0)
80.
4
4(1); 14(1); 18(3); 44(1)
81.
5
7(1); 11(2); 14(2); 17(0); 18(2)
82.
3
29(0); 42(0); 43(1)
83.
3
14(0); 15(0); 45(1)
character (state)
220
Table B17—continued.
Branch
Number (see
figure B44)
Number of
Changes
Character State Changes
84.
3
8(2); 31(1); 37(0)
85.
1
18(3)
86.
3
12(1); 13(2); 42(2)
87.
1
18(1)
88.
1
17(2)
89.
7
1(2); 2(0); 5(2); 6(2); 17(1); 39(1); 44(1)
90.
5
2(2); 13(2); 18(3); 37(0); 44(2)
91.
1
17(2)
92.
4
10(1); 16(2); 24(1); 41(1)
93.
3
14(0); 15(0); 46(0)
94.
4
21(0); 37(1); 42(1); 43(1)
95.
3
17(2); 18(1); 44(2)
96.
4
3(0); 22(1); 29(1); 39(0)
97.
7
2(1); 5(0); 8(1); 10(1); 14(2); 27(0); 31(1)
character (state)
221
REFERENCES
Adrain, J.M.1997. Proetid trilobites from the Silurian (Wenlock-Ludlow) of the Cape
Phillips Formation, Canadian Arctic Archipelago. Palaeontographia Italica, vol. 84, pp.
21-111.
Adrain, J.M., and Fortey, R.A.1997. Ordovician trilobites from the Tourmakeady
Limestone, western Ireland. Bulletin of the Natural History Museum, London. Geology
Series, vol. 53, pp. 79-115.
Adrain, J.M., Lee, D.-C., Westrop, S.R., Chatterton, B.D.E., and Landing, E.2003.
Classification of the trilobite subfamilies Hystricurinae and Hintzecurinae subfam. nov.,
with new genera from the Lower Ordovician (Ibexian) of Idaho and Utah. Memoirs of the
Queensland Museum, vol. 48, pp. 553-586.
Adrain, J.M., and Westrop, S.R.2001. Stratigraphy, phylogeny, and species sampling in
time and space. In Fossils, Phylogeny, and Form: An Analytical Approach(19). J.M.
Adrain, G.D. Edgecombe, and B.S. Lieberman, eds, Kluwer Academic / Plenum
Publishers, New York, NY, pp. 291-322.
Adrain, J.M., and Westrop, S.R.2004a. A Late Cambrian (Sunwaptan) silicified trilobite
fauna from Nevada. Bulletins of American Paleontology, vol. 365, pp. 1-56.
Adrain, J.M., and Westrop, S.R.2004b. Taphonomic control of shallow subtidal fossil
abundance. Abstracts with Programs Geological Society of America, vol. 36, pp. 455456.
Adrain, J.M., and Westrop, S.R.2005. Late Cambrian ptychaspidid trilobites from
western Utah: implications for trilobite systematics and biostratigraphy. Geological
Magazine, vol. 142, pp. 377-398.
Aigner, T.1982. Calcareous tempestites: Storm-dominated stratification in Upper
Muschelkalk limestones (Middle Trias, SW-Germany). In Cyclic and Event
Stratification. G. Einsele, and A. Seilacher, eds, pp. 180-198.
Amsden, T.W., and Barrick, J.E.1986. Late Ordovician—Early Silurian strata in the
central United States and the Hirnantian Stage. Oklahoma Geological Survey Bulletin,
vol. 139, pp. 1-73.
Bell, W.C., Berg, R.R., and Nelson, C.A.1956. Croixan type area—Upper Mississippi
Valley. In El Sistema Cambrico, su Paleogeografia y el Problema de su Base Symposium.
J. Rodgers, ed, Comision Internaconal de Estratigrafia y de la Union Paleontologica
Internacional, Mexico, pp. 415-446.
Bell, W.C., and Ellinwood, H.L.1962. Upper Franconian and lower Trempealeauan
Cambrian trilobites and brachiopods, Wilberns Formation, central Texas. Journal of
Paleontology, vol. 36, pp. 385-423.
Bell, W.C., Feniak, O.W., and Kurtz, V.E.1952. Trilobites of the Franconia Formation,
southeast Minnesota. Journal of Paleontology, vol. 26, pp. 175-198.
222
Berg, R.R.1953. Franconian trilobites from Minnesota and Wisconsin. Journal of
Paleontology, vol. 27, pp. 553-568.
Berg, R.R., and Ross, R.J., Jr.1959. Trilobites from the Peerless and Manitou formations,
Colorado. Journal of Paleontology, vol. 33, pp. 106-119.
Bergström, J.1992. The oldest arthropods and the origin of the crustacea. Acta Zoologica,
vol. 73, pp. 287-291.
Biek, R.F.1999. Geology of Clarkston Mountain (southern Malad Range), Box Elder and
Cache Counties, Utah. In Geology of northern Utah and vicinity(27). L.E. Spangler, and
C.J. Allen, eds, Utah Geological Association, Salt Lake City, UT, pp. 27-43.
Billings, E.1865. Palaeozoic fossils. vol I (4). pp. 169-344.
Bridge, J.1931. Geology of the Eminence and Cardareva quadrangles. Missouri Bureau
of Geology and Mines, 2nd Series, vol. 24, pp. 1-228.
Brown, G., Catt, J.A., Hollyer, S.E., and Ollier, C.D.1969. Partial silicification of chalk
fossils from the Chilterns. Geological Magazine, vol. 106, pp. 583-586.
Bruton, D.L., and Nakrem, H.A.2005. Enrolment in a Middle Ordovician agnostoid
trilobite. Acta Palaeontologica Polanica, vol. 50, pp. 441-448.
Caris, P.L., Geuten, K.P.,Janssens, S.B., and Smets, E.F.2006. Floral development in
three species of Impatiens (Balsaminaceae). American Journal of Botany, vol. 93, pp. 114.
Carson, G.A.1987. Silicification fabrics from the Cenomanian and basal Turonian of
Devon, England: isotopic results. In Diagenesis of Sedimentary Sequences. J.D. Marsall,
ed, Blackwell Scientific Publications, Oxford, pp. 87-102.
Carson, G.A.1991. Silicification of fossils. In Taphonomy: Releasing the Data Locked in
the Fossil Record(9). P.A. Allison, and D.E.G. Briggs, eds, Plenum Press, New York, pp.
456-499.
Chatterton, B.D.E., and Campbell, M.1993. Enrolling in trilobites: A review and some
new characters. Memoirs of the Association of Australasian Palaeontologists, vol. 15, pp.
103-123.
Chatterton, B.D.E., and Ludvigsen, R.1998. Upper Steptoean (Upper Cambrian) trilobites
from the McKay Group of southeastern British Columbia, Canada. In 49. eds, pp. 1-43.
Cherns, L., and Wright, V.P.2000. Missing molluscs as evidence of large-scale, early
skeletal aragonite dissolution in a Silurian sea. Geology, vol. 28, pp. 791-794.
Clark, T.H.1923. A group of new species of Agnostus from Levis, Quebec. Canadian
Field Naturalist, vol. 37, pp. 121-125.
Clarkson, E. N. K., and Whittington, H.B.1997. Enrollment and coaptative structures. In
Part O, Revised. Trilobita. H. B. Whittington, et al., eds. Geological Society of America
and University of Kansas Press, Lawrence, Kansas, pp. 67-74.
223
Clayton, C.J.1986. The chemical environment of flint formation in Upper Cretaceous
chalks. In The Scientific Study of Flint and Chert. G. Sieverking, and M.B. Hart, eds,
Cambridge University Press, Cambridge, pp. 45-54.
Cocks, L.R.M., and Torsvik, T.H.2002. Earth geography from 500 to 400 million years
ago: a faunal and palaeomagnetic review. Journal of the Geological Society, London, vol.
159, pp. 631-644.
Cook, H.E., and Taylor, M.E.1977. Comparison of continental slope and shelf
environments in the Upper Cambrian and lowest Ordovician of Nevada. In Deep-Water
Carbonate Environments. H.E. Cook, and P. Enos, eds, Society of Economic
Paleontologists and Mineralogists, Tulsa, OK, pp. 51-81.
Cotton, T.J., and Fortey, R.A.2005. Comparative morphology and relationships of the
Agnostina. In Crustacea and Arthropod Relationships. S. Koenemann, and R. Jenner, eds,
CRC Press, Boca Raton, FL, pp. 95-136.
Coulter, H.W.1956. Geology of the Southeast Portion of the Preston Quadrangle, Idaho.
Idaho Bureau of Mines and Geology Pamphlet, vol. 107, pp. 1-48.
Daley, R.L., and Boyd, D.W.1996. The role of skeletal microstruture during selective
silicification of brachiopods. Journal of Sedimentary Research, vol. 66, pp. 155-162.
Deiss, C.1938. Cambrian formations and sections in part of the Cordilleran Trough.
Geological Society of America Bulletin, vol. 49, pp. 1067-1168.
Deiss, C.1941. Cambrian geography and sedimentation in the central Cordilleran region.
Bulletin of the Geological Society of America, vol. 52, pp. 1085-1116.
Einsele, G., and Seilacher, A.1991. Distinction of tempestites and turbidites. In Cycles
and Events in Stratigraphy. G. Einsele, W. Ricken, & A. Seilacher, eds, Springer-Verlag,
Berlin, pp. 377-82.
Endo, R., and Resser, C.E.1937. The Sinian and Cambrian formations and faunas of
southern Manchoukuo. In 1. eds, pp. 1-474.
Ervin, M.K.1982. Sedimentary petrology, depositional environment, and diagenesis of
the Middle and Upper Cambrian sequence, Copenhagen Canyon, Bear River Range,
Southeast Idaho. University of Idaho, Moscow, ID, 99 pp.
Ethington, R.L., Droste, J.B., and Rexroad, C.B.1986. Conodonts from subsurface
Champlainian (Ordovician) rocks of eastern Indiana. Indiana Geological Survey Special
Report, vol. 37, pp. 1-32.
Fortey, R.A., and Chatterton, B.D.E.1988. Classification of the trilobite suborder
Asaphina. Palaeontology, vol. 31, pp. 165-222.
Fortey, R.A., and Owens, R.M.1991. A trilobite fauna from the highest Shineton Shales
in Shropshire, and the correlation of the latest Tremadoc. Geological Magazine, vol. 128,
pp. 437-464.
Fortey, R.A., and Theron, J.N.1994. A new Ordovician arthropod, Soomaspis, and the
agnostid problem. Palaeontology, vol. 37, pp. 841-861.
224
Frederickson, E.A.1948. Upper Cambrian trilobites from Oklahoma. Journal of
Paleontology, vol. 22, pp. 798-803.
Frederickson, E.A.1949. Trilobite fauna of the Upper Cambrian Honey Creek Formation.
Journal of Paleontology, vol. 23, pp. 341-363.Furnish, W.M.1938. Conodonts from the
Prairie du Chien (Lower Ordovician) beds of the Upper Mississippi Valley. Journal of
Paleontology, vol. 12, pp. 318-340.
Grant, R.E.1962. Trilobite distribution, upper Franconia Formation (Upper Cambrian),
southeastern Missouri. Journal of Paleontology, vol. 36, pp. 965-998.
Grant, R.E.1965. Faunas and stratigraphy of the Snowy Range Formation (Upper
Cambrian) in southwestern Montana and northwestern Wyoming. Geological Society of
America Memoir, vol. 96, pp. 1-171.
Greggs, R.G.1962. Upper Cambrian biostratigraphy of the southern Rocky Mountains,
Alberta. University of British Columbia, Vancouver, B.C, 255 pp.
Hall, J.1847. Palaeontology of New York, Vol. I, containing descriptions of the organic
remains of the lower division of the New York System (equivalent to the Lower Silurian
rocks of Europe). C/ Van Benthuysen, Albany, 338 pp.
Hall, J.1863. Preliminary notice of the fauna of the Potsdam Sandstone; with remarks
upon the previously known species of fossils and descriptions of some new ones, from
the sandstone of the Upper Mississippi Valley. New York State Cabinet of Natural
History, 16th Annual Report, Appendix D, Contributions to Palaeontology, vol. pp. 119184.
Hall, J. and Clarke, J.M.1892. An introduction to the study of the genera of Palaeozoic
Brachiopoda. Natural History of New York, Palaeontology. Volume 8, Part 1, New York
Geological Survey, C. van Benthuysen & Sons, Albany, 394 pp.
Hall, J., and Whitfield, R.P.1877. Paleontology. United States Geologic Exploration of
the 40th Parallel Report, vol. 4, pp. 198-302.
Hanson, A.M.1953. Upper Cambrian formations in northern Utah and southeastern
Idaho. Intermountain Association of Petroluem Geologists Field Conference Guidebook,
vol. 4, pp. 19-21.
Harlick, A.J.1989. Sedimentology, Paleoecology and diagenesis of the Upper Cambrian
St. Charles Formation, Southern Lakeside Mountains, Utah. University of Utah, Salt
Lake City, UT, 277 pp.
Harrington, H.J., Henningsmoen, G., Howell, B.F., Jaannsson, V., Lochman-Balk, C.,
Moore, R.C., Poulsen, C., Rasetti, F., Richter, E., Richter, R., Schmidt, H., Sdzuy, K.,
Størmer, L., Struve, W., Stubblefield, C.J., Weller, J.M., and Whittington, H.B.1959.
Trilobita. In Treatise on Invertebrate Paleontology, Part O, Arthropoda 1. R.C. Moore,
ed, University of Kansas Press, Lawrence, KS, pp.
Hartz, E. H. and Torsvik, T.H..2002. Baltica upside down; a new plate tectonic model for
Rodinia and the Iapetus Ocean. Geology vol. 30, pp. 255-258.
Hawle, I., and Corda, A.J.C.1847. Prodrom einer Monographie der böhmischen
Trilobiten. pp. 1-176.
225
Haynie, A.V., Jr.1957. The Worm Creek Quartzite Member of the St. Charles Formation,
Utah-Idaho. Utah State, Logan, UT, 39 pp.
Heckel, P.H.1972. Recognition of ancient shallow marine environments. In Recognition
of Ancient Sedimentary Environments. J.K. Rigby, and W.K. Hamblin, eds, pp. 226-286.
Hegna, T.A., Adrain, J.M., and Westrop, S.R.2006. Silicified Upper Cambrian
(Sunwaptan) trilobites from the St. Charles Formation in the Bear River Range of
southeastern Idaho. Palaeontological Association Annual Meeting
Abstracts—Palaeontological Newsletter, vol. 63, pp. 58.
\Henry, J.-L., and Clarkson, E.N.K.1975. Enrollment and coaptations in some species of
the Ordovician trilobite genus Placoparia. Fossils and Strata, vol. 4, pp. 87-95.
Hintze, L.F.1973. Geologic history of Utah. Brigham Young University Geology Studies,
vol. 20, pp. 1-181.
Hintze, L.F., and Palmer, A.R.1976. Upper Cambrian Orr Formation: Its subdivisions and
correlatives in western Utah. United States Geological Survey Bulletin, vol. 1405G, pp.
Holdaway, H.K., and Clayton, C.J.1982. Preservation of shell microstructure in silicified
brachiopods from the Upper Cretaceous Wilmington Sands of Devon. Geological
Magazine, vol. 119, pp. 371-382.
Hou, X.-G.1997. Arthropods of the Lower Cambrian Chengjiang fauna, southwest China.
Fossils and Strata, vol. 45, pp. 1-116.
Howell, B.F., Bridge, J., Deiss, C.F., Edwards, I., Lochman, C., Raasch, G.O., Resser,
C.E., Duncan, D.C., Mason, J.F., and Denson, N.M.1944. Correlation of the Cambrian
formations of North America. Geological Society of America Bulletin, vol. 55, pp. 9931004.
Hu, C.-H.1970. The ontogenies of Ponumia obscura (Lochman), n. g., and of Housia
canadensis (Walcott) (Trilobita) from the Upper Cambrian of the Big Horn Mountains,
Wyoming. Transactions and Proceedings of the Palaeontological Society of Japan, N.S,
vol. 77, pp. 253-264.
Hu, C.-H.1971. Ontogeny and sexual dimorphism of lower Paleozoic Trilobita.
Palaeontographica Americana, vol. 7, pp. 31-155.
Hu, C.-H.1980. Ontogenies of a few Upper Cambrian trilobites from the Deadwood
Formation, South Dakota. Transactions and Proceedings of the Palaeontological Society
of Japan, vol. 119, pp. 371-387.
Hu, C.-H.1986. Ontogenetic development of Cambrian trilobites from British Columbia
and Alberta, Canada (Part II). Journal of Taiwan Museum, vol. 39, pp. 1-44.
Hupé, P.1953. Classification des trilobites. Annales de Paléontologie, vol. 39, pp. 61-168.
Hupé, P.1955. Classification des Trilobites. Annales de Paléontologie, vol. 41, pp. 111345.
Ivshin, N.K.1956. [Upper Cambrian trilobites of Kazakhstan. Part 1]. vol. pp. 1-98.
226
Jacka, A.D.1974. Replacement of fossils by length-slow chalcedony and asociated
dolomitization. Journal of Sedimentary Petrology, vol. 44, pp. 421-427.
Jaekel, O.1909. Über die Agnostiden. Zeitschrift der Deutschen Geologischen
Gesellschaft, vol. 61, pp. 380-401.
Jell, P.A., and Adrain, J.M.2003. Available generic names for trilobites. Memoirs of the
Queensland Museum, vol. 48, pp. 331-553.
Kepper, J.C.1972. Paleoenvironmental patterns in Middle to lower Upper Cambrian
interval in eastern Great Basin. American Association of Petroleum Geologists Bulletin,
vol. 56, pp. 503-527.
Knauth, L.P.1979. A model for the origin of chert in limestone. Geology, vol. 7, pp. 274277.
Knight, J.B.1947. Some new Cambrian bellerophont gastropods. Smithsonian
Miscellaneous Collections, vol. 106, pp. 1-11.
Kobayashi, T.1933. Upper Cambrian of the Wuhutsui Basin, Liaotung, with special
reference to the limit of Chaumitien (or Upper Cambrian), of eastern Asia, and its
subdivision. Japanese Journal of Geology and Geography, vol. 11, pp. 55-155.
Kobayashi, T.1935a. The Cambro-Ordovician formations and faunas of South Chosen.
Palaeontology. Part III. The Cambrian faunas of South Chosen with a special study on the
Cambrian trilobite genera and families. Journal of the Faculty of Science, Tokyo
University, Section 2, vol. 4, pp. 49-344.
Kobayashi, T.1935b. The Briscoia fauna of the late Upper Cambrian in Alaska with
descriptions of a few Upper Cambrian trilobites from Montana and Nevada. Japanese
Journal of Geology and Geography, vol. 12, pp. 39-57.
Kobayashi, T.1936. Cambrian and Lower Ordovician trilobites from northwestern
Canada. Journal of Paleontology, vol. 10, pp. 157-167.
Kobayashi, T.1937. The Cambro-Ordovician shelly faunas of South America. Journal of
the Faculty of Science, Tokyo University, Section 4, vol. 4, pp. 369-522.
Kobayashi, T.1938. Upper Cambrian fossils from British Columbia, with a discussion on
the isolated occurrence of the so-called "Olenus" beds of Mount Jubilee. Japanese Journal
of Geology and Geography, vol. 15, pp. 149-192.
Kobayashi, T.1957. Upper Cambrian fossils from peninsular Thailand. Journal of the
Faculty of Science, Tokyo University, Section 2, vol. 10, pp. 367-382.
Koepnick, R.B.1976. Depositional history of the Upper Dresbachian-Lower Franconian
(Upper Cambrian) Pterocephaliid Biomere from west central Utah. Brigham Young
University Geology Studies, vol. 23, pp. 123-138.
Kreisa, R.D.1981. Storm-generated sedimentary structures in subtidal marine facies with
examples from the Middle and Upper Ordovician of southwestern Virginia. Journal of
Sedimentary Petrology, vol. 51, pp. 823-848.
227
Kushan, B.1973. Stratigraphie und Trilobitenfauna in der Mila-Formation
(Mittelkambrium-Tremadoc) in Alborz-Gebirge (N-Iran). Palaeontographica Abteilung
A, vol. 144, pp. 113-165.
Kwon, Y.K., Chough, S.K., Choi, D.K., and Lee, D.-J.2002. Origin of limestone
conglomerates in the Chosen Supergroup (Cambro-Ordovician), mid-east Korea.
Sedimentary Geology, vol. 146, pp. 265-283.
Lake, P.1907. A monograph of the British Cambrian trilobites. Part II. Monographs of the
Palaeontographical Society, vol. pp. 29-48.
Landing, E.1981. Conodont biostratigraphy and thermal color alteration indices of the
upper St. Charles and lower Garden City Formations, Bear River Range, northern Utah
and southeaster Idaho. Open-File Report, U.S. Geological Survey, vol. 81-740, pp. 1-22.
Lask, P.B.1993. The hydrodynamic behavior of sclerites from the trilobite Flexicalymene
meeki. Palaios, vol. 8, pp. 219-225.
Lee, D.-C., and Chatterton, B.D.E.1997a. Three new proetide trilobite larvae from the
Lower Ordovician Garden City Formation in southern Idaho. Journal of Paleontology,
vol. 71, pp. 434-441.
Lee, D.-C., and Chatterton, B.D.E.1997b. Ontogenies of trilobites from the Lower
Ordovician Garden City Formation of Idaho and their implications for the phylogeny of
the Cheirurina. Journal of Paleontology, vol. 71, pp. 683-702.
Lee, D.-C., and Chatterton, B.D.E.1997c. Hystricurid trilobite larvae from the Garden
City Formation (Lower Ordovician) of Idaho and their phylogenetic implications. Journal
of Paleontology, vol. 71, pp. 862-877.
Lehnert, O., Miller, J.F., Repetski, J.E.1997. Paleogeographic significance of
Clavohamulus hintzei Miller (Conodonta) and other Ibexian conodonts in an early
Paleozoic carbonate platform facies of the Argentine Precordillera. Geological Society of
America Bulletin, vol. 109, pp. 429-443.
Lespérance, P.J.1991. Vincular furrows in some Early Silurian and Devonidan
Phacopidae (Trilobita), predominantly from North America. Journal of Paleontology, vol.
65, pp. 276-294.
Loch, J.D., Stitt, J.H., and Derby, J.R.1993. Cambrian-Ordovician boundary interval
extinctions: implications of revised trilobite and brachiopod data from Mount Wilson,
Alberta, Canada. Journal of Paleontology, vol. 67, pp. 497-517.
Loch, J.D., and Taylor, J.F.2004. New trilobite taxa from Upper Cambrian microbial
reefs in the central Appalachians. Journal of Paleontology, vol. 78, pp. 591-602.
Lochman, C.1956. The evolution of some Upper Cambrian and Lower Ordovician
trilobite families. Journal of Paleontology, vol. 30, pp. 445-462.
Lochman, C.1964. Upper Cambrian faunas from the subsurface Deadwood Formation,
Williston Basin, Montana. Journal of Paleontology, vol. 38, pp. 33-60.
Lochman, C., and Hu, C.-H.1959. A Ptychaspis faunule from the Bear River Range,
southeastern Idaho. Journal of Paleontology, vol. 33, pp. 404-427.
228
Lochman-Balk, C.1956. The Cambrian of the Rocky Mountains and southwest deserts of
the United States and adjoining Sonora Province, Mexico. In El Sistema Cámbrico, su
paleogeografía y el problema de su base; parte II: Australia, América (Congreso
Geológico Internacional, 20), Rogers, J., ed., pp. 529-661.
Lochman-Balk, C.1970. Upper Cambrian faunal patterns on the craton. Geological
Society of America Bulletin, vol. 81, pp. 3197-3224.
Lochman-Balk, C.1971. The Cambrian of the craton of the United States. In Cambrian of
the New World. C.H. Holland, ed, Wiley-Interscience, a division of John Wiley & Sons
Ltd, London, UK, pp. 79-167.
Lochman-Balk, C.1972. Cambrian System. In Geologic atlas of the Rocky Mountain
region. W.W. Mallory, ed, Rocky Mountain Association of Geologists, Denver, pp. 6075.
Longacre, S.A.1970. Trilobites of the Upper Cambrian Ptychaspid Biomere, Wilberns
Formation, central Texas. Paleontological Society Memoir, vol. 4, pp. 1-70.
Ludvigsen, R.1982. Upper Cambrian and Lower Ordovician trilobite biostratigraphy of
the Rabbitkettle Formation, western District of Mackenzie. Royal Ontario Museum Life
Sciences Contributions, vol. 134, pp. 1-188.
Ludvigsen, R., and Westrop, S.R.1983a. Trilobite biofacies of the Cambrian-Ordovician
boundary interval in northern North America. Alcheringa, vol. 7, pp. 301-319.
Ludvigsen, R., and Westrop, S.R.1983b. Franconian trilobites of New York State. New
York State Museum and Science Service Memoir, vol. 23, pp. 1-83.
Ludvigsen, R., and Westrop, S.R.1986. Classification of the Late Cambrian trilobite
Idiomesus Raymond. Canadian Journal of Earth Sciences, vol. 23, pp. 300-307.
Ludvigsen, R., Westrop, S.R., and Kindle, C.H.1989. Sunwaptan (Upper Cambrian)
trilobites of the Cow Head Group, western Newfoundland, Canada. Palaeontographica
Canadiana, vol. 6, pp. 1-175.
M’Coy, F.1849. On the classification of some British fossil Crustacea with notices of
some forms in the University collection at Cambridge. Annals and Magazine of Natural
History, vol. (2) 4, pp. 161-179, 330-335, 392-414.
Maas, A., Waloszek, D., Chen, J.-Y., Braun, A., Wang, X.-Q., and Huang, D.-Y.2004.
Phylogeny and life habits of early arthropods—predation in the Early Cambrian sea.
Progress in Natural Science, vol. 14, pp. 158-166.
Maddison W.P., and Maddison D.R.2005. MacClade. Version 4.08 OSX. Sinauer
Associates, Sunderland, Massachusetts.
Mansfield, G.R.1927. Geography, geology, and mineral resources of part of southeastern
Idaho. United States Geological Survey Professional Paper, vol. 152, pp. 1-453.
Matthew, G.F.1895. The Protolenus Fauna. Transactions of the New York Academy of
Sciences, vol. 14, pp. 101-153.
229
McBride, D.J.1976. Outer shelf communities and trophic groups in the Upper Cambrian
of the Great Basin. Brigham Young University Geology Studies, vol. 23, pp. 139-152.
Miller, S.A.1889. North American Geology and Palaeontology for the use of Amateurs,
Students and Scientists. vol. pp. 718.
Miller, J.F., Ethington, R.L., Evans, K.R., Holmer, L.E., Loch, J.D., Popov, L.E.,
Repetski, J.E., Ripperdan, R.L., and Taylor, J.F.2006. Proposed stratotype for the base of
the highest Cambrian stage at the first appearance datum of Cordylodus andresi, Lawson
Cove section, Utah, USA. Palaeoworld, vol. 15, pp. 384-405.
Müller, K.J., and Walossek, D.1987. Morphology, ontogeny, and life habit of Agnostus
pisiformis from the Upper Cambrian of Sweden. Fossils and Strata, vol. 19, pp. 1-124.
Myrow, P.M., Tice, L., Archuleta, B., Clark, B., Taylor, J.F., and Ripperdan, R.L.2004.
Flat-pebble conglomerate: its multiple origins and relationship to metre-scale
depositional cycles. Sedimentology, vol. 51, pp. 973-996.
Naimark, E.2006. Ontogeny of Agnostida. Palaeoworld, vol. 15, pp. 315-327.
Nelson, C.A.1951. Cambrian trilobites from the St. Croix valley. Journal of Paleontology,
vol. 25, pp. 765-784.
Newell, N.D., Rigby, J.K., Fischer, A.G., Whiteman, A.J., Hickox, J.E., and Bradley,
J.S.1953. Diagenesis of the Capitan Reef Complex and associated rocks. In The Permian
Reef Complex of the Guadalupe Mountains regions, Texas and New Mexico, W. H.
Freeman & Company, San Francisco, pp. 153-182.
Nielson, E.S.1983. Sedimentary petrology, depositional environment, and diagenesis of
the Middle and Upper Cambrian sequence, Two Mile Canyon, Northern Malad Range,
Southeast Idaho. University of Idaho, Moscow, Idaho, 96 pp.
Öpik, A.A.1967. The Mindyallen fauna of north-western Queensland. Bureau of Mineral
Resources, Geology and Geophysics, Australia, Bulletin, vol. 74, pp. vol 1: 404 p. vol 2:
167 p.
Owen, D.D.1852. Description of new and imperfectly known genera and species of
organic remains, collected during the geological surveys of Wisconsin, Iowa, and
Minnesota, by D. D. Owen. Report of a Geological Survey of Wisconsin, Iowa, and
Minnesota; and Incidentally of a Portion of Nebraska Territory, vol. pp. 573-577.
Palmer, A.R.1956. The Cambrian System of the Great Basin in the western United States.
In El Sistema Cámbrico, su paleogeografía y el problema de su base; parte II: Australia,
América (Congreso Geológico Internacional, 20), Rogers, J., ed., pp. 663-681.
Palmer, A.R.1960. Some aspects of the early upper Cambrian stratigraphy of White Pine
County, Nevada and vicinity. Intermountain Association of Petroluem Geologists Field
Conference Guidebook, vol. 11, pp. 53-58.
Palmer, A.R.1962. Glyptagnostus and associated trilobites in the United States. United
States Geological Survey Professional Paper, vol. 374-F, pp. 1-49.
Palmer, A.R.1965. Biomere - a new kind of biostratigraphic unit. Journal of
Paleontology, vol. 39, pp. 149-153.
230
Palmer, A.R.1965. Trilobites of the Late Cambrian Pterocephaliid Biomere in the Great
Basin, United States. United States Geological Survey Professional Paper, vol. 493, pp.
1-105.
Palmer, A.R.1968. Cambrian trilobites of east-central Alaska. United States Geological
Survey Professional Paper, vol. 559-B, pp. 1-115.
Palmer, A.R.1971. The Cambrian of the Great Basin and Adjacent Areas, western United
States. In Cambrian of the New World. C.H. Holland, ed, Wiley-Interscience, a division
of John Wiley & Son Ltd, London, UK, pp. 1-78.
Palmer, A.R.1979. Biomere boundaries reexamined. Alcheringa, vol. 3, pp. 33-41.
Palmer, A.R.1981. Subdivision of the Sauk Sequence. In The Cambrian-Ordovician
transition in the Bear River Range, Utah-Idaho; a preliminary evaluation. In Short Papers
for the Second International Symposium on the Cambrian System. Open-File Report 81743. M.E. Taylor, ed, United States Department of the Interior Geological Survey,
Golden, CO, pp. 161-162.
Paterson, J.R., and Laurie, J.R.2004. Late Cambrian trilobites from the Dolodrook River
limestones, eastern Victoria, Australia. Memoirs of the Association of Australasian
Palaeontologists, vol. 30, pp. 83-111.
Peng, S.-C., Babcock, L.E., Hughes, N.C., and Lin, H.-L.2003. Upper Cambrian
shumardiids from north-western Hunan, China. Special Papers in Palaeontology, vol. 70,
pp. 197-212.
Peng, S.-C., and Robison, R.A.2000. Agnostoid biostratigraphy across the Middle-Upper
Cambrian boundary in Hunan, China. Paleontological Society Memoir, vol. 53, pp. 1104.
Petrunina, Z.E.1973. Novye rody i vidy tremadokskikh trilobitov Zapadnoi Sibiri. Novye
dannye po geologii i poleznym iskopaemym Zapadnoi Sibiri, vol. 8, pp. 59-71.
Pratt, B.R.1992. Trilobites of the Marjuman and Steptoean stages (Upper Cambrian),
Rabbitkettle Formation, southern Mackenzie Mountains, northwest Canada.
Palaeontographica Canadiana, vol. 9, pp. 1-179.
Pratt, B.R.2002. Storms versus tsunamis: Dynamic interplay of sedimentary, diagenetic,
and tectonic processes in the Cambrian of Montana. Geology, vol. 30, pp. 423-426.
Rasetti, F.1944. Upper Cambrian trilobites from the Lévis Conglomerate. Journal of
Paleontology, vol. 18, pp. 229-258.
Rasetti, F.1945. New Upper Cambrian trilobites from the Lévis Conglomerate. Journal of
Paleontology, vol. 19, pp. 462-478.
Rasetti, F.1959. Trempealeauian trilobites from the Conococheague, Frederick and Grove
limestones of the central Appalachians. Journal of Paleontology, vol. 33, pp. 375-399.
Rasetti, F.1961. Dresbachian and Franconian trilobites of the Conococheague and
Frederick limestones of the central Appalachians. Journal of Paleontology, vol. 35, pp.
104-124.
231
Raymond, P.E.1924. New Upper Cambrian and Lower Ordovician trilobites from
Vermont. Proceedings, Boston Society of Natural History, vol. 37, pp. 389-446.
Raymond, P.E.1937. Upper Cambrian and Lower Ordovician Trilobita and Ostracoda
from Vermont. Geological Society of America Bulletin, vol. 48, pp. 1079-1146.
Raymond, P.E.1938. Nomenclature note. Bulletin of the Geological Society of America,
Supplement 48, pp. xv.
Reinhardt, J.1977. Cambrian off-shelf sedimentation, central Appalachians. In DeepWater Carbonate Environments. H.E. Cook, and P. Enos, eds, Society of Economic
Paleontologists and Mineralogists, Tulsa, OK, pp. 83-112.
Resser, C.E.1937. Third contribution to nomenclature of Upper Cambrian trilobites.
Smithsonian Miscellaneous Collections, vol. 95 (22), pp. 1-29.
Resser, C.E.1942. New Upper Cambrian trilobites. Smithsonian Miscellaneous
Collections, vol. 103, pp. 1-136.
Richardson, G.B.1913. The Paleozoic section in northern Utah. American Journal of
Science, vol. 36, pp. 406-416.
Roehl, P.O.1967. Stony Mountain (Ordovician) and Interlake (Silurian) facies analogs of
recent low-energy marine and subaerial carbonates, Bahamas. American Assoication of
Petroleum Geologists Bulletin, vol. 51, pp. 1979-2031.
Roemer, F.1849. Texas, mit besondered Rücksicht auf deutsche Auswanderung und die
physischen Verhaltnisse des Landes. Bonn, pp. 1-464.
Ross, R.J., Jr.1949. Stratigraphy and trilobite faunal zones of the Garden City Formation,
northeastern Utah. American Journal of Science, vol. 247, pp. 472-491.
Ross, R.J., Jr.1951a. Stratigraphy of the Garden City Formation in northeastern Utah, and
its trilobite faunas. Peabody Museum of Natural History, Yale University, Bulletin, vol.
6, pp. 1-161.
Ross, R.J., Jr.1951b. Ontogenies of three Garden City (Early Ordovician) trilobites.
Journal of Paleontology, vol. 25, pp. 578-586.
Ross, R.J., Jr.1953. Additional Garden City (Early Ordovician) trilobites. Journal of
Paleontology, vol. 27, pp. 633-646.
Ross, R.J., Jr.1967. Some Middle Ordovician brachiopods and trilobites from the Basin
Ranges, western United States. United States Geological Survey Professional Paper, vol.
523-D, pp. 1-43.
Runkel, A.C., McKay, R.M., and Palmer, A.R.1998. Origin of a classic cratonic sheet
sandstone: Stratigraphy across the Sauk II-Sauk II boundary in the Upper Mississippi
Valley. Geological Society of Amercia Bulletin, vol. 110, pp. 188-210.
Rushton, A.W.A.1967. The Upper Cambrian trilobite Irvingella nuneatonensis
(Sharman). Palaeontology, vol. 10, pp. 339-348.
232
Salter, J.W.1864. A monograph of the British trilobites from the Cambrian, Silurian, and
Devonian formations. Monographs of the Palaeontographical Society, vol. pp. 1-80.
Saltzman, M. R., C. A. Cowan, A. C. Runkel, B. Runnegar, M. C. Stewart, and A. R.
Palmer. 2004. The Late Cambrian SPICE (∂13C) event and the Sauk II-Sauk III
regression: New evidence from Laurentian basins in Utah, Iowa, and Newfoundland.
Journal of Sedimentary Research 74, no. 3: 366-377.
Sepkoski, J.J., Jr.1982. Flat-pebble conglomerates, storm deposits, and the Cambrian
bottom fauna. In Cyclic and Event Stratification. G. Einsele, and A. Seilacher, eds,
Springer-Verlag, Berlin, pp. 371-385.
Sharman, G.1886. On the new species Olenus nuneatonensis and Obolella granulata,
from the Lower Silurian ('Cambrian", Lapworth), near Nuneaton. Geological Magazine,
vol. (3) 3, pp. 565-566.
Shergold, J.H.1977. Classification of the trilobite Pseudagnostus. Palaeontology, vol. 20,
pp. 69-100.
Shergold, J.H.1988. Review of: Müller, K. J. & Walossek D., 1987. Morphology,
ontogeny, and life habit of Agnostus pisiformis from the Upper Cambrian of Sweden.
Fossils and Strata, 19, 124 pp., 33 pts (US $30.00). Nomen Nudum, vol. 17, pp. 21-25.
Shergold, J.H.1991a. Protaspid and early meraspid growth stages of the eodiscoid
trilobite Pagetia ocellata Jell, and their implications for classification. Alcheringa, vol.
15, pp. 65-86.
Shergold, J.H.1991b. Late Cambrian and Early Ordovician trilobite faunas of the Pacoota
Sandstone, Amadeus Basin, Central Australia. Bureau of Mineral Resources, Geology
and Geophysics, Australia, Bulletin, vol. 237, pp. 15-75.
Shergold, J.H., Burrett, C., Akerman, T., and Stait, B.1988. Late Cambrian trilobites from
Tarutao Island, Thailand. New Mexico Bureau of Mines and Mineral Resources Memoir,
vol. 44, pp. 303-320.
Shergold, J.H., and Geyer, G.2003. The Subcommission on Cambrian Stratigraphy: the
status quo. Geologica Acta, vol. 1, pp. 5-9.
Shiveler, D.J.1986. Sedimentary petrology, depositional environment and diagenesis of
the Cambrian St. Charles Formation southeastern Idaho. University of Idaho, Moscow,
ID, 82 pp.
Shumard, B.F.1861. The Primordial zone of Texas with descriptions of new fossils.
American Journal of Science, 2nd Series, vol. 31, pp. 213-221.
Siebold, C.T.E. von.1845. Lehrbuch ver vergleichenden Anatomie der Wirbellossen
Thiere. In Lehrbuch der Vergleichenden Anatomie. C. T. E. von Siebold and H. Stannius,
eds., Berlin.
Smith, A. B. 1994. Systematics and the Fossil Record: Documenting Evolutionary
Patterns. Oxford: Blackwell Science, 223 pp.
233
Sohn, J.W., and Choi, D.K.2005. Revision of the Upper Cambrian trilobite
biostratigraphy of the Sesong and Hwajeol Formations, Taebaek Group, Korea. Journal
of the Paleontological Society of Korea, vol. 21, pp. 195-200.
Stein, M., Waloszek, D., and Maas, A.2005. Oelandocaris oelandica and the stem
lineage of Crustacea. In Crustacea and Arthropod Relationships. S. Koenenmann, and
R.A. Jenner, eds, pp. 55-71.
Stitt, J.H.1977. Late Cambrian and earliest Ordovician trilobites, Wichita Mountains area,
Oklahoma. Oklahoma Geological Survey Bulletin, vol. 124, pp. 1-79.
Stitt, J.H.1983. Enrolled Late Cambrian trilobites from the Davis Formation, southeast
Missouri. Journal of Paleontology, vol. 57, pp. 93-105.
Stitt, J.H., and Metcalf Straatmann, W.1997. Trilobites from the upper part of the
Deadwood Formation (upper Franconian and Trempealeauan stages, Upper Cambrian),
Black Hills, South Dakota. Journal of Paleontology, vol. 71, pp. 86-102.
Sun, Y.C.1924. Contributions to the Cambrian faunas of North China. Palaeontologia
Sinica, N. S. B, vol. 1 (4), pp. 1-109.
Swofford, D.L.2002. PAUP* Phylogenetic Analysisusing Parsimony and other Methods.
Version 4.0b10. Sinauer Associates, Sunderland, Massachusetts.
Taylor, M.E.1976. Indigenous and redeposited trilobites from Late Cambrian basinal
environments of central Nevada. Journal of Paleontology, vol. 50, pp. 668-700.
Taylor, M.E., and Landing, E.1982. Biostratigraphy of the Cambrian-Ordovician
transition in the Bear River Range, Utah and Idaho, western United States. In The
Cambrian-Ordovician boundary: sections, fossil distributions, and correlations. M.G.
Bassett, and W.T. Dean, eds, Cardiff, pp. 181-191.
Taylor, M.E., Landing, E., and Gillett, S.L.1981. The Cambrian-Ordovician transition in
the Bear River Range, Utah-Idaho; a preliminary evaluation. In Short Papers for the
Second International Symposium on the Cambrian System. Open-File Report 81-743.
M.E. Taylor, ed, United States Department of the Interior Geological Survey, Golden,
CO, pp. 222-227.
Taylor, M.E., and Repetski, J.E.1985. Early Ordovician eustatic sea-level changes in
northern Utah and southeastern Idaho. In Orogenic Patterns and Stratigraphy of northcentral Utah and southeastern Idaho. G.J. Kerns, and R.L. Kerns, Jr., eds, pp. 237-247.
Torsvik, T.H., and Rehnstrom, E.F.2001. Cambrian palaeomagnetic data from Baltica;
implications for true polar wander and Cambrian palaeogeography. Journal of the
Geological Society of London, vol. 158, pp. 321-329.
Tullberg, S.A.1880. Om Agnostus-arterna i de Kambriska aflagringarne vid Andrarum.
Sveriges Geologiska Undersökning., Series C, vol. 42, pp. 1-37.
Turner, F.E.1940. Alsataspis bakeri, a new lower Ordovician trilobite. Journal of
Paleontology, vol. 14, pp. 516-518.
Ulrich, E.O., and Cooper, G.A.1938. Ozarkian and Canadian Brachiopoda. Geological
Society of America Special Papers, vol. 13, pp. 1-323.
234
Vogdes, A.W.1890. A bibliography of Paleozoic Crustacea from 1698 to 1890 including
a list of North American species and a systematic arrangement of genera. In 63. ed, pp. 1177.
Wakeley, L.D.1975. Petrology of the Upper Nounan - Worm Creek Sequence, Upper
Cambrian Nounan and St. Charles Formations, Southeast Idaho. Utah State University,
Logan, UT, 127 pp.
Walch, J.E.I.1771. Die Naturgeschichte der Versteinerungen zur Erläuterung der
Knorrischen Sammlung von Merkwürkigkeiten der Nature., vol. 4, pt. 3. Paul Jonathan
Felstecker, Nürnburg, 184 pp., 81pls.
Walcott, C.D.1879. Description of new species of fossils from the Calciferous Formation.
32nd Annual Report of the New York State Museum of Natural History, vol. pp. 66-67.
Walcott, C.D.1884. The paleontology of the Eureka District, Nevada. United States
Geological Survey Monograph, vol. 8, pp. 1-298.
Walcott, C.D.1885. Note on some Paleozoic pteropods. American Journal of Science,
vol. 30, pp. 17-21.
Walcott, C.D.1890. Description of new forms of Upper Cambrian fossils. Proceedings of
the United States National Museum, vol. 13, pp. 267-279.
Walcott, C.D.1905. Cambrian faunas of China. Proceedings of the United States National
Museum, vol. 29, pp. 1-106.
Walcott, C.D.1908. Cambrian geology and paleontology. No. 1--Nomenclature of some
Cambrian Cordileran formations. Smithsonian Miscellaneous Collections, vol. 53, pp. 112.
Walcott, C.D.1916. Cambrian Geology and Paleontology, III. No. 3 - Cambrian trilobites.
Smithsonian Miscellaneous Collections, vol. 64, pp. 157-258.
Walcott, C.D.1924a. Cambrian geology and palaeontology, V. No. 2 - Cambrian and
Lower Ozarkian trilobites. Smithsonian Miscellaneous Collections, vol. 75(2), pp. 53-60.
Walcott, C.D.1924. Cambrian geology and paleontology, IV. No. 9 - Cambrian and
Ozarkian Brachiopoda, Ozarkian Cephalopoda and Notostraca. Smithsonian
Miscellaneous Collections, vol. 67, pp. 477-544.
Walcott, C.D.1925. Cambrian geology and paleontology, V. No. 3 - Cambrian and Lower
Ozarkian trilobites. Smithsonian Miscellaneous Collections, vol. 75(3), pp. 61-146.
Walossek, D., and Müller, K.J.1990. Upper Cambrian stem-lineage crustaceans and their
bearing upon the monophyletic origin of Crustacea and the position of Agnostus. Lethaia,
vol. 23, pp. 409-427.
Wanless, H.R.1979. Limestone responce to stress: Pressure solution and dolomitization.
Journal of Sedimentary Petrology, vol. 49, pp. 437-462.
Wessa, P.2006. Free Statistics Software, Office for Research Development and
Education. Version 1.1.20, URL http://www.wessa.net/
235
Westergård, A.H.1922. Sveriges olenidskiffer. Sveriges Geologiska Undersökning.
Afhandlingar och Uppsatser Ser. C, vol. 18, pp. 1-205.
Westrop, S.R.1986a. Trilobites of the Upper Cambrian Sunwaptan Stage, southern
Canadian Rocky Mountains, Alberta. Palaeontographica Canadiana, vol. 3, pp. 1-179.
Westrop, S.R.1986b. Taphonomic versus ecologic controls on taxonomic relative
abundance patterns in tempestites. Lethaia, vol. 19, pp. 123-132.
Westrop, S.R.1986c. New ptychaspidid trilobites from the Upper Cambrian Mistaya
Formation of southern Alberta. Canadian Journal of Earth Sciences, vol. 23, pp. 214-221.
Westrop, S.R.1995. Sunwaptan and Ibexian (Upper Cambrian-Lower Ordovician)
trilobites of the Rabbitkettle Formation, Mountain River region, northern Mackenzie
Mountains, northwest Canada. Palaeontographica Canadiana, vol. 12, pp. 1-75.
Westrop, S.R.1996. Temporal persistence and stability of Cambrian biofacies: Sunwaptan
(Upper Cambrian) trilobite faunas of North America. Palaeogeography,
Palaeoclimatology, Palaeoecology, vol. 127, pp. 33-46.
Westrop, S.R., and Adrain, J.M.1998. Trilobite alpha diversity and the reorganization of
Ordovician benthic marine communities. Paleobiology, vol. 24, pp. 1-16.
Westrop, S.R., and Ludvigsen, R.1986. Type species of the basal Ibexian trilobite
Corbinia Walcott, 1924. Journal of Paleontology, vol. 60, pp. 68-75.
Westrop, S.R., Palmer, A.R., and Runkel, A.2005. A new Sunwaptan (Late Cambrian)
trilobite fauna from the Upper Mississippi Valley. Journal of Paleontology, vol. 79, pp.
72-88.
Whitehouse, F.W.1936. The Cambrian faunas of north-eastern Australia. Parts 1 and 2.
Memoirs of the Queensland Museum, vol. 11, pp. 59-112.
Whitfield, R.P.1878. Preliminary descriptions of new species of fossils from the lower
geological formations of Wisconsin. Wisconsin Geological Survey Annual Report for
1877, vol. pp. 50-89.
Whitfield, R.P.1880. Description of new species of fossils from the Palaeozoic
formations of Wisconsin. Annual Report of the Geological Survey of Wisconsin, vol.
1879, pp. 44-71.
Whittington, H.B., and Kelly, S.R.A.1997. Morphological terms applied to Trilobita. In
Part O, Revised. Trilobita. H. B. Whittington, et al., eds. Geological Society of America
and University of Kansas Press, Lawrence, Kansas, pp. 313-329.
Williams, J.S.1948. Geology of the Paleozoic rocks, Logan Quadrangle, Utah. Bulletin of
the Geological Society of America, vol. 59, pp. 1121-1164.
Williams, J.S., and Maxey, G.B.1941. The Cambrian section in the Logan Quadrangle,
Utah and vicinity. American Journal of Science, vol. 239, pp. 276-285.
Wilmot, N.V.1990. Biomechanics of trilobite exoskeletons. Palaeontology, vol. 33, pp.
749-768.
236
Wilson, J.L.1949. The trilobite fauna of the Elvinia Zone in the basal Wilberns
Limestone of Texas. Journal of Paleontology, vol. 23, pp. 25-44.
Wilson, J.L.1951. Franconian trilobites of the central Appalachians. Journal of
Paleontology, vol. 25, pp. 617-654.
Wilson, M.D.1985. Origin of Upper Cambrian flat pebble conglomerates in the northern
Powder River Basin, Wyoming. Rocky Mountain Carbonate Reservoirs: A Core
Workshop SEPM Core Workshop, vol. 7, pp. 1-50.
Winston, D., and Nicholls, H.1967. Late Cambrian and early Ordovician faunas from the
Wilberns Formation of central Texas. Journal of Paleontology, vol. 41, pp. 66-96.
Zhang, W.-T., and Jell, P.A.1987. Cambrian trilobites of North China. Science Press,
Beijing, pp. 1-459.
Zhu, Z.-L., and Wittke, H.W.1989. Upper Cambrian trilobites from Tangshan, Hebei
Province, North China. Palaeontologia Cathayana, vol. 4, pp. 199-230.