Paleobiology,35(1), 2009, pp. 51-62
The influence of lithification on Cenozoic marine biodiversity
trends
Austin
J.W
Hendy
Abstract.-Recent research has corroborated the long-held view that the diversity of genera within
benthic marine communities has increased from the Paleozoic to the Cenozoic as much as three
to fourfold, after mitigating for such biasing influences as secular variation in time-averaging and
environmental coverage. However, these efforts have not accounted for the considerable increase
in the availability of unlithified fossiliferous sediments in strata of lateMesozoic and Cenozoic age.
Analyses presented here on theCenozoic fossil record of New Zealand demonstrate that unlithified
sediments
not only
the amount
increase
of fossil material
and hence
the observed
diversity
therein,
but they also preserve a pool of taxa that is compositionally distinct from lithified sediments. The
implication is that a large component of the difference in estimates of within-community diversity
between Paleozoic and Cenozoic assemblages may relate to the increased availability of unlithified
sediments in the Cenozoic.
Austin
J. W
Hendy.*
Department
of Geology,
University
of Cincinnati,
Cincinnati,
Ohio
45221.
E-mail: [email protected]
*Present
Department
address:
and Geophysics,
of Geology
Post Office
Yale University,
Box 208109,
New
Haven, Connecticut 06520-8109
Accepted:
8August 2008
Introduction
The fossil
record
tors that distort
diversity (Bambach 1977; Sepkoski 1988; Pow
is inherently
apparent
biased
secular
by fac
patterns
of
past biodiversity and ecological change (New
ell 1959; Raup
et al. 1982; Paul
1972; Signor
1998;Alroy 2000;Alroy et al. 2001), including
in available
variations
rock
volume
(Raup
1972, 1976;Miller 2000; Peters and Foote 2001;
Smith
et al. 2003)
2001; Crampton
and patch
iness in the preservation of soft-bodied ani
mals (Allison and Briggs 1991; Briggs 2003).
Recent interest has focused in particular on
temporal
in the quality
variations
of the global
Phanerozoic
fossil
developed
with
methods
can
impose
gists
have
instead
secular
adopted
trends
the ex
their
own
the approach
in the average
of
or
median diversity of individual communities
through
time, commonly
referred
may
be more
com
interval
to interval
sity may
in alpha
variations
a meaningful
provide
diver
yardstick
for
biodiversity change at broader scales, while
avoiding
some of the biases and problems
that
scale (Bambach 1977).
operate on an aggregate
Just as with
the measurement
of global diver
a prerequisite
to stan
sity, it is considered
alpha
diversity
by using
techniques
such
as
es
unique distortions (Bush et al. 2004).
Rather than attempting to census global
biodiversity in aggregate, some paleontolo
monitoring
diversity
rocks
pressed intent to overcome this bias, but sub
sampling
and global
plex than once thought (e.g., Sepkoski 1988),
with
of particular age. Sampling-standardization
have been
pha
and Bambach
rarefaction. This and related methods allow
numerical estimates of diversity at sample siz
leontologists (Miller and Foote 1996;Alroy et
techniques
2002; Bush
the relationship between al
dardize for sampling effort when measuring
of sampling
record by pa
al. 2001), a bias that may be associated
the actual availability
of fossil-bearing
ell and Kowalewski
2004). Although
to as alpha
( 2009 The Paleontological Society. All rights reserved.
(occurrences
or specimens)
smaller
than
those of the original collection,
and hence per
mit
a more meaningful
comparison
among
multiple samples of varying size (e.g.,Miller
and Foote 1996).
Earlier efforts at monitoring variation in
global biodiversity through the Phanerozoic
(e.g., Sepkoski et al. 1981;Sepkoski 1984,1997;
Benton 1995) have suggested that diversity at
the family
level and below
rose exponentially
through theMesozoic-Cenozoic,
a three-
to fourfold
increase
resulting in
relative
to the Pa
0094-8373/09/3501-0004/$1.00
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions
52
J.W.
AUSTIN
A 4000-
80
Global
diversity
iferous sediments in strata of lateMesozoic
and Cenozoic age (Fig. 1B).Given this impor
tant transition in preservation state, its poten
tial effects must be studied more rigorously.
Although an increase in observed local diver
(genera)
3000 -
Within-community
~~~diversity (species)
cu
-60
c
-
c 2000
HENDY
40~
sity of younger
1000
-220
ervational
500
400
50
c,,
c
0
a
40-
-
reflect
the ease
300
200
100
0
Unlithified
Poorly lithified
+ unlithified
30
C.)
biases
that enhance
the recovery
mental
to avoid the confounding
setting
fects of other factors, such as depositional
10
$
ole
I0
500
|SI D I C
400
I PI Tr
300
J leKlIKIPg9N1
200
100
synoptic
of a
analysis
with
1997),
within-community
diversity from open marine environ
ments
(1977)
of Bambach
superimposed.
B, Variation
in
proportion of collections derived from unlithified and
non-lithified (combined unlithified and poorly lithified)
sediments
the Phanerozoic
through
(data from Paleo
Note
that the Cre
biology
Database,
www.paleodb.org).
and Cenozoic
taceous
are subdivided
intervals
into ear
ly and
late Cretaceous
and Paleogene
epochs,
and Neo
gene subperiods.
marine
communities
are
1988), which
Sepkoski
shown an increase from the
Cenozoic
of as much as twoA
recent investigation
IA).
(Bambach
inferred
1977;
to have
to the
Paleozoic
to threefold
(Fig.
(Bush and Bam
has not only confirmed
this long
held view, but also suggested
that the increase
bach
just such an opportunity
to estimate
the loss
of taxonomic
information
lith
associated with
ification bias in the Phanerozoic
fossil record.
Here,
I present
be even higher after adjusting
for such
as secular variation
in ara
influences
biasing
environmental
gonite
dissolution,
coverage,
and
latitudinal
variation
through
the Phaner
ozoic.
That
versity
crease
assessments
of alpha di
said, previous
in
did not account for the considerable
in the availability
of unlithified
fossil
of the diversity
comparisons
mollusc- and brachiopod-dominated
of
fossil as
at a range of spatial scales and with
semblages
environmental
constraints
to demonstrate
not
on the availabil
only the effect of lithification
onomic
composition,
but also its effect on tax
a bias not mitigated
through sampling-standardization techniques.
A
recent
(2009)
independent
addresses
study
similar
by Sessa
issues
affecting
et al.
Pa
leocene-Eocene age skeletal assemblages of
the Gulf
Coastal
Plain, North
America.
Methods
2004)
could
of
in
vertebrate fossil assemblages in the lateMio
cene-Pleistocene of New Zealand provides
ity of fossil material,
(Fig. 1A). A similar pattern has been
demonstrated
for the diversity
of individual
leozoic
benthic
ef
en
self (Kowalewski
et al. 2006). The assembly
a new data set from bulk-sampled
marine
0
1. A, Variation in global Phanerozoic marine in
FIGURE
as perceived
from
biodiversity
database
(redrawn
from Sepkoski
of
vironment, latitudinal position, time-averag
ing, and temporal variations in biodiversity it
Time (Ma)
vertebrate
of
species from unlithified sediments may also
responsible. Alternatively, changes in local di
versity may represent sampling heterogene
ities (different environments or communities
sampled at different times) or real (biological)
increases in regional biodiversity. Therefore,
any investigation into the consequences of
lithification should be sufficiently constrained
geographically and with respect to environ
Time (Ma)
B
rocks may
extracting large numbers of specimens, pres
data
Samples and Preparation.-The
primary
set for this investigation
is composed
of 169
in age from late Mio
fossil samples,
ranging
cene to Pleistocene,
collected
from a narrow
range of sedimentary
tary basins (Wanganui
Zealand.
Neogene
strong
facies in two sedimen
and East Coast) of New
The extensive
and continuous
late
in these basins exhibits a
succession
lithification
its oldest
gradient between
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions
53
LITHIFICATION AND DIVERSITY
and youngest sedimentary components. A
concerted effort was made tomaintain consis
tentmethods of collection (stratigraphic and
spatial integrity of samples), preparation,
counting, and identification, although sample
fal transgressive environmental gradient
through the time series (Hendy and Kamp
2004,
2007; Hendy
may
iments (e.g.,weathered or fresh outcrops, lith
ified or unlithified bedding planes). Neverthe
less,where possible sufficient sampling effort
whereby
to obtain
made
200-300
per
specimens
collection, amalgamated from multiple repli
cates
collected
along
adjacently
single
hori
zons. In contrast tomore exhaustive collection
methodologies aimed at retrieving maximum
diversities
proach
sons
et al. 2006), this ap
for making
compari
(e.g., Cooper
is more
suitable
at equivalent
lithi
size between
sample
fied and unlithified assemblages. Sampling
was restricted tomollusc- or brachiopod-dom
inated transgressive shell bed facies (Hendy et
al. 2006)
to control
tween-sample
to allow
for be
in time-averaging
variation
through
and
the time series. All
sampled skeletal assemblages were contained
within
a matrix
of sandy
silty
silt,
or
sand,
of
sand and the relative composition
in each
remains
similar
lithologies
sampled
These
samples
repre
time interval studied.
to midshelf
bathymet
sented lower shoreface
pebbly
ric settings,
strates, and
from sandy or sandy silty sub
consis
exhibited
characteristics
tentwith within-habitat time-averaging. This
of minimizing
has the advantage
approach
and ta
effects of environment
the potential
phonomy on temporal signals (Peters 2004;
Kowalewski
et al. 2006),
but does
limit
inter
pretations to the chosen environment.
In addition,
a subset
with
a set of analyses
of these samples
inated by a single
Tawera, which
gene
ubiquitous
carried
that were
infaunal
is present
fossiliferous
throughout
in New
deposits
1990). This data
(Beu and Maxwell
53 bulk samples
prises
was
representing
association of lateMiocene-early
to one of three
lith
easily
be
sieved
and
individual
speci
mens are entirely free ofmatrix; poorly lithified,
samples
or disaggre
can be sieved
gated following considerable preparation and
individual specimens cannot be parted entire
ly frommatrix; and lithified,whereby samples
be
cannot
sieved
slabs or broken
are best
and
as
observed
individ
and
rock fragments,
ual specimens remain embedded inmatrix.
data set
additional
Data.-An
Occurrence
Fossil
from the New Zealand
was extracted
a base
(FRF) to provide
Record File database
line against which
to compare
the influence
of
lithification state on occurrence data, with the
from the 169 bulk
data obtained
samples. The FRF is a historic archive that re
fossil lo
cords faunal records for individual
in addition
to
calities around New Zealand
abundance
the sedimentary characteristic of localities (for
consis
of relatively
the comparison
tent environments
as possible
as much
et al. 2006).
assigned
ification grades: unlithified,whereby samples
to assem
treatment varied from assemblage
sed
nature
of
enclosing
the
because
of
blage
was
were
Samples
out
dom
bivalve,
further
2006).
that possessed
North
all faunal
semiquantitative
lists
data on lithi
to soft)
from Wanganui
Basin,
Island, New Zealand. These faunal lists
(presence-absence data) encompass the same
cov
temporal interval and similar geographic
data)
(abundance
erage as the bulk-sampled
above. Because
these rep
data set described
resent historical accounts (sometimes com
effort) and
posed
through repeated collection
in their
to be exhaustive
were often intended
inventory of observed or collected fossils
(rather than standardized sampling efforts),
they should therefore show an uncorrected
bias with
Diversity
rangements
samples,
set com
ocene,
Pleistocene
included
fication (expressed as hardness values, from
Zealand
11 unlithified,
10 poorly
lithi
age, including
This
fied, and 21 lithified fossil assemblages.
is therefore thought to rep
subset of samples
resent a single paleocommunity
from the shel
set
cemented
late Neo
the Tawera
data
et al. 2003,
see Crampton
description
This
respect
to any
Analyses.-I
of the bulk-sampled
late Miocene,
and Pleistocene
containing
lithification
compared
effect.
several
data
early Pliocene,
and
samples,
Tawera-dominated
ar
set: all
late Pli
samples
assemblages.
Although all skeletonized invertebrate taxa
were counted, analyses include only molluscs
and brachiopods
Of particu
(see Appendix).
lar interest are early Pliocene and late Pliocene
the only two time in
samples, which provide
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions
54
AUSTIN J.W. HENDY
tervals
in which
direct
comparison
can
be
made between contemporaneous unlithified
and lithified samples. I estimated genus rich
ness
at sampling
imens
quotas
for each sample,
of 100 and 200 spec
using classical rarefac
size
to lithification
according
grade;
remains
comparable
if the per
centage
of specimens
within
samples
is as
sessed rather than the percentage
of genus di
classes,
the pattern
versity.
tion (Miller and Foote 1996), and determined
mean
richness
values
for samples
each of the lithification
grades,
assigned
to
time intervals,
or combination of lithification and time.Mean
richness of FRF data, however, does not in
clude
any standardization
cause
information
on
of sample
individual
size, be
taxon abun
dance within
faunal lists is not available.
all comparisons
I calculated
an "increase
For
fac
tor" representing the ratio of difference in
mean diversity between lithified and unlithi
fied comparisons. The nonparametric Kolmo
test and parametric
gorov-Smirnov
were
comparison)
carried
out
t-test
to provide
Analysis
of mineralogical
also presented
composition
as the percentage
was
of the genus
roster belonging
to categories
of either domi
or aragonitic
shell mineralogy.
supporting
this analysis were
derived
nantly
calcitic
Data
from
the general
literature
(primarily Moore
et al. 2000); mineralogy
was as
to be consistent
within
families. Taxa
1969; Coan
sumed
with
mixed
aragonitic
Anomiidae)
were
it has been
mineralogy;
citic portion
(for
considerable
sta
summarized
and calcitic
regarded
of these
as having
observed
shells
shells (e.g.,
a calcitic
that the cal
remains
dissolution.
These
in the Appendix.
even after
data
are also
tistical confidence on differences between
mean
richness
of unlithified
and
sets. The Kolmogorov-Smirnov
be carried
out
on
lithified
data
Results and Discussion
test could not
the comparisons
Influence of Lithification
between
unlithified and lithified early Pliocene mean
All
richness
ervation
because
the number
of samples
was
and Size Data.-I
Mineralogy
ed the mineralogy
and body
also investigat
size characteris
tic of the fauna to determine
factors
sible for changing
the composition
of
and unlithified
Data
assemblages.
of body size composition
analysis
of
respon
lithified
for
the
samples
were collected from the literature on Cenozoic
and extant New
Zealand Mollusca
(primarily
1979; Fleming
1966; Beu and Maxwell
et al. unpublished
1990; Cooper
data) and are
in the Appendix.
summarized
Body size is in
Powell
by maximum
skeletal
dimension
of an
average
binned
mm,
and all fossil genera were
adult,
into three classes: <15 mm,
15 to 65
and >65 mm. The somewhat
arbitrary
boundaries
for these size classes were chosen
to allow taxa to be spread among only three
and large) size groupings.
(small, medium,
These
lished
differ
in other pub
groupings
of size distribution
analyses
(e.g.,
Bouchet et al. 2002; Cooper
et al. 2006) that fo
cused on a broader
range of molluscan
taxa,
from
including micro-molluscs
Results
genus
on Occurrence
it is intuitive
equal,
Data.
that pres
in loose, unconsolidated
sediments
enhance
the collection
of larger quan
tities of fossil material,
and this factor often
encourages
repeat sampling
of the same as
should
insufficient.
dicated
else being
are presented
roster belonging
(typically <5 mm).
as the percentage
of the
to each of these three
over time. Analysis
semblages
of the data as
sembled
from the FRF (Fig. 2) illustrates
the
effect of lithification
on the richness of indi
vidual
in a single sedimentary
localities
basin,
without
standardization
for variable
sample
size. The lists from individual
localities
rep
a variety of collection
techniques,
rang
ing from exhaustive
to exploratory
surveys,
and may
represent
composite
lists, amended
resent
as a result
time.
of successive
Hence,
reflect greater
might
reflect
increased
diversity
2A,
lists
increases
fourfold
they might
effort,
collecting.
the mean
Figure
longer
sampling
or repeated
pling,
collecting
through
faunal
lists
although
genus
As
illustrated
richness
through
also
ease of sam
in
of these
the late Neo
gene. Although
this may be interpreted
as a
meaningful
biodiversity
trend, the observed
increase occurs concurrently
a decrease
with
in the lithification
of collections
in
included
the analysis.
mum
greater
genus
In aggregate,
are
richness
for collections
mean
and maxi
about
four
from unlithified
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions
times
sedi
55
LITHIFICATION AND DIVERSITY
4
40-
A
-
Ea) 30
-3
D
-
tion,
((Ma)
-
(D 20
ities, then techniques that standardize for var
iations in sampling intensity, such as rarefac
E
I
10
0
Late
Miocene
Early
Pliocene
5.2
10.0
P
Late
icnes 1
Pliocene-Pleistocene
3.6
1.8
Time (Ma)
0.0
that is further
for each
(4)
mitigate
should
1
(3Clthfid
this
bias.
3A
Figure
shows rarefaction curves for the 169 field-col
lected bulk samples of late Miocene-early
Pleistocene age, representing 37 unlithified
and 66 lithified fossil assemblages. At com
parable levels of sampling, most unlithified
samples show considerably higher richness
than those from lithified sediments, a pattern
amplified
lithification
by
the mean
category
curves
(Fig. 3B). At
a
quota of 100 specimens, unlithified sediments
yielded
on average
to 20 genera, whereas
close
lithified sediments produced slightly fewer
inten
than ten genera for the same sampling
2 indicates
that poorly
lithified as
mean
rich
yield an intermediate
sity. Table
semblages
30T
ness
Lithified
Cemented
FIGURE 2.
data
set
number
Poorly
Unlithfrie
(3)
lithified
(2)
Hardness
category
(4)
Effect
(FRF). A,
of genera)
Variations
and mean
even greater
same
of
degree
lithification
of
sediments,
Zealand.
B, Mean
Basin, New
(cross-hatch)
Wanganui
as
for collections
richness
and maximum
(white)
genus
Zea
from New
Data
to lithification
signed
categories.
land Fossil Record
File (http://data.gns.cri.nz/fred/);
= lithified)
to
hardness
values
range from 4 (cemented
1 (soft = unlithified);
intervals.
ments
than
lithified
error bars
for collections
95% confidence
indicate
from
cemented
or
(Table 1, Fig. 2B).
Influence of Lithification on Abundance Data.
If this pattern were related simply to the size
collected
from
the disparity
in richness
be
at larger quotas.
individual
might
of
range
study
interval,
environments
a more
be to focus on a single
it easier
makes
to maintain
approach
biofacies,
which
in
consistency
lithification categories
among
comparison
the
through
effective
(Fig. 4) of 32 sam
time. Rarefaction
by Tawera indicates again that
through
ples dominated
at comparable
levels
of sampling
unli
most
thified samples show considerably higher
richness than those from lithified sediments,
with poorly lithified assemblages showing an
sediments
of the sample
that
Although efforts were made to sample the
from late Miocene-Pleistocene
collections
w
(1)
on an occurrence-based
in mean
richness
(total
of lithification
and
tween lithified and unlithified samples was
local
intermediate
position
(Table 2). Mean
curves
for each lithification
category confirm this pat
tern. At a quota of 100 specimens
richness in
unlithified sediments was approximately two
and a half
times
that of lithified
sediments
(Ta
TABLE1. Genus richness in lithified, poorly lithified, and unlithified sediments of the lateNeogene New Zealand
from
the Fossil
standardized;
Record
genus
File
richness
(FRF) and
from
for field
samples
field-collected
and Tawera
bulk
samples
samples.
rarefied
Mean
genus
richness
for FRF data is un
to 100 specimens
(and to 200 specimens,
in parentheses).
Data set
Subset
NZ Fossil
Record File
Field samples
Mean
Max
All
Pleistocene
Late Pliocene
Early Pliocene
Late Miocene
Taweraassociation
Unlithified
Poorly lithified
25.1
88
19.7 (25.1)
20.6
17.4
20.9
9.6
54
15.9 (20.5)
19.6
14.8
16.0
17.5 (22.5)
13.4 (14.0)
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions
Lithified
6.0
19
9.9 (10.4)
12.6
8.8
8.6
7.8 (8.7)
56
A
AUSTIN J.W. HENDY
-
40
A
Unlithified (n=37)
Lithified (n=66)
30 -
Unlithified (n=11)
Lithified (n=21)
30
2204
u)
c:20
10
0
I
0
0
50
100
150
200
Specimens
B 25-
B 2510
_
_
Unlithified(n=37)
-
50
100
Specimens
CD
150
20
Unlithified(n=1 1
Lithified (n=21 )
Lithified (n=66)
20
co
L..
a)
15
X 15
ca)
(9 10
5
5
0A
I
0
0
25
50
75
100
Specimens
0
25
50
75
100
Specimens
FIGURE 3.
Rarefaction
of census
counts
from bulk sam
of varying
lithification
from late Miocene-Pleisto
sediments
New
of Wanganui
Basin,
Zealand.
A,
Rarefaction
curves
for individual
samples
coded by lith
ples
cene
ification
category
(poorly
lithified
samples
excluded
curves
in A within
of individual
clarity).
B, Means
lithification
with
categories
95% confidence
shaded
for
each
in
counts
FIGURE 4. Rarefaction
of census
from bulk sam
lithification
from
by Tawera of varying
ples dominated
late Miocene-Pleistocene
sediments
of Wanganui
Basin,
curves
sam
New Zealand.
for individual
A, Rarefaction
coded
lithification
lithified
by
category
(poorly
ples
excluded
for clarity).
of individual
B, Means
samples
curves
in A within
each
lithification
with
categories
shaded
95% confidence
intervals.
tervals.
ble 2). Unlithified
sediments
on aver
yielded
age close to 19 genera, whereas
lithified sed
iments produced
fewer than eight
slightly
genera for the same sampling
intensity.
One further analysis
restricted comparisons
to individual
time intervals,
to minimize
the
that temporal variation
in compo
possibility
sition of faunas affected
illustrat
the patterns
ed in Figures
3 and 4. Although
unlithified
and lithified sediments were lacking from late
Miocene
and Pleistocene
successions,
respec
tively, the pattern of increasing diversity with
is evident for
decreasing
degree of lithification
each time interval
analyzed
independently
1), but
(Table
not
through
time
within
any
gle lithification
category. These analyses
onstrate
that sampling-standardization
sities
sils
cannot
alone
niques
the
from unlithified
diversities
difference
of
composition
samples.
discrepancy
et
Sessa
in
easier
samples
of lithified
fundamental
nal
reconcile
from
yielded
al.
the
the
diver
high
of
recovery
fos
with
the lower
a
suggesting
samples,
in the recoverable
lithified
and
(2009)
found
fau
unlithified
a
similar
sampling-standardized
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions
sin
dem
tech
57
LITHIFICATION AND DIVERSITY
100
A
Paul 1998; Cherns
and Wright
although
2000),
dissolution does not necessarily result in com
plete fossil destruction (Bush and Bambach
2004). Additionally, small or thin-shelled skel
80
2=60
etons might
be more
to damage
vulnerable
by
sediment compaction and cabonate dissolu
tion
40
20
0*
Poorly
Lithified
lithified
Lithificationgrade
Unlithified
and Flessa
et al. 2006). The process
(Cooper
of fossil
ex
traction from lithified fossil assemblages from
in the lab, inherently
the field, or preparation
slabs or the
involves the splitting of hardened
Calcite
D Aragonite
fragmentation of larger blocks, processes dur
60
B
et al. 2006; Kidwell
(Cooper
1995; Jablonski and Sepkoski 1996), and small
fossils might also be more readily overlooked
by collectors in the field because of difficulty
in extracting them from lithified sediments
ing which
50
more
and
small
likely
fragile
to be damaged
specimens
are
or destroyed.
The results presented in Figure 5 suggest
that skeletal
I
o-*
20
1
ac
in tax
Medium
(15-65 mm)
Influence
FIGURE 5.
of lithification
on
*
Large
(>65 mm)
taphonomic
fea
of
tures of skeletal
A, Relative
composition
assemblages.
com
and calcitic
skeletal
types. B, Relative
aragonitic
Error bars indicate
size classes.
95%
of various
position
confidence intervals.
and unlithified
lithified
richness between
of early Paleogene
age.
semblages
A recent independent
study by Sessa
as
et al.
(2009) addresses similar issues effecting Pa
leocene-Eocene age skeletal assemblages of
the Gulf Coastal
Plain, North
carbonate
the cementation
sediment,
genus richness
the preferential
etal hardparts.
decline
of matrix
by
a likely candidate
for the
in lithified sediments
is
destruction
wise
of aragonitic
is commonly
of taxa (and
there
skel
dis
Aragonite
diagenesis
(Kidwell
during carbonate
and Flessa 1995; Jablonski and Sepkoski
1996;
is an increase
in the proportion
of
observed diversity contributed by the smallest
and medium
size
classes
of invertebrates
in
poorly lithified and unlithified sediments
(Fig. 5B). The difference, while slight, corrob
orates
small
of the removal of
analyses
independent
on sample-level
size classes
diversity
(Kowalewski
et al. 2006; Sessa et al. (2009). A
of lith
of taxonomic composition
comparison
in this
samples
used
ified and unlithified
indicates
that the ma
study (see Appendix)
in lithi
taxa
that
are
unrepresented
jority of
24
tend
to
be
rare
of
genera
fied samples
(21
less than 3% of mean
constitute
sample abun
dance)
and are aragonitic
(22 of 24 genera).
Conclusions
America.
Because the process of lithification com
involves
in the proportion
occurrences) with predominantly aragonitic
skeletons in lithified sediment (Fig. 5A). Like
Poorly
Lithified
lithified
Lithificationgrade
Small
(<15 mm)
decrease
small,
,L
Unlithified
solved
indeed
onomic content between lithified and unlithi
fied sediment. There is an observable, albeit
E 0
monly
and mineralogy
size
for at least part of the difference
count
In light of existing
assumptions
about
the
influence of lithification the three- to fourfold
diversity increase observed in unlithified
samples
in the FRF data
set is not an entirely
surprising result. Importantly, however, this
reflection
of in
is not a simple
disparity
sediments.
creased
sample size in unlithified
abundance
Rarefaction
analysis
of relative
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions
AUSTIN J.W. HENDY
58
TABLE 2.
ified and
unlithified
of mean
matrix
of
the mean
unlithified
to lithified
Comparison
the NZ Fossil
100 specimens;
tions:
bulk
samples,
samples
File
Record
means
Data set
Unlithified
Lithified
diversity.
(FRF), which
and
all bulk
of
diversity
estimates
sample-level
the late Neogene
of New
Zealand.
increase
samples;
the Tawera
Mean
cannot
factors
E. Plio.,
early
are based
Pliocene
of 200
bulk
lists and
on
specimens
derived
from lith
is computed
as a ratio of
with
rarefied
are
L. Plio.,
samples;
samples
factor"
comparisons,
statistical
sizes
faunal
"increase
of data
the exception
at samples
diversity
in parentheses.
shown
late Pliocene
bulk
from
sizes
of
Abbrevia
samples;
Tawera,
association.
FRF
mean
n
mean
n
25.1
26
6.0
26
4.1
4.13
<0.0001
0.54
<0.001
t
p
D
p
KolmogorovSmirnov
and
be standardized,
at sample
Parameter
Increase factor
t-test
values
among
The
Samples
L. Plio.
E. Plio.
19.7 (25.1)
37 (10)
9.9 (10.4)
66 (28)
2.0 (2.4)
11.20
<0.0001
0.79
<0.001
Tawera
17.4 (22.7)
12 (10)
12.6 (16.5)
19 (4)
1.4 (1.4)
3.10
<0.0041
0.71
<0.001
20.9 (25.3)
6 (4)
8.8 (8.6)
35 (16)
2.4 (2.9)
7.81
<0.0001
17.5 (22.5)
11 (8)
7.8 (8.7)
21 (13)
2.3 (2.6)
9.64
<0.001
0.91
<0.0001
data from bulk samples demonstrated that unlithified sediments through the Cenozoic
lithified assemblages will generally not yield Era. Macroevolutionary trends in the struc
the diversity of unlithified assemblages at ture of marine communities (e.g., increased
comparable or even significantly larger sam
ecospace utilization and evolutionary escala
ple sizes; instead, there are fundamental dif
tion) are likely explanations for any remaining
ferences in the composition and abundance observed increase in within-community di
structure from assemblages of unlithified ver
versity through the Phanerozoic, after consid
sus lithified sediments, which likely relate to eration of lithification, diagenetic, environ
variation in preservation potential within an mental, and latitudinal biases.
assemblage. Variations in the size, robustness,
and mineralogy of skeletal hardparts could
Acknowledgments
lead to their preferential removal or masking
This project was
funded
in part from a
in lithified samples during diagenesis, collec
NASA
Exobiology
Grant
to Arnold
I.Miller
This bias imposed by lith
tion, or preparation.
ification appears be as great as, if not greater
to variations
in aragonite
than, that related
(NAG5-13426), and from a University Dean's
Distinguished Dissertation Fellowship and
dissolution, latitudinal distribution, or envi
ronmental factors through the Phanerozoic
Summer
Grants
Student
Research
Graduate
from the University
to the au
of Cincinnati
thor. Additional
funding was by the American
(Bush and Bambach
2004).
incorporating sampling-stan
Analyses
dardization of genus occurrences (Alroy et al.
2008) suggest that global Phanerozoic diver
the trajectory of dramatic
sity has not shown
in ear
suggested
increase toward the Recent
lier synoptic
analyses
(Sepkoski
et al. 1981;
Museum
of Natural
History
Lerner-Gray
Fund, Geological Society of America, Paleon
Society,
tological
tion
and
of Petroleum
the American
Geologists.
Associa
I thank
the
members of theMarine InvertebrateWorking
Group
of the Paleobiology
Database
(http://
increase was
1984); the Cenozoic
Sepkoski
more muted
than that suggested
by the raw
paleodb.org), particularly J.Alroy, for encour
data. However, other sampling-standardized
also to the University
of Wai
Thanks
to P. Kamp, K. Bland,
kato, and in particular
and A. Vonk for assistance with fieldwork and
analyses
have
claimed
to show
a tripling
even quadrupling of within-community
versity
(Bush and Bambach
2004). The
or
di
results
that a significant
part of
as much as half of it,may
the increase, perhaps
of
to the increasing
availability
be attributable
of this study
suggest
aging
this
research
and
for helpful
discus
sions.
laboratory
facilities.
I also would
like
to ac
knowledge discussions and feedback from A.
Miller,
guson,
C. Brett, D. Buick, K. Bulinksi,
and J. Sessa, and constructive
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions
C. Fer
reviews
59
LITHIFICATION AND DIVERSITY
from B. Bennington
leobiology
Database
and A. Smith.
publication
Literature
This
is Pa
no. 87.
Cited
Allison, P. A., and D. E. G. Briggs. 1991. The taphonomy of soft
ed. The pro
bodied animals. Pp. 120-140 in S. K. Donovan,
cesses of fossilization.
Columbia University
Press, New York.
-.
curves:
of diversity
approximations
Alroy, J. 2000. Successive
28:1023-1026.
ten more years in the library. Geology
R. K. Bambach, K. Bezusko, M. Foote,
Alroy, J., C. R. Marshall,
L. C. Ivany, D. Ja
S. M. Holland,
F. T. F?rsich, T. A. Hansen,
blonski, D. K. Jacobs, D. C. Jones, M. A. Kosnik, S. Lidgard, S.
M.
T. D. Olszewski,
Low, A. I.Miller, P. M. Novack-Gottshall,
D. M. Raup, K. Roy, J. J. Sepkoski
E. Patzkowsky,
Jr.,M. G.
and A. Webber. 2001. Effects of sam
Sommers, P. J.Wagner,
on estimates of Phanerozoic marine di
pling standardization
versification.
Proceedings
es USA 98:6261-6266.
of the National
Academy
of Scienc
Alroy, J.,M. Aberhan, D. J. Bottjer, M. Foote, F. T. F?rsich, P. J.
L. C Ivany, W Kies
Harries, A. J.W Hendy, S. M. Holland,
A. I.Mill
sling, M. A. Kosnik, C R. Marshall, A. J.McGowan,
M. E. Patzkowsky,
S. E. Peters, L. Villier,
er, T. D. Olszewski,
P. J.Wagner, N. Bonuso, P. S. Borkow, B. Brenneis, M. E. Cla
pham, L. M. Fall, C A. Ferguson, V L. Hanson, A. Z. Krug,
C M. Powers, J.A.
K. M. Layou, E. H. Leckey, S. N?rnberg,
Sessa, C Simpson, A. Tomasovych, C C Visaggi. 2008. Phan
invertebrates.
erozoic trends in the global diversity of marine
321:97-100.
R. K. 1977. Species richness inmarine benthic habitats
3:152-167.
Paleobiology
through the Phanerozoic.
in the history
and extinction
Benton, M. J. 1995. Diversification
Science
Bambach,
of life. Science 268:52-58.
of New
1990. Cenozoic Mollusca
Beu, A. G., and P. A. Maxwell.
Zealand.
New Zealand
Survey Paleontological
Geological
Bulletin 58.
and V. Heros. 2002. As
Bouchet, P., P. Lozouet, P. Maestrati,
of species richness in tropical marine
sessing the magnitude
at a
of molluscs
environments:
exceptionally
high numbers
site. Biological
New Caledonia
Journal of the Linnean Society
75:421-436.
in
Briggs, D. E. G. 2003. The role of decay and mineralization
Review
of
fossils. Annual
of soft-bodied
the preservation
Earth and Planetary Sciences 31:275-301.
in
Bush, A. M., and R. K. Bambach. 2004. Did alpha diversity
crease through the Phanerozoic?
Lifting the veils of tapho
and environmental
biases. Journal of Ge
nomic, latitudinal,
ology 112:625-642.
2004. Removing
Bush, A. M., M. J.Markey, and C R. Marshall.
curves: the effects of spatially organized
bias from diversity
on sampling-standardization.
30:
Paleobiology
biodiversity
666-686.
Cherns, L., and V P.Wright. 2000. Missing molluscs
of large-scale, early skeletal aragonite dissolution
sea. Geology
28:791-794.
on an isolated midlatitude
ri?e biodiversity
32:509-532.
continent.
Paleo
biology
as evidence
in a Silurian -.
Coan, E. V, P. V. Scott, and F. R. Bernard. 2000. Bivalve seashells
of Natural
of western North America. Santa Barbara Museum
History, Santa Barbara, Calif.
-.
Cooper, R. A., A. G. Beu, J. S. Cooper, C. M. Jones, B. Marshall,
of the fossil record: esti
P. A. Maxwell.
2006. Completeness
-.
34:241-244.
losses due to small body size. Geology
mating
M.
B.
Mar
R.
C
A.
G.
A.
S.,
Beu,
Jones,
J.
Cooper,
Crampton,
the rock volume bias in
2003. Estimating
shall, P. A. Maxwell.
studies. Science 301:358-361.
paleobiodiversity
J. S., A. G. Beu, R. A. Cooper, J. S. Cooper, M. Foote,
Crampton,
2006.
I.Matcham,
and P. A. Maxwell.
C. M. Jones, B. Marshall,
to declining Cenozoic
shallow ma
The ark was full! Constant
illustrations
of New Zealand
Fleming, C. A. 1966. Marwick's
shells, with a checklist of New Zealand Cenozoic Mollusca.
of Scientific and Industrial Research Bulletin 173.
Department
Pli
Hendy, A. J.W, and P. J. J.Kamp. 2004. Late Miocene-Early
ocene biofacies of Wanganui
and Taranaki Basins, New Zea
land. New
Zealand
Journal of Geology
and Geophysics
47:
769-785.
of Late Miocene-Early
2007. Paleoecology
Pliocene sixth
in the Manutahi-1
order glacioeustatic
core, Wang
sequences
anui-Taranaki
Basin, New Zealand. Palaios 22:325-337.
Hendy, A. J.W, P. J. J. Kamp, and A. J.Vonk. 2006. Cool-water
from Miocene-Pliocene
shelf sequences:
shell bed taphofacies
Society
analyses. Geological
utility in sequence stratigraphie
255:285-307.
of London Special Publication
commu
Jablonski, D., and J. J. Sepkoski Jr. 1996. Paleobiology,
77:
and scales of ecological
pattern. Ecology
nity ecology,
1367-1378.
S. M., and F.W Flessa. 1995. The quality of the fossil
Kidwell,
Annual Re
record: populations,
species, and communities.
of Earth and Planetary Sciences 24:433-464.
F. T. F?rsich, D.
M. Aberhan,
M., W. Kiessling,
2006.
and A. P. Hoffmeister.
Scarponi, S. L. Barbour Wood,
and taphonomic
of the
taxonomic,
components
Ecological,
view
Kowalewski,
of
increase in sample-level
species diversity
post-Paleozoic
32:533-561.
marine benthos. Paleobiology
about Phanerozoic
Miller, A. I. 2000. Conversations
global di
versity. In D. H. Erwin and S. L. Wing, eds. Deep time: Paleo
to No. 4):53-73.
Paleobiology
26(Suppl.
biology's perspective.
ra
the Ordovician
Miller, A. I., and M. Foote. 1996. Calibrating
for Phanerozoic
life: implications
diation of marine
diversity
22:304-309.
trends. Paleobiology
Part
Moore, R. C. 1969. Treatise on invertebrate paleontology.
6, Bivalvia. Geological
N, Mollusca
Society of America, New
of Kansas, Lawrence.
York, and University
of the fossil record. Journal of Pa
Newell, N. D. 1959. Adequacy
leontology 33:488-499.
of the fossil
Paul, C. R. C. 1998. An overview of the completeness
and C. R. C. Paul, eds. The
record. Pp. 1-22 in S. K. Donovan
adequacy of the fossil record. Wiley, Chichester, U.K.
benthic
of Cambrian-Ordovician
Peters, S. E. 2004. Evenness
30:325
in North America. Paleobiology
marine
communities
346.
in the Phanero
Peters, S. E., and M. Foote. 2001. Biodiversity
zoic: a reinterpretation.
27:583-601.
Paleobiology
land and
Powell, A. W B. 1979. New Zealand Mollusca: marine,
freshwater shells. Collins, Auckland, New Zealand.
2002. Increase in evenness
Powell, M. G., and M. Kowalewski.
com
and sampled alpha diversity
through the Phanerozoic:
and Cenozoic marine
fossil assem
parison of early Paleozoic
30:331-334.
blages. Geology
Raup, D. M. 1972. Taxonomic diversity during the Phanerozoic.
Science 177:1065-1071.
an interpre
in the Phanerozoic:
1976. Species diversity
2:289-297.
tation. Paleobiology
taxonom
Sepkoski, J. J., Jr. 1984. A kinetic model of Phanerozoic
III. Post-Paleozoic
ic diversity.
families and mass extinctions.
10:246-267.
Paleobiology
1988. Alpha, beta, or gamma; where does all the diver
14:221-234.
sity go? Paleobiology
1997. Biodiversity:
past, present, and future. Journal of
71:533-539.
Paleontology
Sepkoski, J. J., Jr.,R. K. Bambach, D. M. Raup, and J.W Valentine.
and the fossil record. Na
1981. Phanerozoic marine diversity
ture 293:435-437.
and T. J. Bralower. 2009. The im
Sessa, J.A., M. E. Patzkowsky,
and re
size distribution,
pact of lithification on the diversity,
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions
AUSTIN J.W. HENDY
60
Geol
of marine
invertebrate
covery dynamics
assemblages.
ogy (in press).
Signor, P.W, J.H. Lipps, and P. H. Schultz. 1982. Sampling bias,
in the fossil rec
gradual extinction patterns, and catastrophes
ord. In I. Silver and P. Silver, eds. Geologic implications of im
pacts of large asteroids and comets on the earth. Geological
Society
of America Special Paper 190:291-296.
of the fossil record: im
Smith, A. B. 2001. Large-scale heterogeneity
for Phanerozoic
studies. Philosophical
biodiversity
plications
Transactions of the Royal Society of London B 356:351-367.
Appendix
in this study.
all samples
included
across
and abundance
data, pooled
and brachiopod
genera,
mixed
calcite
(domi
C, calcite; C/A,
Abbreviations:
Polyplacophora;
Polyplac.,
Genera
are listed alphabetically.
n, num
L, lithified; A, aragonite;
(dominant)
and calcite; U, unlithified;
A/C
aragonite
nant) and aragonite;
mixed
percentage
are derived
from the mean
1, < 15 mm; 2, 15-65 mm; 3, >65 mm. Percentages
Size classes:
ber of samples.
states).
at least n is >2 in both
lithification
or lithified
samples
(where
composition
of each taxon in all unlithified
A
list of molluscan
Mean percent
Total
Class
Genus
Min.
Size
Polyplac.
Gastropoda
Gastropoda
Gastropoda
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Scaphopoda
Gastropoda
Gastropoda
Bivalvia
Bivalvia
Gastropoda
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Gastropoda
Bivalvia
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Gastropoda
Gastropoda
Brachiopoda
Gastropoda
Bivalvia
Bivalvia
Gastropoda
Gastropoda
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Gastropoda
Acanthochitona
Aeneator
Alcithoe
Alocospira
Amphibola
Amygdalum
Anchomasa
Anomia
Antalis
Antimelatoma
Antisolarium
Arca
Asa
Astraea
Atamarcia
Ataxocerithium
Atrina
Aulacomya
Austrodosinia
Austrofusus
Austrotoma
Austrovenus
Barbatia
Baryspira
Barytellina
Bassina
Borehamia
Buccinulum
Cabestana
Calliostoma
Calloria
Callusaria
Cardita
Caryocorbula
Cirsotrema
Coelotrochus
Cominella
Cosa
Crassostrea
Crassula
Crepidula
Cuspidaria
Cyclomactra
Diloma
Divalucina
Dosina
Ellicea
A
A
A
A
A
A/C
A
C/A
A
A
A
A
A
A
A
A
A/C
A/C
A
A
A
A
A
A
A
A
C
A
A
A
C
A
A
A
C
A
A
A
C
A
A
A
A
A
A
A
A
1
3
3
2
2
3
3
3
2
2
1
2
2
3
3
1
3
3
3
2
2
3
3
3
2
3
3
3
3
1
2
3
1
1
2
1
2
1
3
3
2
1
3
1
2
3
2
U
L
3
19
19
U %
U n
4.3
1.5
6
7
26
1
5
554
23
3
2
3
1
72
5
4
18
119
13
54
252
296
71
299
4
7
1
46
81
203
57
87
13
50
6
30
1692
2
425
7
3
36
7
47
13
L%
Ln
4.6
4
0.6
5.5
1.2
0.3
4
64
10
3
1.3
4.0
1.7
3
8
8
3.1
17
2.5
12
0.7
2.4
6
26
18.6
18
13.0
2.8
6
47
1.5
2.0
6
13
8.9
1.6
3.5
1.1
1.4
25
32
56
4
3
2.0
13
1.5
3.5
32
33
1.4
1.3
1.2
1.6
21
30
6
14
2.3
*
t
2
83
2
509
518
4
16
40
2
14
54
6
36
2
45
33
10
5
16
2
1
523
10
1357
35
18
17
2
*
*
3.3
3.0
3
11
1.3
3
*
1.6
2.7
19
7
*
0.5
5
1.2
5
6
32.7
15
9.0
86
13.4
54
5.3
1.0
57
4
4.3
4
1.3
12
4.0
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions
*
t
3
*
LITHIFICATION AND DIVERSITY
61
Appendix. Continued.
Mean percent
Total
Class
Gastropoda
Gastropoda
Bivalvia
Bivalvia
Scaphopoda
Gastropoda
Gastropoda
Bivalvia
Gastropoda
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Gastropoda
Bivalvia
Gastropoda
Gastropoda
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Brachiopoda
Bivalvia
Gastropoda
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Brachiopoda
Bivalvia
Gastropoda
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Genus
Emarginula
Eucominia
Eucrassatella
Eumarcia
Fissidentalium
Friginatica
Galeocorys
Gari
Gemmula
Glaphyrina
Glycymeris
Glycymerula
Gobraeus
Goniomyrtea
Gracilispira
Hiatella
Hiatula
Hunkydora
Iredalula
Josepha
Kereia
Lamprodominea
Leporemax
Lepsiella
Leptomya
Lima
Limaria
Limatula
Liratilia
Lutraria
Macomona
Mactra
Manaia
Maoricardium
Maoricolpus
Maorimactra
Marama
Margasella
Mesopeplum
Micrelenchus
Miltha
Modelia
Modiolarca
Modiolus
Moerella
Monia
Myadora
Myllitella
Nassicola
Neilo
Neolepton
Neothyris
Notirus
Notoacmaea
Nucula
Odostomia
Ostrea
Ovicardium
Panis
Panopea
Paphies
Min.
Size
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A/C
A/C
A/C
A
A
A
A
A
A
A
A
A
C
C
A
A
A
A/C
A/C
A
C/A
A
A
A
A
A
C
A
A
A
A
C
A
C/A
A
A
1
2
3
3
3
1
3
2
1
3
3
2
2
1
2
1
2
1
2
2
2
2
3
1
1
3
2
1
1
3
2
3
3
3
3
1
3
2
3
1
3
1
2
3
1
3
1
1
2
2
1
2
2
1
1
1
3
3
3
3
3
L
U
5
72
29
55
1
2
147
2
36
21
194
50
2
19
1
19
3
6
40
6
1
26
1
112
2
12
17
2
14
U %
U n
L%
Ln
0.5
1.7
3
18
1.5
5
2.1
4.0
14
6
18.9
2.0
14
8
1
237
15
4
14
16
2.7
30
3.4
6
108
12
7
1.4
4.5
2.1
2.5
8
7
54
19
6.6
0.8
0.7
10
6
6
2.4
8
1.2
8
2.9
14
2.0
13
3.7
16
0.9
7
*
78
10
29
3
33
3
4
6
4
1028
*
1
*
1.1
14
t
*
5
10
241
126
30
32
5
11
6
2
13
150
4
4
70
16
2
5
1
61
1
2
346
2
1232
*
*
1.5
104
30
160
47
25
12
10
3.4
3.1
2.3
1.9
0.5
3
46
31
5
13
3
13.2
11
12.8
5.6
1.8
8
13
9
1.3
6
*
*
*
*
5
63
0.9
2.3
4
23
0.5
4.2
5
12
4.8
5
21.4
14
6.7
113
9.8
80
1
3
1
8
525
2
891
2
1
28
9
*
*
8.9
87
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions
1.1
4
62
AUSTIN J.W. HENDY
Appendix. Continued.
Total
Class
Gastropoda
Gastropoda
Bivalvia
Bivalvia
Gastropoda
Gastropoda
Bivalvia
Gastropoda
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Bivalvia
Bivalvia
Gastropoda
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Gastropoda
Bivalvia
Gastropoda
Bivalvia
Gastropoda
Bivalvia
Gastropoda
Bivalvia
Gastropoda
Gastropoda
Bivalvia
Gastropoda
Bivalvia
Gastropoda
Bivalvia
Gastropoda
Bivalvia
Gastropoda
Gastropoda
Gastropoda
Gastropoda
Gastropoda
Bivalvia
Bivalvia
Bivalvia
Gastropoda
Bivalvia
Genus
Min.
Size
U
Paracomitas
Patelloida
Patro
Pecten
Pelicaria
Penion
Perna
Pervicacia
Phacosoma
Phenatoma
Phialopecten
Pholadidea
Pleuromeris
Poirieria
Polinices
Poroleda
Pratulum
Protothaca
Proxiuber
Pseudoxyperas
Pteromyrtea
Pterynotus
Puncturella
Purpurocardia
Raina
Resania
Rexithaerus
Ruditapes
Saccella
Scalpomactra
Sectipecten
Semicassis
Serpulorbis
Serratina
Sigapatella
Spissatella
Stiracolpus
Striacallista
Struthiolaria
Talabrica
Tanea
Taniella
Tawera
Taxonia
Tellinota
Tenuiacteon
Tucetona
Tugali
Xenostrobus
Xymene
Zeacolpus
Zeacumantus
Zegalerus
Zemitrella
Zemysia
Zemysina
Zenatia
Zethalia
Zygochiamys
A
A
C/A
C
A
A
A/C
A
A
A
C
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
C
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
C
1
1
3
3
3
3
3
2
2
2
3
2
2
2
2
1
1
2
1
3
2
2
1
2
3
3
2
3
1
2
3
3
2
2
2
2
2
2
3
1
2
1
2
1
2
2
3
1
3
1
3
2
1
1
1
1
3
1
3
2
2
122
7
72
34
96
8
68
4
16
3
96
12
12
4
62
20
8
2
6
26
227
7
5
6
38
2
260
1
45
971
201
106
1
20
24
12
2960
2
10
2
7
2
354
83
16
129
9
44
2
49
893
Mean percent
L
U %
U n
L%
Ln
342
2.8
0.6
2.0
3.3
1.4
1.5
27
6
17
12
42
5
9.3
25
1.5
1.8
7.8
3
3
13
741
1.4
5
14.1
40
53
1.6
1.0
1.7
29
7
3
2.0
15
1.7
3
1.5
26
1.4
4
1.6
4
9.8
9
6
10
123
t
*
t
3
8
8
1
2
96
5
*
*
2.8
2.1
1.2
3
70
3
5.4
25.6
34
5
16.4
4
9.9
9
9.4
22
5.7
6.1
5
7
249
263
222
2
65
57
2
2
19
329
2
74
1
122
*
1.8
4.5
19
67
5.7
4.4
3
47
2.3
39
5.1
11
*
*
*
*
4
4
5670
15.1
115
1.4
4
2.4
2.6
1.6
3.8
1.0
2.0
1.9
7.3
42.5
54
62
17
7
26
4
17
1.5
13.7
7
22
3.2
11
1.6
6
16
56
12.7
21.0
15
8
1
2
166
234
22
912
54
16
340
348
3
Regionally extinct prior to Pleistocene (likely to be undersampled in unlithified samples).
(likely to be undersampled in lithified samples).
t Regional appearance in late Pliocene-Pleistocene
This content downloaded from 144.92.206.90 on Fri, 08 Jan 2016 22:37:39 UTC
All use subject to JSTOR Terms and Conditions