AMER. ZOOL., 26:121-130 (1986)
A Study of the Evolutionary Relationships of Fundulus
Topminnows (Teleostei: Fundulidae)'
E. O. WILEY
Museum of Natural History and Department of Systematics and Ecology,
University of Kansas, Lawrence, Kansas 66045
SYNOPSIS. A hypothesis of the evolutionary relationships of thirty-four species of Fundulus and their closer relatives is presented. The study is restricted to morphological
characters which could be determined to be primitive or derived using the methods of
phylogenetic systematics. Following Parenti, a family Fundulidae is recognized. It is composed of four genera of North American killifishes. (Cyprinodontidae as usually constituted
is polyphyletic.) No convincing characters demonstrate that Fundulus is a natural group
(a monophyletic group). However, all species of Fundulus share four derived characters
with Lucania. The sister group (closest genealogical relative) of Fundulus plus Lucania is
a group composed of the genera Adinia and Leptolucania. Four monophyletic groups of
Fundulus can be recognized based on shared derived characters: (1) subgenus Fundulus
(seven species excluding three species placed in Fontinus); (2) subgenus Fonlinus (six species);
(3) subgenus Xensima (five species); and (4) subgenus Zygonectes (thirteen species). Three
species, F. (Plancterus) zebrinus, F. lima, and F. parvipinnis are of uncertain affinities within
the Lucania-Fundulus clade.
Fundulus is a relatively large genus of
North American fresh and brackish water
topminnows. Between thirty and thirty-five
species are generally recognized as valid.
The majority of species are found in eastern North America. Species are also found
on the west coast (California and Baja California), Cuba, Bermuda, and Yucatan.
Fundulus and its included species have a
long and complex taxonomic history dating from Linnaeus. The last comprehensive revisions are Garman (1895) and Jordan and Evermann (1896). Between 1896
and Miller's (19556) annotated checklist,
work on the genus includes a synopsis of
species and generic reallocations by Jordan
et al. (1930: generic reallocations not generally followed), various aspects of the systematics and biology of species by Carl L.
Hubbs and co-workers (Hubbs, 1926, 1931,
1936; Hubbs et al, 1943; Hubbs and Raney,
1946), a review of suspect Caribbean records and a description of subspecies from
Cuba (Rivas, 1948), descriptions of fossil
taxa from North America (Hibbard and
Dunkle, 1942; Robertson, 1943; Miller,
1945: not all are now considered Fundulus,
see Farris, 1968) and a survey of sensory-
pore patterns by Gosline (1949). Work on
the genus accelerated after Miller's (19556)
annotated list (which included a rough
alignment of species according to Miller's
perception of their relationships but did
not include subgeneric allocations). Brown
(1957) published a key to eastern U.S.
species based on his Master's thesis (Cornell, 1954) plus several additional studies
(Brown, 1955, 1956a, b, 1958). Other
taxonomic studies have concentrated on
specific species or species groups (Thomerson, 1966, 1969; Wiley and Hall, 1975;
Wiley, 1977; Williams and Etnier, 1982;
Possand Miller, 1983; Relyea, 1983). Gross
karyology is known for about 26 species
(Setzer, 1968; Chen and Ruddle, 1970;
Chen, 1971; Fisher and Rachlin, 1972). In
addition, there is a wealth of largely
unpublished information in three theses
(Brown, 1954; Farris, 1968; Griffith, 1972,
some published in Griffith, 1974).
MATERIALS
Material examined includes both whole
specimens preserved in alcohol and osteological material. Osteological materials
were prepared using clear and stain techniques and a technique for preparing disarticulated skeletons (see Mayden and
1
From the Symposium on The Biology of Fundulus
Wiley,
1984). Abbreviations used in figure
heteroclitus presented at the annual Meeting of the
captions are (1) KU (University of Kansas
American Society of Zoologists, 27-30 December
1983, at Philadelphia, Pennsylvania.
Museum of Natural History), (2) UMMZ
121
122
E. O. WILEY
(Museum of Zoology University of Michigan) and (3) USNM (U.S. National Museum
of Natural History). Space limitations preclude listing all specimens examined. However, a list is available on request.
PHYLOGENETIC ANALYSIS AND THE
AFFINITIES OF FUNDULUS
Phylogenetic analysis is a method
designed to reconstruct the genealogical
relationships among organisms (Hennig,
1966; Wiley, 1982). When characters of a
monophyletic group of species vary in such
a way that one species of a species group
has one character while another species or
species group has the alternate homologous character, the method provides a protocol for determining which of these characters is derived and which is primitive.
Further, only the derived characters shared
between species can be used to indicate a
common ancestry {i.e., genealogical) relationship. Grouping is then accomplished
by uniting species that share such characters. Character conflicts are resolved by
applying a parsimony criterion. There are
a number of ways for determining which
of two characters is the derived homologue. In this paper I shall use the "outgroup" criterion which states that when
two homologous characters (=character
states of some authors) are found within a
group (cf. Fundulus), that character found
outside the group in close relatives is the
primitive character while that found only
within the group is the derived character.
Obviously the outgroup criterion works
best when we have a clear idea of the relationships of the group we are working on.
Fortunately, Parenti (1981) has analyzed
the relationships of killifishes (Order
Cyprinodontiformes) and provided a
placement of Fundulus within the context
of killifish evolution. Fundulus has traditionally been placed in the Family Cyprinodontidae along with such groups as rivulines (Rivulus) and pupfishes (Cypri?iodon)
(Myers, 1931). Within this family Fundulus
was aligned with Profundulus (range, Middle America), and the North American
genera Lucania, Leptolucania, and Adinia.
However, Parenti (1981) has shown that
Cyprinodontidae is an unnatural assemblage containing the most primitive (cf.
rivulines) and derived (cf. Cyprinodon)
members of the order. Parenti (1981) recognized a family Fundulidae containing five
genera: Fundulus, Plancterus (Fundulus
zebrinus of most authors), Lucania, Leptolucania, and Adinia. Profundulus (recognized as Family Profundulidae) was placed
in the phylogeny between fundulids and
the more primitive Aplocheiloidei (including such genera as Aplocheilus, Aphyosemion,
and Rivulus). Above fundulids are all other
groups of killifishes including Cyprinodontidae in the restricted sense and poecillids.
Parenti's (1981) analysis is very important because it provides a basis for selecting
outgroups needed for comparison. In this
study, all characters denoted as derived are
restricted to the groups which shared them
while their alternate homologues are found
in the outgroups. Convergences are noted
when they occur. Outgroups used include
species of Profundulus, Lucania, Leptolucania, Adinia, and Valencia. My comparisons have led to some alternate interpretations concerning the alignment of genera
within Fundulidae. I will briefly discuss
relationships within the family before presenting my findings on relationships within
the genus.
Relationships of fundulids
Parenti (1981) listed two derived characters shared by fundulids: (1) autopalatines projecting anteriorly and not articulating with the lateral ethmoids, and (2)
inner arms of the maxillae directed anteriorly. I have trouble distinguishing the
second character. The inner arms are certainly directed forward in Lucania and some
Fundulus (cf. F. grandis) but the condition
in other Fundulus (cf. F. sciadicus) looks
identical to me to Profundulus. However,
there is another character. In all fundulids
the epipleural ribs overlap the pleural ribs
and are either directly connected to the
parapophysis (Adinia, Leptolucania) or to the
parapophysis via connective tissue (Fundulus, Lucania, "Plancterus").
Parenti (1981) grouped all but one
species of Fundulus, Lucania, Leptolucania,
EVOLUTIONARY RELATIONSHIPS OF FUNDULUS
123
TABLE 1. Subgenera and species of Fundulus recognized in this paper.
Group*
Included species
F. heteroclitus (type), F. bermudae, F. "rhizophorae," F. grandis, F. grandissimus, F.
confluentus, and F. pulvereus
2. Subgenus Xenisma
F. stellifer (type), F. catenalus, F. julisia, F. albolineatus, and F. rathbuni
3. Subgenus Fontinus
F. seminolis(type),F. diaphanus, F. waccamensis, F. similis, F. majalis, and/", persimilis
4. Subgenus Zygonectes
F. olivaceus (type), F. notatus, F. euryzonus, F. sciadicus, F. nottii, F. escambiae, F.
lineolatus, F. blairae, F. dispar, F. jenkinsi, F. luciae, F. cingulatus, and F. chrysotus
5. Other species
F. (or P.) zebrinus, F. lima, and F. parvipinnis
* Groups labeled 1-4 are monophyletic. "Group 5" includes species that cannot be placed in any subgenus.
1. Subgenus Fundulus
and Adinia on the basis of the loss of the (noted by Hubbs, 1926) but absent in Adinposttemporal process. The only fundulids ia, Leptolucania, and Profundulus, (character
with a posttemporal process are members not checked for Valencia). Thus it is posof the subgenus Plancterus which Parenti sible that Fundulus, Lucania, and Fundulus
(1981) recognized as a distinct genus for zebrinus form a monophyletic group. If so,
phylogenetic reasons (to include it in Fun- then there is a conflict between the absence
dulus would have rendered Fundulus as of an arm on the posttemporal, seen in all
unnatural according to Parenti's phyloge- members of the family except Fundulus
netic hypothesis). Plancterus is now consid- zebrinus, and the presence of the anal
ered monotypic (P. zebrinus = F. zebrinus of sheath. I conclude that the placement of
Poss and Miller, 1983), and has the derived nominal genera within the family is probcharacter of a convoluted gut. Parenti lematical and a solution must await addi(1982) then grouped Lucania, Adinia, and tional characters.
Leptolucania on the basis of two derived
In rejecting Parenti's (1981) derived
characters and provided a putative derived character which would unite all Fundulus
character for Fundulus (an expanded artic- except F. (or P.) zebrinus, I am unable to
ular process on the second infrapharyn- provide even one alternate character.
gobranchial).
Therefore Fundulus cannot be shown to
I am less convinced of Parenti's (1981) be monophyletic and we cannot exclude
alignments of genera within Fundulidae the possibility that it might be para- or
than I am of her placement of Fundulidae polyphyletic. Four groups of species can be
within the order. First, I cannot convince corroborated on the basis of derived charmyself that the articular surface of the sec- acters as monophyletic. Of these four there
ond infrapharyngobranchial is expanded is evidence that two form a higher monoin Fundulus. Second, of the two characters phyletic group. These groups are shown in
used to support the monophyly of Lucania, Table 1. Note that three species cannot be
Leptolucania, and Adinia, one is definitely placed in the four recognized groups.
convergent (reduction of supraorbital pores Moreover, they do not form a fifth group.
in Lucania is via pore fusion while in Adinia
I shall discuss the monophyly of each
and Leptolucania, the pores never form) and group, present evidence for a sister group
the other is true only of Adinia and Lep- relationship of Xenisma and Fontinus and
tolucania (epipleural ribs directly attached then discuss relationships within each
to parapophysis), and thus is derived for group.
these genera (as are two additional characters, lack of epiotic processes and failure Monophyly of the subgenera as
of supraoccipital pores to develop). Fur- recognized here
ther, an anal sheath covering the urogen1. Subgenus Fundulus. Members of this
ital opening of females and the proximal subgenus are Atlantic and Gulf coastal
ends of the first few anal fin rays is present species. The seven included species have a
in Fundulus, Lucania, andF. (or P.) zebrinus maxilla with a posterior edge that is dis-
124
E. O. WILEY
tinctly concave anteriorly (Fig. la). In other Xenisma, Williams and Etnier, 1982; 10-14
Fundulus (cf. Fig. lb, c) and the outgroups in Fundulus, Brown, 1954; Relyea, 1983;
this part of the edge is either straight or 12-17 in Fontinus; Hubbs and Raney, 1946;
gently curved, or there is a concavity dis- Brown, 1954; Relyea, 1983— F. persimilis
is an exception: Miller, 19556 reported a
tally.
2. Subgenus Xenisma. Members of this mode of 10 for this species). In contrast,
subgenus are largely restricted to the high- species of Zygonectes have modal dorsal ray
land regions of the south central and south- counts of nine or less (Brown, 1954; Thoeastern United States. At least two color merson, 1966; Wiley and Hall, 1975; Wiley,
pattern characters can be interpreted as 1977; Suttkus and Cashner, 1981). Profunderived for males of the group: (1) lack of dulus has a modal count of 12 (Miller, 1955a)
vertical bars on the side of the body (con- and Lucania has a modal count of 11 (Hubbs
vergent with two Zygonectes, F. sciadicus, andand Miller, 1965). Further, F. zebrinus has
F. blairae) and (2) a dark or chromatic band a dorsal fin-ray mode of 14 to 15 (Poss and
on the posterior edge of the caudal fin in Miller, 1983). It would appear that low
nuptial males (from Williams and Etnier, numbers of dorsal fin rays is a synapomor1982). In addition, Baudelot's ligament phy uniting F. luciae, F. chrysotus, and F.
runs between the neurocranium and the cingulatus with other Zygonectes. There is,
cleithrum rather than the posttemporal and however, a problem. Adinia has a modal
cleithrum (convergent with the same con- count of eight (personal observations, KU
dition in the F. nottii species group of Zygo- 17048, 10 specimens, 17060, 6 specimens)
and Leptolucania has 6 or 7 rays (Hubbs and
nectes).
3. Subgenus Fontinus. Fontinus as rec- Miller, 1965). Thus few dorsal fin rays
ognized by Brown (1954) included only F. might possibly be primitive. This is not
seminolis, F. diaphanus, and F. waccamensis. the most parsimonious interpretation if
The other species listed in Table 1 were Parenti's (1981) phylogeny is even half
previously included in the subgenus Fun- correct. Alternatively, low numbers is
dulus (cf Brown, 1954). However, all share derived. If so, either the modal count in
at least three derived characters: (1) the Adinia and Leptolucania is independently
lateral ethmoids overlap the parasphenoid evolved or they are more closely related to
(Fig. 2a) rather than being laterally dis- Zygonectes than Zygonectes is to other Funplaced (Fig. 2b), (2) the lateral processes of dulus. The anal sheath character discussed
the vomer are long and meet the main body above points to a hypothesis of indepenof the bone at an acute angle (Fig. 2a), and dent evolution.
(3) the posterior border of the lacrimal is
convex rather than concave in shape (Fig. Evidence for uniting Xenisma and Fontinus
3a, b versus 3c, d).
Members of these subgenera might be
4. Subgenus Zygonectes. The traditional loosely termed the "elongate" Fundulus.
Zygonectes has included all of the species They share four derived characters: (1) The
listed in Table 1. All except F. chrysotus, F. posterior edge of the dorsal lacrimal process is convex or sigmoid (Fig. 3a-c) rather
cingulatus, and F. luciae have distinctly
than concave (Fig. 3d); (2) The scapular
elongate and rather rectangular jaws (Fig.
process of the cleithrum is well below the
4a) in contrast to the shorter and rather
triangular jaws seen in other Fundulus junction of the scapula and cleithrum (Fig.
5a) rather than even with or just below it
(including the above-mentioned species and
(Fig. 5b). The posterior "notch" of the lacthe outgroups (Fig. 4b, c). The inclusion
of F. chrysotus, F. cingulatus, and F. luciae is rimal is slightly to very wide (Fig. 3a-c
compared to 3d); the frontals are elongate
a bit more problematical since it depends
with an antero-medial process that articon arguing the derived nature of modal
fin-ray counts. Members of Xenisma, Fon- ulates with the nasals and lateral ethmoids
(Fig. 6a, b compared to 6c, d). Of these,
tinus, and Fundulus have modal dorsal finperhaps only the scapular process characray counts of 10 or greater (10 to 14 in
EVOLUTIONARY RELATIONSHIPS OF FUNDULUS
ter is an independent character for the
other three may be correlated with the
elongate condition of the skull seen in both
subgenera.
RELATIONSHIPS WITHIN SUBGENERA
Some resolution of phylogenetic relationships is possible within each subgenus.
Determination of derived characters is
made using other subgenera as well as the
outgroups.
1. Relationships within the subgenus Fundulus. Two monophyletic groups are provisionally recognized. Members of the F.
confluentus-F. pulvereus species pair (Atlantic and northern Gulf coast) have a dark
ocellus on the dorsal fin. The F. heteroclitus
group includes F. heteroclitus (Atlantic Coast
to northern Florida), F. bermudae and F.
"rhizophorae" (both Bermuda), F. grandis
(Atlantic coast of northern Florida to Tampico, Mexico plus a recognized subspecies
on the northern coast of Cuba), and F.
grandissimus (Yucatan Peninsula, Mexico).
These species have square frontal bones
(Fig. 7a compared to 7b, c). Within the
heteroclitus group, F. grandis and F. grandissimus have a derived mandibular pore
count of 9 to 12 (modally 10 and 12,
respectively; Relyea, 1983: modally 8 in
other subgenera). Fundulus heteroclitus and
the two Bermuda species may be united on
the basis of females having a long anal fin
sheath (Relyea, 1983); it is much shorter
in other Fundulus and the outgroups. Resolution of these three species must await
further analysis.
2. Relationships within Xenisma. A phylogenetic analysis of Xenisma has not been
performed. Fundulus catenatus and F. stellifer have high numbers of dorsal fin rays
(mode 13, range 12-15) compared to the
other three (mode 10 to 11, range 9-13:
Williams and Etnier, 1982). The same is
true for anal rays (mode for F. catenatus
14-15, range 13-17; for F. stellifer 13 or
14, range 12-16; for the other three, mode
10 or 11, range 9-11: Williams and Etnier,
1982). The dorsal fin-ray data is ambiguous. Fontinus has high numbers, subgenus
Fundulus has low numbers. The anal finray data is less ambiguous. Fontinus, sub-
125
genus Fundulus, Zygonectes, and Lucania
have low numbers. Thus there is evidence
to recognize a relationship between F. stellifer and F. catenatus. However, Profundulus
has high numbers of anal fin rays (Miller,
1955a) as does Fundulus zebrinus (Brown,
1957). Given the monophyly of Xenisma,
these distributions suggest convergence,
with the condition in F. stellifer and F.
catenatus being shared and derived. Fundulus julisia might be related to this pair
based on male breeding color (red spots
and/or lines with bluish or greenish body
background), but since F. albolineatus is
extinct, this character remains problematical. In conclusion, while relationships
within Xenisma are suggested by some characters, much work has to be done.
3. Relationships within Fontinus. This
subgenus traditionally has included only the
freshwater species F. diaphanus (eastern
North America), F. waccamensis (originally
endemic to Lake Waccamaw, North Carolina, introduced in Philps Lake, North
Carolina), and F. seminolis (Florida). These
species share three derived characters with
three coastal species, the F. similis species
group, traditionally placed in the subgenus
Fundulus. These species are F. similis
(northeastern Florida to Texas), F. majalis
(Atlantic Coast to northeastern Florida),
and F. persimilis (Yucatan Peninsula). The
characters are: (1) the lateral ethmoids
overlay the parasphenoid (Fig. 2a versus b),
(2) the lateral processes of the vomer are
long and meet the main body of the bone
at an acute angle (Fig. 2a versus b), and (3)
the posterior border of the lacrimal is convex rather than concave (Fig. 3a, b versus
c, d).
Fundulus diaphanus and F. waccamensis
have a downward curved hook on the dorsal process of the cleithrum (Fig. 8a versus
b, c). Fundulus seminolis is more closely
related to the F. similis species group based
on a complex of characters found in the
lower posterior gill arch: (1) the fifth ceratobranchials articulate, (2) there are
molariform teeth on the fifth ceratobranchial and the third infrapharyngobranchials, (3) there is an antero-medial flange on
the fourth ceratobranchial which overlaps
126
E. O. WILEY
a.
\ /b.
V I c.
d
b.
FIGS. 1-14. FIG. 1. Medial view of maxillae of (a) Fundulus pulvereus (KU 17339), and (b) F. chrysotus (KU
18165), and (c) a lateral view of F. lineolatus (USNM 213970). FIG. 2. Ventral views of the ethmoid regions
of (a) F. diaphanus (KU 18172) and (b) F. heteroditus (KU 15351). FIG. 3. Lateral views of lacrimals of (a) F.
diaphanus (KU 18172), (b) F. seminolis (KU 18188), (c) F. catenatus (KU 12484), and (d) F. grandis (KU 17051).
FIG. 4. Lateral views of lower jaws of (a) F. escambiae (KU 17890), (b) F. cingulatus (KU 18170), and (c) Lucania
patva (KU 17042). FIG. 5. Lateral views of shoulder girdles of (a) F. similis (KU 12827) and (b) F. grandis (KU
17051). FIG. 6. Ventral views of the frontals of (a) F. catenatus (KU 12484), (b) F. majalis (KU 18180), (c) F.
pulvereus (KU 17339), and (d) F. escambiae (KU 21001). Fie. 7. Ventral views of the frontals of (a) F. heteroditus
(KU 5115), (b) F. confiuentus (KU 17415), and (c) L parva (KU 21002). FIG. 8. Lateral views of the cleithra
of (a) F. diaphanus (KU 18172), (b) F. seminolis (KU 21003), and (c) F. chr;mtu< (KU 16924). FIG. 9. Dorsal
views of the left posterior gill arch elements of F. similis (KU 12827). FIG. 10. Ventral views of half of the
EVOLUTIONARY RELATIONSHIPS OF FUNDULUS
127
an antero-lateral flange on the fifth ceratobranchial (Fig. 9, "a"), (4) there is an
anterior process on the fourth ceratobranchial which is connected via connective tissue to the third hypobranchial (Fig. 9, "b"),
and (5) there is a stout anterior process on
the third hypobranchial which is oriented
anteriorly rather than ventrally (Fig. 9,
"c"). In addition, all four species have a
wide prootic bridge over the lateral canal
and trigemiofacialis chamber of the prootic
(Fig. 10a versus b-d).
Monophyly of the F. similis species group
is indicated by at least two derived characters: (1) the posterior wing of the pterotic has a posterio-medial process (Fig. l l a
versus b) and (2) the urohyal is distinctly
ovoid in shape (from Farris, 1968: Fig. 12a
versus b, c). Within the group F. similis and
F. majalis are unique in the family in having
the frontal overlapping the parietal rather
than the reverse.
4. Relationships among Zygonectes. Given
longitudinal stripe on the side of the body.
Fundulus sciadicus (Great Plains and Ozark
Plateau) shares two derived characters with
the F. nottii species group: (1) the ventral
edge of the maxilla is concave distally (Farris, 1968; Fig. lc), and (2) the prootic bridge
is narrow and forked at the anterior end
(Fig. 10d, but not so thin in F. sciadicus).
The F. nottii species group is composed of
five species showing largely allopatric distributions in eastern North American
freshwaters. The group is united by five
derived characters: (1) a subocular tear
drop is present, (2) females have numerous
flank stripes, (3) Baudelot's ligament runs
from the neurocranium to the cleithrum
(convergent with Xenisma), (4) the posteror
shelf of the pterotic is missing (Fig. 14a
versus b), and (5) the anterior flange of the
pterotic articulates with a large laterally
oriented flange of the sphenotic (which is
oriented dorsally in other members of the
genus; Fig. 14a versus b). The eastern members
of the group, F. lineolatus, F. nottii, and
that F. luciae, F. chrysotus, and F. cingulatus
escambiae,
share three derived characF.
are members of this subgenus, they form
ters:
(1)
pores
4a
and 4b of the supraorbital
an unresolved polychotomy with the
sensory
canal
are
closely situated, (2) there
remaining species. Other members of the
is
a
distinct
melanophore
spot at the base
subgenus share the derived character of
of
the
pectoral
fin,
and
(3)
the anterior
having a rectangular lower jaw (discussed
above). Fundulus jenkinsi (northern Gulf articulatory process of the fourth epibranCoast, brackish water) is primitive in hav- chial is double headed (single headed in
ing a relatively short hyomandibular pro- other members of the genus). Fundulus notcess on the operculum (Fig. 13c) while the tii and F. escambiae are sister species (charremaining species have a relatively long acters discussed by Wiley, 1977). Fundulus
process (Fig. 13a, b) which is convergently dispar and F. blairae share two derived
similar to species outside the subgenus (Fig. characters: (1) a G-type head squamation
13d). The Fundulus olivaceus species group pattern predominates, and (2) females lack
is composed of F. olivaceus, F. notatus (east- vertical bars on the flank (Wiley, 1977).
ern U.S. freshwaters), and F. euryzonus
(restricted to two streams in Louisiana, see
PHYLOGENETIC SUMMARY
Suttkus and Cashner, 1981). They share a
Relationships within the family Funduunique color-pattern character, a broad lidae and within each of the subgenera of
left prootics of (a) F. similis (KU 21004), (b) F. diaphanus (KU 18172), (c) F. notatus (KU 21005), and (d) F.
nottii (KU uncat.). Fie. 11. Ventral views of the left pterotics of (a) F. majalis (KU 17132) and (b) F. diaphanus
(KU 18172). FIG. 12. Ventral views of urohyals of (a) F. similis (KU 12827), (b) F. diaphanus (KU 18172), and
(c) F. catenatus (KU 11550). FIG. 13. Lateral views of left opercula of (a) F. sciadicus (KU 11047), (b) F. lineolatus
(USNM 213970), (c) F. jenkinsi (KU 17310), and (d) F. heteroclitus (KU 15351). FIG. 14. Ventral views of the
left pterotic (bottom) and part of the left sphenotic of (a) F. escambiae (KU 17890) and (b) F. chrysotus (KU
18165). In each figure the bar(s) is 1 mm in length. Arrows point to structures discussed in the text. Several
specimens are present in each catalogued lot.
Fontinus
17.
^ ^ / ^ < * ^ . ^ > <
<:•
17,18
7-11
5,6
FIGS. 15—18. Phylogenetic hypotheses. FIG. 15. One hypothesis of the relationships of genera of the family
Fundulidae to other killifishes. Characters are: (1) twelve derived characters listed by Parenti (1981:366), (2)
two derived characters listed by Parenti (1981:443), (3) four derived characters listed by Parenti (1981:366),
(4) lateral ethmoids directed anteriorly, not articulating with the lateral ethmoids (Parenti, 1981), (5) epipleural
ribs overlapping pleural ribs and connected to the parapophyses of vertebrae, (6) pores of the anterior part
of the supraorbital sensory canal never develop, (7) lateral processes not present on the epiotics, (8) epipleural
ribs articulate directly with the parapophyses, (9) females with an anal sheath, (10) derived characters listed
by Parenti (1981:366). FIG. 16. A phylogenetic hypothesis of the relationships of species of Fundulus belonging
to the subgenera Xenisma and Fontinus. Derived characters are: (1) posterior edge of the dorsal lacrimal process
is convex or sigmoid rather than concave, (2) posterior notch of the lacrimal is wide (Farris, 1968), (3) the
scapular process of the cleithrum is well below the junction of the cleithrum and scapula, (4) frontals elongate
and with anterior lateral processes, (5) males lacking vertical bars on the side of the body (Williams and Etnier,
1982), (6) nuptial males with a pigment bar on the caudalfin(Williams and Etnier, 1982), (7) Baudelot's
ligament connects the cleithrum to the neurocranium, (8) analfinrays modally 13 to 15 rather than less (data
from Williams and Etnier, 1982), (9) lateral ethmoids overlap the parasphenoid dorsally, (10) lateral processes
of the voraer long, meeting the medial shaft at an acute angle, (11) posterior border of the lacrimal convex,
(12) dorsal processes of the cleithrum distinctly hooked downward, (13) fifth ceratobranchials firmly articu-
EVOLUTIONARY RELATIONSHIPS OF FUNDULUS
129
Fundulus are shown in Figures 15, 16, 17, from the National Science Foundation. My
and 18. In the absence of characters indi- thanks to both institutions for their supcating that Fundulus is monophyletic, I have port.
not combined these phylogenies into a sinREFERENCES
gle summary.
ACKNOWLEDGMENTS
J. D. Stewart and Richard L. Mayden
prepared most of the cleared and stain
material used in this study. In addition,
Rick Mayden collected most of the original
meristic data and assisted me throughout
the project. My thanks to them both.
Michael Stevenson and Rick Mayden
helped collect many of the specimens used
in the project. My thanks to them for their
assistance in the field. Special thanks to Jerram L. Brown for sending me a copy of his
original thesis along with the original data
he collected during his study of the genus.
Dr. Robert R. Miller (Museum of Zoology,
University of Michigan), Dr. Stanley H.
Weitzman (U.S. National Museum of Natural History), Dr. Royal D. Suttkus (Tulane
University Museum of Natural History),
and Dr. Carter R. Gilbert (Florida State
Museum of Natural History) arranged loans
and/or exchanges of material used in the
study for which I am most grateful. This
study was funded through a General
Research Grant from the University of
Kansas and by NSF Grant DEB 8103532
Brown, J. L. 1954. Studies on the genus Fundulus.
Master's Thesis, Cornell University .
Brown, J. L. 1955. Local variation and relationships
of the cyprinodont fish, Fundulus rathbuni Jordan
and Meek. J. Elisha Mitchell Soc. 71(2):207-213.
Brown, J. L. 1956a. Distinguishing characters of the
cyprinodont fishes Fundulus cingulatus and Fundulus chrysotus. Copeia 1956(2):251-255.
Brown, J. L. 1956i. Identification and geographic
variation of the cyprinodontid fishes Fundulus olivaceus (Storer) and Fundulus notatus (Rafinesque).
Tulane Stud. Zool. 3:119-134.
Brown, J. L. 1957. A key to the species and subspecies
of the cyprinodont genus Fundulus in the United
States and Canada east of the Continental Divide.
J. Washington Acad. Sci. 47:69-77.
Brown, J. L. 1958. Geographic variation in southeastern populations of the cyprinodont fish Fundulus notti (Agassiz). Amer. Midi. Natur. 59(2):
477-488.
Chen, T. R. 1971. A comparative study of the genus
Fundulus (Teleostei, Cyprinodontidae). Chromosoma 32:436-453.
Chen, T. R. and F. H. Ruddle. 1970. A chromosome
study of four species and a hybrid of the killifish
genus Fundulus (Cyprinodontidae). Chromosoma
29:255-267.
Farris, J. S. 1968. The evolutionary relationships
between the species of the killifish genera Fundulus and Profundulus (Teleostei: Cyprinodontidae). Ph.D. Diss., Univ. Michigan.
Fisher, P. B. and J. W. Rachlin. 1972. Karyotypic
analysis of two sympatric species offish, Fundulus
lated, (14) molariform teeth on the fifth ceratobranchialsand third infrapharyngobranchials, (15) overlapping
flanges present on the fourth and fifth ceratobranchials, (16) anterior processes present on the proximal ends
of the fourth ceratobranchials, (17) process on the third hypobranchial directed anteriorly rather than ventrally, (18) prootic bridge is wide, (19) posterior wing of the pterotic with a medial process, (20) urohyal ovoid
in shape, (21) frontals overlap parietals rather than the reverse. FIG. 17. A phylogenetic hypothesis of the
relationships of species of Fundulus belonging to the subgenus Fundulus. Derived characters are: (1) proximal
ventral edge of the maxilla concave, (2) a distinct ocellus on the dorsal fin, (3) frontals square in outline, (4)
females with a long anal sheath, (5) mandibular pore number modally 10 to 12 rather than lower. FIG. 18.
A phylogenetic hypothesis of the relationships of species of Fundulus belonging to the subgenus Zygonectes.
Derived characters are: (1) dorsal fin ray count modally 8 rather than higher, (2) jaws rectangular and elongate,
(3) hyomandibular process of the operculum elongate, (4) a broad longitudinal stripe on the side of the body,
(5) the distal ventral edge of the maxilla with a concave depression (Farris, 1968), (6) prootic bridge narrow
and forked anteriorly, (7) a subocular "teardrop" present, (8) females with numerous flank stripes, (9) Baudelot's ligament connecting the cleithrum and the neurocranium, (10) posterior flange of the pterotic absent,
(11) the anterior flange of the pterotic laterally oriented and articulating with a posterior flange on the
sphenotic, (12) pores 4a and 4b of the supraorbital sensory canal closely situated, (13) a melanophore spot at
the base of the pectoral fin,(14) a double-headed rather than a single-headed process on the fourth epibranchial,
(15) pores 4a and 4b of the supraorbital sensory canal fused into a single pore in adults (there is some variation
in this character), (16) a cleithral stripe present, (17) "G-type" head squamation pattern (there is some variation
in this character), (18) females without vertical bars on the side of the body. Characters (7), (8), (12), (13),
(15), (16), (17), and (18) from Wiley and Hall (1975) and/or Wiley (1977).
130
E. O. WILEY
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Yucatan. Occas. Pap. Mus. Zool. Univ. Michigan.
Garman, S. 1895. The cyprinodonts. Mem. Mus.
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Comp. Zool. 19(1):1-179.
Gosline, W. A. 1949. The sensory canals in some Myers, G. S. 1931. The primary groups of oviparous
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cyprinodont fishes, with special reference to the
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Michigan 519:1-21.
Parenti, L. R. 1981. A phylogenetic and biogeoGriffith, R. W. 1972. Studies on the physiology and
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(Teleostei, Atherinomorpha). Bull. Amer. Mus.
Ph.D. Diss., Yale Univ.
Natur. Hist. 168(4):335-557.
Griffith, R. W. 1974. Environmental and salinity tol- Poss, S. G. and R. R. Miller. 1983. Taxonomic status
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Hennig, W. 1966. Phylogenetic systematics. Univ. Illi-Relyea, K. 1983. A systematic study of two species
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species of cyprinodontid fish from the Middle Rivas, L. R. 1948. Cyprinodont fishes of the genus
Pliocene of Kansas. Univ. Kansas Publ., St. Geol.
Fundulus in the West Indies, with description of
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Hubbs, C.L. 1926. Studies of the fishes of the order
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Setzer, P. Y. 1968. A karyological analysis of memHubbs, C. L. 1931. Studies of the fishes of the order
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Cyprinodontes. X. Four nominal species of FunTexas at Austin.
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Hubbs, C. L. and R. R. Miller. 1965. Studies of cyNat. Hist. 6:1-18.
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Hubbs, C. L., B. W. Walker, and R. E.Johnson. 1943. Thomerson.J. E. 1969. Variation and relationships
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Miller, R. R. 19556. An annotated list of the Amer-