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ISSN 0145-9058

BULLETIN

OF CARNEGIE MUSEUM OF NATURAL HISTORY

■

PHYLOGENETIC SYSTEMATICS OF
CROTAPHYTID LIZARDS
(REPTILIA: IGUANIA: CROTAPHYTIDAE)

JIMMY A. McGUIRE

NUMBER 32

PITTSBURGH, 1996

BULLETIN

of CARNEGIE MUSEUM OF NATURAL HISTORY

PHYLOGENETIC SYSTEMATICS OF
CROTAPHYTID LIZARDS
(REPTILIA: IGUANIA: CROTAPHYTIDAE)

JIMMY A. McGUIRE

Department of Biology, San Diego State University, San Diego, California 92182-0057

Current address: Department of Zoology and Texas Memorial Museum,
The University of Texas at Austin, Austin, Texas 78712-1064.

NUMBER 32

PITTSBURGH, 1996

BULLETIN OF CARNEGIE MUSEUM OF NATURAL HISTORY
Number 32, pages 1-143, 52 figures

Issued 25 June 1 996

James E. King, Director

Editorial Staff: John L. Carter, Editor-,

Bradley C. Livezey, Editor-, David R. Watters, Editor
Mary Ann Schmidt, ELS, Assistant Editor

Cover illustration: An adult male Crotaphytus dickersonae photographed
approximately 2 km north of Bahia Kino Nuevo, Sonora, Mexico (see Fig. 3 IB).

BULLETINS OF CARNEGIE MUSEUM OF NATURAL HISTORY are published at irregular intervals
by Carnegie Museum of Natural History, 4400 Forbes Avenue, Pittsburgh, Pennsylvania 15213-4080, by
the authority of the Board of Trustees of Carnegie Institute.

ISSN 0145-9058

THE CARNEGIE

MUSEUM OF
NATURAL HISTORY

Contents

Abstract

Introduction

Historical Review

Materials and Methods 6

Frequency Coding

Allozyme Data Set 8

Ingroup Monophyly 8

Choice of Terminal Taxa 9

Outgroup Taxa 9

Morphology and Character Descriptions 11

Skull Roof 11

Palate 18

Braincase 20

Mandible 20

Miscellaneous Features of the Head Skeleton 24

Axial Skeleton 27

Pectoral Girdle 30

Pelvic Girdle 31

Limbs 32

Squamation 32

Pockets and Folds 36

Additional Morphological Characters 40

Coloration t 42

Behavioral Characters 52

Character List 54

Results 57

Discussion 63

Comparison with Previous Hypotheses 63

Character Evolution 65

Taxonomic Accounts 67

Crotaphytidae 67

Crotaphytus 68

C. antiquus 69

C. bid net ores 72

C. collaris 75

C. dicker sonae 80

C. grismeri 83

C. insular is 84

C. nebrius 88

C. oligocenicus't 92

C. reticulatus 92

C. vestigium 94

Gambelia 97

G. copei 98

G. corona t 102

G. silus 102

G. wislizenii 106

Key to the Species of Crotaphytus and Gambelia Ill

Acknowledgments 112

Literature Cited 113

iii

Appendices 120

1. Specimens Examined 120

2. Data Matrix 126

3. Outgroup Data Matrix 128

4. Step Matrices for Manhattan Distance Frequency Approach 132

5. Character Transformations for Each Stem of the Single Most Parsimonious Tree 134

6. List of Character State Changes by Character 139

7. Scleral Ossicle Data 143

ABSTRACT

A revision of the alpha taxonomy of Crotaphytidae revealed
that there are at least 12 and probably 13 species. A data set
including 88 characters drawn from osteology, squamation, soft
tissues, color pattern, life history, and behavior was collected. In
addition, an allozyme data set composed of ten phylogenetically
informative characters was obtained from the literature. Analysis
of these data resulted in the following hypothesis of relationships:
(( Gambelia silus (G. corona\ ( G . copei + G. wislizenii ))) + ( Cro -
taphytus reticulatus (C. collaris (C. antiquus (C. nebrius (C. dick-
ersonae (C. grismeri ( C . bicinctores (C. insularis + C. vestig-
ium))))))))). Although little character evidence in support of
crotaphytid monophyly has been presented in the literature (Eth-
eridge and de Queiroz, 1988; Frost and Etheridge, 1989), cro-
taphytid monophyly was found to be strongly supported with
five fixed, unambiguous synapomorphies. Strong support was
also discovered for monophyly of Crotaphytus (12 fixed, un-
ambiguous synapomorphies) and Gambelia (six fixed, unambig-

uous synapomorphies). The hypothesis of relationships estimated
here was used to address life history and morphological evolution
within the group including the relationship between head mor-
phology and diet, the evolution of display-oriented morphology
in males, the evolution of bipedal locomotion, and a functional
consideration of gravid coloration. A taxonomic account is pro-
vided for Crotaphytidae, Crotaphytus, Gambelia, and each spe-
cies. Each species account includes a synonymy, an etymology,
a diagnosis for the species, a detailed description of scalation and
coloration, a section describing maximum adult size as well as
size dimorphism, a description of the species geographic distri-
bution with a dot distribution map, an account of the known
fossil record, a summary of available natural history information,
and a listing of references that provide illustrations of the species.
Separate dichotomous keys are provided for males, females, and
juveniles of Crotaphytus and Gambelia.

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

INTRODUCTION

Lizards of the family Crotaphytidae (collared and
leopard lizards) are among the most familiar squa-
mates of western North America. This familiarity
probably stems from their relatively large size (com-
pared to other North American lizards), often vi-
brant coloration, predatory lifestyle, and pugnacious
habits. Crotaphytidae, one of nine iguanian families
proposed by Frost and Etheridge (1989), is currently
comprised of two genera, Crotaphytus (seven or eight
species) and Gambelia (three species), that range
from southern Idaho in the northwestern United
States, southward into southern Baja California and
northern Mexico, and eastward into the states of
Missouri, Arkansas, and Louisiana. They have been
the subject of numerous studies of ecology, physi-
ology, reproduction, hybridization, and historical
biogeography, and many of these studies have ad-
dressed questions of a historical nature (e.g., Savage,
1960; Montanucci, 1970; Ingram andTanner, 1971;
Axtell, 1972; Smith and Tanner, 1974; Montanucci
etal., 1975; Tanner and Banta, 1977; Tanner, 1978;
Sanborn and Loomis, 1979; Tollestrup, 1979, 1983;
Murphy, 1983; Welsh, 1988). However, despite sev-
eral important systematic analyses of the group
(Smith and Tanner, 1972, 1974; Montanucci et ah,

1975), phylogenetic relationships within Crotaphy-
tidae remain largely unresolved. Although the
monophyly of the group has never been questioned,
few derived characters have yet been offered to sup-
port this contention (Etheridge and de Queiroz, 1988;
Frost and Etheridge, 1989). The same can be said
for the monophyly of the genera. The phylogenetic
relationships of the group have been addressed using
cladistic methodology only once (Montanucci et ah,
1975), and that study predated important meth-
odological advances in cladistics, such as outgroup
analysis (Watrous and Wheeler, 1981; Maddison et
ah, 1984).

There are three primary goals of the present study.
The first goal is to revise the alpha taxonomy of
Crotaphytidae in order to provide a better under-
standing of species diversity within the group as well
as an appropriate selection of terminal taxa for phy-
logenetic analysis. The second goal is to provide an
estimate of the phylogenetic relationships of Cro-
taphytidae. The third goal is to use this phylogeny
to investigate morphological and life history evo-
lution among crotaphytids and provide a taxonomy
that is logically consistent with the evolutionary his-
tory of the group.

HISTORICAL REVIEW

The earliest accounts of crotaphytid lizards were
closely associated with the joint military-scientific
exploratory expeditions of the American frontier. In
fact, it was only shortly after the epic Lewis and
Clark expedition of 1803-1806 that the first cro-
taphytid species was described. As a member of a
party headed by Major Stephen H. Long that was
exploring the Great Plains, Thomas Say collected
and later described Agama collaris (James, 1823).
Agama collaris was later placed as the sole member
of the newly erected genus Crotaphytus by Holbrook
(1842) in his classic account of the North American
herpetofauna.

A second crotaphytid species, Crotaphytus wisli-
zenii, was obtained at Santa Fe (New Mexico) by
Dr. Wislizenus, an army surgeon, who made the
collection during the Mexican-American War of
1 846-1848. This species was first described by Baird
and Girard ( 1 852 a), and a more detailed description
was given by the authors (1852c) shortly thereafter
in Stansbury (1852). From their first formal descrip-

tions, crotaphytid lizards have been thought to form
a natural group, despite the difficulty that more re-
cent students have had in discovering synapomor-
phies.

In August of the same year, Baird and Girard
(18526) described two additional species of Crota-
phytus'. C. dorsalis from the desert of Colorado, and
C. gambelii, for which locality data was lacking,
although it was thought to have been collected in
California. In December, Hallowed (1852) de-
scribed a fourth species, C. fasciatus (a junior syn-
onym of G. wislizenii), from the sand hills at the
lower end of Jornada del Muerte, New Mexico. Hal-
lowed's specimens were part of Samuel Wood-
house’s collections made during the early 1850s,
again emphasizing the important role that the early
expeditions of the American West played in crota-
phytid taxonomy. In 1854, Hallowed proposed the
genus Dipsosaurus for C. dorsalis.

Dumeril (1856) transferred Crotaphytus collaris
to the genus Leiosaurus, a decision that was very

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

likely influenced by the similarity in head mor-
phology and squamation in these genera. Further-
more, Dumeril (1856) suggested that C. fasciatus
Hallowell was synonymous with Leiosaurus fascia-
tus Dumeril and Bibron 1837 (= Pristidactylus fas-
ciatus fide Etheridge and Williams, 1 985). However,
he provided the substitute name L. hallowellii to be
used in the event that they were not found to be the
same species. This taxonomy was not addressed by
North American herpetologists until Cope (1900).

Baird (1858) described Crotaphytus reticulatus
based on specimens collected by J. H. Clark and A.
C. B. Schott of the Mexican Boundary Survey. Baird
designated syntypes (both labeled as USNM 2692)
taken from Ringgold Barracks, Texas (Fort Ringgold
Military Reservation, Starr County). In his descrip-
tion, Baird (1858), without comment, erected the
subgenus Gambelia for Crotaphytus wislizenii.

Yarrow ( 18826) described Crotaphytus copeii from
La Paz, California (Baja California Sur, Mexico),
based on a specimen collected by L. Belding.

Stejneger (1890) described Crotaphytus baileyi
from the Painted Desert, Little Colorado River, Ar-
izona. This western form was recognized on the ba-
sis of two rows of interorbital scales, compared with
the single row found in C. collaris, as well as smaller
supraoculars, and a narrower head with a longer
snout. He did not believe that C. baileyi warranted
more than subspecific recognition; however, no in-
tergradation zone was known at the time, and fol-
lowing the rules of the American Ornithologist’s
Union, he felt obligated to describe the form as a
distinct species. Stejneger (1890) also described Cro-
taphytus silus from the San Joaquin valley of Cali-
fornia.

In 1899, Mocquard described Crotaphytus fascia-
tus from Cerro Las Palmas, Baja California. It is
clear from his description and the accompanying
figure that this is a juvenile specimen of what is now
referred to as Crotaphytus vestigium, and, as the
name fasciatus predates that of vestigium by 73 years,
the former name has priority (see the C. vestigium
taxonomic account for an assessment of the no-
menclatorial implications of this taxonomy).

Cope (1900) resolved several long-standing tax-
onomic problems within Crotaphytus when he syn-
onymized C. gambelii, C. fasciatus (Hallowell), and
Leiosaurus hallowellii (= C. fasciatus ), with C. wis-
lizenii. He also synonymized C. copeii and C. silus
with C. wislizenii, citing an absence or gradation of
distinguishing morphological features. Citing the
work of Stejneger (1890), Cope did not support the

recognition of Crotaphytus baileyi at either the spe-
cific or subspecific rank. Over the next 50 years,
there would be considerable disagreement with re-
spect to the proper taxonomic ranking of baileyi,
with some authors recognizing baileyi as a subspe-
cies of C. collaris, others as a distinct species, and
still others choosing not to recognize it at any tax-
onomic level.

Mocquard (1903), apparently realizing that the
name Crotaphytus fasciatus had already been ap-
plied to a leopard lizard species by Hallowell ( 1852),
provided a substitute name (C. fasciolatus ) for the
Baja California species. However, Cope (1900) had
already synonymized C. fasciatus Hallowell with C.
wislizenii. Thus, C. fasciatus Mocquard remained
the senior synonym for the Baja California species
of collared lizard.

Stone and Rehn ( 1 903), noting a series of 1 1 spec-
imens collected in the Pecos region of Texas that
displayed the diagnostic characteristics of both C.
collaris and C. baileyi, recognized the western pop-
ulations as a subspecies of C. collaris, Crotaphytes
(sic) collaris baileyi. Meek (1905), citing the con-
stancy with which the supraorbital semicircles were
unfused in the specimens he examined from Baja
California, California, Arizona, and Utah, again fol-
lowed Stejneger (1890) in recognizing Crotaphytus
baileyi at the specific level. Over the following few
years the taxonomic rank of baileyi jumped back
and forth between the species and subspecies level.
Ruthven (1907) followed Stone and Rehn (1903) in
recognizing baileyi as a subspecies. After 1907, the
taxonomy of baileyi more or less stabilized, with
most workers recognizing this form as a subspecies
of C. collaris.

Van Denburgh and Slevin (1921) provided a brief
description of Crotaphytus insularis from Isla Angel
de La Guarda in the Gulf of California, Mexico.
Van Denburgh (1922) could find no differences be-
tween C. copeii from Islas de Cerros (= Cedros) and
Magdalena and C. wislizenii, and following Cope
(1900), recognized only the latter. Also, Van Den-
burgh (1922) incorrectly synonymized both C. fas-
ciatus Mocquard and C. fasciolatus Mocquard with
C. wislizenii.

In 1922, Schmidt described Crotaphytus dicker-
sonae from Isla Tiburon in the Gulf of California,
Mexico. In the description, he correctly hypothe-
sized that the species might be found on the adjacent
Sonoran mainland as well. Schmidt agreed with Van
Denburgh (1922) in not recognizing C. copeii, citing
extreme variation in the color pattern of this species

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

throughout its range. Burt (1928/?) synonymized
Crotaphytus collaris baileyi with C. c. collaris on the
basis of extensive variation in the interorbital scale
characteristics used to separate the two forms, a
taxonomy that was not followed by subsequent
workers. Allen (1933) reduced Crotaphytus dicker-
sonae to a subspecies of C. collaris, citing intergra-
dation in the hindlimb and tail length characters
that Schmidt (1922) used to distinguish C. dicker-
sonae from C. c. baileyi. Allen (1933) did not follow
Burt’s (1928 b) synonymy of C. c. baileyi with C. c.
collaris.

Mittleman (1942) discussed the higher level phy-
logenetic relationships within North American ig-
uanian lizards. His diagrammatic representation of
relationships placed Crotaphytus as the sister taxon
of Petrosaurus and Streptosaurus. This group was
in turn depicted as the sister group of the phryno-
somatid sand lizards Uma, Callisaurus, and Hol-
brookia. Despite the relationships implied by his
tree, he appears to have considered Crotaphytus to
be a relatively primitive iguanid ( senso lato), be-
cause he suggested that the sand lizards were derived
from Crotaphytus- like stock, as was Sauromalus.

Smith (1946) separated Crotaphytus mslizenii
from C. collaris and C. reticulatus by placing it in
the genus Gambelia, thus elevating Baird’s (1858)
subgenus to generic rank. This controversial deci-
sion initiated much debate among various workers
on the group. Furthermore, Smith (1946) reduced
G. silus to a subspecies of G. mslizenii. With respect
to higher taxonomic relationships within the Igu-
ania, Smith followed Mittleman (1942) in placing
Crotaphytus and Gambelia as the sister group of
Streptosaurus plus Petrosaurus, and this group as
the sister taxon of the phrynosomatid sand lizards.
Smith and Taylor (1950) elevated dickersonae from
a subspecies of Crotaphytus collaris to the rank of
full species.

Fitch and Tanner (1951), reinterpreting the data
of Burt (19286), recognized Crotaphytus collaris
baileyi as a subspecies distinct from C. c. collaris.
This taxonomy had generally been followed in the
literature despite the earlier synonymy of the two
by Burt (19286). In addition, they described a new
subspecies of Crotaphytus, C. c. auriceps, from the
upper Colorado River basin.

Returning to the higher-level relationships within
the Iguania, Savage (1958) presented a phylogeny
that differed radically from that of Mittleman ( 1 942)
and Smith (1946). In his classification, Savage pro-
posed a new subgrouping, the iguanines, that in-

cluded Crotaphytus plus those genera later placed
in the Iguanidae by Frost and Etheridge (1989).

Cochran (1961) recognized Crotaphytus silus as a
full species. Robison and Tanner (1962) attempted
to resolve the Crotaphytus-Gambelia debate by ex-
amining osteological and myological evidence. As
a result, they chose not to recognize Gambelia as a
genus distinct from Crotaphytus.

Tanner and Banta (1963), in the first of a three-
part series examining the systematics of leopard liz-
ards, described a new subspecies, Crotaphytus wis-
lizeni punctatus, from the upper Colorado River ba-
sin of Utah and Colorado. Like Cochran (1961),
those authors did not recognize the genus Gambelia.

Etheridge ( 1 964) removed Crotaphytus from Sav-
age’s (1958) iguanines because he was unable to find
any character or combination of characters that
would serve to diagnose the iguanines if Crotaphytus
was included. Furthermore, he hypothesized that
Crotaphytus may be the sister taxon to the scelo-
porines (= Phrynosomatidae) plus tropidurines (=
Tropiduridae).

Leviton and Banta (1964) resurrected the name
copei for the Baja California populations of Crota-
phytus mslizenii, recognizing C. w. copei.

Weiner and Smith (1965) attempted to resolve
the Gambelia-Crotaphytus controversy by exam-
ining the osteology of the group. They placed all
members of Crotaphytus (including those that had
been placed in the genus Gambelia ) into a grouping
they referred to as the “crotaphytiform” lizards. They
recognized only four species of crotaphytiform liz-
ards: C. collaris, C. reticulatus, C. insularis, and C.
mslizeni (again relegating silus to a subspecies of C.
mslizeni). Thus, without presenting evidence, Wei-
ner and Smith (1965) reduced C. dickersonae to the
rank of subspecies within C. collaris. Those mem-
bers of the genus with a superficial resemblance to
C. collaris (C. collaris, C. reticulatus, and C. insu-
laris) were further separated into the “collariform”
group. Finally, with respect to the Gambelia-Cro-
taphytus debate, they concluded that the subgeneric
rankings, Crotaphytus ( Gambelia ) wislizeni first pro-
posed by Baird (1858) and Crotaphytus ( Crotaphy-
tus) were the lowest levels of taxonomic segregation
that could be justified by the data.

Soule and Sloan ( 1 966) followed Weiner and Smith
(1965) in recognizing dickersonae as a subspecies of
C. collaris and reduced insularis to a subspecies of
C. collaris as well.

Banta and Tanner (1968), in their second study
of leopard lizard systematics, provided a redescrip-

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

tion of Crotaphytus wislizeni copei and described a
new subspecies, C. w. neseotes, from Isla de Cedros
off the west coast of Mexico. They did not follow
Weiner and Smith (1965) with regard to the sub-
generic groupings.

In response to Weiner and Smith (1965), Mon-
tanucci (1969) entered the Gambelia-Crotaphytus
debate. Based on an examination of the osteology
of C. wislizenii, C. silus, C. collaris, and C. reticu-
latus, he concluded that there should be no generic
or subgeneric segregation within the group. He also
recognized C. silus as a species distinct from C. wis-
lizenii, based on unpublished data. Crotaphytus
dickersonae and C. insularis were again recognized
as full species distinct from C. collaris. In a paper
published the following year, Montanucci (1970)
formally elevated Crotaphytus silus from a subspe-
cies of C. mslizenii to a full species based on mor-
phological, ecological, and behavioral differences.

Ingram and Tanner (197 1) described Crotaphytus
collaris fuscus from the Chihuahuan Desert region.
The subspecies could not be diagnosed by discrete
morphological characters and was proposed on the
basis of a distinctive discriminant function.

In 1972, Holman described Crotaphytus oligo-
cenicus on the basis of a right dentary from the early
Oligocene Cypress Hills Formation, Saskatchewan,
Canada.

Smith and Tanner (1972) were the first to rec-
ognize that there were additional distinct Crotaphy-
tus taxa occurring primarily west of the Colorado
River. They described Crotaphytus collaris bicinc-
tores from the Great Basin region and C. insularis
vestigium from the peninsular ranges of Baja Cali-
fornia, Mexico, and southern California. Using a
Ward’s Minimum Variance Cluster Analysis, they
found that there were two phenotypically distinct
groups of collared lizards (excluding C. reticulatus),
each comprised of four named forms. The “western
complex” was found to include C. z. insularis, C. i.
vestigium, C. c. bicinctores, and C. c. dickersonae,
while the “ collaris complex” was found to include
C. c. collaris, C. c. baileyi, C. c. auriceps, and C. c.
fuscus. Despite these findings, they described bi-
cinctores as a subspecies of C. collaris and chose to
recognize C. dickersonae as a subspecies of C. col-
laris, as well. Thus, their own classification did not
follow the phylogenetic relationships they had pro-
posed.

Axtell (1972) considered Crotaphytus collaris bi-
cinctores and C. c. baileyi to be distinct at the species
level based on morphological differences and a nar-

row hybrid zone between the two in the Cerbat
Mountains of Arizona. He tentatively placed bi-
cinctores as a subspecies of C. insularis.

Smith and Tanner (1974) again recognized bi-
cinctores as a subspecies of Crotaphytus collaris. They
based this taxonomic decision on intergrade speci-
mens between C. bicinctores and C. collaris in north-
western Sonora, Mexico, and southwestern Arizona,
as well as the hybrid specimens identified by Axtell
(1972) from the Cerbat Mountains of Arizona.
However, the presumed intergrade specimens were
actually C. c. nebrius, subsequently described by
Axtell and Montanucci (1977), with the character-
istic features of this species. They substantiated their
previous recognition of C. dickersonae as a subspe-
cies of C. collaris on the basis of intergrades between
dickersonae and collaris from the Guaymas region.
However, these specimens are again C. nebrius.
Based on the results of their cluster, canonical, and
discriminant function analyses, they provided two
potential phylogenetic hypotheses for Crotaphytus
shown here in parenthetical form: ( mslizenii { reti-
culatus + (( fuscus { collaris { baileyi + auriceps))) +
(( dickersonae + bicinctores) + ( insularis + vestig-
ium))))) or ( mslizenii ( reticulatus + (( insularis +
vestigium) + (( dickersonae + bicinctores) + {fuscus
{collaris { baileyi + auriceps))))))). These hypotheses
of relationship differ in that the first recognizes a
group that includes C. c. dickersonae, C. c. bicinc-
tores, C. i. insularis, and C. i. vestigium, while the
second recognizes all of the C. collaris subspecies as
a group. In addition, Smith and Tanner (1974) again
recognized silus as a subspecies of C. mslizenii.

Montanucci et al. (1975) made the first attempt
at a cladistic analysis of the group. As a result of
their electrophoretic study, they recommended the
recognition of Gambelia as a valid genus, elevated
Crotaphytus wislizeni silus and C. collaris dicker-
sonae to full specific status, and removed C. c. bi-
cinctores from C. collaris (again recognizing C. z.
bicinctores). They did not recognize C. c. auriceps,
considering it to be a junior synonym of C. c. baileyi.
They found the character states present in C. dick-
ersonae to be confounding and proposed a possible
hybrid origin for the species. Their proposed phy-
logeny of the group was similar to those of Smith
and Tanner (1972, 1974), except that C. dickersonae
was included with Smith and Tanner’s (1972) “co/-
laris- complex.” The soon-to-be-described C. c. ne-
brius (included as C. collaris ssp.) was also included
in this complex. Their data suggested the following
phylogenetic relationships: {{bicinctores {insularis +

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

vestigium )) + [reticulatus [dickersonae (collaris ssp.
(c. collaris (c. fuscus + c. baileyi )))))).

Axtell and Montanucci (1977) described the new
subspecies of Crotaphytus collaris , C. c. nebrius, from
the Sonoran Desert of southeastern Arizona and
Sonora, Mexico. In the same year, Tanner and Banta
(1977) published the third paper in their three-part
study of the systematics of leopard lizards. They did
not follow Montanucci et al. (1975) in recognizing
Gambelia as a valid genus, or Montanucci (1970)
in recognizing G. silus as a species distinct from G.
wislizeni. In addition, they described a new subspe-
cies, Crotaphytus wislizeni maculosus, from the La-
hontan basin of western Nevada and parts of north-
eastern California, southern Oregon, and the Snake
River basin of southwestern Idaho.

Montanucci (1978) again recognized the genus
Gambelia and the species G. silus as valid taxa, while
he synonymized the subspecies G. w. neseotes from
Isla de Cedros with G. w. copei of the adjacent Baja
California peninsula.

Sanborn and Loomis (1979) elevated Crotaphytus
insularis bicinctores to full specific status on the basis
of distribution, squamation, and male display pat-
tern differences.

Wyles (1980) studied albumin immunological
distances between Gambelia wislizenii and the re-
maining crotaphytine species recognized by Mon-
tanucci et al. (1975). Wyles (1980) concluded that
the immunological distance estimates were well
within the range observed for other iguanid ( sensu
lato) genera and thus recommended that Gambelia
again be reduced to a subgenus.

Smith and Brodie (1982) erected the subfamily
Crotaphytinae for Crotaphytus and Gambelia, thus
providing the first higher taxonomic name for the
group.

Montanucci (1983), citing relative phenotypic

similarity between bicinctores and vestigium and
discounting the significance of the behavioral dif-
ferences proposed by Sanborn and Loomis (1979),
again recognized bicinctores as a subspecies of Cro-
taphytus insularis. Estes (1983) synonymized Gam-
belia with Crotaphytus. This taxonomic decision ev-
idently passed unnoticed by most neoherpetologists
and was not followed by later authors. In any event,
Cooper (1984) and all later authors have referred to
Gambelia as a valid taxon.

Etheridge and de Queiroz (1988) were the first to
provide evidence that the Crotaphytinae formed a
monophyletic group, which they referred to under
the informal heading “crotaphytines.” However,
they were unable to find any uniquely derived char-
acter states for the group and hypothesized its
monophyly based on a unique combination of de-
rived yet homoplastic character states.

Frost and Etheridge (1989) reaffirmed the findings
of Etheridge and de Queiroz (1988), although they
also were unable to find any unique derived char-
acters for the group. They elevated the subfamily
Crotaphytinae of Smith and Brodie (1982) to fa-
milial status, recognizing Crotaphytidae as one of
nine monophyletic iguanian families.

Norell (1989) described an extinct species of
Gambelia, G. corona t, from the Pliocene-Pleisto-
cene boundary of the Anza-Borrego Desert, Cali-
fornia.

Collins (1991), citing the evolutionary species
concept of Frost and Hillis (1990), elevated C. i.
vestigium (and, consequently, C. i. insularis) to full
species, although no evidence was presented indi-
cating morphological or genetic differentiation be-
tween the two taxa. McGuire ( 1 99 1 ), in a note sum-
marizing a geographic range extension, again rec-
ognized vestigium (and thus insularis) as a subspe-
cies of Crotaphytus insularis.

MATERIALS AND METHODS

The characters used in this study were obtained
primarily from the skeleton, squamation, and color
pattern, with additional characters taken from the
hemipenes, behavior, and life history (hereafter re-
ferred to as the “morphology” data set). The allo-
zyme data set of Montanucci et al. (1975) also was
reanalyzed. A few specimens were cleared and
stained using the method of Dingerkus and Uhler
(1977). Most external anatomical characters were

scored from formalin-preserved specimens stored
in alcohol, although some color pattern characters
(noted in the character descriptions) could be ob-
served only on live animals or in photographs of
live individuals (field observations were made on
all crotaphytid taxa and photographs taken of all
crotaphytid taxa except Gambelia silus). Characters
were scored primarily from adults, although some
juveniles were included when ontogenetic variation

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYT1D LIZARDS

was not evident in the characters in question. Unless
otherwise stated, scale terminology follows Smith
(1946), skull terminology follows Oelrich (1956),
and postcranial skeletal terminology follows Eth-
eridge (1964, 1965, 1967), Hofstetter and Gasc
(1969), and de Queiroz (1987). Museum numbers
of crotaphytid specimens examined and their lo-
calities are listed in Appendix 1 , along with museum
numbers of iguanian outgroup taxa examined.

Hypotheses of phylogenetic relationships were es-
timated using cladistic analysis (e.g., Hennig, 1966;
Wiley, 1981). Character states were polarized using
outgroup analysis (Watrous and Wheeler, 1981;
Maddison et al., 1984), a procedure that was com-
plicated by the lack of interfamilial resolution within
Iguania (see discussion of outgroup taxa below).
Many characters could not be polarized unequivo-
cally and these were described as “unpolarized” or
“not polarized” in the character descriptions. Once
character polarities were obtained, a hypothetical
ancestor was constructed summarizing the hypoth-
esized ancestral states for each character. The hy-
pothetical ancestor was included in the analysis in
order to root the tree. The phylogenetic software
employed here was a test version of PAUP (version
4.0.0d26, Swofford, 1995). Because the number of
taxa is relatively small, the branch-and-bound al-
gorithm of Hendy and Penny (1982) was employed,
guaranteeing that all most parsimonious trees would
be discovered. Logical incongruencies (e.g., trans-
formations of the collar pattern in species that have
no collar) were coded as missing or unknown data
(“?”). Following the recovery of the most parsi-
monious tree, tree stability and phylogenetic infor-
mation content were tested using the nonparametric
bootstrap (Felsenstein, 1985; 2000 bootstrap rep-
licates), as well as analyses of tree length distribution
skewness (g, statistic; Hillis, 1991; Huelsenbeck,
1991; Hillis and Huelsenbeck, 1992) and the decay
index (Donoghue et al., 1992). Simulations indicate
that a strongly left-skewed distribution of tree lengths
(described by a negative gx value) is an indicator of
phylogenetic information content of the data (Hillis,
1991; Huelsenbeck, 1991; Hillis and Huelsenbeck,
1 992). Hillis and Huelsenbeck ( 1 992) provided crit-
ical gi values for data matrices composed of various
numbers of binary and four state characters. Because
this data set differs from the simulated data sets
generated by Hillis and Huelsenbeck (1992) both in
number of characters and in the numbers of states
per character, new gl critical values were calculated
that are specific to this data set using a computer

Table 1 . — Recalculated g, critical values expected for random data
for the morphology-only, allozyme-only, and morphology + allo-
zyme (allozymes coded using Manhattan distance frequency ap-
proach) data sets and the observed g, value for each.

Number of
informative
characters

Number
of taxa

P = 0.05

P = 0.01

Observed

Morphology only:

-0.15

-0.16

-1.49

Allozymes:

-0.43

-0.45

-0.50

Morphology +
Allozymes:

-0.15

-1.45

program written by J. Huelsenbeck (Table 1). These
values were generated by randomly reshuffling char-
acter states among taxa in the original data set 100
times and recalculating the gx for each reshuffled
matrix. Critical values at both 95 percent and 99
percent confidence intervals were then calculated
from the distribution of gx values generated.

Frequency Coding

The character coding scheme applied to morpho-
logical data in this analysis is a frequency approach
developed by Wiens (19936, 1995). An approach
wherein polymorphic characters are excluded from
the analysis is rejected because it is clear that many
characters will be found to be polymorphic given a
sufficient sample size. This was especially evident
in this analysis as large sample sizes were available
for both preserved (up to 87 specimens per taxon)
and osteological (as many as 55 specimens per tax-
on) material. Under the frequency approach, each
binary character is partitioned into 25 bins (a-y),
each representing 4 percent of the total range of
possible frequencies that may be observed in a poly-
morphic or monomorphic character (i.e., bin a =
0-3%, bin b = 4-7%, and so on; Table 2). Note that
it is necessary for one of the bins to have a range of
5 percent rather than 4 percent in order to encom-
pass the entire range of possible frequencies (0-
100%); this bin was arbitrarily chosen as bin y (96-
100%). Twenty-five frequency bins were used be-
cause this was the maximum number of whole num-
ber bins (i.e., 4 percent vs. 3.26 percent per bin, etc.)
that PAUP is able to include (although PAUP will
allow up to 31 bins; Swofford, 1995). Those char-
acters that were analyzed using frequency coding
were treated as ordered, following the assumption
that any character state transformation must pass
through a polymorphic state, no matter how tran-
sitory, before reaching fixation (Wiens, 1 993 b, 1 995).
Frequency coding was not applied to the three mul-

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Table 2. — Frequency values for the 25 ordered bins employed in
the frequency coding analyses (Wiens, 1995).

a =

0-3.99

b =

4-7.99

c =

8-11.99

d =

12-15.99

e =

16-19.99

f =

20-23.99

g =

24-27.99

h =

28-31.99

i =

32-35.99

j =

36-39.99

k =

40-43.99

1 =

44-47.99

m =

48-51.99

n =

52-55.99

o -

56-59.99

P =

60-63.99

q =

64-67.99

r =

68-71.99

s =

72-75.99

t =

76-79.99

u =

80-83.99

v =

84-87.99

w =

88-91.99

X =

92-95.99

y =

96-100

tistate characters that also showed intraspecific
polymorphism (characters 75, 84, and 85) because
the raw frequency data were not obtained for these
characters. For these three characters, the polymor-
phic OTUs were assigned more than one character
state and PAUP’s “interpret multiple states as un-
certainty” option was invoked. Two additional mul-
tistate characters were included (characters 28 and
68), but in these cases each terminal taxon was fixed
for a particular character state. The frequency cod-
ing approach is unnecessary with respect to these
characters (or fixed binary characters) because fre-
quency coding only behaves differently from stan-
dard binary coding when at least one OTU exhibits
more than one character state. For example, if taxa
A, B, and C are fixed for the ancestral state and taxa
D, E, and F are fixed for the derived state, then
under frequency coding A, B, and C will be assigned
state “a” (0-3.99%) and D, E, and F will be assigned
state “y” (96-100%). The ordered transformation
from “a” to “y” takes one step, the same number
of steps that would be assigned to this transforma-
tion using standard binary coding. As a result, a
clade composed of taxa D, E, and F would be re-
covered and it would be supported by a single com-
plete character state transformation (= one step).

All six multistate characters were treated as unor-
dered because no a priori information was available
that would suggest a particular sequence through
which these character states most likely evolved.

Allozyme Data Set

An allozyme data set taken from Montanucci et
al. (1975) was incorporated into this analysis. These
data were analyzed using a modified version of the
Mabee and Humphries (1993) coding approach. Step
matrices were again used, but frequency information
was incorporated using Manhattan distances (Wiens,
1995). This approach allowed polymorphic allo-
zyme data to be analyzed in a manner analogous to
the frequency coding approach used for the mor-
phology data. Alternatives to the Manhattan dis-
tance frequency approach employed in the analyses
of the allozyme data include the use of polymorphic
coding (terminology taken from Wiens, 1995),
wherein the locus is the character and the allele is
the character state, and the step matrix approach
recommended by Mabee and Humphries (1993).
Wiens (1995) found that the Manhattan distance
frequency approach performed better than either of
these alternatives (plus a number of additional al-
ternative approaches as well). Nevertheless, com-
bined analyses were also undertaken in which the
allozyme data were analyzed using polymorphic
coding and the Mabee and Humphries (1993) ap-
proaches. The allozyme data were analyzed sepa-
rately in order to test for phylogenetic signal (using
the bootstrap and skewness statistic). These data
were then analyzed together with the morphological
data generated in this study in order to determine
whether together they could provide additional res-
olution or modify the topology produced by the
morphological data alone. In the combined analy-
ses, the multistate morphological characters were
assigned a weight of 1 00 in order that they be weight-
ed equally with the allozyme characters (because the
Manhattan distance approach effectively weights
characters 100 times more strongly than standard
binary characters). For the same reason, the fre-
quency bin characters were assigned weights of four
because the frequency bin approach effectively
weights characters by 24. Therefore, all of the char-
acters were given approximately equal weight.

Ingroup Monophyly

The monophyly of crotaphytid lizards has never
been questioned and, as Etheridge and de Queiroz
(1988) pointed out, the most persistent taxonomic

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

debate concerning crotaphytids has been whether or
not Gambelia should be synonymized with Crota-
phytus (Smith, 1946; Robison and Tanner, 1962;
Weiner and Smith, 1965; Montanucci, 1969, 1978;
Montanucci et al., 1975; Tanner and Banta, 1977).
Nevertheless, very little character evidence has been
presented supporting the monophyly of Crotaphy-
tidae. Etheridge and de Queiroz (1988) recognized
crotaphytids as a monophyletic group on the basis
of a unique combination of derived, yet highly ho-
moplastic features: the presence of posterior cora-
coid fenestrae and female gravid coloration, and the
absence of postfrontal bones and a middorsal scale
row. Frost and Etheridge (1989) considered crota-
phytids to be monophyletic on the basis of three
reversals: presence of palatine teeth, posterior cor-
acoid fenestrae, and ribs on the third cervical ver-
tebra (the last of which is only infrequently observed
in crotaphytids). In each of these analyses, character
support for Crotaphytidae was dependent upon its
placement within the ingroup topology. The follow-
ing is a list of synapomorphies of Crotaphytidae
recognized in this study: presence of black oral pig-
mentation (reversed within Crotaphytus ), presence
of a posterolaterally projecting jugal-ectopterygoid
tubercle immediately posterior to the maxillary tooth
row, presence of posterior coracoid fenestrae, the
tympanic crest of the retroarticular process of the
mandible curves posterodorsally, the parietal and
frontal strongly overlap the medial process of the
postorbital, the supratemporal lies in a groove along
the ventral or ventrolateral border of the supratem-
poral process of the parietal (reversed in most G.
silus or convergent in Crotaphytus and other Gam-
belia), presence of palatine teeth, and contact of the
prefrontal and jugal in the anterolateral border of
the orbit.

Choice of Terminal Tax a

The terminal taxa utilized in this study include
the currently recognized species of Crotaphytus (C.
antiquus, C. bicinctores, C. collaris, C. dickersonae,
C. grismeri, C. insularis, C. reticulatus, and C. ves-
tigium) and Gambelia (G. corona f, G. silus, and G.
wislizenii). Over the course of this study, it was de-
termined that at least one and probably two addi-
tional species should be recognized. These include
two taxa currently recognized as subspecies, C. c.
nebrius and G. w. copei (see taxonomic accounts for
data supporting the elevation of these taxa to full
species). These species were also included in the
analysis.

Another population of Gambelia that may even-
tually prove to be a full species is the population of
G. wislizenii on Isla Tiburon in the Gulf of Califor-
nia. The four osteological specimens examined in
this study lacked autotomic fracture planes in the
caudal vertebrae. Fracture planes are present in all
other G. wislizenii (n = 19) and G. silus (n = 5)
specimens examined, although they appeared to be
fused in three of ten G. copei. Unfortunately, no
osteological specimens were available from adjacent
Sonora and it could not be determined if the absence
of fracture planes is confined to this insular popu-
lation. If this population proves to be a separate
species, it may be the only endemic reptile or am-
phibian on Isla Tiburon, a land-bridge island that
supports an extensive herpetofauna.

The remaining subspecies of Crotaphytus collaris
and Gambelia wislizenii were not treated as separate
terminal taxa because no evidence has been pre-
sented, nor has any been discovered over the course
of this investigation, suggesting that these forms are
discrete evolutionary entities. Rather, they are pat-
tern or convenience classes (Frost et al., 1992), color
morphs largely consistent over an extensive area,
but grading smoothly into other color morphs at
their boundaries.

Outgroup Taxa

Etheridge and de Queiroz (1988) and Frost and
Etheridge (1989) provided evidence for the mono-
phyly of nine suprageneric groups (elevated to fam-
ilies in the latter study) within Iguania. Interfamilial
resolution was elusive and their strict consensus tree
(at the familial level) was an unresolved polytomy.
However, they were able to substantially reduce the
number of equally parsimonious interfamilial to-
pologies as depicted in their 1 2 unrooted trees with
rooting points (Fig. 1). Thus, despite the continuing
lack of unambiguous interfamilial resolution, the
outgroup situation has improved considerably. In
this analysis, characters were considered to be po-
larized only when the polarity assessment was con-
sistent with all 12 unrooted trees.

For each of the eight remaining iguanian families,
exemplars were examined for the purpose of char-
acter polarization. The choice of exemplars was
based whenever possible on the results of recent
intrafamilial phylogenetic analyses. Thus, basal lin-
eages have been proposed for clades within the fam-
ilies Phrynosomatidae (Presch, 1969; Montanucci,
1987; Etheridge and de Queiroz, 1988; de Queiroz,
1989, 1992; Wiens, 1993a, 19937>), Tropiduridae

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Co Ch

— Ig Cr Ph Tr

1 1 1 Op Po

Co Ho

— Ch

— Ig Cr Ph Tr

I I I op

Ho Ch

— Ig

—Co Cr Ph Tr Ho

-Ch Ig Cr Ph Tr

— A — J — L — 1 —

— Ch Co Ig

— A-t

Cr Ph Tr

I I I

Op Po

Ho F

— Ip Co Ch Cr Ph Tr

Jp I I I I I

Ho Ch

— Ig

— Co

— Cr

Ph Tr

1 1

— Ig Cr Ph Tr Op

III 1

JLJ

Op Po

Ig Ho

— Ch Cr Ph Tr

— L — LJ

1 1 1

Po Ch

— Ig Cr

— Ph Op

-J —

) 1

— Ig Cr Ph Po Op

Ch Co

— !g Cr Ph Tr

J-J

r mi i

- Tr Po — 1 (j) — (

1 1 1 1

Fig. 1. — The 12 unrooted trees discovered by Frost and Etheridge (1989) in their phylogenetic analysis of iguanian lizards. The open
circles represent the discovered rooting points for these unrooted trees. Ch = Chamaeleonidae, Co = Corytophanidae, Cr = Crotaphytidae,
Ho = Hoplocercidae, Ig = Iguanidae, Op = Opluridae, Ph = Phrynosomatidae, Po = Polychrotidae, Tr = Tropiduridae.

(Etheridge and de Queiroz, 1988; Frost and Ether-
idge, 1989; Frost, 1992; Pregill, 1992; Etheridge,
1995), Corytophanidae (Etheridge and de Queiroz,
1988; Lang, 1989), Hoplocercidae (Etheridge and
de Queiroz, 1988), Iguanidae (de Queiroz, 1987;
Norell and de Queiroz, 1991), Polychrotidae (Guyer
and Savage, 1986, 1992; Etheridge and de Queiroz,
1988; Cannatella and de Queiroz, 1989), and Cha-
maeleonidae (Moody, 1980, 1987; Klaver, 1981;

Klaver and Bohme, 1986; Hillenius, 1986, 1988;
Rieppel, 1987; Frost and Etheridge, 1989). For the
remaining family (Opluridae), only the phenetic
analysis of Blanc et al. (1983) was available. For this
lineage, I examined Chalaradon and as many species
of Opiums as possible. A list of outgroup taxa ex-
amined for this study is provided in Appendix 1
and a data matrix documenting the character states
observed in these taxa is provided in Appendix 3.

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

1 1

MORPHOLOGY AND CHARACTER DESCRIPTIONS

Skull Roof

Premaxilla (Characters 1, 2; Fig. 2-5, 7). — The
posterodorsally projecting nasal process is long and
very slender in Gambelia wislizenii and G. copei
(Fig. 4, 5) and broad in most Crotaphytus (Fig. 2,
7) and the single specimen of G. corona f. Gambelia
situs (Fig. 3) occasionally has a slender but short
nasal process (seven of 30) owing to its truncated
snout. In C. insularis, the nasal process is also long
and extremely narrow, which may be a consequence
of elongation of the snout region. Some variation
occurs in C. vestigium and C. bicinctores, both with
two of 28 specimens having similarly slender nasal
processes, and C. grismeri, with one of five having
a slender nasal process, although not as extreme as
that seen in C. insularis. Among the outgroup taxa,
a narrow nasal process was observed only in Petro-

Fig. 2. — Dorsal view of the skull of Crotaphytus dickersonae (REE
2777, adult male, SVL =116 mm). Scale = 5 mm.

saurus mearnsi and occasional Uta stansburiana,
Dipsosaurus dorsalis, Phymaturus pal/uma, and Ph.
punae (although the condition observed was not as
extreme as that observed in Gambelia and C. in-
sularis). Therefore, an elongate, narrow nasal pro-
cess is considered to be the derived state.

In Gambelia, the anteromedial portion of the al-
veolar shelf at the articulation of the premaxilla and
vomers is in the form of a strong vertical ridge. This
ridge is rarely present in Crotaphytus (three of 51
C. collaris, one of four C. antiquus). Among the
outgroup taxa, a strong vertical ridge was observed
only in Corytophanes hernandezi, Microlophus grayi,
two of three Leiocephalus schreibersi, and one of
three Phymaturus patagonicus zapalensis. There-
fore, a strong vertical ridge at the alveolar shelf is
considered to be the derived state.

The premaxillary base is also subject to much
variation in crotaphytids. In all Gambelia, plus many
C. antiquus, C. collaris (primarily those formerly

Fig. 3. — Dorsal view of the skull of Gambelia silus (CAS 227 1 3,
adult male, SVL =101 mm). Scale = 10 mm.

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 4. — Dorsal view of the skull of Gambelia wislizenii (REE
2918, adult female, SVL =119 mm). Scale = 10 mm.

referred to the subspecies C. c. auriceps and C. c.
baileyi ), C. grismeri, C. nebrius, and C. reticulatus,
the broad, laterally oriented maxillary processes give
the base a rectangular shape as opposed to a trap-
ezoidal shape (Fig. 2-4). This condition is either
absent or appears rarely in C. bicinctores, C. dick-
ersonae, C. insularis, and C. vestigium. Despite this
trend, most Crotaphytus species display continuous
variation in this feature with all intermediates be-
tween the rectangular and nonrectangular condi-
tions present. Therefore, this character was not in-
cluded in the phylogenetic study.

Nasals (Character 3; Fig. 2-4, 7). -In Crotaphytus
dickersonae (Fig. 2), two of four C. antiquus, and
one of 28 C. bicinctores, forward expansion of the
nasals results in their overlap of the nasal process

Fig. 5. — Anterior portion of the skull of Gambelia wislizenii { REE
2918, adult female, SVL =119 mm) depicting the saddle-shaped
premaxillary-maxillary articulations. The premaxilla is vertically
hatched. Max = maxilla, Nas = nasal. Scale = 5 mm.

of the premaxilla well anterior to the posterior bor-
der of the external nares (fenestrae exonarina of Oel-
rich, 1956). This feature varies ontogenetically in
C. dickersonae, with individuals of less than 81 mm
snout-vent length (SVL) having incomplete contact
of the nasals anteriorly (character scored only from
adults). The nasals occasionally overlap the nasal
process of the premaxilla anterior to the posterior
extent of the external nares in Gambelia wislizenii
and G. copei. However, this appears to be the result
of posterior expansion of the nares rather than an
anterior expansion of the nasals and is here consid-
ered to be nonhomologous. The nasals only rarely
overlap the nasal process of the premaxilla anterior
to the posterior extent of the external nares in the
outgroup taxa. This condition was observed in Broo-
kesia stumpffi and in a number of tropidurid taxa
( Ctenoblepharys adspersus, some Phymaturus pa-
tagonicus patagonicus, P. p. payuniae, and P. p. so-
muncurensis [but not other Phymaturus ], many Lei-
ocephalus species, and Microlophus grayi ). Pregill
(1992) considered this feature to be absent from
most basal extant Leiocephalus, including L. her-
minieri, L. greenwayi, L. punctatus, L. inaguae, L.
psammodromus, and some L. carinatus. Therefore,
the conditions observed in Liolaeminae, Leioce-
phalinae, and at least one member of Tropidurinae
may be convergent. Nevertheless, nasals that over-
lap the nasal process of the premaxilla may be an-
cestral for Liolaeminae and Leiocephalinae, and,

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYT1D LIZARDS

Fig. 7. — Dorsal view of the anterior portion of the skull of Cro-
taphytus grismeri (MZFC 665 1, adult male, SVL = 92 mm). The
vertical hatching denotes the extra frontonasal bone present in
two of five specimens examined. Fro = frontal. Max = maxilla,
Nas = nasal, Prf = prefrontal, Prm = premaxilla. Scale = 5 mm.

Fig. 6.— Anterior portion of the orbit showing contact of the
prefrontal and jugal bones ( Crotaphytus dickersonae, adult male,
REE 2777 , SVL =116 mm). Jug = jugal. Lac = lacrimal, Max
= maxilla, Pal = palatine, Prf = prefrontal. Scale = 2 mm.

therefore, for the entire Tropiduridae. Because B.
stumpffi and U. acanthinurus are the only nontro-
pidurid iguanian taxa examined here in which the
nasals overlap the nasal process of the premaxilla,
it is most parsimonious to code extensive overlap
of the nasal process by the nasals as the derived
state.

Prefrontals (Character 4; Fig. 2-4, 6, 7). — In all
crotaphytids, the palatine process of the prefrontal
broadly contacts the jugal just posterior to the lac-
rimal foramen (de Queiroz, 1987; Fig. 6). This con-
dition was observed in Phrynosoma asio, Uma exsul,
U. inornata, U. notata, U. scoparia, some Phyma-
turus patagonicus payuniae, one of three Leioce-
phalus macropus, Microlophus grayi, one of three
Uranoscodon supercihosus, some Pristidactylus tor-
quatus, Polychrus acutirostris, and some Po. mar-
moratus. In Phrynosoma asio and Uma (as well as
other sand lizards), this contact appears to be as-
sociated with loss of the lacrimal bone, which usu-

ally separates the prefrontal from the jugal in other
iguanians. The contact of the prefrontal and jugal is
considered to be the derived state and, thus, rep-
resents a synapomorphy for Crotaphytidae.

Although Norell (1989) stated that crotaphytids
can be diagnosed by the derived loss of the pre-
frontals, clearly (as he stated elsewhere in the paper),
he was referring to the loss of the postfrontals.

Frontal (Character 5; Fig. 2-4, 7, 8).— A separate,
median frontonasal bone (Fig. 7) is present in two
of five Crotaphytus grismeri (MZFC 6650, 6651).
Although the sample size is small for this taxon, its
presence in two specimens suggests that it is a poly-
morphism rather than an aberration. A similar bone
was observed only in one Phymaturus palluma (REE
2313). Although this feature sheds no light on the
phylogenetic relationships within Crotaphytus, it
appears to represent an additional autapomorphy
for the species.

The skulls of Gambelia wislizenii, G. copei, and
G. corona f are more depressed than those of Cro-
taphytus and G. silus. Although this variation ap-
pears to be associated with several bones, it is per-
haps best illustrated by comparing the shape and
orientation of the frontal bone. In Crotaphytus and
G. silus, this bone is more strongly convex, while in

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

G. wislizenii, G. copei, and G. corona t, this bone
usually is relatively flat, providing little height to
the midorbital region of the skull. A description of
the frontal bone only partially explains the complex
variation in skull height within crotaphytids. There-
fore, the character is here defined as “skull de-
pressed” or “skull vaulted.” Although a vaulted mi-
dorbital region of the skull is the more common
condition within Iguania, this character could not
be polarized.

Norell (1989) described the fossil taxon Gambelia
corona t based in part on a broad frontal that is
transversely concave with supraorbital ridges. Many
Gambelia have broad frontals; however, the dorsal
surface is usually flat. Only one of 53 G. wislizenii
(REE 2792) had weakly developed supraorbital
ridges with a slight concavity and no G. copei were
examined with this condition. Gambelia silus also
usually lack the supraorbital ridges; however, three
of 3 1 had well-developed supraorbital ridges with
strong transverse concavity. Although this condi-
tion cannot be considered unique to G. corona f, it
appears to be a useful diagnostic feature for the spe-
cies. Additional fossil material will be required in
order to determine if this character is variable as in
other Gambelia. The frontal may bear supraorbital
ridges that give it a concave appearance in some
Crotaphytus, although, as in Gambelia, it is only
infrequently present. Among the outgroup taxa, a
transversely concave frontal was observed in Eny-
alioides laticeps, Basiliscus basiliscus, B. plumifrons,
B. vittatus, Corytophanes hernandezi, some Cory-
tophanes cristatus, some Laemanctus longipes, some
Phymaturus palluma, some Leiocephalus carinatus,
Uranoscodon superciliosus, Uromastyx hardwickii,
Physignathus lesueurii, Hydrosaurus amboiensis,
Brookesia kersteni, Enyalius perditus, Polychrus
marmoratus, and P. acutirostris. Therefore, this
character could not be polarized.

Norell (1989) considered the frontoparietal suture
anterior to the posterior extent of the orbit to be an
additional autapomorphy of Gambelia corona f. Al-
though it is possible that this condition is an artifact
resulting from damage to the fossil (dorsoventral
compression), it does appear as though the fronto-
parietal suture was indeed anterior to the posterior
extent of the orbits. The postorbitals project more
posteriorly in G. corona t than in other crotaphytids,
which may play some role in the anterior placement
of the suture. Although this character is not phy-
logenetically informative, it provides a diagnostic
autapomorphy for the species.

In articulated skulls of some iguanians, the suture
that binds the frontal with the nasals and prefrontals
takes the form of a “ W.” However, this shape results
from the extensive overlap of the frontal by the
nasals and prefrontals. The underlying anterior bor-
der of the frontal is often squared off or may possess
two small lateral processes that project anteriorly.
In all crotaphytids, the anterior border of the frontal
bears three well-developed processes, two lateral
projections and one medial projection, that extend
forward equidistantly. This condition occurs spo-
radically within Iguania and could not be polarized.
Therefore, this feature was not considered in the
phylogenetic analysis.

Postfrontals. — The postfrontals are small bones
that form part of the posterior border of the orbits
in many iguanian species, but are absent or fused
in all crotaphytids. Postfrontals are absent or oc-
casionally present as minute elements in Phryno-
soma and the phrynosomatid sand lizards, some
Phymaturus ( Phymaturus palluma, some Phyma-
turus punae ), oplurids, Polychrus (contra Frost and
Etheridge, 1989; verified in P. acutirostris and P.
marmoratus ), Basiliscus, Corytophanes, and Cha-
maeleonidae. Although the absence or fusion of the
postfrontal bones may eventually prove to be a syn-
apomorphy for Crotaphytidae, the currently unre-
solved nature of iguanian phylogeny prevents po-
larization of this character.

Postorbitals (Characters 6, 7; Fig. 2-4, 8). — The
dorsal process of the postorbital is roughly triangular
in cross section in all crotaphytids. The dorsomedial
aspect is completely overlapped by the frontal and
parietal while the ventral portion is exposed. Thus,
in an articulated skull it appears as though a long
process projects medially beneath the overlying
frontal and parietal. This condition appears to be
more extreme in Crotaphytus because the parietal
and frontal overlap the postorbital more laterally in
these lizards. However, the condition of the post-
orbital does not vary significantly between Crota-
phytus and Gambelia. In the outgroup taxa, the fron-
tal and parietal usually meet the dorsomedial por-
tion of the postorbital without overlapping it exten-
sively; the only obvious exceptions are hoplocercids,
corytophanids, one of two Uromastyx acanthinurus,
basal agamines ( Physignathus and Hydrosaurus am-
boiensis), and Enyalius iheringi. A strong degree of
overlap at this joint, which appears to provide ad-
ditional structural support, is tentatively recognized
as a synapomorphy of Crotaphytidae.

The angle of the dorsal process often differs be-

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

tween Crotaphytus and Gambelia. In Crotaphytus,
the process is transversely oriented, while in Gam-
belia it is often anteromedially oriented. In many
cases this difference is very obvious. However, con-
tinuous variation within Gambelia prevented the
inclusion of this character in the phylogenetic anal-
ysis.

The postorbital meets the jugal and squamosal in
a tongue-in-groove articulation. In crotaphytids, the
postorbital bears the shallow groove in which the
jugal and squamosal lie. This condition is more de-
veloped in Gambelia, which bears a large flare that
broadly overlaps the jugal and squamosal on the
medial side of the joint. This feature is difficult to
evaluate in the outgroups due to the paucity of dis-
articulated skulls. However, it appears that this con-
dition is widespread within Iguania and it was not
included in the phylogenetic analysis.

Finally, in Gambelia copei (eight of eight), rela-
tively few G. wislizenii (four of 49; REE 425, 2792;
UIMNH 43378-79), and four of 31 G. silus (KU
121753, 121761, 121766, 121768), there is a small
projection or tubercle on the anterolateral surface
of the postorbital at the posterior edge of the orbit
(= character 7). In G. copei, it is usually larger and
more robust than in other Gambelia. This small
tubercle may function as an additional attachment
point for the skin of the head as does the larger dorsal
tubercle. The presence of this tubercle appears to be
unique within Iguania and may be a synapomorphy
for Gambelia, although its more developed state
may be further derived in G. copei. Nevertheless,
this feature is coded as a binary character with the
absence of a tubercle coded as the ancestral condi-
tion (state 0) and the presence of a tubercle as the
derived condition (state 1). Because they were poly-
morphic with respect to this character, G. wislizenii
and G. silus were assigned states c and d respectively.

Parietal (Characters 8, 9; Fig. 2-4, 8). — The pa-
rietal is a median bone that represents the major
element of the skull roof. Its complex shape includes
a trapezoidal roof with short anterolateral processes
and long posterolaterally projecting, laterally com-
pressed supratemporal processes. This shape changes
ontogenetically, although not to the extent seen in
some iguanids, polychrotids, and Leiocephalus (Eth-
eridge, 1959; de Queiroz, 1987; Pregill, 1992). In
juveniles, the parietal roof is roughly square, the
crests of the supratemporal processes are less robust
and project nearly directly posteriorly. During on-
togeny, the posterior edge of the parietal roof be-
comes increasingly constricted such that the lateral

borders of the roof converge. This gives the roof a
trapezoidal shape with the supratemporal processes
projecting posterolaterally rather than posteriorly.
Late in ontogeny, ridges may form along the lateral
and posterior borders of the parietal roof giving the
central portion a depressed appearance. The degree
of constriction of the posterior border of the parietal
roof during ontogeny differs between Crotaphytus
(Fig. 2) and Gambelia (Fig. 3, 4). In Gambelia, the
roof remains relatively broad posteriorly through-
out ontogeny and remains approximately twice the
width of the narrowest portion of the frontal bone.
In Crotaphytus (particularly males) the posterior
border of the parietal shelf becomes more constrict-
ed such that it is approximately equal in width to
the frontal bone or slightly wider. This constriction
is often most dramatic in adult male C. dickersonae,
although enough overlap occurs between species of
Crotaphytus that this was not considered as a sep-
arate character state. There is much variation in the
degree of constriction of the parietal roof within
Iguania, with the basal lineages of all but three fam-
ilies (Phrynosomatidae, not constricted; Coryto-
phanidae, constricted; Hoplocercidae, constricted)
having representatives with both states. Although
the polarity of the character could not be deter-
mined, Gambelia and Crotaphytus always differ in
the degree of constriction of the parietal roof. There-
fore, this feature was coded as an unpolarized binary
character with the Gambelia condition coded as state
0 and the Crotaphytus condition coded as state 1 .

The supratemporal processes are extremely ro-
bust in Crotaphytus and, in lateral view, project well
above the temporal arches (Fig. 8). The lateral faces
of the processes are also concave. The robust char-
acter of the processes gives broad surface area for
the origin of the hypertrophied jaw adductor mus-
cles that these lizards possess. In all Crotaphytus
examined except some eastern C. collaris (13 of 51
specimens), the supratemporal processes are strong-
ly inflected ventrad at their distal ends. The skulls
of some eastern C. collaris tend to be more dorso-
ventrally compressed, which may result in less in-
flected supratemporal processes. Gambelia also pos-
sess ventrally oriented processes, although of a dif-
ferent character. The crests of the supratemporal
processes are well developed anteriorly, but quickly
taper posteriorly, usually terminating anterior to the
articulation of the process with the squamosal. By
contrast, in Crotaphytus, the crests of the supratem-
poral processes continue posteriorly well beyond the
squamosal to its terminus. As a result, in Gambelia,

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 8. — Lateral view of the skull of Crotaphytus dickersonae
(REE 2777, adult male, SVL =116 mm). Scale = 5 mm.

the processes appear less robust and do not arch as
far above the plane of the parietal roof. This vari-
ation, which can be used to quickly differentiate
between skulls of these genera, could not be polar-
ized due to variation in the outgroups.

Supratemporals (Character 10; Fig. 9, 10).— The
supratemporals are small paired bones that lie in
ventrolateral grooves in the supratemporal process-
es of the parietal in most crotaphytids (Etheridge
and de Queiroz, 1988; Frost and Etheridge, 1989).
The supratemporals are more exposed posterola-
terally and form the major portion of the process at

Fig. 9. — Supratemporal region of Crotaphytus vestigium (REE
2935, adult male, SVL = 125 mm). The vertical hatching denotes
the exposed portion of the supratemporal bone. Jug = jugal. Par
= parietal, Pte = pterygoid, Pto = postorbital. Qua = quadrate,
Squ = squamosal. Scale = 5 mm.

Fig. 10. — Supratemporal region of Gambelia silus (CAS 22713,
adult male, SVL =101 mm). The vertical hatching denotes the
exposed portion of the supratemporal bone. Jug = jugal. Par =
parietal, Pte = pterygoid, Pto = postorbital. Qua = quadrate, Squ
= squamosal. Scale = 5 mm.

its articulation with the quadrate and squamosal.
The tongue-in-groove articulation of each supra-
temporal with the parietal is well developed in all
crotaphytids except Gambelia silus (Fig. 9, 10). In-
deed, in most G. silus that could be coded for this
character (25 of 28), the supratemporal does not sit
in a groove, but lies along the lateral surface of the
supratemporal process (Fig. 10). This variation is
occasionally observed in G. wislizenii (four of 49),
C. antiquus (one of four), and C. collaris (one of 5 1).
In iguanian lizards, the tongue-in-groove relation-
ship between the supratemporal and supratemporal
process is seen only in crotaphytids and the tropi-
durid genus Liolaemus and therefore is here con-
sidered to be derived within Crotaphytidae. The
condition observed in G. silus may be a reversal
because some individuals do possess the rare grooved
condition seen in few iguanian lizards.

Septomaxillae (Character 11; Fig. 2-5, 7). — The
septomaxillae are paired sheets of bone situated in
the anteromedial nasal capsule where they form the
floor of the nasal passages and the roof over the
Jacobson’s organ (Oelrich, 1956; Jollie, 1960). In
Gambelia wislizenii and G. copei, the septomaxillae
are slender and more elongate than in either G. silus
or Crotaphytus. It is likely that this condition is

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

associated with the more elongate snout seen in this
species. This hypothesis is corroborated by the rel-
atively slender septomaxillae seen in C. bicinctores,
C. dickersonae, C. grismeri, C. insularis, and C. ves-
tigium, which also have relatively elongate snouts.
However, these taxa do not have the extreme con-
dition present in G. wislizenii and G. copei. Elongate,
slender septomaxillae are rarely observed within Ig-
uania. In Opiums ( O . cuvieri and O. quadrimacu-
latus), they are extremely slender, almost splinter-
like, while in certain other iguanians ( Phrynosoma
asio, P. orbiculare, P. coronatum, some Dipsosaurus
dorsalis ) they are slender, although to a lesser degree.
Elongate, slender septomaxillae are considered to
be the derived state. However, septomaxillae are
often destroyed during the preparation of skeletons
and many outgroup taxa are not represented here.
Because this feature appears to be associated with
the much more elongate snout that occurs in G.
wislizenii and G. copei, this character is treated as
a character complex (although all of the differences
that appear to be associated with an elongate snout
cannot be polarized as can the septomaxillae con-
ditions).

Maxillae (Characters 12, 13; Fig. 2-5, 7, 8).— The
premaxillary process contacts the premaxilla ante-
riorly by means of an overlapping sheet of bone. It
includes a well-developed shelf that passes posterior
to the nasal process of the premaxilla and acts as
the anterior wall of the external naris. The septo-
maxilla contacts the posterodorsal edge of this shelf
while posteroventrally the shelf is contacted by the
vomer. In Gambelia wislizenii, G. silus, and five of
eight G. copei (absent in REE 2798, 2802, 2805), a
protrusion of the premaxillary process overlaps the
lateral edge of the premaxilla such that the suture
is saddle-shaped (Fig. 3-5). This condition is only
rarely observed in the outgroups (present in some
Chalaradon madagascariensis, Petrosaurus mearn-
si, Urostrophus vautieri, some Pristidactylus torqua-
tus, Enyalius brasiliensis, E. pictus, Phymaturus
punae, some P. palluma, Leiocephalus melanoch-
lorus, and some L. carinatus) and is considered to
be the derived state.

The dorsally directed nasal process of the maxilla
contacts the nasal, prefrontal, and lacrimal bones
and forms the posterolateral wall of the external
naris and the lateral wall of the nasal capsule. A
canthal ridge is present on the nasal process and
extends from the rugose protuberance of the pre-
frontal to the base of the premaxillary process near
the posterolateral corner of the external naris. The

angle of the canthal ridge, as well as the posterior
margin of the external naris, is much greater (greater
than 45 degrees) in Crotaphytus, Gambelia corona f,
and G. silus than it is in G. wislizenii and G. copei
due to the elongate snout of the latter two species.
Several potentially useful characters are associated
with the longer snout of G. wislizenii and G. copei,
including the more elongate septomaxillae and vo-
mers. However, as each of these appears to be linked
to rostral elongation, they are considered as one
character (see septomaxillae) in this analysis.

Ventromedially, a thickening of the maxilla forms
a shelf-like process that overlaps the palatine. This
shelf projects further medially in Crotaphytus (Fig.
11, 12) than in Gambelia and is more nearly tri-
angular. In Gambelia, the shape of the process is in
the form of a low, rounded arch. There is extensive
variation in the outgroups with regard to this feature
and it was left unpolarized.

Jugals (Characters 14, 15; Fig. 2-4, 8, 11). — The
general shape of the jugal varies little in crotaphytids
although three potentially useful variations were ob-
served. A ridge, or thickening, is found on the ex-
ternal surface of the jugal, extending from its im-
mediate anterior end posteriorly just beyond the
jugal’s articulation with the postorbital. The ridge
is thicker in Crotaphytus than in Gambelia and is
most developed in C. reticulatus. The function of
this ridge is uncertain, although it provides the sur-
face for attachment of the subocular scales. A lateral
ridge is present on the jugal in many iguanians, al-
though it is usually less strongly developed than that
of Crotaphytus. Although this may eventually prove
to be a phylogenetically useful character, it was not
considered in this analysis.

All crotaphytids possess an enlarged tubercle pos-
terior to the termination of the maxillary tooth row
(Fig. 2, 8, 11). This tubercle is actually comprised
of both the jugal, which forms the anterior portion,
and the ectopterygoid, which forms the posterior
portion. The function of the tubercle appears to be
as an attachment site for the ligamentum quadra-
tomandibulare. The size of the tubercle is interspe-
cifically variable, with Crotaphytus antiquus, C. col-
laris, C. dickersonae, C. nebrius, and C. reticulatus
having very large tubercles and the remaining taxa
having small ones. Despite this variation in size, the
presence or absence of a tubercle was coded as a
binary character. In the outgroups, a similar tubercle
is present in the leiosaurs Pristidactylus, Diplolae-
mus, and Leiosaurus and a less similar laterally com-
pressed tubercle is present in some chamaeleonids

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 1 1. — Ventral view of the skull of Crotaphytus dickersonae
(REE 2777 , adult male, SVL =116 mm). Scale = 5 mm.

( Leiolepis belliana, Physignathus lesueurii). There-
fore, the presence of a tubercle is considered to be
the derived state and represents a synapomorphy
for Crotaphytidae.

There is also variation in the angle of the jugal
where it serves as the ventrolateral border of the
orbit. In Crotaphytus, the medial face of the jugal
is oriented dorsolaterally at about a 45-degree angle
over most of its length. In G. wislizenii, G. copei,
and 1 5 of 3 1 G. silus, the medial face becomes pro-
gressively more vertical anteriorly until it articulates
with the palatine, lacrimal, and prefrontal. As a re-
sult, the region of articulation of the three bones in
Gambelia wislizenii, G. copei, and some G. silus is
box-like because the jugal meets the palatine and
prefrontal at perpendicular angles. In Crotaphytus
and some G. silus, the jugal meets the prefrontal in
a smooth, rounded arc. The box-like condition of

the ventrolateral border of the orbit was approached
only in Petrosaurus mearnsi, Uta stansburiana, Uma
(but not Callisaurus, Cophosaurus, or Holbrookia
maculata), one of two Enyalioides laticeps, and Lei-
olepis belliana and is therefore considered to be the
derived state within Crotaphytidae.

Palate

Vomers (Character 16; Fig. 11, 12). — In Crota-
phytus insularis and C. vestigium, a separate pair of
small bones, here termed extravomerine bones, may
be present posteromedially where the vomers and
palatines meet (Fig. 12). These medially contacting
bones appear to be the result of secondary ossifi-
cation centers in the vomers. In many specimens,
this additional bone is present on one side only and
the region where the bone is absent is filled in by
the vomer from that side. Extravomerine bones are
present in all five C. insularis available for study,
although it is found on the right side only in one
specimen (REE 2797). It is also found on at least
one side in ten of 27 C. vestigium. Extravomerine
bones are not present in the outgroup taxa examined
here and no evidence has been discovered docu-
menting their presence in other lizard species.
Therefore, the presence of either one or two extra-
vomerine bones is considered to be the derived state.

Palatines (Character 17; Fig. 6, 11, 12). — In Cro-
taphytus, the dorsal surface of the maxillary process
usually bears the palatine foramen (Fig. 6), which
may be situated in the suture of the maxillary pro-
cess and the prefrontal or completely within the
palatine. In one C. collaris (USNM 220216), the
foramina were located entirely within the palatine
processes of the prefrontals. A well-developed,
transversely oriented canal, associated with the in-
termediate palatine branch of nerve VII (Oelrich,
1956), projects medially from the palatine foramen
(Fig. 6). In Gambelia, a palatine foramen is only
rarely evident (five of 43 G. wislizenii, zero of eight
G. copei, two of 30 G. silus), although the canal, and
presumably the intermediate palatine branch of
nerve VII, are present. Instead of passing through
the prefrontal and palatine bones, the tube passes
through the connective tissue medial to the palatine
process of the prefrontal along the lateral border of
the orbitonasal fenestra. The absence of a palatine
foramen in the great majority of Gambelia appears
to be the result of the narrower palatine process of
the prefrontal found in this taxon, rather than the
absence or rerouting of the intermediate palatine
branch of nerve VII. Some variation was observed

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

within Crotaphytus including C. collaris (foramen
present in seven of 51), C. grismeri (three of five),
and C. reticulatus (22 of 26). The outgroup taxa are
also extremely variable with respect to this feature,
preventing its polarization. Phylogenetically useful
variation was also observed in the palatine foramina
of Phymaturus. In all specimens of Phymaturus ex-
amined, the foramina were much larger proportion-
ally than those of any other iguanian taxon exam-
ined.

Pterygoids (Characters 18-20; Fig. 2-4, 8, 11).—
The transverse process of the pterygoid of Crota-
phytus bears a sharp vertical crest near its lateral
end. This crest is very weak or absent in Gambelia.
A strong vertical crest is present in many iguanian
species and its absence may be a synapomorphy for
Gambelia. However, this crest appears to be asso-
ciated with a more easily definable character of the
ectopterygoid and its description is given in the dis-
cussion of that element.

The transverse processes of Crotaphytus reticu-
latus and C. dickersonae are more ventrally ex-
panded in comparison to the other crotaphytids.
This condition is especially extreme in adult male
C. dickersonae, which bear a well-developed crest
that extends along the ventral edge of the entire
transverse process terminating at, or near, the in-
terpterygoid vacuity. This crest descends ventrally
to a degree seen in no other crotaphytid species.
Although it is difficult to compare this feature across
a broad range of taxa with very different pterygoid
morphologies, a strongly developed crest appears to
be present in many corytophanids, chamaeleonids,
and polychrotids, as well as within large iguanids.
Therefore, this character was left unpoiarized.

In Gambelia, the quadrate processes are approx-
imately one-third shorter as a percentage of skull
length than they are in Crotaphytus. In Crotaphytus,
the posterior part of the skull is clearly longer than
that of Gambelia and this is best illustrated by com-
paring the posterior extents of the quadrate pro-
cesses of the pterygoids, the supratemporal pro-
cesses, and the paraoccipital processes with the pos-
terior extent of the occipital condyle. In adult Cro-
taphytus, all three processes project well posterior
to the occipital condyle (Weiner and Smith, 1965;
Fig. 2, 11), while in Gambelia, they reach a point
roughly equidistant with the condyle (Fig. 3, 4). This
condition is subject to considerable ontogenetic
variation, with juveniles of both genera having the
three processes extending posteriorly to a point
equidistant with the occipital condyle until they reach

Fig. 12. — Ventral view of skull of Crotaphytus vestigium (REE
2826, adult male, SVL = 105 mm) showing the extravomerine
bones (vertically hatched) present in C. insularis and many C.
vestigium. Scale = 5 mm.

an SVL of approximately 80-85 mm. At this point
in ontogeny, the processes begin to project further
posteriorly in Crotaphytus than in Gambelia. The
condition observed in adult Crotaphytus appears to
be apomorphic and was only observed in large male
Basiliscus basiliscus, Pristidactylus (as well as Di-
plolaemus and Leiosaurus), Uromastyx acanthinu-
rus, U. benti, U. microlepis, and Physignathus le-
sueurii. This condition may represent an adaptation
for more powerful jaw adduction in these lizards.

In Crotaphytus and Gambelia silus, the quadrate
processes project posterolaterally at a greater angle
(approximately 26-3 1 degrees) than in G. wislizenii
and G. copei (approximately 18 degrees). Most of
the outgroup taxa appear to be similar to Crota-
phytus and G. silus with respect to this feature, al-
though enough variation was observed that the char-
acter was left unpolarized.

Ectopterygoids (Character 21; Fig. 2-4, 11). — In
Crotaphytus, the transverse process of the pterygoid
bears a strong vertical crest just medial to its artic-
ulation with the ectopterygoid. In Gambelia, this
crest is weakly defined and this appears to be as-
sociated with the morphology of the ectopterygoid.
The dorsal surface of the ectopterygoid is in the form
of a sharp transverse edge or ridge that extends to
the termination of the medially projecting process.

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

This ridge bears a posterior projection in Crotaphy-
tus that overlaps the strong vertical crest of the
transverse process. The ridge does not bear a strong
posterior projection in Gambelia, instead being
straight or nearly so. Presence or absence of a pos-
terior projection of this ridge are coded as separate
character states. However, there is much variation
in the outgroups and this character could not be
polarized.

The ectopterygoid also bears a strong posterolat-
eral process that is sutured to a similar process of
the jugal. Together they form the tubercle that pro-
jects posterolaterally just beyond the termination of
the maxillary tooth row (see description of jugal
above).

Braincase

Parabasisphenoid (Character 22; Fig. 11). — Pro-
jecting anteriorly from the basisphenoid is the long,
blade-like parasphenoid process. Although this is a
separate osseous element, it is fused with the basi-
sphenoid in postembryonic crotaphytids and, fol-
lowing Jollie (1960:fig. 3), they are here treated as
a single element, the parabasisphenoid.

The posterior suture of the parabasisphenoid with
the basioccipital differs between Gambelia and Cro-
taphytus. In Gambelia, the parabasisphenoid bears
long posterolateral processes that extend to the
sphenoccipital tubercles. These processes are absent
or extend only slightly beyond the transverse plane
of the parabasisphenoid-basioccipital suture in most
Crotaphytus examined (Fig. 1 1), although they may
occasionally reach the base of the lateral process of
the basioccipital. The posterolateral processes never
were observed to reach the sphenoccipital tubercles,
although they nearly reached the tubercle in two of
29 C. collaris (LLG 62, REE 2948).

The majority of the outgroup taxa have long pos-
terolateral processes of the parabasisphenoid that
reach or nearly reach the sphenoccipital tubercles.
Exceptions occur within the families Phrynosoma-
tidae, Chamaeleonidae, Tropiduridae, and Poly-
chrotidae. In Phrynosomatidae, short processes are
present in Petrosaurus, Uta, Urosaurus graciosus,
and Sator grandaevus (but not Sceloporus, at least
those examined here; Appendix 1), while in Phry-
nosoma and the sand lizards they are long. There-
fore, short processes may be an additional syna-
pomorphy for Petrosaurus plus the Sceloporus group,
with a reversal in Sceloporus.

Within Chamaeleonidae, short processes are pres-
ent in Leiolepis belliana, but not Uromastyx or the

basal agamines Physignathus lesueurii and Hydro-
saurus amboiensis. Within chamaeleonines, Broo-
kesia stumpffi has short processes, while all of the
remaining chamaeleonines examined (Appendix 1)
except Chamaeleo kerstenii have long processes. In
C. kerstenii, the basioccipital is displaced forward
by the exoccipitals such that it does not form the
ventral portion of the occipital condyle. As a result,
the basioccipital tubercles are found on the exoc-
cipitals rather than the basioccipital. Thus, the ho-
mology of the posterolateral processes (or lack there-
of) of this species is questionable.

In tropidurids, the processes are short in Cten-
oblephary’s, Liolaemus, and some Leiocephalus { short
in L. barahonensis, L. carinatus, L. lunatus, L. ma-
cropus, and L. psammodromus; long in L. green-
way i, L. melanochlorus, L. personatus, L. schrei-
bersi, L. stictigaster, and L. vinculum ), but long in
all of the Stenocercini and Tropidurini examined
(Appendix 1) except T. spinulosus and T. melano-
pleurus, which are nonbasal taxa (Frost, 1992).

Within polychrotids, the processes are short in
Pristidactylus, Diplolaemus, Leiosaurus, the anoles,
the para-anoles (intraspecifically variable in Uros-
trophus vautieri), and some Polychrus acutirostris
(but not P. marmoratus), but long in Enyalius.

Long posterolateral processes represent the an-
cestral condition in Hoplocercidae, Opluridae, Cor-
ytophanidae, Iguanidae, and Chamaeleonidae, and
the polarity of this character is equivocal for Phry-
nosomatidae and Tropiduridae (but long processes
may be ancestral for Tropiduridae). It is most par-
simonious to assume that short posterolateral pro-
cesses were present in the common ancestor of Po-
lychrotidae. Thus, the presence of short posterolat-
eral processes are treated as the derived state within
Crotaphytidae.

Additional intergeneric variation was also ob-
served in the parabasisphenoid. At the anterodorsal
end of the basisphenoid is a depression, the sella
turcica, that houses the pituitary gland. In adult Cro-
taphytus, the sella turcica usually is elevated such
that in lateral view, it is visible above the quadrate
process of the pterygoid. In Gambelia, the sella tur-
cica is more depressed and is rarely visible above
the quadrate process. However, continuous varia-
tion exists in this characteristic and it was omitted
from the phylogenetic study.

Mandible

Dentary ( Fig. 13, 14). — In many iguanian lizards,
the dentary is tubular anterior to the splenial and

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYT1D LIZARDS

Fig. 13. — Lingual view of the right mandible of (A) Crotaphytus
reticulatus (REE 2912, adult male, SVL = 122 mm) and (B)
Gambelia copei (REE 2800, adult female, SVL = 123 mm). Ang
= angular. Art = articular. Cor = coronoid, Den = dentary, Pmf
= posterior mylohyoid foramen, Pre = prearticular, Spl = splen-
ial, Sur = surangular. Scale = 5 mm.

completely encloses Meckel’s cartilage. In crota-
phytids, the tubular nature of the dentary is incom-
plete. The anterior end of the dentary is open, while
posteriorly the groove is closed, but not fused. In
Crotaphytus, with the exception of C. grismeri, the
groove is usually closed over less than one-half of
its length anterior to the splenial and there is rela-
tively consistent interspecific variation in this char-
acteristic. In C. collaris, C. nebrius, and C. reticu-
latus, Meckel’s groove is often open over its entire
length anterior to the splenial, and most of the re-
maining specimens have the groove closed over less
than one-third of its length. In C. antiquus and C.
dickersonae, the groove is not open over its entire
length, but as in the above-mentioned taxa, it was
nearly always closed over less than one-third of its
length. In C. bicinctores, C. insu/aris, and C. vestig-
ium, Meckel’s groove is usually closed over between
one-third and one-half of its length anterior to the
splenial and was only once observed to be open over
its entire length (C. vestigium, REE 2811). Crota-
phytus grismeri is unique among Crotaphytus in that
Meckel’s groove is closed over between approxi-
mately 50 percent and 70 percent of its length in all
specimens examined (five of five). Norell (1989)
noted that in Gambelia, the groove is usually closed
over two-thirds of its length anterior to the splenial.
Unfortunately, this condition is much more variable
in Gambelia than in Crotaphytus, and although the
groove in most specimens is closed over greater than
one-half of its length anterior to the splenial, 12 of
30 G. silus, two of nine G. copei, and 12 of 45 G.

Fig. 14. — Labial view of the right mandible of (A) Crotaphytus
reticulatus (REE 2912, adult male, SVL = 122 mm) and (B)
Gambelia copei (REE 2800, adult female, SVL = 123 mm). Cor
= coronoid, Den = dentary, Pre = prearticular, Sur = surangular.
Scale = 5 mm.

wislizenii had a condition similar to that observed
in Crotaphytus, with the groove closed over less than
half of its length anterior to the splenial. Because of
this variation, this character was not considered in
the phylogenetic analysis.

Norell (1989) also considered an elongate dentary
(with a posterior process projecting posterior to the
superior apex of the coronoid, Etheridge and de
Queiroz, 1988) to be a synapomorphy for Crota-
phytidae. Although this character state was found
to be derived in their phylogenetic analysis of pleu-
rodont iguanians (possibly a paraphyletic assem-
blage with respect to acrodont iguanians [Chamae-
leonidae]), this state is widespread within Iguania
and may be a synapomorphy for a group more in-
clusive than Crotaphytidae.

The dentary bears between three and eight mental
foramina anteriorly. In Crotaphytus, the mental fo-
ramina are usually restricted to the distal end of the
dentary, while in Gambelia they may extend pos-
teriorly to the midpoint of the bone. Continuous
variation in this feature prevented its inclusion in
the phylogenetic analysis.

Angular (Characters 23, 24; Fig. 13). — In Crota-
phytus, the exposed portion of the angular extends
further anteriorly than in Gambelia wislizenii and
G. copei. Defining states for this character is com-
plicated by the variation that exists in those struc-
tures that may serve as reference points. For this
reason, two points of reference are included in the
description of this character. In adult Crotaphytus,
with very few exceptions, the angular extends an-
teriorly at least to the fourth tooth (counting from

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

the rear of the tooth row) and usually well beyond
this point. Juveniles are not always comparable be-
cause their teeth are relatively larger than those of
adults and are often widely spaced. The angular also
extends well beyond the anterior extent of the cor-
onoid in both adults and juveniles. In G. wislizenii
and G. copei, the angular was never observed to
reach the fourth tooth (from the rear of the tooth
row) and rarely reached beyond the first. In most
specimens, the angular does not extend as far an-
teriorly as does the coronoid. In C. bicinctores, C.
grismeri, and G. silus, the anterior extent of the
angular shows continuous variation with most spec-
imens having an intermediate condition but others
with character states similar to those observed in
G. wislizenii and G. copei or the remaining species
of Crotaphytus. Because of this continuous variation
in these three taxa, I have coded each as unknown
for this character. With respect to the outgroup taxa,
the angular projects well anteriorly in chamaeleon-
ids, hoplocercids, the corytophamds Basiliscus bas-
iliscus, B. vittatus, B. plumifrons, some Coryto-
phanes cristatus, C. percarinatus, some Laemanctus
longipes, L. serratus, and many polychrotids, while
it is short in tropidurids (except Uranoscodon su-
perciliosus ), phrynosomatids, oplurids (except O.
fierinensis), and iguanids.

The angular bears the posterior mylohyoid fora-
men. This foramen usually is positioned well pos-
terior to the superior apex of the coronoid in Gam-
belia (eight of eight G. copei, 26 of 29 G. silus, 50
of 5 1 G. wislizenii ), while it is equidistant with, or
anterior to, the superior apex in most Crotaphytus
(posterior to the superior apex in two of 49 C. col-
laris, three of 1 5 C. dickersonae, two of 1 7 C. ne-
brius, two of 23 C. reticulatus, one of 27 C. vestig-
ium). Although most of the outgroup taxa exhibit
the condition observed in Crotaphytus, the presence
of the posterior mylohyoid foramen posterior to the
apex of the coronoid in phrynosomatids, some tro-
pidurids, and some polychrotids (Frost and Ether-
idge, 1989) as well as some oplurids prohibits po-
larization of this character.

Coronoid (Character 25; Fig. 13, 14). — The angle
of the posterolingual process of the coronoid is near-
ly vertical in Crotaphytus, while it extends poster-
oventrally at an angle of approximately 45 degrees
in G. wislizenii, G. copei, and G. corona\ (Norell,
1989). Gambelia silus may be intermediate in this
feature or may approach the conditions observed in
Crotaphytus or G. wislizenii-G . copei. Therefore, G.
silus was coded as unknown (“?”) for this character.

Most outgroup taxa have a condition similar to Cro-
taphytus (state 0) or occasionally the intermediate
condition usually present in G. silus. The outgroup
taxa with the G. wislizenii-G. copei condition in-
clude only Petrosaurus mearnsi, Phrynosoma doug-
lassi, P. coronatum, Uromastyx, Brookesia stumpffi,
and Chamaeleo kersteni (chamaeleonines as a whole
are variable with respect to this feature). Therefore,
the angled posterolingual process of the coronoid
(state 1) is considered to be derived and the vertical
condition ancestral. Norell (1989) considered this
feature to be an unambiguous synapomorphy of
Gambelia, presumably because he did not examine
specimens of G. silus.

Surangular (Characters 26-28; Fig. 13-15). — Im-
mediately anterior to the articular facet lies a me-
dially oriented knob-like process here referred to as
the medial process. A thin shelf of bone may extend
anteriorly between the distal extremity of the medial
process and the body of the surangular (Fig. 15).
This shelf is usually much more strongly developed
in Gambelia and, to a lesser degree, Crotaphytus
insularis than in the remaining Crotaphytus species.
Crotaphytus vestigium is variable with respect to this
character with seven of 27 having a shelf present.
A lesser amount of variation was observed with a
smaller shelf present in C. bicinctores (one of 25),
C. collaris (five of 50), C. dickersonae (two of 16),
C. nebrius (one of 17), and C. reticulatus (one of
14). In Gambelia, the shelf may entirely fill this
space such that its edge may be either straight or,
more frequently, convex in shape. The strongly de-
veloped condition present in Gambelia suggests that
it may be a further modification or intensification
of the condition observed occasionally in Crota-
phytus. Thin shelves of bone between the medial
process and the ramus of the mandible are present
in a small number of iguanian taxa, including Lei-
olepis belliana, Opiums cuvieri, some Brachylophus
fasciatus, some Uta stansburiana, Urosaurus auri-
culatus, Microlophus grayi, and most Phymaturus
taxa (absent only in P. palluma and some P. punae).
The shelves only approached the condition of Gam-
belia in the four Phymaturus patagonicus subspe-
cies. This character was coded as a binary character
with the absence of a shelf coded as state 0 and its
presence as state 1 (taxa with intermediate frequen-
cies coded appropriately). The presence of thin
shelves of bone between the medial process of the
surangular and the ramus of the mandible is inter-
preted as the derived state.

An additional process of the surangular may be

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

present immediately anterolateral to the articular
facet. In Crotaphytus, a large knob-like process is
present (here referred to as the lateral process), pre-
sumably to provide a large surface area for insertion
of the jaw adductor musculature of these lizards. In
most Gambelia, no obvious process is visible, al-
though in some individuals, a small elevation is
present. In the outgroup taxa, a large lateral process
is present in JJromastyx acanthinurus, U. microle-
pis, Opiums fierinensis, some Leiocephalus macro-
pus, Phrynosoma coronatum, some P. doug/assi,
some Uma inornata, Urosaurus auriculatus, the
leiosaurs Pristidactylus, Diplolaemus, and Leiosau-
rus, the para-anoles, and Polychrus (although in
Polychrus, the process is displaced further anteri-
orly). The lateral process was enlarged to the degree
observed in Crotaphytus only in Pristidactylus, Di-
plolaemus, and Leiosaurus. The presence of an en-
larged lateral process of the surangular is interpreted
as the derived state within Crotaphytidae.

In crotaphytids, a ridge on the dorsolateral surface
of the surangular extends between the lateral process
and the labial process of the coronoid. This ridge
provides a broader area for insertion of M. adductor
mandibularis extemus on the dorsal surface of the
surangular. In Gambelia, the ridge is either absent
or only weakly developed. In Crotaphytus, the ridge
and corresponding dorsal shelf are more strongly
developed, and in C. reticulatus, the ridge is ex-
tremely well developed providing a concave area for
muscle insertion in adults (Fig. 1 5). This feature was
coded as an unordered multistate character with
Gambelia given state 0, Crotaphytus (except C. re-
ticulatus) given state 1 , and C. reticulatus given state
2. All of the outgroup taxa either lacked this ridge
or had a very weakly developed one (state 0), with
the possible exception of Hydrosaurus amboiensis,
in which a ridge is present near the ventrolateral
border of the mandible. Opiums fierinensis, and some
Phrynosoma (P. asio and some P. doug/assi and P.
orbiculare), in which the ventrolateral portion of the
mandible is greatly expanded. The absence of a ridge
or the presence of a weakly developed one is con-
sidered to be the ancestral state.

Prearticular (Character 29; Fig. 1 3-1 5). — Poste-
riorly, the prearticular bears two large processes that
serve as insertion sites for jaw adductor and de-
pressor muscles. The angular process projects ven-
tromedially from a point just below the articular
facet, while the retroarticular process projects pos-
teriorly. In Gambelia, thin shelves of bone extend
between the processes of the posterior portion of the

A B

Fig. 15. — Dorsal view of the posterior portion of the right man-
dible in (A) Crotaphytus reticulatus (REE 29 1 2, adult male, SVL
= 122 mm) and (B) Gambelia copei (REE 280CT, adult female,
SVL = 123 mm). LP = lateral process, TC = tympanic crest.
Arrow indicates the shelf that extends between the medial process
and the ramus of the mandible in Gambelia. Scale = 3 mm.

mandible and the ramus of the mandible. One such
shelf was discussed above with the surangular. Two
additional shelves may also be present, both of which
are associated with the angular process. One extends
between the angular process and the retroarticular
process, while the other extends forward from the
angular process to the body of the lower jaw. Shelves
of bone that extend between the processes of the
mandible and the ramus of the mandible were treat-
ed as a single character (see surangular).

The shape of the retroarticular process and its
tympanic crest in crotaphytids is distinctive. In dor-
sal view, the retroarticular process is roughly qua-
drangular, while in lateral view it is more nearly
triangular. The distal terminus of the process is ex-
panded, giving it a bulbous appearance. The tym-
panic crest is more broadly expanded in Gambelia
than in Crotaphytus (Fig. 1 5), but was not scored as
a separate character state. The tympanic crest in all
crotaphytids is robust and its edge expands poste-
riorly such that at the end of the process, it is nearly

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

as broad as the process itself. Furthermore, the tym-
panic crest angles posterodorsally and, thus, does
not form the lateral border of the retroarticular pro-
cess as it does in most other iguanian taxa examined
(illustrations of the ancestral condition of the tym-
panic crest can be seen for Dipsosaurus dorsalis in
de Queiroz, 1987:fig. 29; for Basiliscus vittatus and
Corytophanes cristatus in Lang, 1989:fig. 31; and for
Physignathus cocincinus in Moody, 1980:fig. 16).
The angle of the tympanic crest gives the retroar-
ticular process a twisted appearance. The orienta-
tion of the tympanic crest appears to undergo an
ontogenetic change from the standard position along
the lateral border of the retroarticular process in
juveniles to a more posterodorsal orientation in
adults. The medial crest of the retroarticular pro-
cess, discussed by de Queiroz (1987), is only vari-
ably present in crotaphytids. A similar posterodor-
sal curvature of the tympanic crest was observed
only in Opiums cuvieri and one Polychrus acutiros-
tris (REE 568). Therefore, this condition is inter-
preted as a synapomorphy for Crotaphytidae.

Miscellaneous Features of the
Head Skeleton

Marginal Teeth (Characters 30, 31; Fig. 8, 11-
14). — The marginal teeth of crotaphytids are char-
acteristic of most pleurodont iguanians in that the
anterior teeth are conical and the posterior maxillary
and dentary teeth are compressed and tricuspid. The
dentition of crotaphytids has been described as het-
erodont or weakly subheterodont (Marx, 1950; Wei-
ner and Smith, 1965) because the teeth sometimes
grade from conical to bicuspid then tricuspid (the
bicuspid state is often omitted). This transition usu-
ally begins further anteriorly in Crotaphytus (mean
maxillary tooth position x = 8.11 , n - 152) and
Gambelia situs (x = 8.08, n = 30) than in G. wis-
lizenii (x = 1 1.27, n = 43) or G. copei (x = 11.13,
n = 8), although the ranges overlap extensively. Het-
erodonty was considered to be more developed in
Gambelia than Crotaphytus by Marx (1950) and
Weiner and Smith (1965) and was used as a char-
acter to distinguish between the genera. However,
Montanucci (1969) found that the degree of heter-
odonty was indistinguishable between adult G. wis-
lizenii and many C. collaris, especially juveniles.
The degree of cuspation is certainly more pro-
nounced in Gambelia than Crotaphytus and, despite
the ontogenetic variation discussed by Montanucci
(1969), this subtle variation could probably be cod-

ed into discrete character states. However, degree
of cuspation varies continuously within iguanians
and this character therefore may be added to the
long list of currently unpolarizable differences be-
tween Crotaphytus and Gambelia. As in many ig-
uanian lizards, the number of maxillary and dentary
teeth increases ontogenetically, at least early in on-
togeny. The number of premaxillary teeth does not
increase ontogenetically.

In some individuals of both Crotaphytus (Ether-
idge, 1960; personal observation) and Gambelia, the
tooth rows of the mandibles and/or maxillae may
be doubled for a short distance (two sets of teeth
occurring side by side). Although Etheridge (1960)
hypothesized that this variation may be restricted
to males, it actually occurs in both sexes.

The number of maxillary and dentary teeth tends
to be greatest in Gambelia wislizenii, G. copei, and
Crotaphytus dickersonae (Tables 3, 4). The large
number of teeth in these Gambelia is not surprising
given the elongate snout that is characteristic of these
species. The large number of teeth observed in C.
dickersonae is the result of very closely spaced den-
tition. The small number of teeth present in G. silus
is probably correlated with the truncated snout of
this species and may therefore be a plesiomorphic
retention. Discrete character states could not be as-
signed describing numbers of maxillary and dentary
teeth. Therefore, this variation was not considered
in the phylogenetic analysis.

The number of premaxillary teeth varies within
Crotaphytidae (Tables 3, 4). Gambelia is character-
ized by the strong statistical mode of seven pre-
maxillary teeth, while most Crotaphytus taxa have
a somewhat weaker statistical mode of six. How-
ever, C. dickersonae and some populations of C.
collaris (those formerly referred to the subspecies C.
c. baileyi) have modes of seven. This variation was
coded as a multistate character using a step matrix
and the Manhattan distance frequency approach (see
Appendix 4). This character was not polarized.

All crotaphytids have recurved anterior maxillary
and dentary teeth, a condition that is more devel-
oped in Gambelia than Crotaphytus, which have
broader, more peg-like teeth (especially evident in
C. reticulatus). Long, slender, recurved maxillary
and dentary teeth, as present in Gambelia, were not
observed in any of the outgroup taxa and are there-
fore treated as the derived state.

Palatal Teeth (Characters 32, 33; Fig. 11).— At
the base of the pterygoid process of each palatine,

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

Table 3 . — Tooth count data for Crotaphytus.

Premaxillary teeth

Maxillary teeth

Dentary teeth

Crotaphytus :
antiquus ( n = 4)

mean ± SD

5.8 ± 0.50

16.9 ± 0.44

22.0 ± 1.20

range

(5-6)

(15-19)

(21-24)

bicinctores (n = 24)

mean ± SD

6.2 ± 0.53

16.9 ± 0.44

23.0 ± 2.25

range

(5-7)

(15-21)

(18-28)

collaris ( n — 49)

mean ± SD

6.2 ± 0.76

17.2 ± 1.78

21.5 ± 2.48

range

(5-8)

(14-22)

(16-26)

dickersonae (n = 16)

mean ± SD

7.1 ± 0.95

20.3 ± 2.60

24.8 ± 3.51

range

(6-9)

(16-25)

(19-31)

grismeri (n = 5)

mean ± SD

6.4 ± 0.89

18.6 ± 1.96

23.1 ± 2.23

range

(6-8)

(16-21)

(19-26)

insularis (n = 5)

mean ± SD

6.0 ± 0.00

18.1 ± 1.60

23.8 ± 1.99

range

(6)

(15-20)

(22-28)

nebrius (n = 17)

mean ± SD

6.2 ± 2.17

18.3 ± 2.17

22.4 ± 2.73

range

(5-7)

(15-23)

(19-30)

reticulatus ( n = 25)

mean ± SD

6.0 ± 0.64

17.7 ± 1.69

21.9 ± 1.75

range

(5-7)

(14-21)

(17-25)

vestigium ( n = 28)
mean ± SD

6.2 ± 0.39

18.3 ± 1.61

23.3 ± 2.12

range

(6-7)

(15-22)

(19-28)

most crotaphytids have an enlarged ridge that may collaris, 19 of 45; C. dickersonae, 12 of 16; C. gris-

support palatine teeth. This ridge is usually more meri, two of five; C. nebrius, 11 of 15; C. reticulatus,

developed in Gambelia than Crotaphytus. Most 17 of 26; C. vestigium, ten of 25), although only C.

Gambelia (G. wislizenii, 39 of 46; G. copei, eight of insularis (zero of five) always lacked palatine den-

nine; G. silus, 17 of 3 1) have palatine teeth. Within tition. Among the outgroup taxa examined, palatine

Crotaphytus, the palatine ridge is almost always teeth are present only in some Opiums ( O . quadri-

present but the teeth are only variably present (C. maculatus) and most polychrotids (all but Poly-

bicinctores, ten of 24; C. antiquus, three of four; C. chrus, although palatine teeth are also absent in all

Table 4. — Tooth count data for Gambelia.

Premaxillary teeth

Maxillary teeth

Dentary teeth

Gambelia-.

copei (n = 9)

mean ± SD

7.0 ± 0.00

20.9 ± 1.09

26.2 ± 1.54

range

(19-23)

(23-29)

silus (n = 31)

mean ± SD

6.6 ± 0.57

17.7 ± 1.46

22.0 ± 1.56

range

(5-7)

(14-20)

(19-25)

wislizenii (n = 45)

mean ± SD

6.9 ± 0.42

19.9 ± 2.26

24.9 ± 2.80

range

(6-8)

(15-24)

(18-31)

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

anoles except Chamaeleolis). Because Frost and
Etheridge (1989) found Polychrus to be the sister
taxon of the anoles, the presence of palatine teeth
is considered as the ancestral state for Polychroti-
dae. Therefore, if palatine teeth are to be considered
apomorphic for Crotaphytidae, it must be assumed
that Crotaphytidae and Polychrotidae are not sister
taxa. Such a relationship was not supported in the
analysis of Frost and Etheridge (1989) as depicted
in their 12 equally parsimonious unrooted trees.
Therefore, palatine teeth are tentatively considered
to be apomorphic for Crotaphytidae.

All crotaphytids possess pterygoid teeth on the
posteromedial border of the palatine process (Fig.
1 1). These teeth may form a single row or, late in
ontogeny, exist as a patch. During ontogeny, the
number of pterygoid teeth clearly increases, al-
though there is not a perfect correlation between
number of teeth and SVL and some very large in-
dividuals have relatively few teeth. Additional teeth
are usually added to the posterior portion of the
patch, and in larger individuals, the majority of the
teeth are found posteriorly. In some juvenile and
most adult Crotaphytus, the posterior aspect of the
pterygoid tooth row curves laterally away from the
interpterygoid vacuity (Fig. 1 1), while in Gambelia
the tooth row follows the margin of the vacuity.
Polarization of this character is complicated by the
absence of pterygoid teeth in the families Phryno-
somatidae and Chamaeleonidae and in some Phy-
maturus and Leiocephalus. Furthermore, pterygoid
teeth are often intraspecifically variable and limited
sample sizes for certain outgroup species probably
did not allow them to be coded adequately for this
character. However, in the remaining outgroup taxa
examined, the pterygoid tooth patch was observed
to curve posterolaterally only in Uranoscodon su-
perciliosus, Corytophanes percarinatus, some C.
cristatus, some Laemanctus serratus, Brachylophus
fasciatus, and Pristidactylus casuhatiensis (see de
Queiroz, 1 987, for additional iguamd taxa with pos-
terolaterally curved pterygoid tooth patches). There-
fore, the posterolateral curving of the pterygoid tooth
patch was considered to be the derived state within
Crotaphytidae.

Scleral Ossicles.- The scleral ossicles are thin,
overlapping platelets of bone that form a supportive
ring within the anterior portion of the sclera of the
eye. De Queiroz (1982) found that most iguanian
taxa are characterized by a standard pattern con-
sisting of 14 ossicles, with numbers one, six, and

eight positive (overlapping both of the adjacent os-
sicles), numbers four, seven, and ten negative (over-
lapped by both of the adjacent ossicles), and the
remaining ossicles imbricating (overlapping one of
the adjacent ossicles, but itself overlapped by the
other). He noted that this pattern is present in Cro-
taphytus collaris, C. vestigium, and Gambelia wis-
lizenii. I have verified his observations for these
species, and report further that the remaining cro-
taphytid taxa are also characterized by this appar-
ently ancestral iguanian condition. A list of speci-
mens for which the scleral ossicles have been ex-
amined is provided in Appendix 7.

Hyoid Apparatus (Characters 34-36; Fig. 16). — A
number of differences in the morphology of the hy-
oid apparatus exist between Crotaphytus and Gam-
belia. In Crotaphytus, the ceratohyals may be greatly
expanded proximally, such that a large hook or pro-
cess is present (processes absent in one of four C.
antiquus). Their development is subject to ontoge-
netic variation and subadults did not have the hook;
therefore, the character was scored only from adults.
In Gambelia, the proximal portion of the ceratohyal
may be somewhat compressed; however, well-de-
veloped hooks are absent. This character varies ex-
tensively in the outgroups and was therefore left
unpolarized.

In Gambelia, the second ceratobranchials are
short, extending posteriorly for about half the length
of the ceratohyals and first ceratobranchials, while
in Crotaphytus they are longer, extending more than
two-thirds the length of the ceratohyals and first
ceratobranchials (Robison and Tanner, 1962; Fig.
16). The second ceratobranchials of C. dickersonae
are often particularly long and in adult males usually
extend as far posteriorly as do the ceratohyals and
first ceratobranchials. However, this was not treated
as a separate character state because of continuous
variation between the extreme C. dickersonae con-
dition and that present in other Crotaphytus, par-
ticularly in C. collaris. The longer second cerato-
branchials of Crotaphytus may function in the de-
pression of their more strongly developed gular
pouch. The outgroups vary continuously in the length
of the second ceratobranchials ranging in relative
length from very short in Phymaturus to extremely
elongate in Polychrus, the anoles, and Brachylophus.
Therefore, this character was left unpolarized.

In Crotaphytus, the second ceratobranchials are
in close contact, although they are not actually fused,
whereas in Gambelia, they may be widely separated

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

(Fig. 16). They were separated in one of four C.
antiquus, in all specimens of G. copei and G. silus,
and in at least ten of 1 5 G. wislizenii. However, in
those five specimens of G. wislizenii in which the
second ceratobranchials were in contact, the contact
may have been an artifact of preparation. Separated
second ceratobranchials are relatively rare in igu-
anians and were only observed in Uta stansburiana,
some Petrosaurus mearnsi, Phrynosoma asio, some
Uma exsul, some Brachvlophus fasciatus, Phyma-
turus, some Leiolepis belliana, and Enyalius bili-
neatus. Separated second ceratobranchials was con-
sidered to be the derived state within Crotaphytidae.
However, this character could not be evaluated in
many outgroup taxa because the hyoid apparatus is
often damaged in preparation and this polarity as-
sessment should only be considered tentative.

Skull Rugosity (Character 37). — Rugosity of the
skull was considered to be a synapomorphy for Cro-
taphytus by Frost and Etheridge (1989). Although
rugosities may indeed be found in all Crotaphytus
taxa (rugosities are not found in Gambelia ), there is
much variation with respect to the ontogenetic pe-
riod during which rugosities develop. For example,
most C. collaris develop rugosities as subadults, while
C. bicinctores , C. dickersonae, and C. nebrius con-
sistently develop rugosities only after reaching adult
size. In C. grismeri, C. insu/aris, C. reticulatus, and
C. vestigium, rugosities may be lacking even in large
adults. For example, an extremely large C. vestigium
(REE 2935; SVL = 125 mm) completely lacks skull
rugosity, while several much smaller individuals
have them. This variation was coded as a binary
character with the absence of skull rugosity as state
0, and the presence of skull rugosity at some point
in ontogeny as state 1 . This character could not be
polarized.

Axial Skeleton

Presacral Vertebrae (Character 38). — The presa-
cral vertebrae of crotaphytids are procoelous and
have supplemental articular facets, zygosphenes and
zygantra, medial to the pre- and postzygapophyses.
A large posterodorsally oriented suprazygapophy-
sial process is present on the atlas. Crotaphytids
retain the apparently plesiomorphic mode of eight
cervical vertebrae and 24 presacral vertebrae, al-
though individuals occasionally have nine cervicals
and more frequently may have 23 or 25 total pre-
sacrals. Four to seven ventrally keeled intercentra

Fig. 16. — Hyoid skeletons of (A) Crotaphytus collaris ( REE 2952,
adult male, SVL = 131 mm), (B) C. dickersonae (REE 2905,
adult male, SVL = 1 06 mm), and (C) Gambelia copei (REE 2800,
adult female, SVL = 1 23 mm). B = body of hyoid, Bh = Basihyal,
Cbl = first ceratobranchial, Cb2 = second ceratobranchial, Ch
= Ceratohyal, Hh = hypohyal. Scale = 10 mm.

occur between the anteriormost cervical vertebrae
and these decrease in size posteriorly.

The zygosphenes and zygantra of all crotaphytid
taxa except Gambelia silus are weakly to moderately
developed, according to the criteria established by
Hoffstetter and Gasc (1969) and modified by de
Queiroz (1987). In the weak form, the facet of the
zygosphene faces dorsolaterally, while in the mod-
erately developed form, the facet faces either lat-
erally or ventrolaterally. The most strongly devel-
oped form of zygosphene is characterized by a ven-
trolaterally facing facet with a notch separating this
facet from the prezygapophysis. This condition is
approached in four of five G. silus, in which either
a notch is present or a very thin sheet of transparent
bone fills the space. Although notched zygosphenes
are present in several of the outgroup taxa, including
corytophanids, iguanids exclusive of Dipsosaurus,
Uranoscodon superciliosus, Polychrus marmoratus,
and some Enyalius ( E . boulengeri, E. bilineatus),
the condition of G. silus is considered to be the
derived state within Crotaphytidae.

Caudal Vertebrae (Characters 39, 40). — The num-
ber of caudal vertebrae present in crotaphytids is
remarkably consistent with all of the species having
between 54 and 63. No gaps were observed sug-
gesting that the number of caudal vertebrae is not
phylogenetically informative within Crotaphytidae.
Most of the caudal vertebrae bear neural arches,
transverse processes, and haemal arches, all of which

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

decrease in size posteriorly and disappear before the
caudal terminus. The first haemal arch or rudimen-
tary haemal arch usually occurs between the second
and third or third and fourth caudal vertebrae, al-
though it may occasionally lie between the first and
second caudal vertebrae. The number of transverse
processes is highly variable. Relatively few trans-
verse processes are present in C. insularis (14-18,
x = 16.6), C. grismeri (16-22, x = 18.0), G. silus
(14-24 + ,x= 18.0), G. wislizenii^ 13-26, x = 18.4),
C. antiquus (19-22, x = 20.3), C. vestigium (17-30,
x = 21.3), C. bicinctores (16-26, x = 21.9), and G.
copei ( 1 7-26, x = 23.3), while an intermediate num-
ber is present in C. dickersonae (24-35, x = 28.6),
and a relatively large number are found in C. reti-
culatus (29-38, x = 33.4), C. nebrius (23-42, x =
34.9), and C. collaris (27-47, x = 37.4). These num-
bers may be complicated by ontogenetic variation
as juveniles tended to have fewer transverse pro-
cesses than adults. Although the data presented here
are suggestive, the extensive interspecific overlap in
ranges prevented the assignment of discrete char-
acter states for each taxon. Therefore, this variation
was not considered in the phylogenetic analysis.

In many iguanian lizards, the transverse processes
of the more anterior caudal vertebrae project pos-
terolaterally but abruptly change to an anterolateral
orientation over the span of a few vertebrae (Eth-
eridge, 1967). As Etheridge (1967) pointed out, this
condition is present in crotaphytids, although in two
taxa unavailable to Etheridge at the time, C. grismeri
(five of five) and C. insularis (four of five), this change
in orientation usually does not occur. The shift in
orientation did not occur in seven of 15 C. bicinc-
tores, one of four C. antiquus, one of 1 5 C. dicker-
sonae, three of 2 1 C. vestigium, and four of 2 1 G.
wislizenii. The ranges and means for the caudal ver-
tebra number at which the shift in orientation of the
transverse processes occurs for each taxon follows:
C. antiquus (8-15, x = 10.7), C. dickersonae (8-12,
x = 1 1.3), C. insularis (12), C. nebrius (10-17, x =
12.5), C. collaris (10-18, x = 13.3), G. silus (13-16,
x= 14.2), C. vestigium (9-22, x = 14.3), G. wislizenii
(13-18, x= 15.4), C. reticulatus (14-20, x = 16.1),
G. copei (16-23, x = 17.1), and C. bicinctores (17-
23, x = 19.9). Again, the extensive interspecific
overlap in ranges limits the phylogenetic usefulness
of this variation and it was not considered in the
phylogenetic analysis.

Adult male C. bicinctores, C. dickersonae, C. gris-
meri, C. insularis, and C. vestigium are characterized

by the presence of a strongly laterally compressed
tail (Fig. 3 IB, 32A-D). In each of these species, the
tail is not only compressed, but relatively taller than
in other crotaphytids and this is reflected in the
morphology of the caudal vertebrae. The neural and
haemal arches are relatively longer and the trans-
verse processes narrower. In the species with strong-
ly compressed tails the neural spines are approxi-
mately 2. 0-3.0 times longer than the transverse pro-
cesses while in the remaining species of Crotaphytus
and in Gambelia, the neural spines are shorter than
the transverse processes, approximately equal in
length, or, in the case of C. reticulatus, approxi-
mately 1.5 times longer than the transverse pro-
cesses. The tail of C. reticulatus may be weakly lat-
erally compressed. However, the tail is never com-
pressed to the degree observed in the species men-
tioned above and in some individuals may not be
compressed at all. Furthermore, the height of the
laterally compressed tail of the other species is en-
hanced by the presence of large fat bodies on the
dorsal and ventral crests of the tail. These large fat
bodies are not present in C. reticulatus or any other
crotaphytid, although I have observed a minute line
of fat on the dorsal surface of the tail of one C.
collaris. Although several anatomical systems have
been modified to produce the lateral tail compres-
sion of C. bicinctores, C. dickersonae, C. grismeri,
C. insularis, and C. vestigium, these modifications
are clearly associated with one complex character
and are treated as such in this analysis. Although
lateral tail compression occurs in several iguanian
families, I have not observed similar fat bodies in
the tails of these taxa. Therefore, lateral tail com-
pression with the presence of dorsal and ventral fat
bodies is considered to be the derived state within
Crotaphytidae.

Autotomic fracture planes of the caudal vertebrae
are widespread in squamates and rhynchocepha-
lians and at the level of Iguania certainly represent
a plesiomorphic retention (Etheridge, 1967; Hoffs-
tetter and Gasc, 1969). While fracture planes are
present in most Gambelia, fracture planes are absent
from Crotaphytus (Etheridge, 1967). Fracture planes
were present in five of five G. silus and seven of ten
G. copei (and apparently fused in the remaining
three). Fracture planes were present in 19 of 23 G.
wislizenii; however, the four that lacked them were
the only four specimens available from Isla Tiburon
and, thus, may represent a derived feature for this
insular population. Many iguanian taxa lack auto-

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

tomic fracture planes, including the hoplocercid Ho-
plocercus, the phrynosomatid Phrynosoma, some
tropidurids of the genus Tropidurus, the polychro-
tids Phenacosaurus, Chamaeleolis, Leiosaurus, Po-
lychrus, Urostrophus, Anisolepis, Chamaelinorops,
and some Enyalius and Anolis, the corytophanids
Corytophanes and Laemanctus, the iguanids Iguana
delicatissima, Conolophus, Amblyrhynchus, and
Brachylophus, and all chamaeleonids except occa-
sional Uromastyx (Etheridge, 1967; de Queiroz,
1987; Frost and Etheridge, 1989; R. Etheridge, per-
sonal communication, 1993). Thus, it is most par-
simonious to assume that autotomic fracture planes
were present in the common ancestors of the fam-
ilies Opluridae, Hoplocercidae, Iguanidae, Phry-
nosomatidae, and Tropiduridae, given the phylo-
genetic relationships that have been proposed for
these groups (Etheridge and de Queiroz, 1988; Frost
and Etheridge, 1989; Norell and de Queiroz, 1991;
Frost, 1992). The polarity of this character is equiv-
ocal for Corytophanidae and Polychrotidae (given
the relationships proposed by Frost and Etheridge,
1989). The absence of fracture planes is known to
be the ancestral condition only with respect to the
family Chamaeleonidae. Although this character
cannot be unequivocally polarized given the out-
group uncertainties, I have tentatively coded the
absence of autotomic fracture planes as the derived
state.

Etheridge (1967) mentioned that iguanians with
the autotomic version of the type one iguanid ( senso
lato) vertebral pattern (vertebrae with single trans-
verse processes and fracture planes, when present,
that pass posterior to the transverse process), of
which Gambelia is an example, usually have be-
tween five and 1 5 nonautotomic vertebrae that pre-
cede the first autotomic vertebra. Gambelia gener-
ally fits this pattern with the first fracture plane oc-
curring in G. wislizenii somewhere between the 1 4th
and 22nd vertebrae, in G. copei between the 1 8th
and 21st vertebrae, and in G. silus between the 13th
and 1 5th vertebrae.

Ribs (Character 41). — Crotaphytids are charac-
terized by a generally plesiomorphic complement of
ribs, although phylogenetically informative varia-
tion is present. As in other iguanians, most of the
ribs have a bony dorsal portion and a cartilaginous
ventral portion, the inscriptional rib, that may either
connect the bony portion with the sternum or xiphi-
stemum or end free. The first rib-bearing cervical
vertebra is usually the fourth, although the third

vertebra supports ribs in numerous individuals, and
in a few, the second vertebra supports ribs. Thus,
there are usually five cervical ribs, although six or
seven are not uncommon. The cervical ribs are fol-
lowed by four sternal ribs that connect the vertebral
column to the posterolateral border of the sternum
(only three sternal ribs present in one of four C.
antiquus). The sternal ribs are followed by either
one ( Gambelia ) or two ( Crotaphytus ) xiphisternal
ribs that connect the vertebral column with the
xiphisternum. Finally, there may be a series of post-
xiphisternal ribs that end freely. The ribs rapidly
decrease in length posteriorly to a width roughly
equal to that of the sacral pleuropophyses. The ter-
minal presacral ribs are often smaller than those
immediately anterior to them and are very rarely
fused to the vertebra.

Three xiphisternal patterns were observed and two
of these appear to be quite consistent. Crotaphytus
has a pattern of two xiphisternal ribs with an oc-
casional free xiphisternal rod. Gambelia have just
one xiphisternal rib and one free xiphisternal rod
that curves anteromedially. Variation was observed
in two specimens of Crotaphytus (C. bicinctores, REE
2934; C. collaris, REE 2948) and two specimens of
Gambelia (G. silus, CAS 22742; G. wislizenii, REE
2918). Both Crotaphytus specimens had the con-
dition characteristic of Gambelia, although REE
2934 varied on one side only. The apparently anom-
alous specimens of G. silus and G. wislizenii had
two xiphisternal ribs plus a free xiphisternal rod, a
condition observed infrequently in Crotaphytus.
Etheridge (1959) found two xiphisternal ribs to be
present in oplurids, corytophanids, iguanids, hoplo-
cercids, polychrotids, tropidurids (with the excep-
tion of Phymaturus and Uracentron), and phryno-
somatids (except Phrynosoma,, which have no xiph-
isternal ribs, and Callisaurus,, with three). Frost
(1992) listed several additional species of Tropi-
durus and one Microlophus with three xiphisternal
ribs. In chamaeleonids exclusive of chamaeleonines,
one xiphisternal rib is the common condition and
is present in the presumably basal lineages of aga-
minae ( Physignathus , Hydrosaurus), while the ab-
sence of xiphisternal ribs were characteristic of Uro-
mastyx and Leiolepis (Moody, 1980). In the few
chamaeleonines that I have examined ( Chamaeleo
senegalensis, C.johnstoni), two xiphisternal ribs were
present, although variation within chamaeleonines
seems likely. Because two xiphisternal ribs is clearly
the ancestral condition in all of the iguanian families

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

except Chamaeleonidae, the presence of two xiph-
isternal ribs is assumed to be the ancestral state
within Crotaphytidae. Therefore, two xiphisternal
ribs was coded as state 0 and that of a single xiph-
isternal rib as state 1 .

The shape of the xiphisternal rod of Gambelia is
similar to that described in Tropidurus semitaen-
iatus (Frost, 1992) in that the free end of the car-
tilaginous rod curves anteromedially, crossing su-
perficially to the xiphisternal rib and posteriormost
sternal ribs. The posterior xiphisternal rod serves as
the origin for nearly the entire posterior portion of
M. pectoralis major, although it does not serve as
the entire origin as in T. semitaeniatus. Regardless
of whether the posteriormost xiphisternal cartilage
ends freely or is continuous with a bony rib, it ap-
pears to serve as the site of origin for a portion of
M. pectoralis major. This appears to be the case
even in those taxa that have extremely short carti-
laginous protuberances projecting posteriorly from
a second xiphisternal rib, for example G. silus and
certain phrynosomatids (Etheridge, 1964).

Pectoral Girdle

Suprascapulae (Character 42). — The suprasca-
pulae are composed entirely of calcified cartilage
and lie dorsal to the scapulae. In Crotaphytus and
some Gambelia, a deep notch is present in the an-
terior margin of the suprascapula giving it the ap-
pearance of a hook. This notch is usually present in
Crotaphytus and variably present in Gambelia (five
of 23 wislizenii, one of seven copei, one of five G.
silus). Most of the outgroup taxa lack a strongly
developed notch in the suprascapula (present in one
of one Corytophanes hernandezi and four of four
Uma scoparia). Therefore, the presence of a supra-
scapular notch is treated as the derived state.

Scapulae, Coracoids, and Epicoracoids (Charac-
ters 43, 44). — In crotaphytids, the posterior coracoid
fenestrae are nearly always present (absent on one
side only in one of five specimens of C. insularis,
and on one side only in one of 23 G. wislizenii). In
C. reticulatus, the posterior coracoid fenestrae were
observed to be absent in three of nine individuals.
Furthermore, they were either proportionally small-
er or present unilaterally in the remaining large spec-
imens, suggesting that the fenestrae are lost late in
ontogeny in this species. Posterior coracoid fenes-
trae are absent in the great majority of iguanians
and among the outgroup taxa are present in Uro-

mastyx, Liolaemus, Stenocercini, Tropidurini, ig-
uanids exclusive of Dipsosaurus and Brachylophus,
para-anoles, Enyalius, Pristidactylus, Leiosaurus,
and Diplolaemus (Savage, 1958; Etheridge, 1959;
Moody, 1980; de Queiroz, 1987; Frost and Ether-
idge, 1989). The weakly developed posterior cora-
coid fenestrae of the latter three taxa were consid-
ered by Frost and Etheridge (1989) to represent a
separate character state. The presence of posterior
coracoid fenestrae are considered to be the derived
state and may represent a synapomorphy for Cro-
taphytidae. The ontogenetic loss of the posterior
coracoid fenestrae in C. reticulatus may represent
an autapomorphy for the species. However, addi-
tional osteological material is required to evaluate
this potentially distinct character state and it was
not treated as such in the phylogenetic analysis.

In Gambelia, a calcified extension of the epicor-
acoid cartilage forms the anterior border of the scap-
ular fenestra. The anterior border of the scapular
fenestra was either absent or incomplete in all of the
Crotaphytus specimens examined except three of 2 1
C. bicinctores, one of 12 C. collaris, one of five C.
grismeri, one of five C. insularis, and three of 2 1 C.
vestigium. However, in all of these specimens except
two of the three C. vestigium and the one C. collaris,
the border of the fenestra was not completed by
calcified cartilage, but rather by a thin sheet of bone
or connective tissue. In adult C. reticulatus, the cal-
cified cartilage extends dorsally from the ventral
border of the scapular fenestra approximately half
way to the dorsal border of the fenestra, a condition
that may represent an intermediate step between the
condition observed in Gambelia and that observed
in most other Crotaphytus. Because the cartilage was
present in 34 of 35 specimens of Gambelia exam-
ined, it seems unlikely that the variation observed
was an artifact of preparation. Character polarity
could not be evaluated in many of the outgroup taxa
because they lack scapular fenestrae, including Cha-
maeleonidae, Polychrotidae (variable in Polvchrus),
Corytophanidae, Liolaeminae, Hoplocercidae (ex-
cept Enyalioides laticeps), Petrosaurus, Uta, and
Urosaurus (Frost and Etheridge, 1 989). In those out-
group taxa that have scapular fenestrae, most have
the calcified cartilage borders, including phrynoso-
matids (except P. orbiculare), hoplocercids, oplur-
ids, iguanids, tropidurids ( Leiocephalus and Ura-
noscodon), and Hydrosaurus amboiensis (other aga-
mines lack scapular fenestrae [Frost and Etheridge,
1 989]). Therefore, the absence of a calcified cartilage

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

anterior border of the scapular fenestra is tentatively
coded as the derived condition.

Clavicles (Character 45). — In Gambelia, the clav-
icles usually (all Gambelia except two of 23 G. wis-
lizenii ) bear extensive fenestrations. Fenestrations
were also present in all Crotaphytus reticulatus ex-
amined, although Montanucci (1969) found that they
were absent in six of the 14 specimens he examined.
These fenestrations were absent in all 39 C. collaris
examined, as well as in the 14 C. nebrius and five
C. insularis examined. However, in the remaining
species of Crotaphytus, there was much variability
in this character with four of 2 1 C. bicinctores, two
of four C. antiquus, five of 1 6 C. dickersonae, three
of five C. grismeri, and two of 2 1 C. vestigium having
fenestrated clavicles. Although Weiner and Smith
(1965) noted that clavicular fenestrations were ab-
sent in the 54 specimens of C. collaris they exam-
ined, Robison and Tanner (1962) observed them in
20 percent of their specimens (although they in-
cluded specimens of the yet-to-be-described C. bi-
cinctores in their sample, which at the time was
considered to be C. c. baileyi ) and Montanucci (1969)
observed them in one of 45 specimens collected
from Kansas and Oklahoma. Thus, clavicular fen-
estrations, although uncommon, are occasionally
present in C. collaris and it seems likely that addi-
tional specimens will reveal their presence in C.
nebrius and C. insularis as well. Clavicular fenes-
trations are rare in the basal lineages of the outgroup
taxa, being found only in Basiliscus, Laemanctus,
some Corytophanes hernandezi( REE 1800, SDSNH
68090, although considered absent from this species
by Lang, 1989), some Uma inornata, Ctenoble-
pharys adspersus, some Leiolepis belliana, Physig-
nathus concincinus, some P. lesueurii, and Enyalius
brasiliensis. Therefore, the presence of clavicular
fenestrations is considered to be the derived state.

Interclavicle.— The interclavicle is an unpaired
median element that lies along the ventral margin
of the pectoral girdle. It varies extensively in form,
although it usually is in the shape of an anchor or
arrow. Lateral processes, present anteriorly, are in
close contact with the proximal ends of the clavicles,
while a long, narrow posterior process is bordered
laterally by the epicoracoid cartilages and the ster-
num. In most Crotaphytus and some Gambelia, the
interclavicle expands laterally becoming diamond-
shaped just anterior to the sternum. Although Wei-
ner and Smith (1965) considered this character to
be phylogenetically informative, there is continuous

variation in this feature and it was not included in
the phylogenetic analysis.

Sternum and Xiphisterna. — The sternum is a me-
dian, diamond-shaped element composed entirely
of calcified cartilage. Anterolaterally, the sternum
thickens, forming grooves into which fit the epicor-
acoid cartilages. These tongue-in-groove joints al-
low for extensive mobility of the pectoral girdle el-
ements during locomotion (Jenkins and Goslow,
1983). The sternum also articulates medially with
the posterior process of the interclavicle. In the cen-
ter of the sternum there may be a fontanelle that,
when present, is usually invaded by the mterclavicle.
Posterolaterally, the sternum bears four or five fac-
ets that serve as attachment points for the sternal
and xiphisternal ribs and the postxiphisternal rods.
The posteriormost facets (those that give rise to the
xiphisternal ribs) are separated slightly more widely
in eastern Crotaphytus collaris than in other crota-
phytids. A similar, albeit more extreme, condition
is observed in Sauromalus (de Queiroz, 1987). This
may be related to the more depressed habitus of
eastern C. collaris and their greater propensity for
crevice dwelling. This condition was not coded as
a character. Weiner and Smith (1965) noted that the
sternum of Crotaphytus is broader and shorter than
in Gambelia. Although there does appear to be a
trend in this direction, this character appears to vary
continuously and was not included in the phyloge-
netic portion of this analysis. No phylogenetically
informative variation was discovered in the ster-
num (but see above section titled “Ribs” for dis-
cussion of xiphisternal rib variation).

Pelvic Girdle

Illium and Pubis (Character 46). — In Gambelia,
the iliac blades are robust and roughly cylindrical
at their distal termini, while in Crotaphytus, they
are usually laterally compressed. However, in some
C. collaris (primarily those formerly referred to C.
c. collaris ), they may approach the cylindrical con-
dition observed in Gambelia. The outgroup taxa are
extremely variable with respect to this character and
it could not be polarized.

Weiner and Smith (1965) discuss ventrolateral
curvature of the pubes and the angle at which the
two halves of the pelvic girdle meet. There does not
appear to be consistent interspecific variation in ei-
ther of these features (in fact, I am unaware of any
ventrolateral curvature of the pubes, although they

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 17. — Ventral view of the fifth metatarsal bone of Crotaphytus
collaris showing the contact of the medial and lateral plantar
tubercles forming an arch (redrawn from Snyder, 1954).

may be referring to ventromedial curvature). They
may have been referring to the presence of a pro-
portionally shorter and broader pelvic girdle in east-
ern populations of Crotaphytus collaris (the only
representative of the “collariform” group that they
examined) than in other Crotaphytus species or
Gambelia. This difference appears to be related, at
least in part, to modification of the pubic rami, which
are nearly transverse in orientation, rather than
acutely angled anteriorly. However, the condition
in the remaining populations of C. collaris (formerly
referred to C. c. fuscus, C. c. baileyi, and C. c. au-
riceps) appears to be intermediate in each of these
features. Coding of this variation is further com-
plicated by individual variation in pelvic girdle
structure, such that some individuals approach the
eastern C. collaris condition, while others approach
the condition of other Crotaphytus species. Short,
broad pelvic girdles are often observed in crevice-
dwelling species (e.g., Sauromalus) and the rela-
tively short, broad, pelvic girdles of eastern C. col-
laris may be related to the crevice-dwelling behavior
observed in these lizards.

Limbs

(Character 47; Fig. 17)

On the plantar surface of the fifth metatarsal are
two large tubercles termed the medial and lateral
plantar tubercles by Robinson (1975). These tuber-
cles serve as attachment points for the tendons of
M. gastrocnemius. In the majority of iguanian spe-
cies, a groove runs between the two tubercles and a

tendon of M. flexor digitorum longus passes within
it (Robinson, 1975). In Crotaphytus, the medial
plantar tubercle usually curves laterally such that it
contacts the lateral plantar tubercle forming a com-
plete arch (Fig. 1 7), through which passes the tendon
of M. flexor digitorum longus (noted and figured by
Snyder, 1954). The contact of the tubercles is usually
extensive and in some individuals, the tubercles may
fuse completely. The arch condition was absent in
the entire available series of Gambelia (41 speci-
mens) and, in adults, it was always present in the
20 C. bicinctores, four C. antiquus, 1 2 C. dickerson-
ae, five C. grismeri, and 22 C. vestigium examined.
It was complete on at least one pes in 28 of 36 C.
collaris, three of five C. insularis, 1 1 of 12 C. nebrius,
and six of seven C. reticulatus. The majority of spec-
imens that lacked the complete arch were juveniles,
and in most cases the gap between the medial and
lateral plantar tubercles was narrow. Therefore, this
character was scored only for adults. Among the
outgroup taxa examined, the arched form of the
medial and lateral plantar tubercles was present only
in the phrynosomatid sand lizards ( Uma , Callisau-
rus, Cophosaurus, and Holbrookia). This feature ap-
pears to represent a synapomorphy for Crotaphytus,
as well as providing additional character support for
the monophyly of the phrynosomatid sand lizards.

The hindlimb of Crotaphytus is much longer than
that of Gambelia of similar SVL. A relatively long
hindlimb is typical of lizard species that utilize bi-
pedal locomotion (Snyder, 1952, 1954, 1962), al-
though agamines provide an interesting exception.
Much of the variation in hindlimb length between
Crotaphytus and Gambelia is realized in the longer
crus of the former, while the pes appears to be of
relatively similar length. Although a greater relative
hindlimb length appears to be a derived character-
istic of Crotaphytus, there is great variation in the
outgroup taxa and this feature was not included in
the phylogenetic analysis.

Squamation

The dorsal body squamation of Crotaphytus and
Gambelia is remarkably similar in that both genera
are characterized by relatively undifferentiated head
scales and fine homogeneous dorsal body squama-
tion. However, despite many similarities in scale
patterns and scale sizes on the various regions of
the body, phylogenetically useful variation in squa-
mation exists. A more detailed description of the
squamation of crotaphytids is provided in the tax-
onomic accounts of the family, genera, and species.

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

Fig. 1 8. — Squamation of the dorsal portion of the head of Cro-
taphytus collaris (USNM 17183, adult male). Scale = 5 mm.

Rostral Scale (Character 48). — In all crotaphytids
except Crotaphytus dickersonae, the rostral scale is
approximately four times wider than high. In C.
dickersonae, the rostral is less elongate and approx-
imately two times wider than high. There is much
variation in the outgroups, although most taxa have
a rostral that is much wider than high. Consequent-
ly, this character was left unpolarized.

Supraorbital Semicircles (Character 49; Fig. 18,
19 ). — Crotaphytus have supraorbital semicircles
composed of scales that are much larger than the
adjacent supraoculars. In Gambelia, obvious supra-
orbital semicircles are absent, with the supraoculars
tending to grade into the frontal series. The out-
groups vary considerably in the presence of discrete
supraorbital semicircles. They are present in all
oplurids and polychrotids examined (except Cha-
maeleolis ), and variable within the remaining fam-
ilies. Within Hoplocercidae, they are absent in En-
yalioides laticeps, but present in E. praestabilis and
E. oshaugnessyi. Within Phrynosomatidae, they are
present in Petrosaurus and the Sceloporus group,
Uma notata, U. scoparia, and U. inornata, but ab-
sent in Phrynosoma and Uma exsul. In tropidurids,
they are present in some Phymaturus patagonicus,
Leiocephalus, Liolaemus, Stenocercini, basal Tro-
pidurini (except Uranoscodon superciliosus ), and
absent in Ctenoblepharys adspersus, most Phyma-

Fig. 19.— Squamation of the dorsal portion of the head of Gam-
belia wislizenii (SDSNH 68662, adult female). Scale = 5 mm.

turns, and Uranoscodon superciliosus. In iguanids,
they are present in Dipsosaurus, absent in Brachy-
lophus fasciatus, and generally absent in the re-
maining taxa. In chamaeleonids, they are absent in
Hydrosaurus pustulatus, Leiolepis be/liana, Uro-
mastyx loricatus, and U. ocellatus, variable in U.
geyrii, U. microlepis, and U. acanthinurus, and pres-
ent in U. aegypticus, U. asmussi, U. hardwickii, U.
macfadyeni, U. philbyi, and U. thomasi. In coryto-
phanids, they are present in Basiliscus plumifrons,
B. vitattus, Corytophanes hernandezi, absent in C.
cristatus and C. percarinatus, and variable in Lae-
manctus. Because of this extensive variation, this
character was left unpolarized.

Suboculars (Character 50; Fig. 20, 21). — In Cro-
taphytus, the suboculars are subquadrate, with the
third scale occasionally larger than the others,
whereas in Gambelia, the second subocular is four
to five times larger than the others. Assessing po-
larity of this feature is difficult because both states
are widespread within the Iguania. At least one sub-
ocular is much longer than the others in phryno-
somatids except Phrynosoma, the oplurids Opiums

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 20. — Squamation of the lateral portion of the head of Cro-
taphytus collaris (USNM 17183, adult male). Scale = 5 mm.

saxicola, O. fierinensis, and O. quadrimaculatus, the
chamaeleonid Leiolepis bel/iana, the tropidurids
Phymaturus patagonicus, Leiocephalus, Liolaemus,
Stenocercini, Microlophus, Plesiomicrolophus, and
all but terminal Tropidurus (Frost, 1992), the igua-
nid Dipsosaurus, and the polychrotids Anisolepis,
Pristidactylus, and Eny alius bilineatus. Multiple
subequal suboculars are present in the oplurids
Opiums cyclurus, O. cuvieri, and Chalaradon, the
chamaeleonids Uromastyx and Hydrosaurus pus-
tulatus, hoplocercids, the tropidurids Phymaturus
punae, P. palluma, Ctenoblepharys, and Uranos-
codon superciliosus, the polychrotids Urostrophus,
Polychrus, Phenacosaurus, Chamaeleolis, Anolis, and
Enyalius (except E. bilineatus), iguanids (except
Dipsosaurus ), and corytophanids. An elongate sub-
ocular appears to be the ancestral state in Phryno-
somatidae, Tropiduridae, and Opluridae, and
equivocal in Iguanidae, and Polychrotidae. The
presence of subequal suboculars is the ancestral state
for Corytophanidae, Hoplocercidae, and Chamae-
leonidae. Therefore, this character could not be po-
larized.

Terminal Supradigital Scales (Character 5 1). — In
Gambelia, C. collaris, and C. reticulatus, the ter-
minal supradigital scales nearly always lie flat against
the dorsal surface of the claws. In the remaining
Crotaphytus, the terminal supradigitals project dor-
sally such that each is elevated from the claw. A
similar elevated condition occurs occasionally in
various iguanians including the phrynosomatids Pe-
trosaurus, Uta stansburiana (three of four), U. pal-
meri (one of four), and Uta squamata (one of three),

the tropidurids Plesiomicrolophus koepkeorum (one
of four), Microlophus grayi (one of four), M. ther-
esioides (one of four), M. tigris (one of four), and M.
stolzmanni (three of four), and the hoplocercid En-
yalioides laticeps (one of five). Despite this varia-
tion, the presence of elevated terminal supradigital
scales is most parsimoniously considered to be the
derived state.

Femoral Pores (Characters 52, 53; Fig. 22, 23).—
In Gambelia, the femoral pores extend distally at
least to the inferior angle of the knee. The femoral
pore series of G. silus usually just reaches this point,
while the femoral pore series of G. wislizenii and G.
copei almost always extend beyond and may even
arch posteriorly onto the lower leg. The femoral pore
series of Crotaphytus does not reach the inferior
angle of the knee and usually terminates well prox-
imal to this point.

Polarization of this character is complicated by
the absence of femoral pores in the Tropiduridae,
Opluridae, and Corytophanidae. However, in the
remaining outgroups, the femoral pore series always
terminates before reaching the inferior angle of the
knee ( Phrynosoma coronatum is variable with re-
spect to this character). Therefore, the condition
observed in Gambelia is interpreted as the derived
state.

In Gambelia wislizenii and G. copei, the femoral
pores of females are large and contain substantial
quantities of exudate, although the pores are usually
slightly larger in males. In G. silus, Crotaphytus, and
all of the outgroup taxa examined that have femoral
pores except Enyalioides laticeps, they are much
larger and fuller in males than in females and, in-
deed, in females the pores may be devoid of exudate.
Therefore, the condition observed in G. wislizenii
and G. copei is considered to be the derived state.

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

Fig. 22.— Ventral view of Gambelia wislizenii (TNHC 33200) showing the femoral pore series extending beyond the angle of the knee.

Fig. 23.— Ventral view of Crotaphytus reticulatus (TNHC 28364) showing the jet black femoral pores present in males. AGF = antegular
fold, GF = gular fold.

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 24. — Ventral view of the neck folds of Crotaphytus reticulatus
(EL 3250). Fold terminology follows Frost (1992). AGF = an-
tegular fold, GF = gular fold.

Postanal Scales. — In some iguanian lizards, males
can be differentiated from females by the presence
of enlarged postanal scales. Within Crotaphytidae,
the postanal scales are enlarged in all male Gam-
belia, as well as C. grismeri, Crotaphytus nebrius,
and most C. bicinctores and C. collaris. The con-
dition of the postanal scales is more variable in C.
vestigium and C. insularis, with roughly equal pro-
portions of males having large or only slightly en-
larged scales. The postanal scales are not enlarged
or are only slightly enlarged in C. antiquus, C. re-
ticulatus, and C. dickersonae, although they may be
larger than in females. Attempts to code this char-
acter were prohibited by continuous variation in the
size of the postanal scales in C. bicinctores, C. col-
laris, C. dickersonae, C. insularis, C. reticulatus, and
C. vestigium. Furthermore, this character could not
be polarized as enlarged postanal scales are present
in phrynosomatids, oplurids, many anoles (Cha-

maeleolis chamaeleonides, Phenacosaurus, and most
Anolis), and some Leiocephalus (although Pregill
[1992] found that enlarged postanal scales were de-
rived within the genus).

Tail Skin (Character 54). — In all crotaphytids, the
skin of the tail is relatively weakly adherent to the
underlying musculature such that the skin can be
removed easily. This condition contrasts strongly
with that observed in most iguanians with fracture
planes, such as Dipsosaurus, Sceloporus, and Opiu-
ms, in which the skin is bound to the underlying
musculature by connective tissue and is nearly im-
possible to remove in one piece. This condition is
more strongly developed in Crotaphytus than in
Gambelia, such that in the former, the skin of the
posterior 40-50 mm of the tail easily slips off. Loosely
adherent skin that is easily removed from the ter-
minal portion of the tail appears to be unusual if
not unique among iguanians and is therefore con-
sidered to be the derived state (1) in this analysis.

Pockets and Folds

Crotaphytids, like many fine-scaled iguanian liz-
ards, have extensive lateral neck and gular folding.
Both Crotaphytus and Gambelia share a standard
complement of folds that includes gular, antegular,
antehumeral, postauricular, longitudinal neck, and
supra-auricular folds (terminology follows Frost,
1992). None of these folds are unique to Crotaphy-
tidae and most are similar to folds present in a wide
range of iguanian lizards. For example, the gular
fold is well developed, enclosing a region of reduced
squamation, and is continuous with the antehu-
meral fold. Also, the antegular fold is continuous
with the oblique neck fold. However, phylogeneti-
cally informative variation does occur in the folds.
As is the case with most fine-scaled species, addi-
tional folds are often present with varying degrees
of consistency. Thus, I have referred to the above-
mentioned complement of folds as the standard pat-
tern and will restrict the discussion to this series.

Gular Fold (Character 55; Fig. 24-27). — The gular
fold of Crotaphytus differs from that of Gambelia
in that there is a pair of skin folds that separate from
the gular fold and project posteromedially. These
folds, which may be ventromedial continuations of
the antehumeral folds (R. Etheridge, personal com-
munication, 1993) usually meet midventrally and
form a single longitudinally oriented midventral fold
that extends posteriorly for a short distance. In the
triangular-shaped region between the folds, the scales
are reduced in size. In Gambelia, a pair of similar

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

Fig. 25.— Ventral view of the neck folds of Gambelia wislizenii
(SDSNH 68663). Fold terminology follows Frost (1992). AGF
= antegular fold, GF = gular fold.

folds may occur; however, they are shorter and ap-
pear near the lateral borders of the gular fold. As a
result, the area of reduced squamation seen in Gam-
belia takes the form of a uniform band that extends
across the width of the gular fold. Those outgroup
taxa with gular folds examined here display both
conditions of the fold with phrynosomatids, the
oplurid Chalaradon madagascariensis, chamae-
leonids (except Hydrosaurus pustulatus ), the cory-
tophanids Basiliscus vittatus and Laemanctus, the
hoplocercid Enyalioides laticeps (four of five), and
polychrotids displaying the Gambelia form, and the
hoplocercids Enyalioides praestabilis and E. os-
haugnessyi, the corytophanid Basiliscus p/umifrons,
the oplurid genus Oplurus ( O . fierinensis and O.
saxicolus variable), and the iguanid Dipsosaurus
displaying the Crotaphytus form. Most tropidurids
have incomplete gular folds or lack them altogether;
thus, the evaluation of this character for Tropidur-
idae is difficult. Uranoscodon super ciliosus, which
has a complete gular fold, displays the Gambelia
form. The only other species within Tropidurini with

Longitudinal neck

Fig. 26. — Lateral view of the neck folds of Crotaphytus reticulatus
(EL 3250). Fold terminology follows Frost (1992).

complete gular folds are Tropidurus azureutn, T.
flaviceps, and T. plica (Frost, 1992), species far re-
moved from the basal lineages of the clade, and,
thus, unable to shed light on this polarity decision.
Because of ambiguity in the outgroup taxa, this char-
acter was left unpolarized.

Supra- auricular Fold (Character 56; Fig. 26, 27).—
Frost (1992) defined the supra-auricular fold as a
continuation of the dorsolateral fold that passes
above the tympanum. In crotaphytids, a similar fold
is present; however, it originates from the postaur-
icular fold at a point roughly midway between the
dorsal and ventral borders of the external auditory
meatus. Without strong evidence to the contrary, I
treat the crotaphytid fold as homologous with that
described by Frost (1992) and therefore apply his
standardized nomenclature. The condition of the
supra-auricular fold, in which it originates midway
between dorsal and ventral borders of the external
auditory meatus, is present in many iguanian taxa

Longitudinal neck

Fig. 27. -Lateral view of the neck folds of Gambelia wislizenii
(SDSNH 68663). Fold terminology follows Frost (1992).

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 28. — An antehumeral mite pocket in a juvenile Crotaphytus grismeri.

and, therefore, could not be included in the phy-
logenetic analysis.

The supra-auricular fold differs between Crota-
phytus and Gambelia. In Crotaphytus, the fold ex-
tends posterodorsally at an angle of roughly 45 de-
grees. In Gambelia, the fold extends posteriorly along
a horizontal plane. In most of the outgroup taxa that
have a supra-auricular fold, the fold either projects
posteriorly along a horizontal axis, or occasionally,
posteroventrally. However, some taxa may have a
Crotaphytus- like supra-auricular fold (often vari-
ably), including the phrynosomatids Petrosaurus re-
pens, Uta stansburiana, U. squamata, U. palmeri,
Urosaurus auriculatus, and Phrynosoma coronatum,
the tropidurids Leiocephalus schreibersi, L. melan-
ochlorus, and L. psammodromus, the hoplocercid
Enyalioides oshaughnessyi, and the chamaeleonids
Uromastyx acanthinurus and U. philbyi. Because of
this variation and because many outgroup taxa can-
not be scored for this feature, this character was left
unpolarized.

Antehumeral Fold (Fig. 26-28).— The antehu-
meral fold of crotaphytids is strongly developed,
curving posteriorly over the forelimb insertion. The

deepest portion of the fold is directly dorsal to the
forelimb, a condition rarely observed in the out-
groups. Furthermore, the antehumeral fold often ex-
tends posteriorly beyond the forelimb insertion, then
continues posteroventrally or ventrally forming a
complete arc. This condition is again uncommon in
the outgroups. However, there is sufficient variation
within Iguania that I have chosen not to code this
as a character. The antehumeral fold of Crotaphytus
dickersonae is unique among crotaphytids in ter-
minating anterior to the forelimb insertion. Al-
though this condition is probably derived within
Crotaphytidae, another character, presence or ab-
sence of an antehumeral mite pocket, is certainly
not independent. Therefore, this character is con-
sidered under the section dealing with the antehu-
meral mite pocket.

Antehumeral Mite Pocket (Character 57; Fig.
28). — In all Crotaphytus except C. dickersonae, the
antehumeral fold is well developed (deep), with an
area of reduced squamation dorsal to the forelimb
insertion. The pocket almost always is inhabited by
large numbers of trombiculid mite larvae. The pres-
ence of a mite pocket in this portion of the ante-

1996

McGUIRE- SYSTEMATICS OF CROTAPHYTID LIZARDS

Fig. 29.— A postfemoral mite pocket in a juvenile Crotaphytus bicinctores.

humeral fold was not observed in any of the out-
group taxa examined and, thus, appears to be unique
to Crotaphytus, excluding C. dickersonae. As dis-
cussed above, the antehumeral fold of C. dicker-
sonae terminates further anteriorly than in any other
crotaphytid, usually failing to reach the forelimb
insertion, which probably explains the absence of
an antehumeral mite pocket in this species.

Postfemoral Mite Pockets (Character 58; Fig.
29). — In most crotaphytids, subdermal mite pockets
are present at the posterodorsal border of the hind-
limb insertion where a patch of finely scaled or un-
sealed skin dips inward between M. iliofibularis and
M. iliofemoralis. These pockets usually are inhab-
ited by trombiculid mite larvae and occasionally
ticks. Arnold (1986) noted that mite pockets, which
may occur in a variety of anatomical regions, often
vary both intra- and interspecifically in terms of
their presence, degree of development (e.g., depth),
and in the nature of their squamation, and in this
respect Crotaphytidae is no exception. However,
pockets were absent only in Crotaphytus reticulatus
and occasionally in C. col laris and C. nebrius.

In Crotaphytus, the depth of the mite pocket may

be correlated with the degree of development of the
antehumeral mite fold. For example, in C. reticu-
latus, which lacks the postfemoral pocket, the mite
pockets of the antehumeral fold (discussed above)
are strongly developed. In contrast, the mite pockets
of the antehumeral fold are absent in C. dickersonae,
while the postfemoral pockets are the most strongly
developed (deepest) of all Crotaphytus.

Postfemoral mite pockets are not unique to Cro-
taphytidae. Smith (1939) noted that they are present
in seven species of Sceloporus, including the five
species in his S. variabi/is group, as well as S', ma-
culosus and S. gadoviae. Shallow postfemoral pock-
ets were also observed in Uta squamata and U. pal-
med, but not other Uta. Although not observed here,
shallow mite pockets are occasionally present in sev-
eral species of Urosaurus (J. Wiens, personal com-
munication, 1994). However, the absence of post-
femoral pockets in Phrynosoma, the sand lizards,
Petrosaurus, most Uta (in those species that lack
pockets, mites may accumulate in the postfemoral
region, but an obvious subdermal pocket is lacking),
most Urosaurus, Sator, as well as most Sceloporus,
suggests that the pockets observed in subsets of Uro-

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

saurus, Uta, and Sceloporus are not homologous
with crotaphytid postfemoral pockets.

Most Stenocercus and at least two species for-
merly referred to Ophryoessoides ( S . ornatus and S'.
trachycephalus ) have postfemoral mite pockets
(Fritts, 1974; Arnold, 1986). However, the postfe-
moral pocket of those Stenocercus species examined
here ( S . trachycephalus, S. chrysopygus, S. guenth-
eri, S. imitator, S. roseiventris) occurs as a vertical
fold along the lateral body wall immediately pos-
terior to the hmdlimb insertion and, thus, does not
appear to be homologous with the postfemoral mite
pocket of crotaphytids. Furthermore, postfemoral
mite pockets appear to be absent from the basal
lineages of Liolaeminae ( Phymaturus and Ctenob-
lepharys: species examined include Ctenoblepharys
adspersus, Phymaturus sp., P. palluma, P. patagon-
icus, P. punae), Leiocephalinae (G. Pregill, personal
communication, 1993; verified in Leiocephalus car-
inatus, L. inaguae, L. macropus, L. melanochlorus,
L. pratensis [folds present, but no reduction in squa-
mation], L. psammodromus, L. schreibersi), and
Tropidurini ( Uranoscodon superciliosus, Plesiomi-
crolophus koepkeorum, Microlophus theresioides, M.
tigris, M. stolzmani, personal observation). Thus,
the postfemoral mite pockets of certain members of
the Stenocercini are considered to be nonhomolo-
gous with crotaphytid postfemoral mite pockets.

Several oplurids have postfemoral mite pockets
that appear to be structurally identical with those
of crotaphytids. That is, the pocket occurs as an
invagination between M. iliofibularis and M. iliofe-
moralis. Arnold (1986) noted the presence of post-
femoral mite pockets in Opiums cuvieri and O. cy-
clurus and I have observed them in O. cyclurus, as
well as in O. saxicola, O.ferinensis, and Chalaradon
madagascariensis. Postfemoral mite pockets appear
to be absent in O. quadrimaculatus. Because we have
no hypothesis of phylogenetic relationships for
oplurids, it is not possible to say whether the pockets
are derived within the family or were present an-
cestrally. Therefore, the possibility that postfemoral
mite pockets were present in the common ancestor
of Opluridae cannot be discounted.

Among iguanids, Dipsosaurus dorsalis has a weak-
ly developed postfemoral pocket that occurs in the
same anatomical position as the postfemoral mite
pocket of crotaphytids. Because Dipsosaurus (along
with the fossil species Armandisaurus exploratory
is the sister taxon of the remaining iguanids (de
Queiroz, 1987; Norell and de Queiroz, 1991), the
possibility that postfemoral pockets were present in

the common ancestor of Iguanidae cannot be elim-
inated.

Postfemoral mite pockets appear to be absent from
Corytophanidae, Hoplocercidae, Chamaeleonidae,
and Polychrotidae, although all of their constituent
species have not been examined. Although postfe-
moral mite pockets may have been present in the
common ancestors of the families Opluridae and
Iguanidae, their presence is most parsimoniously
treated as the derived state for Crotaphytidae.

Additional Morphological
Characters

Hemipenes (Character 59). — Hemipenes were ex-
amined for all of the crotaphytid species except Cro-
taphytus reticulatus. The hemipenes of crotaphytids
are bulbous and weakly bilobed with a short median
fissure separating the two lobes apically. The sulcus
spermaticus is covered by a large fleshy flap of in-
tegument that folds over it from its lateral margin.
This fold does not project directly toward the apex
but rather extends laterally toward the outer margin
of the lateral lobe. The sulcus spermaticus itself ap-
pears to terminate in a broad, shallow depression at
the base of the lobes.

The entire sulcate surface of the hemipenis is only
weakly ornamented with a fine papillate or dimpled
texture. Immediately outside of the sulcus sper-
maticus, the surface is ornamented with plicae that
are continuous with those of the asulcate surface.
Distally, the lateral surfaces of the lobes bear small
knob-like processes that are covered with extremely
fine calyculae.

The base of the asulcate surface of the hemipenis
is naked. More distally, ornamentation is present in
the form of plicae and calyculae. The proximal lat-
eral surfaces of the ornamented region of the hem-
ipenis are covered by fine plicae. These plicae grade
medially into calyculae and this calyculate zone ex-
tends distally toward the apex of the hemipenis where
it spreads laterally. As a result, the entire surface of
the hemipenis distal to the median apical fissure is
ornamented with minute calyces. The lateral surface
of each lobe bears a shallow depression ornamented
with extremely fine calyces. The calyces reach their
smallest sizes here and in the apical region of the
hemipenis.

The only obvious difference between the hemi-
penes of Crotaphytus and those of Gambelia is in
their relative size. The hemipenes of Gambelia are
roughly twice the size of those of similar-sized Cro-
taphytus. Although the hemipenes of Crotaphytus

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

Fig. 30. — (A) Gambelia wislizenii (adult female), (B) G. copei (adult male), (C) Crotaphytus reticulatus (adult male), (D) C. antiquus (adult male)

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

appear to be unusually small, no attempt was made
to polarize this character because adequate com-
parative material was not available.

Sexual Dimorphism (Character 60). — Most igu-
anian lizards are sexually dimorphic with males
reaching larger SVLs than females (Fitch, 1981).
This condition is exhibited in all Crotaphytus (Burt,
1929; Axtell, 1972; Fitch, 1981; McGuire, 1994;
personal observation) as well as Gambelia silus (Tol-
lestrup, 1979, 1982), while females are much larger
than males in G. wislizenii (Tollestrup, 1979, 1982)
and G. copei (Banta and Tanner, 1968). Sexual di-
morphism in which males are larger than females
appears to be the ancestral state for the families
Chamaeleonidae (Parcher, 1974; Fitch, 1981), Igua-
nidae (Fitch, 198 1; Gibbons, 198 1; Carothers, 1984),
Opluridae (Blanc and Carpenter, 1969), Phrynoso-
matidae (Fitch, 1981), and Tropiduridae (Dixon and
Wright, 1975; Fitch, 1981; Cadle, 1991; Etheridge,
1992, 1994, 1995; Pregill, 1992; R. Etheridge, per-
sonal communication, 1994). The ancestral state is
equivocal for Hoplocercidae (Duellman, 1978),
Corytophanidae (Fitch, 1981), and Polychrotidae
(Lazell, 1969; Fitch, 1981; Frost and Etheridge, 1989;
Etheridge and Williams, 1991; Schwartz and Hen-
derson, 1991). Although the data regarding sexual
dimorphism in iguanians are somewhat fragmen-
tary, the most parsimonious conclusion at this time
is that the ancestral condition for Crotaphytidae is
males larger than females. Therefore the character
state present in Gambelia copei and G. wislizenii
(females larger than males) is treated as the derived
state.

Coloration

Gravid and Subadult Coloration (Characters 61,
62; Fig. 3 1C, D). — All female crotaphytids display
red or orange dorsal banding or spotting when grav-
id. Although Frost and Etheridge (1989) suggested
that gravid coloration may be a synapomorphy for
the family, the presence of gravid coloration in many
phrynosomatids and tropidurids and several cha-
maeleonids (Cooper and Greenberg, 1992; personal
observation) suggests that this condition may rep-
resent a synapomorphy for a more inclusive group
than Crotaphytidae.

Subadult male Crotaphytus collaris develop a col-
or pattern of red or orange dorsal banding that is
very similar to that of gravid females, both in terms
of its anatomical position and chromatic qualities
of the pigments (Rand, 1986). The author has also
observed this coloration in C. bicinctores, C. dick-
er so nae, C. grismeri, C. insular is, C. nebrius, C. re-

ticulatus, and C. vestigium. Rand (1986) demon-
strated that the subadult male coloration of C. col-
laris is not induced by progesterone, as it is in fe-
males, which suggests that subadult male and gravid
female coloration are independent. The presence in
subadult males (but not subadult females) of orange
or red banding similar to that of gravid females
appears to be unique to Crotaphytus. The only spe-
cies (that I am aware of) that exhibits a similar sub-
adult coloration is Microlophus delanonis (Werner,
1978). This species has gravid coloration and ju-
veniles of both sexes develop coloration similar to
that of gravid females. Therefore, the presence of
ephemeral red banding in subadult males is treated
as the derived state.

Juvenile Gambelia are characterized by the pres-
ence of paravertebrally arranged rows of blood-red
spots that extend from the top of the head to the
proximal portion of the tail and may be present on
the limbs as well. Each row generally consists of four
large spots, although smaller spots may be present
further laterally. These blood-red spots gradually
fade into solid brown spotting in adult Gambelia.
This condition, which was not observed in the out-
groups, is coded as a character independent of the
subadult male coloration character described for
Crotaphytus because it does not occur in the same
anatomical position and because it occurs in both
sexes.

Tail Color (Characters 63-65; Fig. 3 IB, 3 1C, 32A-
D; observable only in live individuals). — Adult Cro-
taphytus dickersonae females exhibit a unique fea-
ture among crotaphytids in that the hindlimbs and
in particular the tail may be bright lemon yellow in
comparison to other species in which the tail is the
same general color as the rest of the body. This
description is based on a sample of only two living
females. An examination of preserved specimens
suggests that many adult female C. dickersonae have
a substantial blue component to their color pattern
and, thus, the yellow pigmentation may be restricted
to a particular season or age class. Because this type
of yellow pigmentation in adult females was not
observed in the outgroups, I consider it the derived
state. However, bright coloration often fades in pre-
servative and it is possible that this character state
has been overlooked in other taxa.

Gambelia situs juveniles have yellow pigmenta-
tion in the form of a narrow strip along the posterior
surface of the thigh and on the anteroventral surface
of the tail. The pigmentation ends abruptly at the
cloaca. Similar coloration was present in the only
subadult female C. antiquus that was observed and

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

this taxon is tentatively coded as having the same
character state as that observed in G. silus. In other
crotaphytids, the coloration of the tail and hin-
dlimbs does not differ from that of the rest of the
body. The presence of this juvenile coloration is
treated as the derived state.

In those species with strongly laterally com-
pressed tails (C. bicinctores, C. dickersonae, C. gris-
meri, C. insularis, and C. vestigium), a pale white
or cream stripe runs down the dorsal surface of the
tail (Fig. 3 IB, 32A-D). Presumably, the laterally
compressed tail serves a display function and this
white pattern may somehow enhance this role. The
presence of a pale dorsal caudal stripe appears to be
unique to these lizards as it was not observed in any
of the outgroup taxa and is therefore considered to
be the derived state.

Reticulate Pattern (Characters 66, 67; Fig. 30C,
30D, 31A-D, 32A-D, 33-35). — All male Crotaphy-
tus, except some C. nebrius, have some form of
white reticulation in the dorsal and/or gular pattern.
Indeed, all Crotaphytus neonates have an extensive
reticulated dorsal pattern, with some of the reticu-
lations surrounding black pigment. This is a con-
dition very similar to that seen in adult C. reticulatus
and C. antiquus of both sexes. The extent and place-
ment of the reticulated pattern varies considerably
between species resulting in somewhat bewildering
interspecific variation. Nevertheless, a pair of dis-
crete characters were obtained from this aspect of
the color pattern.

The first character (66) describes the presence or
absence of a reticulate pattern in neonates. This con-
dition is present in all Crotaphytus neonates, and is
absent from Gambelia and the outgroups (although
the number of outgroup species for which juveniles
were examined is relatively small). Therefore, the
presence of a neonatal pattern of white reticulations
enclosing dark pigments is treated as the derived
state.

A second character (67) is the presence of small,
almost granular, reticulations on the ventrolateral
surface of the abdomen. This condition is present
only in C. bicinctores and C. antiquus, although the
abdominal reticulations of C. antiquus are slightly
larger than those of C. bicinctores. Ventrolateral ab-
dominal reticulations were not observed in the out-
group taxa; therefore, their presence is treated as the
derived state.

In Crotaphytus, there are two common dorsal pat-
tern types, reticulation and spotting. It seems likely
that spots are formed when reticulations have be-
come fragmented. For example, in large C. vestig-

ium, the typical reticulated pattern of the hindlimbs
may be fragmented on the dorsal portion of the
femoral region, resulting in spots. The anterior and
posterior surfaces of the leg retain their reticulated
pattern. Thus, the spotted pattern that occurs on the
dorsum of all Crotaphytus except C. reticulatus and
C. antiquus may be the derived condition. This same
situation applies to additional characters associated
with reticulation. However, the dangers of polar-
izing characters using ontogenetic methods are well
known (de Queiroz, 1985; Mabee, 1989, 1993) and
I present this scenario as a hypothesis and nothing
more. The reticulated versus spotted adult dorsal
body patterns are considered in the discussion of
the white component of the dorsal pattern (see be-
low).

White Component of Dorsal Pattern (Character
68; Fig. 30-32). — The white component of the dor-
sal pattern of crotaphytids is quite variable between
species, but within species there is little variation.
The two main dorsal pattern types present in adult
Crotaphytus are reticulated and spotted. Crotaphy-
tus antiquus and C. reticulatus exhibit the reticulated
pattern, while the remaining species of Crotaphytus
have a pattern that incorporates white spots or dash-
es. Crotaphytus vestigium and C. insularis (see be-
low) each differ from the other spotted species in
their own way. Crotaphytus vestigium has thin, white,
transverse dorsal bands (Fig. 32C). Axtell (1972)
noted the presence of similar banding in C. bicinc-
tores from the northern portion of its range, which
he attributed to the retention of the juvenile pattern.
However, an examination of approximately 300
specimens of C. bicinctores in the California Acad-
emy of Sciences collection revealed that the white
bands present in juveniles change during ontogeny
into the broad, pale orange bands characteristic of
adults. In adults that are dark from preservative,
these orange bands fade and sometimes appear to
be broad white bands. Although females may oc-
casionally retain the juvenile white bands until near
adult size is attained, males do not and no adult C.
bicinctores that were not dark from preservative had
white transverse banding. Only C. insularis ap-
proaches the condition of C. vestigium, with most
specimens having broad, wavy dorsal lines or dashes
and a few specimens having what appear to be wavy
transverse dorsal bands (Fig. 32D). Although the
wavy dashes present in C. insularis may be modified
transverse dorsal bands, the C. insularis condition
is treated as a separate character state and no a priori
assumptions were made regarding the order of trans-
formation. Because Crotaphytus and Gambelia are

NO. 32

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

with orange subadult male coloration).

1996

McGUIRE — SYSTEMATICS OF CROTAPHYTID LIZARDS

Fig. 32. — (A) Crotaphytus bicinctores (adult male), (B) C. grismeri (adult male), (C) C. vestigium (adult male), (D) C. insularis (adult male).

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

variable with respect to the white component of the
dorsum, this variation was coded as an unordered
multistate character. The Gambelia condition often
consists of broad, white or cream-colored, offsetting
transverse bars with large, brown dorsal spots and
is coded as state 0; the C. reticulatus and C. antiquus
condition of a white reticulum, some or all of which
enclose black pigmentation, is coded as state 1; the
pattern composed of numerous small white spots
(present in C. bicinctores, C. collaris, C. dickersonae,
C. grismeri, and C. nebrius ) is coded as state 2; the
C. vestigium condition of white, transverse dorsal
bands on a background of white spots and dashes
is coded as state 3, and the C. insularis condition
of wavy, white dorsal dashes is coded as state 4.
This character was left unpolarized.

Sexual Dichromatism (Character 69; Fig. 3 IB,
C). — Sexual dichromatism is widespread within the
Iguania (Cooper and Greenberg, 1992) and, thus, it
is not surprising that most crotaphytids also display
strong sexual dichromatism. However, Gambelia
and Crotaphytus reticulatus generally lack sexual di-
chromatism in their permanent dorsal patterns (al-
though G. silus and C. reticulatus do have male
breeding coloration). There is obvious sexual di-
chromatism in the gular pattern and femoral pore
coloration and a small amount of sexual variation
in the collar of C. reticulatus. However, the re-
maining species of Crotaphytus have much more
obvious sexual dichromatism throughout the year,
with males differing from females in most aspects
of dorsal coloration (e.g., much more vibrant blue,
green, and/or yellow dorsal coloration in C. collaris ),
as well as in the gular pattern. Although sexual di-
chromatism is present in many iguanian taxa, data
could not be obtained for many of the more obscure
and poorly known species. Therefore, this character
was left unpolarized.

Paired Melanie Keels on Scales of Ventral Caudal
Extremity (Character 70). — All Crotaphytus species
except C. reticulatus (50 specimens examined) and
C. insularis (23 specimens examined) are charac-
terized by the presence, in at least some individuals,
of darkly pigmented obtuse keels on the scales of
the ventral surface of the tail tip (noted as present
in C. nebrius and some C. collaris by Axtell and
Montanucci, 1977). These take the appearance of
paired dark spots that may extend along the ventral
surface of the tail over the distal 2-30 mm. This
feature is fixed in some species, polymorphic in oth-
ers, and the percentage of individuals with the pig-
mented keels may vary extensively between popu-
lations of the same species.

Crotaphytus collaris is polymorphic with respect
to this character and there is much geographic vari-
ation in the percentage of individuals with the paired
pigmented scales. Individuals from regions of Mex-
ico generally referred to the subspecies C. c. fuscus
and C. c. baileyi usually possess this character (21
of 33 specimens examined). It is less often present
(six of 23) in specimens from midwestern and south-
ern United States (generally referred to the subspe-
cies C. c. collaris ). It was absent in all specimens of
C. collaris examined from Arizona, eastern Utah,
and western Colorado (generally referred to the sub-
species C. c. baileyi and C. c. auriceps, n = 38).
Although the percentage of individuals with pig-
mented keels varies regionally, the observed fre-
quency for C. collaris (29 of 94) was employed in
the phylogenetic analysis.

In Crotaphytus nebrius, this characteristic appears
to be nearly fixed. The pigmented scales were ob-
served in 48 of 49 specimens examined. The only
specimen that lacked the scales (KU 121460) was
from the Tucson Mountains, an isolated range in-
habited by what may be a distinct species. Unfor-
tunately, this is one of only two preserved specimens
available from the Tucson Mountains (the other
specimen, SDSNH 15208, had pigmented scales).
The pigmented scales are much darker, and thus
more obvious, in C. nebrius than in C. collaris.

Crotaphytus bicinctores is another species in which
this characteristic is polymorphic. It was present in
37 of 79 specimens examined. However, the per-
centage of individuals with the pigmented scales
varied considerably between populations. Speci-
mens from southern populations (Palo Verde
Mountains, California; Chocolate Mountains, Cal-
ifornia; Kofa Mountains, Arizona; Sentinel, Ari-
zona) have the scales in high frequency (26 of 32),
while specimens from more northern populations
(Idaho; Inyo County, California; Washington Coun-
ty, Utah) usually lack them (present in three of 30
specimens examined).

The pigmented scales appear to be fixed in Cro-
taphytus dickersonae (present in 44 of 44 specimens
examined), C. grismeri (present in ten of ten spec-
imens examined), C. vestigium (present in 43 of 43
specimens examined), and in C. antiquus (present
in 17 of 17 specimens examined). The presence of
paired melanic keels on the distal caudal extremity
is considered to be the derived state as they appear
to be unique to Crotaphytus.

Black Oral Mucosa (Character 71). — In all cro-
taphytids except Crotaphytus bicinctores, C. gris-
meri, C. insularis, and C. vestigium, black pigments

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

Fig. 33.— Ventral view of a series of Crotaphytus col laris.

are deposited in the oral mucosa and at least some
of the underlying fascia of the M. adductor man-
dibulae complex. There is interspecific variation in
the extent of the pigmentation as well. In Gambelia,
C. collaris, C. nebrius, and C. reticulatus, the cov-
erage and density of the oral melanin is extensive.
The pigments are present on the floor of the buccal
cavity as well as on the fauces of the roof of the
cavity. In C. antiquus and C. dickersonae, black oral
melanin is present but it is less extensive in both
coverage and density. Stebbins (1954) noted that G.
wis/izenii from the Painted Desert region of Arizona
may lack this coloration. However, this observation
has not been confirmed in the present study and
Stebbins himself (personal communication, 1991)
does not recall where he obtained this information.

A black oral mucosa appears to be absent from
all basal outgroup taxa outside of the family Poly-
chrotidae (the throat lining is deep violet in Tro-
pidurus umbra, Etheridge, 1970). Within Polychro-
tidae, black oral melanin is present in some Poly-
chrus(P. marmoratus, P. acutirostris), Pristidactylus
volcanensis, Leiosaurus catamarcensis, Urostrophus
vautieri (Etheridge and Williams, 1991), Anisolepis

grilli (Etheridge and Williams, 1991), Phenacosau-
rus heterodermis, and all three species of Chamae-
leolis (Schwartz and Henderson, 1991). It is variably
present in Pristidactylus torquatus. The absence of
black oral melanin has been verified in Polvchrus
liogaster, P. guttarosus, Pristidactylus acha/ensis, P.
scapulatus, P. casuhatiensis, Leiosaurus belli, U. gal-
lardoi, Enyalius bilineatus, E. brazi/ienesis, E. ca-
tenatus, E. iheringii, E. perditus, and E. pictus. Al-
though black oral melanin may prove to be the an-
cestral condition for Polychrotidae, the family does
not appear to be the sister taxon of Crotaphytidae
(Frost and Etheridge, 1989). Therefore, the presence
of black oral melanin is treated as the derived state.

Collars (Characters 72-75; Fig. 30-36). — Al-
though all Crotaphytus species are characterized by
the presence of at least one collar, there is consid-
erable interspecific variation. Most species have two
well-developed black collars, with relatively thick
white borders that encircle or partially encircle them.
The collar configurations of Crotaphytus reticulatus
and C. antiquus suggest that the transversely ar-
ranged series of black spots (each of which is bor-
dered with white) present in these species may have

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 34. — Ventral view of an adult male Crotaphytus nebrius.

been the precursor to the black collars outlined in
white that are found in all Crotaphytus species. This
is especially evident in the posterior collar markings,
which in C. reticulatus are usually little more than
a few closely approximating black spots with white
borders. Furthermore, in most individuals there are
dark pigments bleeding into the intervening areas
between the black spots. A similar situation is some-
times present in the anterior collar as well. With
respect to the outgroup taxa, it is unlikely that a
white-bordered collar or pair of collars is the an-
cestral state in all but Opluridae (collars present in
O. cuvieri and O. cyclurus ). Therefore, the presence
of white-bordered collars is treated as the derived
state.

Additional variation occurs in C. bicinctores, C.
antiquus, C. collaris, C. dickersonae, C. grismeri,
and C. nebrius, where the posterior collars are either
in contact or only narrowly separated at their medial
margins (Fig. 30-32, 36). In C. insularis and C. ves-
tigium, the posterior collars are broadly separated
(Fig. 32C, D). The condition in C. reticulatus is more
difficult to interpret because of the weak develop-
ment of the posterior collar and it is tentatively
coded as widely separated. Because Gambelia, the
nearest outgroup to Crotaphytus, lacks collars, this
character was left unpolarized.

In all adult male Crotaphytus except C. collaris,
the anterior collar is complete ventrally by way of
dark brown or black pigmentation within the trans-
verse gular fold (Fig. 33-35). Because the nearest
outgroup taxa lack collars, this character was left
unpolarized.

In Crotaphytus collaris and C. nebrius, the pos-
terior collar passes through the antehumeral fold
before reaching the proximal dorsal surface of the
brachium. A less developed condition usually oc-
curs in C. reticulatus, where the collar passes through
the extensive antehumeral mite pocket and isolated
black patches may extend a short distance onto the
proximal dorsal surface of the brachium. In C. an-
tiquus, the posterior collar marking of males either
terminates at the forelimb insertion or melanic spots
extend onto the brachium, while in females, the
collar marking generally terminates before entering
the antehumeral fold (although in one individual
[MZFC 6755], the marking seems to continue
through much of the underlying mite pocket). In C.
dickersonae, the posterior collar just reaches the dor-
sal surface of the forelimb insertion and may extend
slightly onto the brachium as in C. reticulatus. How-
ever, the collar marking does not pass through the
antehumeral fold in this species because the ante-
humeral fold terminates anterior to the posterior

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

Fig. 35. — Ventral view of a series of adult male Crotaphytus vestigium.

collar. In C. bicinctores and C. grismeri, the poste-
rior collar terminates within the antehumeral fold.
In C. vestigium and C. insularis, the posterior collar
almost always terminates before reaching the an-
tehumeral fold. The extreme situation exists in C.
insularis where, in the few individuals that have a
posterior collar, it terminates just before reaching
the antehumeral fold. This character is less consis-
tent in females, especially with respect to C. reti-
culatus, in which females either lack collars or have
them poorly developed. The four conditions de-
scribed above were coded as separate character states
of an unordered multistate character (state 0 = collar
extends well out onto dorsal surface of brachium,
state 1 = collar just reaches forelimb insertion, state

2 = collar terminates within antehumeral fold, state

3 = collar terminates before entering antehumeral
fold). Again, because the nearest outgroups lack col-
lars, this character was left unpolarized.

As stated above, all Crotaphytus species are char-
acterized by the presence of at least one collar (but
see C. insularis below). In fact, with few exceptions,
all Crotaphytus species except C. insularis and fe-
male C. reticulatus have two collars. Crotaphytus
insularis almost always have only the anterior collar,

the posterior collar having apparently been lost (Fig.
32D). The fact that five specimens (CAS 21948,
50879, 86754, 148652; SDSNH 53064) have an ex-
tremely reduced, but visible, posterior collar is con-
sistent with the hypothesis that collar reduction has
occurred in this species. Males have a more densely
pigmented anterior collar than females, which
sometimes have no collar at all. This reduction in
both the posterior and anterior collars appears to
be derived and hence an autapomorphy for this in-
sular species. In C. reticulatus females, the anterior
collar marking may be lacking while the posterior
collars remain. However, the posterior collar mark-
ing in both sexes of this species is often little more
than a slightly modified band of black-filled retic-
ulations. This variation was not included in the phy-
logenetic analysis because of the potential problem
of lack of independence between this state and the
wide separation of the posterior collars described
above.

Dark Nuchal Spots (Character 76; Fig. 36). — A
pair of black or dark spots usually occurs between
the dorsal extensions of the anterior collar markings
in Crotaphytus reticulatus (39 of 51), C. antiquus
(16 of 16), and C. collaris (58 of 75), and are oc-

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

casionally present in C. nebrius ( 1 2 of 5 1 ). The spots,
which occur between the dorsal extensions of the
anterior collar markings, appear to be homologous
with the first transversely arranged row of black-
filled hexagonal reticulations seen in C. reticulatus.
In C. antiquus, the nuchal spots are always present,
but often incompletely separated from the remain-
der of the anterior collar markings. Black nuchal
spots are not present in the outgroup taxa and their
presence is coded as the derived state.

Inguinal Patches (Characters 77, 78; Fig. 32C, 34,
35). — In several species of Crotaphytus, adult males
develop dark brown or black ventral patches in the
inguinal region. These patches vary considerably in
size with C. bicinctores, C. dickersonae, C. grismeri,
C. insularis, and C. vestigium having large patches
and C. antiquus, C. nebrius, and C. collaris having
smaller ones. All adult male C. bicinctores, C. an-
tiquus, C. dickersonae, C. grismeri, C. insularis, C.
nebrius, and C. vestigium develop these patches while
only some C. collaris have them. Interestingly, only
C. collaris from the western periphery of its range
(in the area usually referred to the subspecies C. c.
baileyi ) are known to have inguinal patches. Thus,
there are at least two characters associated with in-
guinal patches: size of the patches and the frequency
with which they occur. Homology of the patches
seems likely. Both large and small patches begin
development as small ventral spots near the hind
limb insertion and the large patches differ only in
that they continue to become larger (and probably
grow faster). Inguinal patches of the type present in
some Crotaphytus are extremely rare in the outgroup
taxa. Similar markings are present in Uma exsul and
U. paraphygas (de Queiroz, 1989; although they oc-
cur more laterally than in Crotaphytus), Uta nolas-
censis, Uromastyx hardwickii (concentrated on the
thigh), and Enyalius iheringii (again, more laterally
oriented). This character has been coded two ways:
first, as a binary character with the absence of in-
guinal patches (of any size) as state 0 and the pres-
ence of patches as state 1 ; and secondly, as a separate
binary character with the presence of small patches
as state 0 and the presence of large patches as state
1. Taxa without inguinal patches were scored as
unknown (“?”) for this second character. Because
the first character (77) considers the frequency in
which patches are present, the second character (78)
does not take frequency into consideration. For
character 78, the presence of small patches in any
frequency is assigned state 0 and the presence of
large patches in any frequency is coded as state 1.

Femoral Pore Secretions (Character 79; Fig. 22,
23, 33-35).— The femoral pore secretions of male
Crotaphytus reticulatus and C. antiquus are jet black.
Unlike other Crotaphytus species, such as C. ne-
brius, which often have grayish secretions, the sub-
cutaneous glands themselves are also jet black. This
condition was not observed in other species of ig-
uanian lizards and is treated as the derived state.

Gular Pattern (Characters 80-82; Fig. 33—35). —
There is much variation in the gular pattern of male
Crotaphytus, especially in the wide-ranging species
C. collaris. However, the general arrangement of the
gular colors is similar in all of the species. For ex-
ample, each has a relatively uniformly colored cen-
tral gular region that is surrounded by a peripheral
reticulated or spotted pattern superficial to the man-
dibles. It is in the context of this general pattern that
the following discussion of variation is based. Be-
cause the pattern and extent of the gular coloration
is sexually dichromatic, the following discussion
pertains only to adult male Crotaphytus.

Adult male Crotaphytus bicinctores, C. antiquus,
C. dickersonae, C. grismeri, C. insularis, C. reticu-
latus, and C. vestigium (Fig. 35) have a patch of
black pigment in the posteromedial portion of the
gular region. This pigmentation corresponds with
that portion of the gular pouch that is depressed by
the second ceratobranchials of the hyoid apparatus,
and thus presumably increases the visibility of the
depressed gular pouch during aggressive display. The
black patch is continuous with the black pigmen-
tation of the gular fold and the ontogenetic devel-
opment of the gular patch suggests that it may be
an extension of the gular fold coloration. However,
the presence of black pigmentation in the gular fold
and in the posteromedial portion of the central gular
region are treated as separate characters because the
presence of black pigmentation in the gular fold is
not always associated with a black central gular patch
(e.g., C. nebrius). Because the outgroups do not have
a gular pattern that is similar to Crotaphytus, out-
group analysis cannot be utilized to assess polarity.
Therefore, this character was left unpolarized.

There is considerable variation in the peripheral
gular pattern of Crotaphytus as well. In all Crota-
phytus except C. nebrius, the peripheral gular pattern
is composed of white reticulations on a dark field.
In most C. collaris, the dark pigmentation within
each subquadrate reticulation has a light center,
which results in a pattern reminiscent of the dorsal
pattern of a jaguar. A similar pattern is sometimes
evident in other species, such as C. bicinctores. In

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

C. nebrius, at least three easily recognizable patterns
occur. One of two available preserved specimens
from the Tucson Mountains (SDSNH 15208), as
well as a photographic record of a specimen from
this locality, have a peripheral gular pattern that is
is very similar to that of C. collaris. More specifi-
cally, the pattern is composed of white reticulations
filled with dark pigment (in this case dark blue) with
pale, light centers. This is in striking contrast to the
peripheral gular pattern of other C. nebrius. A sec-
ond pattern, which has been observed in individuals
from the Gila and Mohawk mountains of Arizona
and the volcanic mountains immediately adjacent
to Mexican Highway 2, at least as far south and east
as 30 mi west of Caborca, Sonora, Mexico, is com-
posed of radiating, oblique, white and dark blue
stripes. These localities represent the northwestern
portion of the range of C. nebrius. The third pattern,
which corresponds to the pattern that Axtell and
Montanucci (1977) used in their diagnosis of the
species, is composed of pale white spots on a light
blue to slate blue field. This pattern is seen in in-
dividuals from the Silverbell Mountains, the Es-
trella Mountains, and from Why, Arizona, and in
one of three specimens from the Tucson Mountains,
as well as from 1 6 mi south of Nogales, the vicinities
of Nacori Chico and Bacadehuachi, 30 mi west of
Caborca, and Guaymas, Sonora, Mexico. The pres-
ence of the second and third peripheral pattern types
from identical localities, 30 mi west of Caborca and
in the Tucson Mountains, suggests that these pat-
terns may occur polymorphically. A similar situa-
tion occurs 0.9 mi south of Why, Arizona, where
one individual has the pattern of white spots on a
pale blue field and a second has a pattern inter-
mediate between the spotted pattern and the one
composed of radiating blue and white stripes
(SDSNH 68645-46). Therefore, a taxonomic deci-
sion based on the differences between the spotted
and striped gular patterns would certainly be pre-
mature.

A binary character associated with this variation
in peripheral gular pattern is recognized. One state
is the presence of a reticulated pattern in the pe-
ripheral gular region, the other is the presence of a
pattern of pale spots or of radiating obliquely ori-
ented stripes extending outward from the edge of
the central gular region. If future collecting shows
that the spotted and obliquely striped patterns do
not grade into one another, and thus represent phy-
logenetically useful variations in gular pattern, then
this a priori assessment of homology will have to

be reevaluated. Neither of the two character states
that I have described above are present in the out-
group taxa and therefore this character is left un-
polarized.

The gular pattern of Gambelia is very different
from that of Crotaphytus. The pattern is composed
of longitudinally arranged black streaks or spots that
extend from the posterior gular region to the man-
dibular symphysis. This gular pattern is present in
all age classes of Gambelia and in both sexes, which
is in contrast to the Crotaphytus condition, in which
only adult males have a fully developed gular pat-
tern. A single character was formulated in which the
alternative states are a fully developed gular pattern
in all age classes and in both sexes or a gular pattern
that is only fully developed in adult males. Variation
in the outgroups prevented polarization of this char-
acter.

Enlarged Melanie Axillary Patches (Character
8 3). — Enlarged melanic axillary patches are variably
present in Crotaphytus bicinctores, C. collaris, C.
insularis, C. nebrius, and C. vestigium. They are
absent from C. antiquus, C. dickersonae, C. gris-
meri, and C. reticulatus, although in C. reticulatus
and C. antiquus, black-filled reticulations may occur
in the same axillary position as the melanic spots
seen in other Crotaphytus. Axillary patches are not
a fixed feature in any Crotaphytus species. Within
C. collaris, they are present only in western popu-
lations from Arizona (and potentially Utah). Among
the outgroup taxa, axillary patches were observed
only in Uta, Uma exsul, and Leiocephalus macropus
(within Leiocephalus, axillary patches are variable
within L. macropus, but present in male L. lunatus,
and male and female L. greenwayi; G. Pregill, per-
sonal communication, 1994), and, therefore, the
presence of axillary patches is treated as the derived
condition.

Ventrolateral Coloration (Character 84; often
unobservable in preserved specimens). — Conspic-
uous ventrolateral coloration is present in adult male
C. dickersonae, Crotaphytus insularis, and C. ves-
tigium, as well as some male C. collaris and C. ne-
brius. The coloration present in C. insularis, C. ne-
brius, and C. vestigium appears to be ephemeral in
nature, appearing only in the breeding season,
whereas the coloration in C. collaris and C. dick-
ersonae appears to be an extension of the normal
adult male dorsal coloration onto the ventrolateral
abdominal region. If this observation holds true,
then it would appear unlikely that the ventrolateral
coloration observed within all of these species is

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

homologous. However, a survey of the ventrolateral
coloration over the entire activity season has not
been completed for each species and an assessment
of homology is not possible.

Breeding male Crotaphytus insularis are charac-
terized by olive green ventrolateral coloration that
contrasts strongly with their brown dorsal colora-
tion. Coloration that is identical in appearance oc-
curs in C. vestigium males from the northern part
of their range (north of Bahia de San Luis Gonzaga,
Baja California, Mexico). Between Bahia de San Luis
Gonzaga and Bahia de Los Angeles (a distance of
approximately 120 km), a shift in ventrolateral col-
oration from olive green to golden orange occurs.
The golden orange coloration is present in C. ves-
tigium at least from Bahia de Los Angeles south-
ward. In C. nebrius, coloration similar to that ob-
served in southern C. vestigium may be present. This
coloration has been observed in specimens from the
Mohawk Mountains (Yuma County, Arizona), the
Tucson Mountains (Pima County, Arizona), and
66.6 mi W Sonoita along Mexican Highway 2, and
suggests that orange ventrolateral breeding colora-
tion is characteristic of the species. Crotaphytus
dickersonae and some C. collaris (those with tur-
quoise or green dorsal coloration) may have bluish
ventrolateral coloration.

Ventrolateral coloration was coded as an unor-
dered multistate character with the absence of ven-
trolateral coloration coded as state 0, the presence
of olive green coloration coded as state 1, the pres-
ence of orange coloration coded as state 2, and the
presence of bluish coloration as state 3. Crotaphytus
vestigium is polymorphic for this feature with states
1 and 2 present; C. nebrius is assigned state 2; C.
dickersonae is assigned state 3; and C. collaris is
assigned states 0 and 3. All other Crotaphytus and
Gambelia are assigned state 0. No attempt was made
to polarize this character.

Dorsal Coloration (Character 85; Fig. 30-32; some
character states are not observable in preserved
specimens).— The dorsal coloration of adult male
Crotaphytus is characterized by much interspecific
variation. Crotaphytus reticulatus has a dorsal col-
oration of golden tan, while C. nebrius has a similar
straw yellow coloration that lacks the golden hue of
C. reticulatus. Crotaphytus dickersonae is unique
among Crotaphytus in that its coloration ranges from
aquamarine to cobalt blue. The coloration of this
species is generally dissimilar to that of C. collaris,
although the aquamarine phase of C. dickersonae is
occasionally approached by C. collaris. Crotaphytus
bicinctores, C. antiquus, C. grismeri, C. insularis,

and C. vestigium have a brown dorsal coloration.
Crotaphytus collaris is extremely variable geograph-
ically, with some populations characterized by a tur-
quoise body pattern with a yellow head (eastern Ar-
izona, eastern Utah, western Colorado, western New
Mexico, as well as some Great Plains populations,
for example Altus, Oklahoma, and Flint Hills, Kan-
sas), others by a bright green coloration (many east-
ern populations), others by a pale to dark brown
coloration (Chihuahuan Desert populations in
southern New Mexico, western Texas, and Chihua-
hua, Mexico), and still others by a combination of
olive green and/or gray (Coahuila, Durango, Zaca-
tecas). Most populations of Gambelia are off-white
to tan in coloration. However, G. copei may range
from golden tan to dark brown. An unordered mul-
tistate character was coded with the off-white to tan
coloration of most Gambelia represented by state
0, the golden tan of C. reticulatus by state 1, the
straw yellow coloration of C. nebrius by state 2, the
blue coloration of C. dickersonae and some C. col-
laris by state 3, a brown coloration by state 4, and
green and/or gray coloration by state 5. Crotaphytus
collaris is considered polymorphic with states 3, 4,
and 5 present, as is G. copei with states 0 and 4.
This character was not polarized.

Behavioral Characters

Saxicoly (Character 86). — Gambelia and Crota-
phytus reticulatus generally occur in flatland desert
habitats and have a generalized terrestrial lifestyle.
Montanucci (1965, 1967, 1969, 1971) performed
ecological investigations of Gambelia silus, G. wis-
lizenii, and C. reticulatus and concluded that they
are virtually ecological equivalents. Although each
will utilize rocks as perching points when they are
available, they often are found in areas quite re-
moved from any rocky habitat. Also consistent with
the assumption that the terrestrial lifestyles of Gam-
belia and C. reticulatus are homologous is the com-
mon utilization of “freeze behavior” in G. wislizenii
(McCoy, 1967), G. copei, and C. reticulatus. Mon-
tanucci ( 1 967) described a similar behavior in young
G. silus, although he later suggested that this be-
havior is rare in this species (Montanucci, 1978).
When disturbed, these species often take refuge be-
neath a nearby bush and remain motionless, ap-
parently relying on crypsis to avoid detection. In
many cases, the lizard can be approached within
one or two meters without causing it to flee. In con-
trast with the terrestrial lifestyles of Gambelia and
C. reticulatus, the remaining species of Crotaphytus
are saxicolous such that they appear to be extremely

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

Fig. 36.— A juvenile Crotaphytus nebrius exhibiting lateral tail coiling behavior.

dependent on rocky habitats and are almost never
observed in areas devoid of rocks. Montanucci
(1974) noted that C. col laris may be found in and
flatland desert in at least two localities in Coahuila,
Mexico. However, this behavior is certainly atypical
for the species and similar behavior has not been
observed by me or discussed in the literature for
any of the other Crotaphytus taxa.

Although saxicoly certainly is not unique to Cro-
taphytus, this particular form of saxicoly, in which
the lizards are restricted to boulder-strewn hillsides,
alluvia, canyons, etc., where they scamper bipedally
from rock to rock, perch atop rocks, and scan the
immediate vicinity for potential prey and predators,
is rare in the outgroup taxa. Nevertheless, because
there are a diversity of character states present in
the outgroup taxa that are absent from either Cro-
taphytus or Gambelia (such as arboreality, burrow-
ing, and crevice-dwelling), a clear polarity decision
was not possible for this character. Therefore, this
character was left unpolarized.

Territoriality (Character 87). — Territoriality is
known to be absent in Gambelia wislizenii (McCoy,
1967; Montanucci, 1970; Tanner and Krogh, 1974a;

Tollestrup, 1979, 1982, 1983). Crotaphytus as well
as G. silus are known to be highly territorial (Fitch,
1956; Montanucci, 1965, 1971; Yedlin and Fergu-
son, 1973;Moehn, 1976; Sanborn and Loomis, 1979;
Tollestrup, 1979, 1982, 1983). It has not been de-
termined whether territoriality is present or absent
in G. copei, although the behavior of this species
appears to be quite similar to that of G. wislizenii.
Territoriality is widespread within Iguania, and is
known to be present in all of the remaining iguanian
families except Hoplocercidae (Carpenter, 1967;
Stamps, 1977), a group for which data were un-
available. Of the many outgroup taxa that have been
studied. Stamps (1977) could list only two, Phry-
nosoma and Anolis agassizi, that are known to lack
territorial behavior. Therefore, the absence of ter-
ritoriality is here treated as the derived state.

Lateral Tail Coiling (Character 89; Fig. 36). — All
Crotaphytus coil their tails laterally when taking ref-
uge under stones or debris, while at rest, and while
hibernating (Legler and Fitch, 1957). Presumably,
this behavior assists in keeping the tail out of the
reach of predators. Lateral tail coiling is also known
in the members of the Anolis homolechis complex

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

of Cuba (Hardy, 1958; Ruibal and Williams, 1961)
and in several species of Leiocephalus (C. A. Haas,
S. B. Hedges, personal communication, 1994; K. de
Queiroz, personal communication, 1995 — although
they are described as coiling their tails vertically
over their backs by Schwartz and Henderson, 1991).
However, these groups are nested within Polychro-
tidae and Tropiduridae, respectively, indicating that
their behaviors are convergent with that observed
in Crotaphytus. The presence of lateral tail coiling
is considered to be the derived state.

Consumption of Vertebrates.— All crotaphytids
except Crotaphytus antiquus, C. grismeri, and C.
nebrius have either been documented in the litera-
ture to include vertebrates in their diets (C. bicinc-
tores : Banta, 1960; Snyder, 1972; Nussbaum et al.,
1983; C. collaris : Fitch, 1956; McAllister and Trauth,
1982; C. reticulatus: Klein, 1951; Montanucci, 1971;
Gambelia copei : Banta and Tanner, 1968; Montan-
ucci, 1965; G. wislizenii : Stejneger, 1893; McCoy,
1967; Montanucci, 1967; Snyder, 1972; Tanner and
Krogh, 1974a; Parker and Pianka, 1976; Tollestrup,
1979, 1983; Pietruszka et al., 1981; Crowley and
Pietruszka, 1983) or have been observed to do so
by the author. The primary vertebrate prey is other
lizards, although rodents and snakes also have been
recorded. There appears to be variation in the rel-
ative proportion of vertebrates included in the diets
of the various species, with Gambelia wislizenii
(Parker and Pianka, 1976; Tollestrup, 1979, 1982,
1983) and G. copei consuming a greater proportion
of vertebrate prey than other species.

Many other iguanian species are known to eat
vertebrates, including the phrynosomatid genera Pe-
trosaurus, Uma, Holbrookia, and Sceloporus, which
are all known to include other lizards in their diets
(Stebbins, 1985); the corytophanid Basiliscus (Van

Devender, 1982); the polychrotid Anolis equestris
(Ruibal, 1964); and the chamaeleonids Chlamydo-
saurus kingii and Physignathus lesueurii (Cogger,
1992). I have not attempted to review the feeding
habits of all of the potential outgroup taxa, but it is
likely that many other species have similar feeding
habits. Thus, the presence or absence of carnivory
may not be a polarizable character, limiting its use-
fulness in this analysis. Furthermore, since most
lizards will eat anything palatable that they are able
to overcome, the inclusion of vertebrates in the diet
may be, at least in part, a function of maximum
adult size. For these reasons, this characteristic was
not included in this analysis. However, the carniv-
orous predatory habits of Crotaphytus and Gam-
belia are consistent with a hypothesis of crotaphytid
monophyly.

Vocalization.— The ability to vocalize is rare in
squamates, with gekkotans being the only family in
which it is known to occur commonly. Within ig-
uanian lizards, vocalization is apparently limited to
crotaphytids and certain polychrotids. A squealing
sound is known to be emitted by Gambelia wislizenii
(Jorgenson et al., 1963; Wever et al., 1966; Smith,
1974) and Crotaphytus bicinctores (Smith, 1974)
during periods of stress. Similar vocalizations were
discussed by Ruibal ( 1964) in three species of Cuban
anoles, Anolis iso/epis, A. lucius, and A. vermiculatus
and by Lynn and Grant (1940) in A. grahami and
A. opalinus (also noted in A. grahami by Etheridge,
1955). Because vocalization data are lacking for the
majority of crotaphytid species, I have not included
this character in the phylogenetic analysis. How-
ever, as with carnivory, the presence of vocalization
in some species of Crotaphytus and Gambelia is
consistent with the hypothesis of crotaphytid mono-
phyly.

CHARACTER LIST

The following character list includes the morpho-
logical characters (informative or uninformative)
discussed in the text, as well as the nine informative
allozyme characters (characters 89-98) that could
be coded using the Manhattan distance frequency
approach discussed in Wiens ( 1 995). One multistate
morphological character (31) was also coded using
the Manhattan distance frequency approach. Its step
matrix is presented in Appendix 4 along with the
step matrices for the allozyme characters. Character
descriptions followed by (P) are polarized, those fol-
lowed by (U) are unpolarized, and those followed

by (UO) are unordered. Characters 28, 68, 75, 84,
and 85 were not analyzed using frequency coding
(see Materials and Methods).

Skull and Mandible

1. Nasal process of the premaxilla (P): (0) broad,
(1) narrow and elongate.

2. Ventral suture between vomers and premaxilla
(P): (0) does not form a strong vertical ridge,
(1) forms a strong vertical ridge.

3. Nasals (P): (0) do not overlap nasal process of
the premaxilla anterior to posterior extent of

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

external nares, (1) overlap nasal process of the
premaxilla anterior to posterior extent of ex-
ternal nares.

4. Prefrontals (P): (0) not in contact with jugals,
(1) contact jugals.

5. Cranium (U): (0) vaulted, (1) not vaulted.

6. Postorbitals (P): (0) weakly overlapped dorsally
by frontal and parietal, (1) strongly overlapped
dorsally by frontal and parietal.

7. Tubercle on anterolateral portion of postorbi-
tals (P): (0) absent, (1) present.

8. Posterior border of parietal roof (P): (0) ap-
proximately twice as wide as narrowest portion
of frontal bone (unconstricted), (1) equal in
width or only slightly wider than narrowest por-
tion of frontal bone (constricted).

9. Supratemporal processes (in lateral view) (P):

(0) tapered, rapidly narrowing dorsoventrally at
their midpoints; (1) not tapered, remain broad
over entire length.

10. Supratemporals (P): (0) broadly exposed on the
lateral surface of the supratemporal process of
the parietal, (1) lies in a groove on ventral sur-
face of supratemporal process of parietal.

1 1. Septomaxillae (P): (0) wide, (1) narrow.

12. Suture of maxillae with premaxilla (P): (0) not
saddle-shaped, no process of the maxilla over-
laps the lateral border of the premaxillary base;

(1) saddle-shaped, a process of the maxilla over-
laps lateral border of premaxillary base.

13. Shape of maxilla-palatine articulation (U): (0)
low arch, (1) triangular.

14. Jugal-ectopterygoid tubercle (P): (0) absent, (1)
present.

15. Angle of jugal along antero ventral border of
orbit (P): (0) approximately 45 degrees, (1) ap-
proximately 90 degrees (box-like condition).

16. Extravomerine bones (P): (0) absent, ( 1 ) at least
one present.

17. Palatine foramen (U): (0) present, (1) absent.

18. Transverse process of the pterygoid with (U):
(0) weakly developed ventral process, (1)
strongly developed ventral process.

19. Paraoccipital processes project posteriorly (P):
(0) to level of occipital condyle, ( 1 ) well beyond
occipital condyle.

20. Angle of the quadrate process of the pterygoid
(U): (0) approximately 18 degrees, (1) approx-
imately 26-3 1 degrees.

21. Posterior projection of ectopterygoid crest (U):
(0) present, (1) absent.

22. Posterior projections of parabasisphenoid (P):
(0) reach the sphenoccipital tubercles; (1) ter-

minate at, or anterior to, the base of the sphen-
occipital tubercles.

23. Anterior extent of angular (U): (0) never reaches
the fourth dentary tooth (counting forward from
the posteriormost tooth) and rarely extends an-
teriorly beyond the posteriormost tooth, (1) ex-
tends at least to the fourth tooth (counting for-
ward from the posteriormost tooth) and usually
beyond.

24. Posterior mylohyoid foramen (U): (0) equal with
apex of coronoid, (1) posterior to apex of cor-
onoid.

25. Posterolingual process of the coronoid (P): (0)
oriented vertically, (1) angled posteroventrally
at approximately 45 degrees.

26. Bony shelf extending between medial process
of surangular and ramus of mandible (P): (0)
absent, (1) present.

27. Lateral process of surangular (P): (0) absent or
present as a weakly elevated ridge, (1) present
as a large protuberance.

28. Ridge on lateral surface of surangular (P, UO):

(0) absent, (1) moderately developed, (2) strong-
ly developed such that the dorsal surface of the
mandible is concave.

29. Tympanic crest (P): (0) forms lateral border of
retroarticular process, (1) curves posteromedi-
ally.

30. Maxillary and dentary teeth (P): (0) stout, either
straight or slightly recurved; (1) long, slender,
and more strongly recurved.

3 1 . Number of premaxillary teeth (U, UO): (0) five,

(1) six, (2) seven, (3) eight, (4) nine.

32. Palatine teeth (P): (0) absent, (1) present.

33. Pterygoid tooth patch (P): (0) follows margin of
interpterygoid vacuity, (1) curves posterolater-
ally.

Hyoid Apparatus

34. Ceratohyals (U): (0) without hook-like process-
es on proximal, medial edge; (1) with hook-like
processes on proximal, medial edge.

35. Length of second ceratobranchials (U): (0) ap-
proximately one-half length of ceratohyals, (1)
more than two-thirds length of ceratohyals.

36. Second ceratobranchials (P): (0) in contact me-
dially, (1) widely separated.

Miscellaneous Features of the
Head Skeleton

37. Skull rugosity at some point in ontogeny (U):
(0) absent, (1) present.

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NO. 32

POSTCRANIAL SKELETON

38. Zygosphenes (P): (0) not separated from pre-
zygapophyses by notch, (1) separated from pre-
zygapophyses by notch.

39. Tail shape (P): (0) round or subcyhndrical with-
out well-developed dorsal and ventral fat bod-
ies, (1) laterally compressed with well-devel-
oped dorsal and ventral fat bodies.

40. Autotomic fracture planes of caudal vertebrae
(P): (0) present, (1) absent.

4 1 . Number of xiphisternal ribs (P): (0) two, ( 1 ) one.

42. Notch on the anterior edge of the suprascapular
cartilage (P): (0) absent, (1) present.

43. Posterior coracoid fenestrae (P): (0) absent, (1)
present.

44. Calcified cartilage anterior border of scapular
fenestra (P): (0) present, (1) absent.

45. Clavicular fenestrations (P): (0) absent, (1) pres-
ent.

46. Termini of iliac blades (U): (0) laterally com-
pressed, (1) round.

47. Arch formed by contact of the medial and lat-
eral plantar tubercles (P): (0) absent, ( 1 ) present.

Squamation

48. Rostral scale (U): (0) broad, approximately four
times wider than high; (1) narrow, approxi-
mately two times wider than high.

49. Some of the prefrontal, frontal, interparietal,
and parietal scales are (U): (0) enlarged relative
to the surrounding scales in such a way as to
form conspicuous supraorbital semicircles, (1)
not enlarged relative to surrounding scales such
that conspicuous supraorbital semicircles are
not distinguishable.

50. Elongate scale in subocular series (P): (0) pres-
ent, (1) absent.

51. Terminal supradigital scales (P): (0) not elevat-
ed from dorsal surface of claws, (1) elevated
from dorsal surface of claws.

52. Femoral pore series (P): (0) terminates before
reaching inferior angle of knee, (1) extends be-
yond inferior angle of knee.

53. Femoral pores (P): (0) much larger and more
strongly developed in males than females, (1)
roughly equal in size or only slightly larger in
males than females.

54. Distal tail skin (P): (0) bound to underlying
musculature, (1) loosely adherent to underlying
musculature.

55. Posteromedially angled folds within gular fold
(U): (0) present, (1) absent.

56. Angle of supra-auricular fold (U): (0) horizon-
tal, (1) at 45-degree angle.

57. Antehumeral mite pockets (P): (0) absent, (1)
present.

58. Postfemoral mite pockets (P): (0) absent, (1)
present.

Additional Structural
Characters

59. Hemipenes (U): (0) large, (1) small.

60. Sexual dimorphism (P): (0) males larger than
females, (1) females larger than males.

Coloration

6 1 . Ephemeral orange coloration in subadult males
(P): (0) absent, (1) present.

62. Paired, paravertebrally arranged, blood-red
spots in juveniles of both sexes (P): (0) absent,
(1) present.

63. Bright yellow tail coloration in adult females
(P): (0) absent, (1) present.

64. Bright yellow tail coloration in juveniles of both
sexes (P): (0) absent, (1) present.

65. Off-white stripe on dorsal crest of tail (P): (0)
absent, (1) present.

66. Juvenile dorsal pattern with a white reticular
component (P): (0) absent, (1) present.

67. Granular reticulations on ventrolateral surface
of abdomen (P): (0) absent, (1) present.

68. White component of adult dorsal body pattern
in the form of (U, UO): (0) broad, offset, trans-
verse bars; (1) a reticulum over the entire dorsal
surface; (2) spots; (3) spots along with slender
transverse dorsal stripes; (4) spots along with
wavy lines and dashes.

69. Sexual dichromatism of the dorsal pattern (U):
(0) absent; (1) present, such that the dorsal col-
oration of males and females is conspicuously
different.

70. Paired melanic keels on ventral caudal extrem-
ity (P): (0) absent, (1) present.

71. Black oral melanin (P): (0) absent, (1) present.

72. Black collar or collars with white borders (P):
(0) collars absent, (1) collars present.

73. Posterior collar markings (U): (0) in contact
dorsally or nearly so, (1) widely separated dor-
sally.

74. Anterior collar (U): (0) incomplete ventrally (no
dark pigments in gular fold), (1) complete ven-
trally (dark pigments present in gular fold).

75. Ventral extent of the posterior collar (U, UO):
(0) extends onto dorsal surface ofbrachium, (1)

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

just reaches forelimb insertion, (2) terminates
within antehumeral fold, (3) terminates before
entering antehumeral fold.

76. Dark nuchal spots (P): (0) absent, (1) present.

77. Inguinal patches (P): (0) absent, (1) present.

78. Inguinal patches (U): (0) small, (1) large (taxa
without inguinal patches coded as unknown
[”?”])

79. Femoral pore secretions (P): (0) off-white to gray,
(1) black.

80. Black pigmentation in central region of gular
pattern (U): (0) absent, (1) present.

8 1 . Peripheral gular pattern (U): (0) reticulated, ( 1 )
pale spots or radiating oblique stripes.

82. Gular pattern (U): (0) present only in adults and
well developed in males only, (1) well devel-
oped in all age classes and in both sexes.

83. Enlarged melanic axillary patches (P): (0) ab-
sent, (1) present.

84. Ventrolateral coloration (P, UO): (0) does not
differ from ventral coloration (white), (1) olive
green, (2) orange, (3) blue.

85. Dorsal coloration (U, UO): (0) off-white to tan;

An initial analysis was performed on the mor-
phological data set of 88 characters (allozyme data
of Montanucci et al. [1975] not included). This re-
sulted in the discovery of a single tree (Fig. 37) with
a length of 12,334 (123.34 when the effect of weight-
ing the characters is removed) and a consistency
index (Cl; excluding uninformative characters) of
0.761, a retention index (RI) of 0.848, and a gx tree
length frequency distribution skewness value of
— 1.49 (the critical gx value for this data set when
randomized is —0. 16 [ P < 0.01]); Table 1). This Cl
is greater than that expected for an analysis of 1 3
taxa (expected Cl = 0.649; Sanderson and Dono-
ghue, 1989), indicating that there is less homoplasy
than expected in these data when compared with
the 60 data sets reexamined by Sanderson and Don-
oghue (1989). The gx value is strongly left skewed
suggesting that the data are phylogenetically infor-
mative. The tree generated in the bootstrap analysis
is presented in Figure 38.

Reanalysis of the allozyme data set of Montanucci
etal. (1975) using the Manhattan distance frequency
approach resulted in the discovery of a single most
parsimonious tree (Fig. 39A). The tree length fre-
quency distribution data, summarized by the gx sta-

(1) golden tan; (2) straw yellow; (3) aquamarine
to cobalt blue; (4) brown; (5) olive green, tur-
quoise, or gray.

Behavior

86. Saxicoly (including the use of saltatory bipedal
locomotion in rocky habitats) (U): (0) absent,
(1) present.

87. Territoriality (P): (0) present, (1) absent.

88. Lateral tail coiling (P): (0) absent, (1) present.

Allozymes

89. H-LDH (U): four electromorphs.

90. aGPD (U): two electromorphs.

91. 6-PGD (U): three electromorphs.

92. ICDs (U): four electromorphs.

93. ICDm (U): four electromorphs.

94. GOTs (U): three electromorphs.

95. Pro (U): two electromorphs.

96. Estl (U): three electromorphs.

97. Hbpf (U): two electromorphs.

98. Tr (U): four electromorphs.

tistic (Hillis and Fluelsenbeck, 1992), suggests that
there is phylogenetically informative signal in this
data set (observed gx value of —0.50; the critical gx
value for this data set when randomized is —0.45
[P < 0.01]). The bootstrap tree for the analysis is
given in Figure 39B (see comments below regarding
interpretation of bootstrap P values).

Because analysis of both the morphological and
allozyme data sets suggests that they contain phy-
logenetic signal, these data sets were combined and
the larger data set was analyzed. Analysis of the
combined morphology and allozyme data sets re-
sulted in the same tree as did the analysis of the
morphology data alone (Fig. 37). The tree length is
139.91, while the Cl (excluding uninformative char-
acters) for the combined tree is 0.761, the RI is
0.848, and the gj value is —1.45 (critical gx value
= —0. 1 5 [P < 0.01]). PAUP is unable to incorporate
the step matrix characters into the Cl and RI cal-
culations, which explains why the Cl and RI values
are identical to those discovered in the analysis of
the morphological data alone. The gx and Cl values
indicate that the data harbor substantial phyloge-
netic signal. The 50 percent majority-rule consensus
tree generated in the bootstrap analysis of the com-

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

combined morphology + allozymes data analyses.

bined data set is presented in Figure 40. The boot-
strap analysis and values indicate that there is
similar support for tree A with or without the allo-
zyme data.

Reanalysis of the allozyme data set using the poly-
morphic coding and Mabee and Humphries (1993)
approaches each resulted in different trees than that
estimated using the step matrix approach. However,
the combined analyses always resulted in the same
tree as the morphology data alone, regardless of the
coding approach employed with the allozyme data.

Character support for each stem of the cladogram
discovered in the combined analysis (Fig. 37) is pre-
sented below. A complete listing of apomorphies,
including the autapomorphies of the terminal taxa,
is presented in Appendix 5. Transformations that
are described as “unambiguous” are supported un-
der both ACCTRAN and DELTRAN optimization.
Therefore, when a node is described as “ambigu-
ously” supported by a particular character state
change, this means that the character in question

Fig. 38.— The 50 percent majority-rule consensus tree generated
from the bootstrap analysis of the morphology-only data set.

supports this node under either ACCTRAN or
DELTRAN optimization but not under both.
“Fixed” transformations are those that involve a
change from one fixed state to another (state “a” to
state “y,” or vice versa). When a transformation is
not fixed it may be referred to as “polymorphic.”
Such transformations involve incomplete changes
(for example from state “a” to state “m”) and re-
ceive a reduced weight due to the frequency coding
approach employed. Unambiguous fixed transfor-
mations include those character state changes from
one fixed state to another that are discovered under
both ACCTRAN and DELTRAN optimization.

Stem A (Crotaphytidae) is supported by 1 1 un-
ambiguous transformations. Five of the synapo-
morphies represent fixed character state changes: 4. 1
(prefrontals contact jugals), 6.1 (parietal and frontal
strongly overlap the postorbital), 14.1 (jugal-ectop-
terygoid tubercle present), 29.1 (tympanic crest of
the retroarticular process curves posteroventrally),
and 71.1 (black oral melanin present, reversed in

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

G. wislizenii
C. vestigium
C. bicinctores

C. reticulatus
C. nebrius
C. collaris

C. dickersonae

G. wislizenii

C. vestigium
C. bicinctores

C. reticulatus

C. nebrius

C. collaris

C. dickersonae

Fig. 39.— (A) The single most parsimonious tree discovered in
the reanalysis of the allozyme data set of Montanucci et al. ( 1 9 7 5)
employing the approach in which frequency values are encoded
into step matrices using Manhattan distances. (B) The 50 percent
majority-rule consensus tree generated in the bootstrap analysis
of this data set.

stem J). Six additional unambiguous yet polymor-
phic apomorphies support this stem: 10.1 (supra-
temporal lies in a groove in ventral surface of su-
pratemporal process of parietal, 23/24 of one step
under ACCTRAN optimization, 2/24 of one step
under DELTRAN optimization), 26.1 (bony shelf
extends between medial process of surangular and
ramus of mandible, 2/24 of one step under both
ACCTRAN and DELTRAN optimization), 32.1
(palatine teeth present, 16/24 of one step ACCT-
RAN, 1 3/24 of one step DELTRAN), 42. 1 (scapular
notch present, 10/24 of one step ACCTRAN, 5/24
of one step DELTRAN), 43.1 (posterior coracoid
fenestrae present, fixed ACCTRAN, 16/24 of one
step DELTRAN), and 45. 1 (clavicular fenestrations
present, fixed ACCTRAN, 8/24 of one step DEL-
TRAN). Finally, Crotaphytidae may also be sup-
ported by two ambiguously placed synapomorphies:
40. 1 (autotomic fracture planes of caudal vertebrae
absent, 4/24 of one step ACCTRAN) and 58.1 (post-
femoral mite pockets present, fixed ACCTRAN).

Stem B ( Gambelia ) is supported by 1 3 unambig-

Fig. 40. — The 50 percent majority-rule consensus tree generated
in the bootstrap analysis of the complete (morphology + allo-
zymes) data set.

uous synapomorphies, six of which represent fixed
character state changes: 12.1 (saddle-shaped suture
between premaxilla and maxilla), 30. 1 (slender, re-
curved maxillary and dentary teeth), 44.1 (loss of
the calcified cartilage border of the scapular fenes-
tra), 46.1 (termini of the iliac blades round), 52.1
(femoral pore series extends beyond the inferior an-
gle of the knee), and 62.1 (paired, paravertebrally
arranged, blood-red spots present in juveniles of
both sexes). This stem is also supported by seven
unambiguous but polymorphic apomorphies: 2.1
(articulation between premaxilla and vomers in the
form of a vertical ridge, 23/24 of one step ACCT-
RAN, fixed DELTRAN), 15.1 (angle of jugal along
anteroventral border of orbit approximately 90 de-
grees, 1 2/24 of one step under both ACCTRAN and
DELTRAN), 17.1 (palatine foramen absent, 19/24
of one step ACCTRAN, 18/24 of one step DEL-
TRAN), 24.1 (posterior mylohyoid foramen pos-

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

tenor to apex of coronoid, 20/24 of one step under
both ACCTRAN and DELTRAN), 26. 1 (bony shelf
between the median process and ramus of the man-
dible, 22/24 of one step under both ACCTRAN and
DELTRAN), 36.1 (second ceratobranchials widely
separated, fixed ACCTRAN, 16/24 of one step
DELTRAN), and 41.1 (one rather than two xiph-
isternal ribs, 20/24 of one step under both ACCT-
RAN and DELTRAN). This stem also may be sup-
ported by five ambiguously placed transformations,
the placements of which depend upon the optimi-
zation routine employed: 1 . 1 (nasal process of pre-
maxilla narrow, 5/24 of one step ACCTRAN), 7.1
(tubercle present on anterolateral portion of post-
orbital, 2/24 of one step ACCTRAN), 25.1 (poster-
olingual process of coronoid angled posterolaterally
at approximately 45 degrees, fixed ACCTRAN), 43. 1
(posterior coracoid fenestrae absent, 8/24 of one
step DELTRAN), and 58. 1 (postfemoral mite pock-
et present, fixed DELTRAN). Finally, this stem may
be further supported by as many as 12 unpolarized
characters: 8.0 (parietal roof not constricted poste-
riorly), 9.0 (supratemporal processes tapered), 13.0
(maxilla-palatine articulation in the form of a low,
rounded arch), 21.1 (posterior process of the ectop-
terygoid crest absent), 23.0 (angular does not extend
anteriorly beyond the fourth dentary tooth [counting
forward] and rarely extends beyond the posterior-
most tooth), 37.0 (skull nonrugose), 49.0 (supraor-
bital semicircles absent), 50.0 (subocular scale series
includes one very elongate scale), 55.1 (gular fold
without closely approximating posteromedial folds),

56.0 (supra-auricular fold horizontal), 59.0 (hemi-
penes large), and 82. 1 (fully developed gular pattern
in females). It is equally parsimonious for each of
these characters to support stem E ( Crotaphytus )
depending upon their true polarity assignments.

Stem C is supported by four unambiguous syna-
pomorphies, two of which are fixed: 5.1 (loss of a
vaulted cranium) and 20.0 (angle of the quadrate
processes of the pterygoid approximately 18 de-
grees). The polymorphic apomorphies are charac-
ters 31.1 (number of premaxillary teeth, 0.35 of one
step under both ACCTRAN and DELTRAN) and

32. 1 (palatine teeth present, 6/24 of one step ACCT-
RAN, 8/24 of one step DELTRAN). Nine more
potential synapomorphies depend upon the partic-
ular optimization routine employed. All but one of
these (discovered during ACCTRAN optimization
data runs) were coded as missing (“?”) for G. co-
ronal and thus may actually represent synapomor-

phies for stem D: 11.1 (septomaxillae slender and
elongate, fixed), 15.1 (angle of jugal along antero-
ventral border of orbit approximately 90 degrees,
12/24 of one step), 24.1 (posterior mylohyoid fo-
ramen posterior to apex of coronoid, 2/24 of one
step), 41.1 (one rather than two xiphisternal ribs,
3/24 of one step), 42.0 (scapular notch absent, 5/24
of one step), 53.1 (femoral pores of approximately
equal size in males and females, fixed), 60. 1 (females
attain larger adult SVL than males, fixed), and 87. 1
(territoriality absent, fixed). Finally, 25.2 (postero-
lingual process of the coronoid angled posteroven-
trally at approximately 45 degrees) may represent a
fixed synapomorphy for this node (fixed DEL-
TRAN).

Stem D is supported by one unambiguous syna-
pomorphy: 1 . 1 (nasal process of premaxilla long and
slender, 19/24 of one step ACCTRAN, fixed DEL-
TRAN). It may be further supported by as many as
nine ambiguous (DELTRAN) characters including
six of the characters (with the same frequency val-
ues) discussed under stem C (1 1, 15, 24, 41, 53, 60)
for which G. corona f was coded as missing (“?”).
The three remaining potential synapomorphies in-
clude: 7.1 (tubercle on anterolateral border of post-
orbital, 2/24 of one step), 10.1 (supratemporal lies
in a groove along ventral border of supratemporal
process, 21/24 of one step), and 40,1 (autotomic
fracture planes absent, 4/24 of one steb).

Stem E ( Crotaphytus ) is supported by 24 unam-
biguous synapomorphies, 12 of which are fixed in-
cluding: 19.1 (paraoccipital processes extend pos-
terior to the occipital condyle), 27. 1 (lateral process
of the surangular present as a large protuberance),

33.1 (pterygoid tooth patch curls posterolaterally),

34.1 (ceratohyals with hook-like processes on prox-
imal, medial edge), 35.1 (second ceratobranchials
more than two-thirds the length of the ceratohyals),

54.1 (skin of the distal portion of tail weakly ad-
herent to underlying musculature), 57.1 (presence
of antehumeral mite pockets), 61.1 (subadult males
acquire “gravid female” coloration), 66.1 (juvenile
color pattern composed of white reticulations), 72. 1
(acquisition of a black collar or collars outlined in
white), 88.1 (lateral tail coiling behavior), and 98.3
(electromorph Tr). This stem is also supported by
12 unambiguously placed yet polymorphic trans-
formations depending upon the optimization rou-
tine employed: 10.1 (supratemporal lies in a groove
along ventral border of supratemporal process, 1/24
of one step ACCTRAN, 22/24 of one step DEL-

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

TRAN), 22.1 (posterior projections of the parabas-
isphenoid terminate at, or anterior to, the base of
the sphenoccipital tubercles, fixed ACCTRAN, 23/
24 of one step DELTRAN), 31.1 (number of pre-
maxillary teeth, 0.38 of one step under both ACCT-
RAN and DELTRAN), 40. 1 (loss of autotomic frac-
ture planes of the caudal vertebrae, 20/24 of one
step ACCTRAN, fixed DELTRAN), 42.1 (supra-
scapular notch present, 12/24 of one step ACCT-
RAN, 13/24 of one step DELTRAN), 47.1 (medial
and lateral plantar tubercles contact to form an arch,
21/24 of one step ACCTRAN, 19/24 of one step
DELTRAN), 76.1 (dark nuchal spots present, 19/
24 of one step under both ACCTRAN and DEL-
TRAN), 90.6 (aGPD, 0.08 of one step under both
ACCTRAN and DELTRAN), 9 1 .2 or 9 1 .6 (6-PGD,
0. 1 2 of one step ACCTRAN, 0.05 of one step DEL-
TRAN), 94.2 (GOTs, 0.69 of one step under both
ACCTRAN and DELTRAN), 95.2 or 95.7 (Pro,
0.58 of one step ACCTRAN, 0.56 of one step DEL-
TRAN), and 96.6 (Estl, 0.7 1 of one step under both
ACCTRAN and DELTRAN). Four additional po-
tential transformations at this node are discovered
only under ACCTRAN optimization including: 28.1
(moderately developed ridge present on lateral sur-
face of the surangular, fixed), 68. 1 (white component
of adult dorsal pattern composed of reticulations,
fixed), 85.1 (dorsal coloration golden tan, fixed), and
89.2 (H-LDH, fixed). Finally, this stem may be sup-
ported by as many as 1 2 transformations that could
not be polarized. It is equally parsimonious for each
of these characters to support stem B ( Gambelia )
and a complete listing is given under the discussion
of stem B.

Stem F is supported by nine unambiguously placed
transformations, four of which are fixed: 68.2 (white
portion of dorsal pattern in the form of spots), 69. 1
(sexual dichromatism of the dorsal color pattern),
85.4 (brown dorsal body coloration), 86. 1 (saxicoly).
The five unambiguous yet polymorphic apomor-
phies include: 24.0 (posterior mylohyoid foramen
equal with apex of coronoid, 1/24 of one step under
both ACCTRAN and DELTRAN), 31.0 (number
of premaxillary teeth, 0.01 of one step under both
ACCTRAN and DELTRAN), 51.1 (terminal su-
pradigital scales elevated from dorsal surface of claw,
4/24 of one step under both ACCTRAN and DEL-
TRAN), 70. 1 (paired melanic keels on ventral cau-
dal extremity, 7/24 of one step under both ACCT-
RAN and DELTRAN), and 77.1 (inguinal patches
present, 7/24 of one step under both ACCTRAN

and DELTRAN). This stem may also be supported
by the following five ambiguously placed transfor-
mations, depending upon the optimization routine
employed: 28.1 (ridge on lateral surface of the sur-
angular, fixed DELTRAN), 43. 1 (posterior coracoid
fenestrae present, 8/24 of one step DELTRAN), 45.0
(clavicular fenestrations lost, 16/24 of one step
ACCTRAN), 58.1 (postfemoral mite pockets pres-
ent, fixed DELTRAN), and 89.2 (H-LDH, fixed
DELTRAN).

Stem G is weakly supported by eight unambigu-
ously placed transformations, none of which are
fixed. The unambiguous, yet polymorphic apomor-
phies include 17.0 (palatine foramen present, 4/24
of one step under both ACCTRAN and DEL-
TRAN), 26.0 (no bony shelf present between medial
process of the surangular and ramus of mandible,
1/24 of one step under both ACCTRAN and DEL-
TRAN), 32.1 (palatine teeth present, 2/24 of one
step ACCTRAN, 5/24 of one step DELTRAN), 42. 1
(suprascapular notch present, 2/24 of one step
ACCTRAN, 5/24 of one step DELTRAN), 47.1
(arch formed by contact of medial and lateral plantar
tubercles, 3/24 of one step under both ACCTRAN
and DELTRAN), 51.1 (terminal supradigital scales
elevated from dorsal surface of claws, 20/24 of one
step under both ACCTRAN and DELTRAN), 70. 1
(paired melanic keels present on ventral caudal ex-
tremity, 17/24 of one step under both ACCTRAN
and DELTRAN), and 77.1 (inguinal patches pres-
ent, 17/24 of one step under both ACCTRAN and
DELTRAN). Four ambiguously placed transfor-
mations may also support this node: 22. 1 (posterior
projections of parabasisphenoid terminate at, or an-
terior to, the base of the sphenoccipital tubercles,
1/24 of one step DELTRAN), 24.0 (posterior my-
lohyoid foramen equal with apex of coronoid, 1/24
of one step ACCTRAN), 90.1 (aGPD, 0.08 of one
step ACCTRAN), and 95.5 (Pro, 0.43 of one step
ACCTRAN).

Stem H is weakly supported by one unambigu-
ously placed polymorphic transformation: 76.0 (ab-
sence of dark nuchal spots, 13/24 of one step under
both ACCTRAN and DELTRAN). This node may
also be supported by two ambiguously placed trans-
formations: 2.0 (ventral suture between vomers and
premaxilla does not form a vertical ridge, 1/24 of
one step ACCTRAN) and 90.1 (aGPD, 0.08 of one
step, DELTRAN).

Stem I is supported by five unambiguously placed
transformations, three of which are fixed: 39.1 (lat-

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

erally compressed tail with dorsal and ventral fat
bodies), 65.1 (off-white dorsal caudal stripe present),
and 78.1 (enlarged inguinal patches in adult males).
The two unambiguous yet polymorphic transfor-
mations are 31.1 (number of premaxillary teeth, 0.0 1
of one step under both ACCTRAN and DELTRAN)
and 76.0 (dark nuchal spots lost, 6/24 of one step
under both ACCTRAN and DELTRAN). Three
ambiguously placed transformations may also sup-
port this node: 24.0 (posterior mylohyoid foramen
equal with the apex of coronoid, 1/24 of one step
ACCTRAN), 47.1 (arch formed by contact of the
medial and lateral plantar tubercles, 2/24 of one step
ACCTRAN), and 75.1 (ventral extent of posterior
collar marking just reaches forelimb insertion, fixed
ACCTRAN).

Stem J is supported by six unambiguously placed
transformations, two of which represent fixed
changes: 71.0 (loss of black oral melanin) and 75.2
(posterior collar terminates within antehumeral fold).
The unambiguous yet polymorphic transformations
include: 1.1 (nasal process of premaxilla narrow,
1/24 of one step under both ACCTRAN and DEL-
TRAN), 32.0 (palatine teeth lost, 8/24 of one step
under both ACCTRAN and DELTRAN), 44. 1 (cal-
cified cartilage anterior border of scapular fenestra
absent, 3/24 of one step under both ACCTRAN and
DELTRAN), and 95.4 or 95.5 (Pro, 0. 1 1 of one step
under ACCTRAN, 0.41 under DELTRAN). This
stem may be further supported by two ambiguously
placed transformations, both of which were discov-
ered under ACCTRAN optimization: 89.3 (H-LDH,
fixed) and 94.3 (GOTs, fixed).

Stem K is weakly supported by two unambigu-
ously placed transformations, neither of which is
fixed: 45.1 (clavicular fenestrations present, 4/24 of
one step under both ACCTRAN and DELTRAN)
and 83.1 (enlarged melanic axillary patches present,
18/24 of one step ACCTRAN, 15/24 of one step
DELTRAN). The stem may be further supported
by four ambiguously placed transformations: 70.0
(paired melanic keels absent from ventral caudal
extremity, 13/24 of one step ACCTRAN), 89.3
(H-LDH, fixed DELTRAN), 94.3 (GOTs, fixed
DELTRAN), and 95.4 (Pro, 0.1 1 of one step DEL-
TRAN).

Stem L is supported by seven unambiguously
placed synapomorphies, three of which are fixed:
73.1 (posterior collars widely separated), 75.3 (pos-
terior collar terminates ventrally before entering the
antehumeral fold), and 84. 1 (olive green ventrolat-

eral coloration present). Olive green ventrolateral
coloration is not a fixed state in C. vestigium as
northern populations are characterized by burnt-
orange ventrolateral coloration. This was an artifact
of the multistate character coding scheme employed
in this analysis and resulted at least in part because
a satisfying estimate of the frequencies of the orange
and green ventrolateral conditions in C. vestigium
could not be obtained from preserved material. The
four unambiguous but polymorphic transforma-
tions include: 16.1 (acquisition of extravomerine
bones, 9/24 of one step under both ACCTRAN and
DELTRAN), 26.1 (bony shelf between medial pro-
cess of surangular and ramus of the mandible pres-
ent, 5/24 of one step under both ACCTRAN and
DELTRAN), 31.1 (number of premaxillary teeth,
0.14 of one step under both ACCTRAN and DEL-
TRAN), and 45.0 (clavicular fenestrations lost, 2/24
of one step under both ACCTRAN and DEL-
TRAN). Finally, four ambiguously placed transfor-
mations may also support this node: 68.3 (presence
of slender, transversely arranged, white dorsal stripes,
fixed ACCTRAN), 91.1 (6-PGD, 0.12 of one step
ACCTRAN), 95.3 (Pro, 0.29 of one step ACCT-
RAN), and 96.1 (Est 1,0.71 of one step ACCTRAN).

In an attempt to assess the amount of character
support for each clade, bootstrap and decay index
analyses were performed for the combined data set.
From each of these analyses it is clear that a number
of clades are rather unstable. For example, in the
bootstrap analysis (Fig. 40), nodes G and H were
supported in less than 50 percent of the bootstrap
replications. Stems D and F also were found to be
relatively weakly supported with bootstrap propor-
tion values of 66 and 60, respectively. Despite its
low bootstrap P value, stem F is supported by four
fixed, unambiguous synapomorphies. The amount
of support for stem D may be underestimated be-
cause a number of derived character states were
coded as missing (“?”) for the fossil taxon G. co-
rona|, thus rendering these transformations ambig-
uous when both ACCTRAN and DELTRAN op-
timization routines are considered. Notably, when
G. corona t is excluded from the analysis, the boot-
strap P value of stem D is 1 00. The remaining clades
appear to be well supported, given that Hillis and
Bull (1993) found bootstrap proportions to be con-
servative estimates of stem support with P values
> 70 corresponding to a probability > 0.95 that the
corresponding clade is real.

The results of the decay index analysis (Fig. 41)

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

in parentheses indicates the number of additional steps that must
be considered before the node is no longer supported. The num-
ber in parentheses represents the number of equally parsimonious
trees discovered when the given number of additonal steps are
permitted.

agree with those of the bootstrap analysis in sug-
gesting that a number of clades (nodes D, F, G, H,
and K) are relatively unstable. Particularly well-sup-
ported clades appear to be stems B ( Gambelia ), E
( Crotaphytus ), and L (C. insularis + C. vestigium).

The allozyme and morphology data sets are not
entirely consistent with one another in that the allo-
zyme data suggest that C. dickersonae shares a com-
mon ancestor with C. collaris, C. nebrius, and C.
reticulatus, whereas the morphological data suggest
that C. dickersonae is more closely related to C.
vestigium and C. bicinctores. The much smaller allo-
zyme data set (ten characters) seems to contain less
phylogenetic signal than does the morphology data
set. For example, the differential between the ob-
served gi and the critical gx value for random data
is substantially greater for the morphological data
set than it is for the allozyme data set (criterion
suggested by J. Huelsenbeck as noted in Wiens
[1995]). Nevertheless, because the topology of the
single most parsimonious tree is unaffected by the
inclusion or exclusion of the allozyme data, the rel-
ative phylogenetic informativeness of the allozyme
data is not a critical issue. However, the bootstrap
results for both the morphology-only and combined
analyses should be considered when evaluating to-
pology robustness for the single most parsimonious
tree.

DISCUSSION

Comparison with Previous Hypotheses

The results of this analysis agree with those of
Etheridge and de Queiroz (1988), Frost and Ether-
idge (1989), and virtually every other study that has
considered the systematics of this group in that Cro-
taphytus and Gambelia are found to be sister taxa.
The intrageneric relationships also are largely con-
sistent with previous hypotheses with some notable
exceptions. A major distinction between this anal-
ysis and all previous studies is the complete repre-
sentation of species included here, several of which
were undiscovered or were not known to be distinct
lineages at the times of the previous analyses.

A phenetic analysis (Ward’s Minimum Variance
Cluster Analysis; Wishart. 1968) of unspecified
morphological data performed by Smith and Tanner
(1972) provided the first estimate of interspecific
relationships within Crotaphytus (exclusive of C.
reticulatus). They concluded that there were two
clusters of taxa within their study group, the collaris
complex, composed of C. collaris populations, and
the western complex, composed of C. bicinctores,
C. vestigium, C. insularis, and C. dickersonae. The
two clusters are consistent with the results presented
here, as both groups appear to be monophyletic.

Smith and Tanner (1974) performed another phe-

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

C. insularis

C. vestigium

C. bicinctores
C. reticulatus

C. dickersonae

C. nebrius

C. collaris

Fig. 42. — The single tree discovered by Montanucci et al. (1975)
in their analysis of crotaphytid relationships.

netic analysis of Crotaphytus relationships (again
without considering Crotaphytus reticulatus ). The
Ward’s Minimum Variance Cluster Analysis (Wis-
hart, 1968) employed morphometric and color pat-
tern data. Their results were consistent with those
of their 1972 study, although they were more specific
in their assessment of relationships in this later anal-
ysis. They discussed the interspecific relationships
of the western complex species and recognized two
pairs of sister taxa, (C. dickersonae + C. bicinctores )
and (C. vestigium + C. insularis). Their tree indi-
cates that they were unsure whether the western
complex was monophyletic or if (C. bicinctores +
C. dickersonae) was actually the sister taxon of C.
collaris (= the collaris complex). Their phyletic tree
suggested Gambelia (= G. wislizenii) to be the sister
taxon of Crotaphytus, and C. reticulatus to be the
sister taxon of the remainder of Crotaphytus. How-
ever, data were not presented for these species and
it is therefore unclear how these conclusions were
reached. The phylogenetic conclusions of this anal-
ysis agree in most respects with those of the present
study except in the placement of C. dickersonae,
which was found to be the sister taxon of C. grismeri,
C. bicinctores, C. vestigium, and C. insularis in this
analysis.

Montanucci et al. (1975) performed the first cla-
distic analysis of Crotaphytus, utilizing 1 2 allozyme,
discrete morphological, and morphometric char-
acters. Their analysis of these data (using the Wagner

program, Kluge and Farris, 1969) resulted in the
tree depicted in Figure 42. This tree is similar to
those discovered here in the placement of C. bi-
cinctores as the sister taxon of (C. vestigium + C.
insularis). However, their tree differs from the trees
discovered here in the placement of C. dickersonae
as the sister taxon of (C. nebrius + C. collaris ), in
the placement of C. reticulatus as the sister taxon
of this group, and in placing (C. bicinctores (C. ves-
tigium + C. insularis)) as the sister taxon of (C.
reticulatus (C. dickersonae (C. nebrius + C. collar-
is))). As with the previous analyses, several taxa
could not be included, such as C. grismeri (not yet
recognized as a distinct lineage) and C. antiquus (yet
to be discovered).

Few comparisons can be drawn between the re-
sults of this analysis and those of previous studies
regarding the phylogenetic relationships of Gam-
belia. Those previous workers who recognized G.
silus as a distinct species generally assumed it to be
the sister taxon of G. wislizenii. Only Norell (1989)
attempted to elucidate the phylogenetic relation-
ships of Gambelia and he was primarily interested
in the position of G. corona |. Although Norell (1989)
described a number of useful characters, he was un-
able to provide phylogenetic resolution. A distinc-
tion between this analysis and several others relates
to the evolution of G. silus. Some previous workers
suggested that G. silus may have evolved as recently
as 1 1,000 years ago by peripheral isolation (Mon-
tanucci, 1967, 1970; Tollestrup, 1979), although
Montanucci (1970) also entertained the possibility
that G. silus entered the valley much earlier. Re-
gardless of the timing of the event, Montanucci
(1970) suggested that differences between G. silus
and G. wislizenii are examples of derived character
states in G. silus rather than derived characteristics
of G. wislizenii. However, most of these features,
such as the presence of territoriality, a truncated
snout, and sexual dimorphism wherein males are
larger than females, are more parsimoniously inter-
preted as plesiomorphic retentions in G. silus. This
interpretation is consistent with that of Tollestrup
(1983), at least with respect to the loss of territori-
ality in G. wislizenii. Thus, it appears that G. silus
is a relatively plesiomorphic taxon and not a re-
cently derived offshoot of G. wislizenii.

It may seem counterintuitive that a narrowly dis-
tributed peripheral species such as Gambelia silus
would be relatively plesiomorphic in comparison
with a wide-ranging taxon such as G. wislizenii (plus
its sister taxon, G. copei). However, there are ex-

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

amples of this phenomenon discussed in the her-
petological literature. For example, Lynch (1982)
found that the widely distributed species Cerato-
phrys cornuta exhibits numerous autapomorphies,
while its close relatives, C. calcarata and C. stolz-
manni are peripherally isolated and exhibit no known
autapomorphies. Wiens (1993 b) discussed a similar
situation in Urosaurus. Urosaurus gadovi has a very
restricted distribution in the Balsas-Tepalcatepec
valley, Michoacan, Mexico, in comparison with its
widely distributed sister taxon, U. bicarinatus. Yet,
U. bicarinatus is relatively derived with several au-
tapomorphies, while U. gadovi is relatively plesiom-
orphic and has no fixed autapomorphies.

Character Evolution

Several evolutionary trends in the morphology
and ecology of crotaphytids can be addressed in the
context of the recovered phylogeny. These include
the correlation between head morphology and sau-
rophagy, the evolution of sexual dichromatism and
morphologies that appear to be display oriented,
bipedalism and the evolution of morphologies as-
sociated with this form of locomotion, and the func-
tion of gravid coloration and the evolution of similar
coloration in subadult males.

Head Morphology and Dietary Correlates. — Head
morphology and dietary preferences appear to be
related in crotaphytids. Within Gambelia, G. copei
and G. wislizenii share the derived condition of an
elongate head, while G. situs retains the plesiom-
orphic blunt-snouted condition. Several studies,
particularly those of Tollestrup (1979, 1983), sug-
gest that G. wislizenii preys on vertebrates much
more heavily than does G. silus and, based on my
observations of stomach contents both in the field
and in museum specimens, I suggest that G. copei
will prove to be just as reliant on vertebrates as is
G. wislizenii. A similar correlation is apparent in
Crotaphytus. Crotaphytus reticulatus, C. collaris, C.
nebrius, and C. antiquus have relatively broad heads
with blunt snouts in contrast with the narrower,
more elongate heads of C. dickersonae, C. grismeri,
C. bicinctores, C. vestigium, and C. insularis (which
form a monophyletic group; Fig. 37). The majority
of the published dietary studies related to Crota-
phytus have been confined to C. collaris, which is
primarily insectivorous (Fitch, 1956, plus numerous
additional references). Examination of preserved
specimens with slit bellies and the skeletal prepa-
ration of preserved and fresh material has allowed
for numerous observations of stomach contents, al-

though precise records have not been maintained.
These observations suggest that the “long snout”
clade specializes in vertebrate prey to a greater de-
gree than C. reticulatus, C. collaris, C. nebrius, and
presumably C. antiquus. The saurophagous species
may have elongate heads to allow for faster jaw
adduction and predation on fast-moving prey,
whereas the short-snouted condition might be as-
sociated with more powerful jaw adduction for
crushing hard-shelled prey, perhaps certain insect
taxa. A detailed dietary analysis to confirm these
anecdotal observations for Crotaphytus, followed by
an analysis of the functional morphology of crota-
phytids (using kinematic and strain gauge analyses
to measure jaw speed and jaw adductor power) would
shed much light on this situation.

The Evolution of Display-oriented Morphologies
in Males.— Gambelia and Crotaphytus reticulatus
essentially lack sexual dichromatism outside of the
breeding season, whereas the remaining species of
Crotaphytus are characterized by the derived con-
dition of strong sexual dichromatism throughout the
year. This is the first in a series of evolutionary
modifications presumably associated with an in-
crease in display-oriented morphologies within
males. There appears to have been selection for black
coloration within a number of clades, the best ex-
ample of which is associated with the evolution of
inguinal patches in adult males. Inguinal patches
appear to have passed through the following trans-
formation series: absent — * small — ► large, with a
reversal to the polymorphic condition observed in
C. collaris. The common ancestor of Crotaphytus
exclusive of C. reticulatus appears to have been fixed
for the presence of small inguinal patches. This con-
dition persists in C. antiquus and C. nebrius, and
appears to have been elaborated upon to produce
much larger inguinal patches in the common an-
cestor of C. dickersonae, C. grismeri, C. bicinctores,
C. vestigium, and C. insularis (Fig. 34, 35). The
inguinal region is prominently displayed by male
Crotaphytus regardless of whether or not they have
inguinal patches and this may have led first to the
acquisition and then enlargement of inguinal patch-
es. If this scenario holds true, a reversion to the
polymorphic state in C. collaris is puzzling. Two
additional examples of derived black components
of the color pattern are the jet-black femoral pores
of C. reticulatus and C. antiquus (Fig. 23) and the
enlarged, melanic axillary patches present poly-
morphically in C. collaris, C. nebrius, C. bicinctores,
C. vestigium, and C. insularis.

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

An additional series of evolutionary modifica-
tions that is presumably associated with male dis-
play behavior are associated with lateral tail com-
pression in the common ancestor of C. dickersonae,
C. grismeri, C. bicinctores, C. vestigium, and C. in-
sular is (Fig. 3 IB. 32A-D). This character complex
includes the derived acquisition of dorsal and ven-
tral caudal fat bodies as well as modifications of the
neural and haemal arches and transverse processes
of the caudal vertebrae. Lateral tail compression
presumably increases the apparent size of adult males
in lateral view. The evolution of sexual dichroma-
tism, the acquisition and modification of black color
pattern components that are restricted to males, and
the development of lateral tail compression in males
each suggest an increase in the importance of male
display within Crotaphytus.

Bipedalism.— The form of bipedalism present in
Crotaphytus appears to be unique among iguanians
(see below). Several morphological modifications
within the genus appear to be related to this behav-
ior, including the loss of autotomic fracture planes
of the caudal vertebrae (character 39), the modifi-
cation of the skin of the distal portion of the tail
such that the skin may easily slip free (character 52;
Fig. 34), the acquisition of lateral tail coiling be-
havior (character 87; Fig. 36), and the contact of the
medial and lateral plantar tubercles of the fifth meta-
tarsal such that they form an arch (character 45; Fig.
1 7). The reference to the last character requires some
explanation. Snyder (1952, 1954, 1962) observed
that M. gastrocnemius is usually slightly larger in
bipedal lizards than in quadrupedal species. Al-
though he emphasized that the differences in muscle
mass between quadrupedal and bipedal lizards are
not usually great, he noted that M. gastrocnemius
was conspicuously larger in Crotaphytus than in any
other quadrupedal or bipedal lizard that he exam-
ined (Snyder, 1962). Because M. gastrocnemius in-
serts on the medial and lateral plantar tubercles, it
is possible that the arch structure found in Crota-
phytus increases the surface area for insertion of this
muscle.

Crotaphytus utilizes a unique form of bipedal lo-
comotion, wherein individuals jump bipedally from
rock to rock on the boulder-strewn hillsides that
they inhabit. This saltatory form of bipedalism al-
lows them to move rapidly over a complex substrate
and, presumably, an individual would be at a dis-
advantage if it were not able to maintain a bipedal
gait. Snyder (1949, 1954, 1962) found that the tail
of Crotaphytus acts as a counterbalance during bi-

pedal locomotion and that the removal of between
25 and 33 percent of the tail prohibits a bipedal gait
for more than three to five strides, while the removal
of more than 50 percent prevents bipedal locomo-
tion for more than one step. This may have been
the selective factor that lead to the loss of autotomic
fracture planes in the common ancestor of Crota-
phytus. However, the tail of Crotaphytus is very long
and it seems likely that there would be strong se-
lective pressure to prevent predators from capturing
them by this appendage, especially given that the
tail cannot be broken easily (tail breakage can still
occur, but requires an intervertebral separation or
a fracture of the caudal vertebra itself; Etheridge,
1967). At least two evolutionary modifications have
occurred in Crotaphytus that appear to play a role
in minimizing predation by “tail capture.” First, the
lateral tail-coiling behavior utilized by Crotaphytus
when taking refuge from predators beneath rocks or
surface debris, during hibernation, and when resting
beneath stones appears to function as a means of
keeping the tail out of the reach of potential pred-
ators. Second, the presence of loosely adherent skin
over the distal approximately 20 percent of the tail
allows the skin of the caudal terminus to slip off
when grasped, thus providing an alternative to cau-
dal autotomy over the portion of the tail the lizard
can lose without hindering its ability to run bipe-
dally. Once the skin is removed, the underlying ver-
tebrae and soft tissues wither and are lost. This hy-
pothesis for the function of the loosely adherent
caudal skin is based on three separate instances in
which I experienced this phenomenon while at-
tempting to capture lizards, as well as on the ob-
servation of numerous museum specimens that lack
the skin of the distal portion of the tail.

Gravid Coloration.— Gravid coloration occurs in
all crotaphytid taxa and a similar color pattern de-
velops in subadult male Crotaphytus (character 59).
Although gravid coloration itself may be a plesiom-
orphic retention of Crotaphytidae, the subadult male
coloration is almost certainly derived (see above).
The coloration of the subadult males, which devel-
ops soon after hatching and fades just before ma-
turity (Fitch, 1956; Rand, 1986) is virtually indis-
tinguishable both in terms of its chromatic char-
acteristics and in its anatomical placement and,
therefore, suggests that the young males may be
mimicking females in order to incur some selective
benefit. In fact, the presence of this coloration in
young males may provide a clue to its function both
in females and in the subadult males themselves.

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

The presence of bright red or orange dorsal pig-
mentation makes gravid Crotaphytus conspicuous
at a time when crypticity presumably would be at
a premium. Therefore, it is likely that the coloration
provides some form of visual signal to predators or
conspecihcs that provides a greater selective benefit
than cost to gravid females. The behavior of repro-
ductive females toward males changes dramatically
from submissive to aggressive soon after copulation,
and this corresponds with an intensification of the
coloration (Fitch, 1956; Clarke, 1965; Cooper and
Crews, 1988). Therefore, Clarke (1965) and Cooper
(1988) suggested that gravid coloration may act as
an inhibitor of male aggression. If this is the case,
subadult males with red or orange coloration po-
tentially could benefit by being allowed to forage
within adult male territories without being attacked.
Indeed, Gambelia are well known for their canni-

balistic habits and such coloration in Crotaphytus
may limit predation on subadults by adult males.
Because females are generally allowed to set up ter-
ritories within male territories in many territorial
species (Stamps, 1977; noted in C. collaris by Fitch,
1956, and Yedlin and Ferguson, 1973), subadult
females potentially would benefit less by bearing red
or orange dorsal coloration. If this is the case in
Crotaphytus, the presence of bright red or orange
coloration in subadult females might more likely be
selected against (assuming the presence of vibrant
orange or red coloration leaves them more conspic-
uous to visually oriented predators such as raptors
and loggerhead shrikes). Although this hypothesis
is highly speculative, it is consistent with the idea
that gravid coloration has a functional value in fe-
males on which subadult males could also capitalize.

TAXONOMIC ACCOUNTS

The following taxonomic accounts include: (1)
synonymies for each taxon name, (2) phylogenetic
definitions for the three clade names (Crotaphyti-
dae, Crotaphytus, and Gambelia ) following the rec-
ommendations of de Queiroz and Gauthier (1992),
(3) an etymology for each taxon, (4) a general de-
scription of squamation for Crotaphytidae, (5) a
more specific description of squamation for each
species, (6) general descriptions of coloration in life
for Crotaphytus and Gambelia, (7) more specific de-
scriptions of coloration for each species, (8) a de-
tailed summary of geographic distribution for the
genera and species (locality data used in producing
the distribution maps are available from the author
upon request), (9) a discussion of natural history
where appropriate, and ( 1 0) a remarks section under
each species account that includes references to il-
lustrations, as well as various additional comments.
The list of published illustrations may be complete
for the rarer taxa, but is certainly incomplete for
wide-ranging, common species such as C. collaris
and G. wislizenii. Natural history observations that
are not followed by a literature citation are my own.

Crotaphytidae Smith and Brodie, 1982

Crotaphytinae Smith and Brodie, 1982:106. Type genus: Cro-
taphytus Holbrook, 1842.

Crotaphytidae Frost and Etheridge, 1989:36.

Definition. —Crotaphytidae is here defined as a
node-based name for the most recent common an-

cestor of Crotaphytus and Gambelia and all of its
descendants.

Description.— A description of the squamation of crotaphytids
is given here to provide a consolidated view of those features
common to the family. To prevent an unnecessary duplication
of information, only variable features will be discussed under the
separate species accounts. General color pattern descriptions are
provided under the generic accounts of Crotaphytus and Gam-
belia, with more specific characterizations given under each spe-
cies account.

Dorsal cephalic scales smooth, convex, polygonal, occasionally
with numerous inconspicuous surface irregularities. Rostral ap-
proximately two to four times wider than high, usually rectan-
gular in shape. Rostral bordered by two to eight postrostrals.
Remaining snout scales irregularly arranged, an enlarged mid-
dorsal series may be present. Nasals form a thin-walled ring,
pierced centrally by external nares; nares face laterally at a slight
dorsal angle; nasals separated by three to nine intemasals. Fron-
tonasals occasionally enlarged. Three or four canthals, posterior
one or two wider than high; four to ten scales separate canthals
of left and right sides; canthus rostralis forms prominent ridge.
Supraorbital semicircles present or absent; when present some
scales may fuse to form azygous frontals. Interparietal small,
approximately twice as long as wide, with opalescent “eye.” Pa-
rietals generally small and irregular. Supraoculars small, flat or
convex, smooth, becoming progressively larger medially such
that medial scales are two to four times larger than lateral ones.
Circumorbitals present or absent; when present not well differ-
entiated from supraoculars. Superciliaries six to 15, extremely
elongate medial scale present or absent; anterior scales with oblique
sutures oriented posterodorsally, posterior scales with oblique
sutures oriented anterodorsally. Palpebrals ovoid, slightly con-
vex, may be interspersed with numerous interstitial granules.
Inner ciliaries deeper than wide, outer ciliaries of upper eyelid
usually projecting, anterior and posterior ones projecting slightly

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

further than medial ones; outer ciliaries of lower eyelid larger
than those of upper lid, strongly projecting, conical, with anterior
and posterior scales projecting slightly further than medial ones.
Preoculars, suboculars, and postoculars form an arc of four to
13 rectangular scales, second, third, or fourth scale elongate or
not, all with strong superior keel, strongly concave below keel.
Supralabials 11 to 18, usually slightly longer than high except
anteriormost scale, which is square or pentagonal. Supralabials
followed posteriorly by a series of elongate postlabials. Lorilabials
in one to four rows, ovoid to rectangular, juxtaposed, separating
supralabials from suboculars and nasals. Loreals numerous, larg-
er than adjacent lorilabials. Lower temporals small, convex, oval,
often separated by interstitial granules; zone of less convex, po-
lygonal or rounded, juxtaposed scales approximately 1.5 to two
times larger than bordering upper and lower temporals, extending
posteriorly from postoculars but not reaching external auditory
meatus; corresponding to underlying postorbital bones. Aperture
of external auditory meatus rectangular or ovoid, often constrict-
ed at or above the midpoint, approximately two to four times
higher than wide, with small, strongly convex, somewhat conical
auricular scales lining anterior margin. Mental pentagonal, one
to 1.5 times wider than high, bordered laterally by anterior in-
fralabials and posteriorly by a pair of large postmentals. Post-
mentals may or may not be separated from infralabials by sub-
labials. Chinshields weakly differentiated or undifferentiated. In-
fralabials ten to 18, square or wider than high, inferior border
convex. Gulars granular, strongly convex and beadlike or flat,
each scale may be separated from adjacent scales by numerous
asymmetrically arranged interstitial granules. Gulars flattened
and discoid in gular pouch region. Gulars within symphysial
groove much smaller than surrounding scales that overlie man-
dibles.

Dorsal scales of neck and body very small, rounded, strongly
convex, nonimbricate, each characteristically surrounded by six
interstitial granules giving appearance of a six-pointed star. Me-
dian dorsal scales 1 . 5 to two times larger than lateral dorsal scales.
Dorsals grade smoothly into ventrals, approximately 136 to 224
rows encircle body midway between forelimb and hindlimb in-
sertions. Ventrals smooth, flat, varying from oval to rhombic in
shape, approximately three to four times larger than adjacent
laterals, occasionally slightly imbricate.

Tail long, cylindrical to oval over entire length or anterior one-
half strongly compressed laterally. Caudals usually keeled over
distal 85 percent, keeling more pronounced distally. Paired, me-
dian row of subcaudals larger than adjacent subcaudals and lateral
caudals present or absent; posteriorly subcaudals become pro-
gressively more distinctly keeled and often mucronate. Enlarged
postanal scales in males present or absent, scales between post-
anal plates and cloaca extremely small compared to remaining
subcaudals.

Scales in immediate vicinity of forelimb insertion minute, ex-
cept for a patch of large, discoid scales at anterior forelimb ar-
ticulation. Suprabrachials discoid, separated by interstitial gran-
ules, becoming larger and slightly imbricate distally; distal su-
prabrachials approximately two times larger than dorsal body
scales. Suprabrachials grade smoothly into smaller postbrachials.
Prebrachials convex, beadlike, each surrounded by six symmet-
rically arranged interstitial granules; prebrachials grade abruptly
into smaller, convex infrabrachials. Supra-antebrachials and pos-
tantebrachials small, discoid, nonoverlapping proximally, prean-
tebrachials slightly imbricate proximally; supra-antebrachials,
preantebrachials, and postantebrachials much larger and strongly
imbricate adjacent to supracarpals. Infra-antebrachials convex,

smaller than adjacent preantebrachials and slightly smaller than
postantebrachials. Supracarpals large, strongly imbricate, contin-
uous with large supradigital scales. Proximal supradigitals wider
than long. Infracarpals strongly imbricate, usually with three strong
mucrons. Subdigital lamellae moderately imbricate, each with
three to six short mucrons.

Deep postfemoral dermal mite pocket may or may not be
present at hindlimb insertion. Suprafemorals small, convex, near-
ly equal in size to lateral dorsals, separated by numerous inter-
stitial granules, grading into prefemorals. Prefemorals becoming
more discoid, slightly imbricate and larger distally; prefemorals
at knee larger than surrounding scales, five to ten times larger
than suprafemorals. Prefemorals grade into smaller infrafemo-
rals; 1 5 to 3 1 femoral pores, femoral pores extend beyond angle
of knee or not, separated medially by ten to 26 granular scales.
Suprafemorals grade smoothly into minute, convex, oblong post-
femorals, interspersed with interstitial granules. Supratibials small,
convex, grade into larger, flattened, juxtaposed posttibials and
larger, similarly shaped pretibials; pretibials granular where ad-
jacent to supratarsals. Infratibials smooth, flat, juxtaposed or
weakly imbricate proximally, becoming imbricate distally, much
larger than adjacent pretibials and slightly larger than posttibials.
Supratarsals large, imbricate anteriorly, slightly convex, granular
posteriorly. Infratarsals strongly imbricate, one to three keels per
scale. Supradigital scales smooth, large, strongly imbricate. Sub-
digital scales imbricate, with three to seven keels, each with a
terminal mucron; subdigital lamellae on fourth toe 15 to 25.

Size. — All crotaphytid species are sexually di-
morphic; however, males are larger than females in
some species while the reverse relationship pertains
in others. Maximum adult sizes range from ap-
proximately 99 mm SVL in male Crotaphytus gris-
meri to approximately 1 44 mm SVL in adult female
Gambelia wis/izenii.

Crotaphytus Holbrook

Crotaphytus Holbrook, 1842:79. Type species (by original des-
ignation): Agama collaris Say 1823.

Leiosaurus, part— Dumeril, 1856:532.

Crotaphytes— Stone and Rehn, 1903:30.

Definition. — Crotaphytus is defined as a node-
based name for the clade stemming from the most
recent common ancestor of Crotaphytus collaris and
all species that are more closely related to that spe-
cies than to Gambelia.

Etymology. — From the Greek krotaphos, referring to the side
of the head or temple region; and phyton, a creature or animal.
The name apparently refers to the hypertrophied jaw adductor
musculature of these lizards.

Coloration in Life. — Dorsal body coloration is ex-
tremely variable within adult male Crotaphytus,
ranging between cobalt blue, aquamarine, green,
turquoise green, golden tan, straw yellow, brown,
and gray. Females of all species except C. reticulatus
are generally characterized by a more faded version
of the color present in males of their species or by

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

pale tan or green hues. Head coloration in males
may differ from that of the body, most notably in
those populations of C. collaris characterized by a
pale yellow to fluorescent yellow head. A pattern of
white reticulations is a recurring phenomenon with-
in the genus and may be present over the entire
dorsal surface of the body and limbs, as well as on
the temporal and superficial mandibular regions or
some subset thereof. A number of species have a
dorsal body and limb pattern composed of white
spots or dashes rather than net-like reticulations,
and narrow, transverse dorsal bars may be present.
A broad white or off-white vertebral stripe may ex-
tend from the base of the tail posteriorly for most
of its length. The dorsal surface of the head may be
pale-colored, with a more or less patternless surface.
All Crotaphytus are characterized by a ventral col-
oration of white, off-white, or pale yellow, although
additional markings may be present. Olive green,
golden orange, or burnt orange ventrolateral col-
oration may be present in males as well. The tail
may or not be bright lemon yellow in adult females
or burnt orange in subadult females.

Gular coloration in adult males is highly variable
with olive green, gun-barrel blue, slate gray, dark
brown, dark blue, turquoise blue, yellow, or orange
all characterizing the adult males of certain popu-
lations. The gular region of females is generally white
or only faintly patterned. The gular coloration of
adult males may or may not include a black central
component. The pattern surrounding the gular re-
gion of adult males is also variable and may be
composed of pale reticulations, white spots on a sky
blue background, or radiating, obliquely oriented,
white lines.

Black is an important color component within the
genus with all species having some combination of
black markings. All Crotaphytus except some female
C. insularis and C. reticulatus have at least one pair
of black collar markings and most have two pairs.
The anterior and posterior collar markings are sep-
arated by a broad white bar that may or may not
be complete middorsally. The anterior pair of collar
markings contact ventrally through the gular fold in
adult males of some species. The posterior collar
markings may contact middorsally in some species
as well. A pair of black spots may be present mid-
dorsally between the anterior collar markings. A pair
of enlarged melanic axillary patches are variably
present immediately posterior to the forelimb in-
sertion in adult males of several species. Small or
large melanic inguinal patches are also present in
the adult males of several species. All Crotaphytus

neonates are characterized by a pattern of white
reticulations, some of which enclose black pigments.
This pattern may or may not be retained into adult-
hood with little modification. The femoral pores are
generally off-white to gray in color but are black in
males of two species (C. antiquus and C. reticulatus).
Paired, melanic keels may or may not be present on
the ventral surface of the caudal extremity.

All Crotaphytus females develop “gravid color-
ation” in the form of red or orange lateral bars or
spots. A similar pattern develops in subadult males
of all Crotaphytus species.

Size. — All Crotaphytus exhibit sexual dimor-
phism wherein males are larger than females. Max-
imum adult sizes range from approximately 99 mm
SVL in C. grismeri to approximately 1 3 1 mm SVL
in C. collaris (C. reticulatus may reach 1 37 mm SVL;
Montanucci, 1976).

Distribution.— Western and southcentral United
States from southern Idaho and eastern Oregon
southward and eastward across the southern Great
Plains into Missouri, northwestern Arkansas, and
extreme northwestern Louisiana, southward into
southern Baja California and northcentral mainland
Mexico.

Fossil Record. —Numerous Pleistocene fossils
have been referred to the genus, all of which have
been placed within C. collaris or listed as C. sp.
(Estes, 1983). However, the localities from which
some of these specimens have been collected suggest
that a few of these fossils may be C. bicinctores and
C. nebrius (Brattstrom, 1954; Van Devender et al.,
1977; Van Devender and Mead, 1978). The frag-
mentary nature of most of the material renders spe-
cific identification on the basis of character evidence
impossible.

Crotaphytus antiquus Axtell and Webb
(Fig. 30D)

Crotaphytus antiquus Axtell and Webb, 1995:1; fig. 1, 2. Type
locality: “2.1 km N-1.7 km E Vizcaya (25°46'04"N-
103°1 1 '48"W, el 1 100± m) in the Sierra Texas, Coahuila, Mex-
ico” (Holotype: UTEP 15900).

Etymology. — From the latin antiquus, meaning old or of an-
tiquity. The name was chosen by the authors because it “incor-
porates (their) interpretation regarding the probable ancientness
of the lizard.”

Diagnosis.— Crotaphytus antiquus can be distin-
guished from all other Crotaphytus by the presence
of gravid coloration that is limited to the anterior
15 to 50 percent of the portion of the abdomen
between the forelimb and hindlimb insertions and
a much larger total number of white reticulations

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

that enclose melanic pigments. Crotaphytus antiq-
uus can be distinguished further from C. reticulatus
on the basis of its postfemoral mite pockets, sexual
dichromatism of the dorsal color pattern such that
females have much more subdued coloration than
males, and the presence of paired, melanic mucrons
on the distal subcaudal scales. It can be distin-
guished from all Crotaphytus except C. nebrius and
western populations of C. collaris by its small me-
lanic inguinal patches (patches absent in C. reticu-
latus, patches much larger and extending onto the
ventral surface of the abdomen in C. bicinctores, C.
dickersonae, C. grismeri, C. insularis, and C. vestig-
ium. It can be distinguished further from all Cro-
taphytus except C. reticulatus by its dorsal pattern
composed of a white, net-like reticulum, some of
which enclose melanic pigments. It can be distin-
guished further from all other Crotaphytus except
C. reticulatus and C. insularis by the the weakly
defined collar markings of females. It can be distin-
guished further from C. collaris by its ventrally com-
plete anterior collar marking in adult males. It can
be distinguished further from C. collaris and C. ne-
brius by the presence in adult males of black pig-
ments extending from the gular fold anteriorly into
the central gular area. From C. dickersonae, C. bi-
cinctores, C. grismeri, C. insularis, and C. vestigium,
it can be distinguished further by its round, rather
than laterally compressed, tail that lacks a white
dorsal vertebral stripe (present in adult males of the
latter five species). Finally, from C. bicinctores, C.
grismeri, C. insularis, and C. vestigium, C. antiquus
can be distinguished by its black buccal lining.

In addition to the characters listed above, C. an-
tiquus can usually be distinguished from all other
Crotaphytus (with the possible exception of C. dick-
ersonae) on the basis of a series of scales that either
completely separates or nearly separates the supra-
orbital semicircles. In nine of 16 C. antiquus, the
supraorbital semicircles are separated by a row of
small scales, while in six of 16 specimens, a single
pair of scales is in contact, and in one specimen,
two scales are in contact. In all other Crotaphytus
except C. dickersonae, at least two scales of the su-
praorbital semicircles were in contact and this was
a relatively rare condition (more than two scales in
contact in six of eight C. bicinctores, 26 of 27 C.
collaris, four of four C. grismeri, 15 of 20 C. insu-
laris, nine of ten C. nebrius, eight of eight C. reti-
culatus, and six of seven C. vestigium). Crotaphytus
dickersonae is considered most similar with respect
to this character to C. antiquus only because one
specimen had one pair of scales of the semicircles

in narrow contact and three of four additional spec-
imens had two scales in contact. Thus, the prevalent
condition of C. antiquus (supraorbital semicircles
completely separated by a row of scales) was not
observed in any other species of Crotaphytus, al-
though the condition may very well occur in C.
dickersonae given a larger sample size. Thus, C. an-
tiquus and other Crotaphytus overlap but little with
respect to this feature.

Variation (n = 19). — Rostral approximately four
times wider than high, usually rectangular in shape.
Rostral bordered by three to six postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by five to six internasals. Frontonasals oc-
casionally enlarged. Canthals three; five to seven
scales separate canthals of left and right sides. Su-
praorbital semicircles present with 12 to 13 scales
per semicircle, median scales never fuse to form
azygous frontals, a series of small scales may sep-
arate the right and left supraorbital semicircles or
one, or rarely two, of the scales of the semicircles
may be in contact. Supraoculars flat or convex,
smooth, becoming progressively larger medially such
that medial scales are 1.5 to two times larger than
lateral ones. Circumorbitals present, not well dif-
ferentiated from supraoculars. Superciliaries eight
to 1 1, extremely elongate medial scale usually pres-
ent. Palpebrals ovoid, slightly convex, interspersed
with numerous interstitial granules. Preoculars, su-
boculars, and postoculars form an arc of seven to
1 1 rectangular scales, second, third, or fourth scale
not elongate. Supralabials 12 to 16, usually slightly
longer than high. Lorilabials in two to three rows,
ovoid to rectangular, juxtaposed, separating su-
pralabials from suboculars and nasals. Aperture of
external auditory meatus rectangular or ovoid, often
constricted at or above the midpoint, approximately
two to four times higher than wide, with small,
strongly convex, somewhat conical auricular scales
lining anterior margin. Mental pentagonal, one to
1.5 times wider than high, bordered laterally by an-
terior infralabials and posteriorly by a pair of large
postmentals. Postmentals sometimes separated from
infralabials by sublabials; mental occasionally con-
tacted by one or two sublabials. Chinshields weakly
differentiated or undifferentiated. Infralabials 13 to
16, square or wider than high, inferior border con-
vex. Gulars granular, strongly convex and beadlike,
each scale separated from adjacent scales by nu-
merous asymmetrically arranged interstitial gran-
ules.

Dorsal scales in approximately 128 to 161 rows

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

midway between forelimb and hindlimb insertions.
Tail long, cylindrical in both sexes and all age groups.
Paired, median row of subcaudals may or may not
be larger than adjacent subcaudals and lateral cau-
dals. Enlarged or slightly enlarged postanal scales
present in males.

Deep postfemoral dermal mite pocket present at
hindlimb insertion. Femoral pores 16 to 20, femoral
pores do not extend beyond angle of knee, separated
medially by 19 to 25 granular scales. Subdigital la-
mellae on fourth toe 18 to 22.

Coloration in Life.— Males of this species are
characterized by a dorsal color pattern consisting of
a thick white reticulum on a dark brown field. The
reticulations differ from those of C. reticulatus in
that they are thicker, and all, or nearly all, of the
dorsal body reticulations enclose black pigments. A
few of the forelimb and hindlimb reticulations may
also enclose black pigments. As in C. reticulatus, the
reticulum is present on nearly the entire dorsal sur-
face including the body, the anterior half of the tail,
all four limbs, the lateral surface of the head, and
the superficial mandibular area. The anterior and
posterior collar markings are better developed than
those of C. reticulatus and the anterior collar is com-
plete ventrally. Black pigmentation is present in the
central gular region, as in all other adult male Cro-
taphytus except C. collar is and C. nebrius. The dor-
sal surface of the head is patternless, but it is not of
paler coloration than the remaining dorsal surfaces,
as is usually the case with C. dickersonae, C. bi-
cinctores, C. grismeri, C. vestigium, and C. insularis.
Small inguinal patches largely confined to the prox-
imal ventral surface of the thigh are present in all
adult males. The femoral pores are jet black.

The coloration of females is less vibrant than that
of males. The dorsal base color is grayish brown,
the white reticulum is not as bright, the dorsal re-
ticulum encloses dark gray pigments rather than
black, the femoral pore exudate is gray, and the
melanic inguinal patches and black pigments of the
gular fold and central gular region are absent. Fe-
males develop orange gravid coloration during the
reproductive period. The one subadult female that
I have examined in life had a bright yellow tail and
hindlimbs.

Distribution (Fig. 43). — Known to occur in the
Sierras de San Lorenzo, Texas, and Solis of extreme
southwestern Coahuila, Mexico.

Fossil Record. —None.

Natural History.— The following natural history
observations were made on 23 and 25 June 1994.
As are all Crotaphytus except C. reticulatus, C. an-

Fig. 43. — Geographic distribution of Crotaphytus antiquus. The
asterisk indicates the location of the Sierras de San Lorenzo,
Texas, and Solis in southwestern Coahuila, Mexico.

tiquus is strongly saxicolous and usually is observed
basking on large limestone rocks and outcrops. When
alarmed, they generally take refuge beneath a nearby
rock or under the rock upon which they were perched.
The habitat at the type locality is fairly typical Chi-
huahuan Desert scrub with the dominant plant spe-
cies being Larrea divaricata, Jatropha dioica, Fou-
quieria splendens, Agave lechuguilla, Lippia grav-
eolens, Opuntia cholla, two unidentified species of
Opuntia (one resembling prickly pear, the other sim-
ilar in habitus to pencil cholla), and (possibly) Echi-
nocactus sp. Additional reptile and amphibian spe-
cies observed at the type locality include Cnemi-
dophorus inornatus, C. septemvittatus, Coleonyx
brevis, Cophosaurus texanus, Phrynosoma modes-
tum, Uta stansburiana, Scaphiopus couchii, and an
undescribed species of Sceloporus similar to *S. jar-
rovii cyanostictus. A third species of Cnemidophorus
(possibly C. marmoratus ) is also present.

Crotaphytus antiquus are abundant and I ob-
served more than 25 individuals in an area of about
1.5 km in length and roughly 200 m in width. This
species usually runs quadrupedally, but was ob-
served to use bipedal locomotion on occasion. They

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

are able to take off bipedally from a standing start,
as are all other Crotaphytus species. This species
appears to be territorial, which is the case for all
other Crotaphytus that have been studied (Fitch,
1956; Moehn, 1976; Montanucci, 1971; Sanborn
and Loomis, 1979; Yedlin and Ferguson, 1973; plus
numerous additional references). On 25 June 1994,

I witnessed apparent territorial behavior when an
adult male chased another adult male over approx-
imately 10 m after the first male ventured into the
area occupied by the second male. During the in-
teraction, the pursuing male appeared to have its
gular pouch fully depressed, a behavior that appears
to be associated with aggression in all Crotaphytus
species (Fitch, 1956; Sanborn and Loomis, 1979;
personal observation).

Very little is known about the reproductive be-
havior of this species. However, since all but one of
the females observed displayed orange gravid col-
oration in various stages of intensity, it is clear that
the reproductive cycle includes late June. One of the
females bearing gravid coloration appeared emaci-
ated, as if she had just oviposited. No juveniles were
observed, suggesting that the year’s early clutches
had not yet hatched. Some individuals (TNHC
53154, 53159) contained yolked ovarian follicles
together with corpora lutea and distended, vascu-
larized oviducts, suggesting that this species can pro-
duce at least two clutches in a single reproductive
season. One large female (SVL = 89 mm) contained
four shelled eggs, another (SVL = 89 mm) contained
three shelled eggs, and four additional females con-
tained between one and four yolked ovarian folli-
cles, suggesting that the species has a relatively small
clutch size.

The only observation made regarding feeding
habits is that one adult male that was prepared as
a skeleton contained the remains of an unidentified
coleopteran insect.

Illustrations. — Black-and-white photographs of
males and females were provided by Axtell and
Webb (1995).

Crotaphytus bicinctores
Smith and Tanner
(Fig. 32A)

Crotaphytus collaris bicinctores Smith and Tanner, 1972:27; fig.

1 , 2. Type locality: “Mercury Pass, Nevada Test Site, Nye Co.,

Nevada” (holotype: BYU 23883).

Crotaphytus insularis bicinctores— Axtell, 1972:721; fig. 2,

5b-c, 6.

Crotaphytus bicinctores— Sanborn and Loomis, 1979:105.

Etymology. — From the Latin bi, two, and cinct, banded or
girdled, in reference to “the divided banding (presumably of the
collar) in the Great Basin populations” (fide Tanner, personal
communication, 1993).

Diagnosis. — Crotaphytus bicinctores can be dis-
tinguished from C. reticulatus. C. collaris, C. ne-
brius, and C. dicker sonae by the absence of black
oral melanin. It can be further distinguished from
C. reticulatus, C. collaris, and C. nebrius by the pres-
ence in adult males of a strongly laterally com-
pressed tail with a pale white dorsal caudal stripe,
enlarged dark brown or black inguinal patches that
extend between one-third and two-thirds of the dis-
tance between the hindlimb and forelimb insertions,
and a pale tan or off-white patternless region on the
dorsal surface of the head. It may be further distin-
guished from C. reticulatus as well as C. antiquus
by a dorsal body pattern of white spots and dashes
on a brown field rather than white reticulations on
a gold, tan, or brown field. It may be further distin-
guished from C. nebrius by its brown dorsal col-
oration rather than pale tan. It may be further dis-
tinguished from C. collaris by the presence of dark
brown or black pigmentation in the gular fold (=
ventrally complete anterior collar). It may be dis-
tinguished from C. grismeri, C. vestigium, and C.
insularis by the presence of broad tan or buff trans-
verse dorsal body bands. It may be further distin-
guished from C. grismeri by the absence of a green-
ish tint to the white bar that separates the collars,
by a pattern of white reticulations on a brown field
on the forelimbs and hindlimbs rather than a pattern
of yellow forelimbs with minute brown spotting on
the proximal dorsal surface of the brachium and a
hindlimb coloration that is nearly patternless yellow
with scattered minute brown spots from the distal
thigh to the distal terminus of the limb, by the ab-
sence of a pale orange tail coloration in subadult
females, and by the absence of a well-defined pale
tan dorsal caudal stripe in juveniles of both sexes.
It may be further distinguished from C. insularis
and C. vestigium by the presence of a dorsally com-
plete or narrowly separated posterior collar rather
than a posterior collar that is broadly separated dor-
sally or completely absent. It can be further distin-
guished from C. insularis by the presence of a rel-
atively broad nasal process of the premaxilla, the
absence of olive green ventrolateral coloration in
adult males, the presence of a pattern of small white
spots and dashes (occasionally transverse bands),
rather than a pattern of thicker, elongate white dash-

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

es, and the absence of extravomerine bones. It can
be further distinguished from C. vestigium by the
absence of olive green or burnt orange ventrolateral
coloration.

Variation (n = 20). — Rostral approximately four
times wider than high, usually rectangular in shape.
Rostral bordered by three to five postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by five to six intemasals. Frontonasals oc-
casionally enlarged. Canthals three; five to eight
scales separate canthals of left and right sides. Su-
praorbital semicircles present with ten to 14 scales
per semicircle, median scales do not fuse to form
azygous frontals. Supraoculars flat or convex,
smooth, becoming progressively larger medially such
that medial scales are two to four times larger than
lateral ones. Circumorbitals present, not well dif-
ferentiated from supraoculars. Superciliaries six to
15, extremely elongate medial scale occasionally
present. Palpebrals ovoid, slightly convex, inter-
spersed with numerous interstitial granules. Preo-
culars, suboculars, and postoculars form an arc of
five to 1 3 rectangular scales, second, third, or fourth
scale only rarely elongate. Supralabials 13 to 17,
usually slightly longer than high except anteriormost
scale, which is square or pentagonal. Lorilabials in
one to three rows, ovoid to rectangular, juxtaposed,
separating supralabials from suboculars and nasals.
Aperture of external auditory meatus rectangular or
ovoid, often constricted at or above the midpoint,
approximately two to four times higher than wide,
with small, strongly convex, somewhat conical au-
ricular scales lining anterior margin. Mental pen-
tagonal, one to 1.5 times wider than high, bordered
laterally by anterior infralabials and posteriorly by
a pair of large postmentals. Postmentals may or may
not be separated from infralabials by one to three
sublabials. Chinshields weakly differentiated or un-
differentiated. Infralabials 12 to 18, square or wider
than high, inferior border convex. Gulars granular,
strongly convex and beadlike, each scale separated
from adjacent scales by numerous asymmetrically
arranged interstitial granules.

Dorsal scales in approximately 144 to 200 rows
midway between forelimb and hindlimb insertions.
Tail long, cylindrical to oval in females and juve-
niles over entire length, anterior one-half strongly
compressed laterally in adult males. Paired, median
row of subcaudals larger than adjacent subcaudals

and lateral caudals. Enlarged postanal scales in males
present.

Deep postfemoral dermal mite pocket present at
hindlimb insertion. Femoral pores 1 6 to 2 1 , femoral
pores do not extend beyond angle of knee, separated
medially by 16 to 26 granular scales. Subdigital la-
mellae on fourth toe 17 to 23.

Coloration in Life.— Dorsal body coloration in
adult males is brown, with pale orange or peach-
colored body bands. The white component of the
dorsal pattern is composed of white spots and dashes
on the body, and a reticulum on the tail, hindlimbs,
and forelimbs. The reticulate pattern of the fore-
limbs may occasionally be broken into spots. Trans-
verse body bars are absent. Reticulations are always
present on the superficial mandibular and temporal
regions. A broad white or off-white caudal vertebral
stripe is present. The dorsal surface of the head is
pale-colored, and is conspicuously patternless. Ol-
ive green or burnt orange ventrolateral coloration
is lacking, although fine ventrolateral reticulations
are present. The gular coloration in adult males is
generally slate gray or gun-barrel blue, with a black
central gular component. The peripheral gular pat-
tern is the standard reticulate form. Anterior and
posterior collar markings are always present and the
posterior markings often contact middorsally. The
anterior collars are complete ventrally in adult males
as black pigments are present within the gular fold.
A pair of black nuchal spots are not present mid-
dorsally between the anterior collar markings. En-
larged melanic axillary patches immediately pos-
terior to the forelimb insertion are variably present.
Large melanic inguinal patches are always present.
The femoral pores are generally off-white to gray in
color. Paired, melanic keels are variably present on
the ventral surface of the caudal extremity.

Females are less vividly marked than males. The
dorsal coloration is grayish brown and they lack the
white dorsal caudal stripe, black pigments of the
gular fold, and melanic inguinal patches, axillary'
patches, and gular spot. Gravid females develop
vivid orange or reddish lateral bars during the gravid
period. The tail is not vividly colored in adult or
subadult females of this species.

Size. — This species exhibits strong sexual dimor-
phism with males reaching larger adult size (maxi-
mum observed SVL =111 mm) than females (max-
imum observed SVL = 98 mm).

Distribution (Fig. 44). — Occurs in xeric rocky hab-
itats in southeastern and extreme northeastern Cal-

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 44.— Geographic distribution of Crotaphytus bicinctores. The
“?” near Flagstaff denotes a questionable record for the species
at Williams, Arizona. The “?” in central Utah represents two
records from Emery County that could not be precisely located:
Nine miles W of Hanksville Highway at Nixon Uranium Mine
and the Mamie Stover Incline.

ifomia, western and northern Arizona, southeastern
Oregon, western Idaho, western and central Utah,
and much of Nevada. In Idaho, the species occurs
primarily in association with the Snake River drain-
age. Two additional localities in Idaho (approxi-
mately 24 km NNE of Atomic City, Butte County,
and Montpelier, Bear Lake County) are not indi-
cated on the Crotaphytus bicinctores distribution map
(Fig. 44) but may represent relict populations. There
is a series of three specimens in the Museum of
Vertebrate Zoology (MVZ 43415-17) listed as col-
lected at Cheney, Spokane County, Washington. This
disjunct locality should be considered questionable
until verified by additional field work.

In southwestern Arizona, the species occurs
throughout the volcanic mountain ranges north of

the Gila River, while C. nebrius occupies most of
the mountain systems south of the Gila River. How-
ever, C. bicinctores occurs south of the Gila River
near the town of Sentinel, a locality that is not oc-
cupied by C. nebrius. In at least two localities, C.
bicinctores and C. nebrius are only narrowly sepa-
rated by the Gila River. Crotaphytus bicinctores oc-
curs in the Laguna Mountains which lie on the north
side of the Gila River, while C. nebrius occurs in
the Gila Mountains on the south side of the Gila
River. Also, C. bicinctores occurs in the Gila Bend
Mountains on the west shore of the Gila River, while
C. nebrius occurs in the Buckeye Hills on the ad-
jacent east shore. I observed a subadult C. bicinc-
tores at Black Gap, Maricopa County, Arizona, a
narrow pass on the western periphery of the Sauceda
Mountains through which Arizona State Highway
85 passes. This observation was extremely surpris-
ing given that this area is apparently well isolated
from known C. bicinctores populations north of the
Gila Bend River and on the Sentinel Plain. If C.
bicinctores has an established population at this lo-
cality, it is likely that C. nebrius and C. bicinctores
contact somewhere in the Sauceda or Maricopa
mountains. Several later attempts to find C. bicinc-
tores or C. nebrius at this locality were unsuccessful.

In northern Arizona, C. bicinctores occurs within
and north of the Colorado River drainage (Grand
Canyon) and follows the Little Colorado River
drainage as well. Over much of this area, the species
occurs in close geographic proximity to C. collaris.
Two hybrid zones between these species have been
documented based on morphological and electro-
phoretic evidence (Axtell, 1972; Montanucci, 1983),
although it seems likely that additional contact zones
exist. The symbol “?” west of Flagstaff on Figure 44
represents a series of specimens (SDSNH 19474-
80) that includes both C. bicinctores and C. collaris.
It seems likely that the locality data for the C. bi-
cinctores in this series is incorrect.

In Utah, Crotaphytus bicinctores occupies most
of the desert mountain ranges west of the Wasatch
Range and also appears to occupy the arid regions
to the east of the Wasatch Range. The symbol “?”
on the C. bicinctores map (Fig. 44) represents two
localities in Emery County (9 mi W of Hanksville
Highway (Hwy 24) near the Nixon Uranium Mine
(BYU 16496) and the Mamie Stover Incline [BYU
20089-90]) that are represented by specimens, but
for which I could not find the specific localities on
topographical maps.

Fossil Record. — Pleistocene fossils collected from
Rampart Cave, Arizona (Van Devender et al., 1977),

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

Gypsum Cave, Clark County, Nevada (Brattstrom,
1954), and Smith Creek Cave, White Pine County,
Nevada (Mead et al., 1982) were identified as Cro-
taphytus collaris. All fall within the current distri-
butional range of C. bicinctores and therefore, on
distributional grounds, may be more appropriately
referred to this taxon.

Natural History. — Many anecdotal reports re-
garding the natural history of Crotaphytus bicinc-
tores have appeared, although no general treatment
of the ecology of the species has been published.
The species occurs in some of the most inhospitable
regions of North America including the rugged, vol-
canic basin and range mountains of the Sonoran,
Mojave, and Great Basin deserts. It is generally re-
stricted to rocky habitats with scant vegetation, such
as alluvia, lava flows, mountain sides, canyons, and
rocky plains, but occasionally may be found in pe-
ripheral areas with only limited rocky cover. I have
observed individuals more than a mile away from
the nearest extensive rocky habitat in association
with rolling gravely hills with only occasional rocks.
Their ability to inhabit such areas may allow this
species to disperse across the suboptimal habitats
that separate isolated desert mountain ranges, as
they are known to inhabit numerous isolated moun-
tain systems. These are diurnal lizards often seen
perched atop dark volcanic rocks at temperatures
over 37°C. When disturbed, they may take refuge
beneath a nearby stone or bound bipedally from one
rock to the next before taking refuge under a stone
or in a nearby rodent hole. Although primarily sax-
icolous, this species occasionally may ascend small
shrubs (Banta, 1967), possibly to avoid high sub-
strate temperatures or in search of food.

The diet of this species appears to consist pri-
marily of arthropods, including orthopterans, co-
leopterans, hemipterans, homopterans, hymenop-
terans, lepidopterans, and arachnids, as well as small
vertebrates (Camp, 1916; Knowlton and Thomas,
1936; Snyder, 1972; Nussbaum et al., 1983; per-
sonal observation). Uta stansburiana is probably the
most commonly consumed vertebrate species (Sny-
der, 1972; personal observation), although other re-
corded taxa include Sce/oporus, Cnemidophorus,
Phrynosoma, and Xantusia vigi/is (Banta, 1960;
Nussbaum et al., 1983). As do other crotaphytids,
C. bicinctores occasionally includes plant matter in
its diet (Banta, 1960).

Snyder (1972) found that adult Crotaphytus bi-
cinctores in northwestern Nevada may become ac-
tive as early as April 17 and large numbers may be
observed in early May. I have observed adults active

as early as March 19 in southwestern Arizona. In
southeastern California, I have observed juveniles
(probably hatched the previous season), gravid fe-
males, and adult males on May 2, indicating that
mating activities probably commenced in April. Ne-
onates have been observed in August in eastern Or-
egon (Brooking, 1934). Axtell (1972) hatched eggs
in the laboratory on September 19. Andre and
MacMahon (1980) studied the reproductive biology
of C. bicinctores in Tule Valley, Millard County,
Utah. They discovered that females reached repro-
ductive maturity at 85 mm SVL. All females sur-
veyed in the first week of June contained oviducal
eggs and by the end of June no females contained
yolked follicles or oviducal eggs. Mean clutch size
was reported as 5.38 with a range of three to seven.
Larger females were found to produce larger clutches
of eggs.

Moehn (1976) showed that exposure to sunlight
stimulates aggressive activity and despotism in cap-
tives of this species. Sanborn and Loomis (1979)
discussed male display patterns. Smith (1974) noted
that C. bicinctores may elicit a high-pitched squeal
when under duress. Snyder (1972) discussed home
range size and territoriality in populations adjacent
to Pyramid Lake, Storey County, Nevada.

Illustrations.— A detailed black-and-white illus-
tration of the entire animal was provided in Stebbins
(1954); line drawings of the head squamation were
included in Burt ( 1 928Z>:fig. 8) and Axtell (1972).
Line drawings of the dorsal and ventral color pat-
terns were given in Smith and Tanner (1 974); black-
and-white photographs were provided in Axtell
(1972), Pickwell (1972), Smith and Tanner (1972),
and Nussbaum et al. (1983); color photographs were
given by Behler and King (1979) and Sprackland
(1990, 1993).

Crotaphytus collaris Say

Agama collaris Say, 1823:252. Type locality: not given; Arkansas
Territory (now Oklahoma) near the Verdigris River implied
(holotype: Academy of Natural Sciences of Philadelphia, now
lost). Restricted type locality (Stejneger, 1890): “the Verdigris
River, near its junction with the Neosho River, Creek Nation,
Indian Territory”; (Stejneger and Barbour, 1917): “Verdigris
River near its union with the Arkansas River, Oklahoma”;
(Webb, 1970): “near Colonel Hugh Glenn’s Trading Post on
the east bank of the Verdigris River, about two miles above
its confluence with the Arkansas River”; (Axtell, 1989a): Ver-
digris River near its union with the Arkansas River, Oklahoma.
Crotaphytus collaris— Holbrook, 1842:79; pi. 10.

Leiosaurus collaris— Dumeril, 1856:532.

Crotaphytus bai/eyi Stejneger (syn. fide Cope, 1900), 1890:103;
fig. 1, 2. Type locality: “Painted Desert, Little Colorado River,
Arizona” (holotype: USNM 15821).

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NO. 32

Crotaphytes collaris baileyi -Stone and Rehn, 1903:30.
[Crotaphytes collaris collaris]- Stone and Rehn, 1903:30.
Crotaphytus collaris auriceps Fitch and Tanner (syn. fide Mon-
tanucci, Axtell, and Dessauer 1975), 1951:553. Type locality:
“3 1/2 mi. NNE Dewey, west side of the Colorado River,
Grand County, Utah” (holotype: KU 29934).

Crotaphytus ( Crotaphytus ) baileyi— Weiner and Smith, 1965:187.
Crotaphytus ( Crotaphytus ) collaris- Weiner and Smith, 1965:
174; fig. 1-6.

Crotaphytus collaris fuscus Ingram and Tanner, 1971:23; fig. 1.
Type locality; “6.5 mi. N. and 1.5 mi. W. of Chihuahua City,
Chihuahua, Mexico” (holotype: BYU 16970).

Crotaphytus collaris melanomaculatus Axtell and Webb, 1995:
6; fig. 1, 2. Type locality: “25°14T0"N-103°47'W or 3.8 km
S-l .7 km E Graseros on the highway to Presa Francisco Zarca,
el 1 250 ± m, Durango, Mexico” (holotype: UTEP 15915).

Etymology. — From the Latin collaris, in reference to the paired
black collars on the lateral and dorsal surfaces of the neck.

Diagnosis. — Crotaphytus collaris may be distin-
guished from all other species of Crotaphytus by the
absence of dark brown or black pigmentation in the
gular fold (= ventrally complete anterior collar) of
adult males. It may be further distinguished from
C. reticulatus and C. antiquus by the absence of a
reticulate dorsal pattern in adults of both sexes and
from C. reticulatus by the absence of jet black fem-
oral pores in males. It may be further distinguished
from C. dickersonae, C. grismeri, C. bicinctores, C.
vestigium, and C. insularis by the absence in adult
males of enlarged dark brown or black inguinal
patches, a laterally compressed tail, a white or pale
tan dorsal caudal stripe, and a pale tan or off-white
patternless region on the dorsal surface of the head.
It may be further distinguished from C. grismeri, C.
bicinctores, C. vestigium, and C. insularis by the
presence of black oral melanin.

Variation (n = 30). — Rostral approximately four
times wider than high, usually rectangular in shape.
Rostral bordered by four to six postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by four to six internasals. Frontonasals oc-
casionally enlarged. Canthals three; five to seven
scales separate canthals of left and right sides. Su-
praorbital semicircles present with eight to 1 3 scales
per semicircle, median scales may fuse to form azy-
gous frontals, especially in eastern part of range.
Supraoculars flat or convex, smooth, becoming pro-
gressively larger medially such that medial scales
are two to four times larger than lateral ones. Cir-
cumorbitals present, not well differentiated from su-
praoculars. Superciliaries six to 13, extremely elon-
gate medial scale occasionally present. Palpebrals
ovoid, slightly convex, interspersed with numerous

interstitial granules. Preoculars, suboculars, and
postoculars form an arc of four to ten rectangular
scales, second, third, or fourth scale not elongate.
Supralabials 11 to 17, usually slightly longer than
high except anteriormost scale, which is square or
pentagonal. Lorilabials in one to four rows, ovoid
to rectangular, juxtaposed, separating supralabials
from suboculars and nasals. Aperture of external
auditory meatus rectangular or ovoid, often con-
stricted at or above the midpoint, approximately
two to four times higher than wide, with small,
strongly convex, somewhat conical auricular scales
lining anterior margin. Mental pentagonal, one to
1.5 times wider than high, bordered laterally by an-
terior infralabials and posteriorly by a pair of large
postmentals. Postmentals usually not separated from
infralabials by sublabials; mental occasionally con-
tacted by one or two sublabials. Chinshields weakly
differentiated or undifferentiated. Infralabials 1 1 to
15, square or wider than high, inferior border con-
vex. Gulars granular, strongly convex and beadlike,
each scale separated from adjacent scales by nu-
merous asymmetrically arranged interstitial gran-
ules.

Dorsal scales in approximately 136 to 186 rows
midway between forelimb and hindlimb insertions.
Tail long, cylindrical in both sexes and all age groups.
Paired, median row of subcaudals larger than ad-
jacent subcaudals and lateral caudals. Enlarged post-
anal scales present in males.

Deep postfemoral dermal mite pocket usually
present at hindlimb insertion. Femoral pores 15 to
24, femoral pores do not extend beyond angle of
knee, separated medially by 1 4 to 24 granular scales.
Subdigital lamellae on fourth toe 15 to 22.

Coloration in Life.— The color pattern of Crota-
phytus collaris is extremely variable and it is prob-
ably not possible to give a complete description of
the various color phases that characterize different
populations of this wide-ranging species, especially
given that the often vibrant coloration displayed by
these lizards is quickly lost in preservative. For this
reason, the following description of coloration in C.
collaris is limited in some respects to those color
morphs that I have examined firsthand.

Dorsal body coloration of adult males is extreme-
ly variable with some populations characterized by
a green dorsal coloration, others by a turquoise to
pale green body with a yellow head and feet, others
by a pale or dark brown coloration, and still others
by a gray or combination of gray and olive green.
In those populations characterized by a yellow head,
the intensity of the yellow pigments may range from

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

pale to fluorescent. The white component of the
dorsal pattern is retained well in preservative and
is easily characterized as nearly all populations have
white spots on the body with spots or reticulations
present on the tail and hindlimbs. Some populations
from Coahuila, Durango, Nuevo Leon, San Luis
Potosi, and Zacatecas may have a dorsal pattern
consisting at least in part of black spots that may or
may not be surrounded by white, a pattern that is
reminiscent of that of C. antiquus and C. reticulatus
and potentially the result of introgression from the
latter species (Montanucci, 1 974). The forelimbs are
generally patternless or only obscurely patterned,
but may occasionally bear pale reticulations or spots.
Transverse body bars are absent. Reticulations gen-
erally are confined to the superficial mandibular and
temporal regions, as well as the hindlimbs and tail.
A broad white or off-white caudal vertebral stripe
is lacking. The dorsal surface of the head is not pale-
colored, and generally is covered with spots that
range in color from rust to chocolate brown. Olive
green or orange ventrolateral coloration is lacking.
Most of the variation in gular pattern coloration
observed within Crotaphytus is restricted to C. col-
laris. The gular coloration observed in living adult
males examined over the course of this study range
between olive green, dark blue, turquoise blue, slate
gray, yellow, or orange. However, a black central
component is not found in this species. As stated
above, the peripheral gular pattern is always com-
posed of a white reticulated pattern. Anterior and
posterior collar markings are always present and the
posterior markings occasionally may contact mid-
dorsally. The anterior collars are not complete ven-
trally as black pigments are absent from the gular
fold. A pair of black spots may be present middor-
sally between the anterior collar markings. A pair
of enlarged melanic axillary patches are variably
present immediately posterior to the forelimb in-
sertion, although they are restricted to populations
from the western portion of the species’ range (Ar-
izona). Small melanic inguinal patches are also vari-
ably present in adult males from this portion of the
range. The femoral pores are generally off-white to
gray in color. Paired, melanic keels may or may not
be present on the ventral surface of the caudal ex-
tremity.

Female Crotaphytus collaris are much less con-
spicuously marked than males, particularly in those
populations characterized by green dorsal colora-
tion. While females may retain a green component
in their pattern, it is always of a much duller hue.
As in other Crotaphytus, the gular pattern of females

is less developed. Inguinal patches, which are vari-
ably present in adult males, are lacking in females.
Females develop vivid orange or reddish lateral bars
during the gravid period. The tail is not vividly
colored in either adult or subadult females.

Size. — This species exhibits strong sexual dimor-
phism with males reaching larger adult size (maxi-
mum observed SVL =131 mm) than females (max-
imum observed SVL = 106 mm).

Distribution (Fig. 45). — Crotaphytus collaris has
an extensive distribution in the western and south-
central United States and northern Mexico extend-
ing from northwestern Arizona, eastern Utah, and
western Colorado eastward across the southern Great
Plains into Missouri, northern Arkansas, and pos-
sibly extreme northwestern Louisiana; and south-
ward into extreme northern Sonora and northcen-
tral mainland Mexico. Numerous isolated popula-
tions occur on the eastern periphery of its range in
Missouri and Arkansas. In Texas, the eastern dis-
tributional extent of C. collaris is limited by the
Balcones Escarpment as suitable rocky habitat does
not extend east of this point. For this reason, a num-
ber of localities that lie east of the escarpment are
considered questionable (FMNH 1171 1 6— 18 — “Ce-
dar Creek, Bastrop Co.”; USNM 12762 — “Tehu-
acana, Limestone Co.,” 145 18 — “Gainesville, Cooke
Co.”; UTA 892-“ 10 mi. S Dallas, Dallas Co.”; see
Axtell [1989a] for a more complete assessment of
potentially erroneous localities for Texas speci-
mens). In Mexico, C. collaris extends as far east as
the eastern slopes of the Sierra Madre Oriental, while
C. reticulatus occupies the flatland Tamaulipan
thomscrub habitats to the immediate east. These
two species approach one another closely in the vi-
cinity of Allende, Coahuila, Mexico. In western and
northern Arizona, the distributions of C. collaris
and C. bicinctores abut one another and at least two
hybrid zones occur (see description of the distri-
bution of C. bicinctores). The questionable (“?”)
Colorado locality on the dot distribution map (Fig.
45) refers to a specimen (USNM 58603) from Ar-
chuleta County, Colorado, for which no specific lo-
cality data were given. The questionable (“?”) lo-
cality from near the border between Tamaulipas and
San Luis Potosi, Mexico, represents a locality given
for C. reticulatus (AMNH 104448 — “rte. 101, 12
mi. SW jet. with side rd. to Tula, 13 mi. NE San
Luis Potosi state line”). This locality is dubious for
C. reticulatus, but would not be unexpected for C.
collaris.

An extremely detailed dot distribution map for
C. collaris in Texas was provided by Axtell (1989a).

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 45. — Geographic distribution of Crotaphytus collaris and C. reticulatus. The “?” in southern Colorado denotes a specimen without
precise locality data from Archuleta County. The “?“s along the eastern periphery of C. collaris’ range in Texas represent dubious
localities that lie east of the Balcones Escarpment. The “?” locality from near the border between Tamaulipas and San Luis Potosi,
Mexico, represents a locality given for C. reticulatus that is dubious for this species, but would not be unexpected for C. collaris.

Dot distribution maps for the states of Colorado
(Hammerson, 1986), Kansas (Collins, 1982), Mis-
souri (Johnson, 1987), and Oklahoma (Webb, 1970)
have also been published.

Dundee and Rossman ( 1 989) questioned whether
C. collaris occurs naturally in the state of Louisiana.
Two specimens are known, one of which may have
been accidentally introduced (Frierson, 1 927), while
the other was collected by D. Leslie at Boone’s Land-
ing on the Toledo Bend Reservoir southwest of Ne-

greet, Sabine Parish (cited as a personal commu-
nication in Dundee and Rossman, 1989).

Fossil Record. —Numerous Pleistocene fossils
from several western states have been referred to
this taxon, including a number of fossils more rea-
sonably referred to other species (see C. bicinctores
and C. nebrius accounts). All of the fossils, with the
above exceptions, fall within the current distribu-
tional limits of C. collaris (Estes, 1983).

Natural History. — More has been written about

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

the natural history of this species than any other
Crotaphytus, with the major ecological study being
Fitch (1956). Numerous unpublished master’s the-
ses and Ph.D. dissertations have dealt with ecology
of C. collaris including (but not necessarily limited
to) Mosley (1963), Trauth (1974), Hipp (1977), Bon-
trager (1980), McAllister (1980), Rostker (1983),
Malaret (1985), Rand (1986), and Uzee (1990). More
specific published works have dealt with feeding
(Burt, 1928a; Blair and Blair, 1941; McAllister and
Trauth, 1982), growth (Sexton et al., 1992), endo-
parasites (McAllister, 1985), reproduction (Green-
berg, 1945; Clark, 1946; Robison and Tanner, 1962;
Cooper and Ferguson, 1972, 1973; Parker, 1973;
Ferguson, 1976; Trauth, 1978, 1979; Montanucci,
1983; Ballinger and Hipp, 1985), territoriality and
aggression (Greenberg, 1945; Yedlin and Ferguson,
1973; Fox and Baird, 1992), hibernation (Legler and
Fitch, 1957), aquatic behavior (McAllister, 1983),
and thermoregulatory behavior (Dawson and Tem-
pleton, 1963; Cothran and Hutchison, 1979) to
highlight just a small sample of the vast amount of
literature pertaining to this species.

Illustrations. —Numerous illustrations and pho-
tographs have appeared in publications and this list,
by necessity, is not intended to be complete. Pub-
lished figures include black-and-white illustrations
of the entire animal (Harlan, 1835; Holbrook, 1842;
Baird, 1859), head squamation (Baird, 1859;Stejne-
ger, 1890; Cope, 1900; Burt, 19287*; Stebbins, 1954,
Ingram and Tanner, 1971), dorsal pattern (Ingram
and Tanner, 1971; Smith and Tanner, 1974), limb
and preanal squamation (Cope, 1900), and skull,
pectoral girdle, and pelvic girdle (Weiner and Smith,
1965). Black-and-white photographs are found in
Ditmars (1920) and Van Denburgh (1922); color
plates in Ditmars (1920), Webb (1970), Stebbins
(1985), Dundee and Rossman (1989), and Conant
and Collins (1991); color photographs in Cochran
and Goin (1970), Leviton (1971), Behler and King
(1979), Collins (1982), Hammerson (1986), Garrett
and Barker (1987), Johnson (1987), and Sprackland
(1990, 1993). Color photos showing greater road-
runners ( Geococcyx californianus ) capturing and
consuming C. collaris were presented by Meinzer
(1993).

Taxonomic Remarks.— As discussed in the Ma-
terials and Methods section, all of the subspecies of
C. collaris except C. nebrius (C. c. auriceps, C. c.
baileyi, C. c.fuscus, and C. c. melanomaculatus) are
here synonymized with C. collaris because no evi-
dence has ever been presented, nor has any been
discovered here, that these taxa represent indepen-

dent lineages. For example, Ingram and Tanner
(1971) showed the intergrade zone between C. c.
auriceps and C. c. baileyi to be larger than the range
of C. c. auriceps itself. The only characters that have
been presented that are thought to separate C. c.
baileyi from C. c. collaris are the following C. c.
collaris features: supraorbital semicircles fused me-
dially to form one or more azygous frontal scales,
gular pouch yellow-orange, a shorter broader head,
and larger supraocular scales. Of these, the first two
are usually considered to be the principle diagnostic
features (Brown, 1903; Meek, 1905; Ruthven, 1907;
Strecker, 1909; Burt, 1928 7?; plus numerous other
references) and both intergrade extensively. The
condition of the supraorbital semicircles varies con-
siderably in Colorado, New Mexico, and Texas pop-
ulations (Burt, 19287?; personal observation), which
prompted Burt (19287?) to synonymize C. c. baileyi
with C. c. collaris. The yellow-orange gular pattern
of C. c. collaris occurs at least as far south as Fred-
ericksburg, Gillespie County, in southern Texas. In-
dividuals from northeastern Mexico near the south
end of Don Martin Dam and the vicinity of Allende,
Coahuila, and 3.2 km NW of Mina, Nuevo Leon,
have a gular coloration of yellow-orange surrounded
by olive green. Individuals to the south and west
(for example, 30 km SSW of Cuatrocienegas) have
the standard olive green gular coloration. Thus, it
appears that gular coloration grades smoothly from
yellow-orange to olive green in northeastern Mex-
ico. Fitch and Tanner (1951) were the last to com-
ment extensively on the taxonomic status of C. c.
collaris and C. c. baileyi. They clearly recognized
the two as pattern classes and on these grounds ac-
corded them the rank of subspecies. With respect
to C. c. fuscus, diagnostic characters were not pre-
sented in the type description, which was described
on the basis of a distinctive discriminant function
(Ingram and Tanner, 1971). Furthermore, Axtell
(1989a) suggested that C. c.fuscus, C. c. collaris,
and C. c. baileyi show three-way intergradation in
western Texas, again implying that all three are pat-
tern classes.

An additional problem with the current alpha tax-
onomy of Crotaphyt us collaris is that the paucity or
lack of adequate character support for the subspecies
makes it necessary to rely on color pattern differ-
ences as a means of identification. Thus, although
it was not mentioned in the original description,
many herpetologists tend to think of C. c. baileyi as
a green collared lizard with a yellow head and C. c.
fuscus as a brown or grayish lizard (e.g., Stebbins,
1985; Conant and Collin s, 1 9 9 1 ). U nfortunately , the

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

ranges of these subspecies, as they are currently con-
strued, are not consistent with these color pattern
concepts. Crotaphytus c. baileyi, whose recognized
range has been fragmented over the years by the
descriptions of C. c. auriceps, C. c.fuscus, and C. c.
melanomaculatus, is thought to extend from west-
ern Arizona, eastward through central New Mexico,
and southward through the panhandle of Texas into
northcentral Mexico. The currently recognized dis-
tribution of C. c. baileyi makes little sense when one
considers that individuals from the Big Bend region
(C. c. baileyi) may appear phenotypically identical
to those from the Organ Mountains of New Mexico
(C. c. fuscus). Thus, the subspecies of C. collaris do
not appear to be on separate phylogenetic trajec-
tories and do not even seem to represent useful pat-
tern classes.

Crotaphytus dickersonae Schmidt
(Fig. 3 IB, C)

Crotaphytus dickersonae Schmidt, 1922:638; fig. 2. Type locality:

Isla Tiburon, Gulf of California, Mexico (holotype: USNM

64451).

Crotaphytus collaris dickersonae— Allen, 1933:7.

Crotaphytus ( Crotaphytus ) collaris dickersonae— Weiner and

Smith, 1965:187.

Etymology. — Named in honor of Mary C. Dickerson, former
curator of herpetology at the American Museum of Natural His-
tory, who studied the insular herpetofauna of the Gulf of Cali-
fornia, Mexico.

Diagnosis. — Crotaphytus dickersonae can be dis-
tinguished from Crotaphytus bicinctores, C. gris-
meri, C. insularis, and C. vestigium by the presence
of black oral melanin, a blue or turquoise dorsal
coloration, and the absence of enlarged postanal
scales in males. It may be distinguished from C.
reticulatus, C. collaris, and C. nebrius by the pres-
ence in adult males of a strongly laterally com-
pressed tail with a white or pale stripe extending
vertebrally and enlarged dark brown or black in-
guinal patches extending between one-half and one-
third of the distance between the hindlimb and fore-
limb insertions. It may be further distinguished from
C. reticulatus and C. antiquus by the presence of a
dorsal pattern of white spots on a blue or turquoise
field rather than white reticulations on a gold, tan,
or brown field. It may be further distinguished from
C. collaris by the presence of dark brown or black
pigmentation in the gular fold (= ventrally complete
anterior collar) and the absence of enlarged postanal

scales in males. It may be further distinguished from
C. nebrius by the presence of a blue or turquoise
dorsal coloration rather than tan and the absence of
enlarged postanal scales in males.

Variation (n = 20). — Rostral approximately two
times wider than high, usually rectangular in shape.
Rostral bordered by two to four postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by four to six internasals. Frontonasals oc-
casionally enlarged. Canthals three; four to seven
scales separate canthals of left and right sides. Su-
praorbital semicircles present with 11 to 15 scales
per semicircle, median scales do not fuse to form
azygous frontals. Supraoculars flat or convex,
smooth, becoming progressively larger medially such
that medial scales are two to four times larger than
lateral ones. Circumorbitals present, not well dif-
ferentiated from supraoculars. Superciliaries eight
to 12, extremely elongate medial scale absent. Pal-
pebrals ovoid, slightly convex, interspersed with nu-
merous interstitial granules. Preoculars, suboculars,
and postoculars form an arc of six to nine rectan-
gular scales, second, third, or fourth scale not elon-
gate. Supralabials 13 to 17, usually slightly longer
than high except anteriormost scale, which is square
or pentagonal. Lorilabials in two to four rows, ovoid
to rectangular, juxtaposed, separating supralabials
from suboculars and nasals. Aperture of external
auditory meatus rectangular or ovoid, often con-
stricted at or above the midpoint, approximately
two to four times higher than wide, with small,
strongly convex, somewhat conical auricular scales
lining anterior margin. Mental pentagonal, one to
1.5 times wider than high, bordered laterally by an-
terior infralabials and posteriorly by a pair of large
postmentals. Postmentals usually separated from
infralabials by a pair of sublabials; sublabials oc-
casionally absent on one or both sides. Chinshields
weakly differentiated or undifferentiated. Infrala-
bials ten to 16, square or wider than high, inferior
border convex. Gulars granular, strongly convex and
beadlike, each scale separated from adjacent scales
by numerous asymmetrically arranged interstitial
granules.

Dorsal scales in approximately 154 to 186 rows
midway between forelimb and hindlimb insertions.
Tail long, cylindrical to oval in females and juve-
niles of both sexes over entire length, anterior one-
half strongly laterally compressed in adult males.
Paired, median row of subcaudals larger than ad-

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

jacent subcaudals and lateral caudals. Enlarged post-
anal scales absent in males.

Deep postfemoral dermal mite pocket present at
hindlimb insertion. Femoral pores 1 6 to 2 1 , femoral
pores do not extend beyond angle of knee, separated
medially by 17 to 25 granular scales. Subdigital la-
mellae on fourth toe 17 to 21.

Coloration in Life. — Dorsal body coloration in
adult males is vibrant aquamarine to cobalt blue
over the entire dorsal surface of the body except the
distal half of the tail. There is no trace of yellow as
seen in Crotaphytus collaris. The white component
of the dorsal pattern is composed of large white spots
and dashes on the body, a reticulated tail and hin-
dlimbs, and forelimbs that are generally spotted or
mottled. Transverse body bars are absent. Reticu-
lations are always present on the superficial man-
dibular and temporal regions. A broad white or off-
white caudal vertebral stripe is present. The dorsal
surface of the head is pale-colored, and is conspic-
uously patternless. Olive green or burnt orange ven-
trolateral coloration is lacking. The gular coloration
is generally slate gray with a black central gular com-
ponent. The peripheral gular pattern is the standard
reticulate form. Anterior and posterior collar mark-
ings are always present and the posterior markings
often contact middorsally. The anterior collars are
complete ventrally by way of black pigments present
within the gular fold. A pair of black nuchal spots
are not present middorsally between the anterior
collar markings. Enlarged melanic axillary patches
immediately posterior to the forelimb insertion are
lacking. Large melanic inguinal patches are always
present. The femoral pores are generally off-white
to gray in color. Paired, melanic keels are always or
nearly always present on the ventral surface of the
caudal extremity.

The coloration of females is much more subdued
than that of males. The dorsal coloration is gray or
brownish gray, rather than vivid blue, and females
lack the melanic inguinal patches, black pigments
in the gular fold, black central gular blotch, and
white dorsal caudal stripe. Gravid females develop
vivid orange or reddish lateral bars. The tail of re-
productive females is bright lemon yellow.

Size. —This species exhibits strong sexual dimor-
phism with males reaching larger adult size (maxi-
mum observed SVL =116 mm) than females (max-
imum observed SVL = 97 mm).

Distribution (Fig. 46). — Isla Tiburon in the Gulf
of California, Mexico, and the desert mountains of

the adjacent Sonoran coastline (Sierra Bacha and
Sierra Seri) between Punta Cirio (1 1 .6 km S Puerto
Libertad) and Bahia Kino, Mexico.

Fossil Record. — None.

Natural History. — No natural history data con-
cerning this species have been published to date.
Crotaphytus dickersonae apparently does not devi-
ate significantly from other saxicolous Crotaphytus
species with respect to basic aspects of its ecology
and behavior. The species is common on south and
east facing slopes with sparse vegetation and scat-
tered granitic rocks of various sizes, with lizards
generally observed basking on smaller rocks on these
slopes. In coastal Sonora, C. dickersonae were ob-
served on hillsides characterized by the following
plant species: Bursera microphylla, Encelia fannosa,
Jatropha cuneata, Pachycereus pring/ei, Stenocereus
thurberi, Lycium sp., and Harfordia macroptera. The
lizards Uta stansburiana, Cnemidophorus tigris, and
Callisaurus draconoides are common on these hill-
sides and very likely comprise a large component
of the diet of C. dickersonae, a species that appears
to prey heavily on lizards (based on gut content
observations). This species tends to occur in similar
habitats on Isla Tiburon, although juveniles ob-
served on the island were concentrated around rocky
outcroppings at the summits of the low hills rather
than on the scattered rocks along the lower slopes
of the hills. However, this observation should not
be taken to represent a general phenomenon as very
little time (two days) was actually spent on the is-
land.

Adults of both sexes were observed on 22 March
1991 in coastal Sonora and adults and juveniles
were active on Isla Tiburon on 24 March 1991.
Adult females did not bear gravid coloration, in-
dicating that mating had not yet commenced. How-
ever, an adult female observed on 14 April 1992
had striking orange gravid coloration indicating that
mating takes place early in the spring in this species.

Bright blue Crotaphytus dickersonae males stand
out boldly on the pale rocks while basking and one
might expect this species to be nervous and difficult
to approach. This is not the case, however. Indeed,
a Red-tailed Hawk ( Buteo jamaicensis) was ob-
served to pass directly over a basking adult male C.
dickersonae at a height no greater than 1 0 m without
eliciting any observable reaction from the lizard.

Illustrations- A black-and-white illustration of the
lateral and dorsal head squamation of the holotype
specimen is given in Schmidt (1922). Color pho-

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 46.— Geographic distribution of Crotaphytus dickersonae. The map depicts a small section of Sonoran coastline along the eastern
margin of the Gulf of California.

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

tographs were provided in Avila (1995) and Sprack-
land (1993).

Crotaphytus grismeri McGuire
(Fig. 32B)

Crotaphytus grismeri McGuire, 1994:439; fig. 1. Type locality:
“Canon David, a low pass that separates the contiguous Sierra
de Los Cucapas and Sierra El Mayor, approximately 2 km W
Mex. Hwy. 5 on the dirt road to the sulfur mine (turnoff at km
49 S. Mexicali), Baja California, Mexico” (holotype: CES 067-
629).

Etymology. — Named in honor of L. Lee Grismer, noted au-
thority on the herpetology of Baja California.

Diagnosis.— Crotaphytus grismeri differs from all
other Crotaphytus in the presence of a dull orange
colored tail and hind limbs in subadult females,
green pigmentation within the pale gray or white bar
that separates the anterior and posterior black col-
lars, a well-defined pale tan dorsal caudal stripe in
juveniles of both sexes, a hindlimb pattern wherein
the region between the middle of the thigh and its
distal extremity is yellow and unmarked except for
scattered minute brown spots, and in its small adult
size (maximum male SVL = 99 mm, n = 7; x =
93.3). The presence in subadult females ( n = 6, in-
cluding photographs of living individuals) of three
large, lateral black spots with bold white borders
may represent another diagnostic feature. Crota-
phytus grismeri is further distinguished from C. re-
ticulatus, C. antiquus, and C. collaris by the pres-
ence, in adult males, of large black or dark brown
inguinal patches, a strongly laterally compressed tail,
and a bold white dorsal caudal stripe. It differs from
these species and from C. dickersonae in that it lacks
(in both sexes) black pigmentation of the oral mu-
cosa and in the dark brown dorsal ground color of
adult males. It differs from the remaining Crota-
phytus (C. bicinctores, C. insu/aris, and C. vestigium )
in that the dorsal surface of the forelimb is yellow
and almost without pattern, except for a small patch
of minute brown spots near the forelimb insertion.
It differs further from C. insularis and C. vestigium
in that the posterior collar is only narrowly incom-
plete middorsally rather than broadly incomplete
and in having a dorsal pattern of subequal white
spots without transversely oriented white bars.

Variation ( n = 10). — Rostral approximately four
times wider than high, usually rectangular in shape.
Rostral bordered by three to four postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by five to six intemasals. Frontonasals oc-

casionally enlarged. Canthals three; five to seven
scales separate canthals of left and right sides. Su-
praorbital semicircles present with ten to 15 scales
per semicircle, median scales sometimes fuse to form
an azygous frontal. Supraoculars fiat or convex,
smooth, becoming progressively larger medially such
that medial scales are two to four times larger than
lateral ones. Circumorbitals present, not well dif-
ferentiated from supraoculars. Superciliaries nine to
13, elongate medial scale occasionally present. Pal-
pebrals ovoid, slightly convex, interspersed with nu-
merous interstitial granules. Preoculars, suboculars,
and postoculars form an arc of seven to 1 3 rectan-
gular scales, the second, third, or fourth scale only
rarely elongate. Supralabials 14 to 17, usually slight-
ly longer than high except anteriormost scale, which
is square or pentagonal. Lorilabials in two or three
rows, ovoid to rectangular, juxtaposed, separating
supralabials from suboculars and nasals. Aperture
of external auditory meatus rectangular or ovoid,
often constricted at or above the midpoint, approx-
imately four times higher than wide, with small,
strongly convex, somewhat conical auricular scales
lining anterior margin. Mental pentagonal, one to
1.5 times wider than high, bordered laterally by an-
terior infralabials and posteriorly by a pair of large
postmentals. Postmentals may or may not be sep-
arated from infralabials by a pair of sublabials.
Chinshields weakly differentiated or undifferentiat-
ed. Infralabials 13 to 18, square or wider than high,
inferior border convex. Gulars granular, strongly
convex and beadlike, each scale separated from ad-
jacent scales by numerous asymmetrically arranged
interstitial granules.

Dorsal scales in approximately 164 to 190 rows
midway between forelimb and hindlimb insertions.
Tail long, cylindrical to oval in females and juve-
niles over entire length, anterior one-half strongly
compressed laterally in adult males. Paired, median
row of subcaudals larger than adjacent subcaudals
and lateral caudals. Enlarged postanal scales present
in males.

Deep postfemoral dermal mite pocket present at
hindlimb insertion. Femoral pores 19 to 23, femoral
pores do not extend beyond angle of knee, separated
medially by 20 to 25 granular scales. Subdigital la-
mellae on fourth toe 18 to 20.

Coloration in Life. — Dorsal body coloration in
adult males is brown, without pale orange or peach
colored body bands. The white component of the
dorsal pattern is composed of white spots and oc-
casional dashes on the body, as well as the proximal

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

portions of the tail and hindlimbs. Transverse body
bars are absent. The forelimbs are tan with yellow
blotching above and lack the white reticulations or
spotting found on other Crotaphytus. The hindlimb
is brown with white spots proximally, grading
abruptly at about midthigh into yellow-tan with
small light brown spots. The minute brown spots
terminate proximal to the pes, which is uniform
yellow-tan. The lateral surfaces of the proximal half
of the tail are brown with white spots, the white
component gradually expands distally such that the
distal half of the tail becomes uniform pale gray. A
broad white or off-white caudal vertebral stripe is
present in adult males. The dorsal surface of the
head is pale golden tan, and is conspicuously pat-
ternless. Reticulations are always present on the su-
perficial mandibular and temporal regions. Olive
green or burnt orange ventrolateral coloration is
lacking. The gular coloration in adult males is dark
blue-gray with a black central gular component. The
peripheral gular pattern is the standard reticulate
form. Anterior and posterior collar markings are
always present. The anterior collars are complete
ventrally, with black pigments extending through
the gular fold. A pair of black nuchal spots are not
present middorsally between the anterior collar
markings. Enlarged melanic axillary patches im-
mediately posterior to the forelimb insertion are
absent. Large melanic inguinal patches are always
present in adult males. The femoral pores are gen-
erally off-white to gray in color. Paired, melanic
keels are present on the ventral surface of the caudal
extremity.

Females are less vividly marked than males. The
limbs are not as distinctly yellow as in males, the
head and gular markings are duller, the white dorsal
caudal stripe is either absent or much less devel-
oped, and the melanic inguinal patches, ventrally
complete anterior collar marking, and central gular
spot are absent. Gravid females develop vivid or-
ange or reddish lateral bars. The tail of subadult
females is burnt orange in coloration.

Size. — This species exhibits strong sexual dimor-
phism with males reaching larger adult size (maxi-
mum observed SVL = 99 mm) than females (max-
imum observed SVL = 83 mm).

Distribution (Fig. 47, 48). — Crotaphytus grismeri
is known only from the type locality and a sight
record in Canada La Palma, approximately 6 km
W of El Faro. It is presumed to be restricted to the
Sierra de Los Cucapas and the contiguous Sierra El
Mayor, an isolated granitic mountain range in ex-

treme northeastern Baja California, Mexico. This
80 km-long, 10 km-wide mountain range is isolated
from the Sierra de Juarez of the peninsular ranges
(inhabited by C. vestigium) to the west by Laguna
Salada, a 15 km-wide flood plain that occasionally
is inundated by waters from the Gulf of California.
The substrate within Laguna Salada is hardpan with
scattered aeolian sand. The rocky substratum re-
quired by the saxicolous C. grismeri is entirely ab-
sent, thus isolating this species to this mountain
range.

Fossil Record. — None

Natural History. — Crotaphytus grismeri is saxic-
olous and all lizards observed at the type locality
were basking on small- to medium-sized granitic
rocks on rock-strewn hillsides. Lizards were ob-
served at all levels on the hillsides, from the rocky
rubble at the bases of the hills to the tops of the
hillsides 100 to 200 m above (McGuire, 1994).

The activity season for the species extends at least
from early March to early November. An adult male
(98 mm SVL) was observed on 6 March 1993 and
a juvenile male was observed on 7 November 1992.
The latest date on which an adult has been observed
was 1 2 September 1 992. However, this was a gravid
female and it is certain that the activity period ex-
tends at least for a few more weeks. Several gravid
females were observed on 2 May and 16 May 1992
and this, together with the presence of a gravid fe-
male in early September, suggests that second
clutches may be produced. Several neonates ranging
in SVL between 50 and 63 mm were observed on
1 2 September along with the gravid female, which
further supports the contention that second clutches
may occur (McGuire, 1994).

Illustrations.— Color photographs of adult male,
a gravid female, and a subadult female, as well as a
black-and-white photo of the ventral pattern of adult
males appeared in McGuire (1994).

Crotaphytus insularis
Van Denburgh and Slevin
(Fig. 32D)

Crotaphytus insularis Van Denburgh and Slevin, 1921:96. Type

locality: “East coast of Angel de la Guardia Island seven miles

north of Pond Island, Gulf of California, Mexico” (holotype:

CAS 49151).

Crotaphytus ( Crotaphytus ) insularis— Weiner and Smith, 1965:

187.

Crotaphytus collaris insularis— Soule and Sloan, 1966:140.
Crotaphytus insularis insularis— Smith and Tanner, 1972:27.

Etymology. — From the Latin insula, island, and aris, pertain-
ing to. In reference to the insular distribution of this species.

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

Fig. 47.— Geographic distribution of Crotaphytus grismeri. The wavy pattern indicates the ephemeral playa Laguna Salada. The hand-
drawn hatched lines represent the borders of mountain ranges.

f a

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 48. — Geographic distribution of Crotaphytus vestigium, C. grismeri, and C. insularis.

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

Diagnosis.— Crotaphytus insularis can be distin-
guished from all other Crotaphytus by the slender
and elongate nasal process of the premaxilla and its
dorsal pattern of elongate white dashes, some of
which may form thick, wavy transverse lines. It can
be distinguished from all Crotaphytus except female
C. reticulatus and occasional C. vestigium by the
extreme reduction of the posterior collar in both
sexes such that it is nearly always absent, and when
present, it is extremely reduced. It can be distin-
guished from all but C. vestigium by the presence
of extravomerine bones. It can be distinguished from
all but some C. vestigium (those from north of Bahia
de Los Angeles, Baja California) and some C. col-
laris by the presence in adult males of olive green
ventrolateral coloration. It can be distinguished from
C. reticulatus, C. collaris, C. nebrius, and C. dick-
ersonae by the absence of black oral melanin. It can
be further distinguished from C. reticulatus, C. col-
laris, and C. nebrius by the presence in adult males
of a strongly laterally compressed tail, a white or
off-white dorsal caudal stripe, a pale tan or white
patternless region on the dorsal surface of the head,
and enlarged dark brown or black inguinal patches
(rather than the small inguinal patches of C. nebrius
and some C. collaris). It can be further distinguished
from C. collaris by the presence in adult males of
dark brown or black pigmentation in the gular fold
(= ventrally complete anterior collar). It can be fur-
ther distinguished from C. grismeri by its forelimb
and hindlimb patterns consisting of white reticu-
lations on a brown field and the absence of a greenish
tint in the white bar that separates the anterior and
posterior collars. It can be further distinguished from
C. reticulatus and from C. antiquus by the absence
of the white dorsal reticulum characteristic of these
species.

Variation ( n = 14). — Rostral approximately four
times wider than high, usually rectangular in shape.
Rostral bordered by four to six postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by five to six intemasals. Frontonasals oc-
casionally enlarged. Canthals three; six to eight scales
separate canthals of left and right sides. Supraorbital
semicircles present with ten to 14 scales per semi-
circle, median scales do not fuse to form azygous
frontals. Supraoculars flat or convex, smooth, be-
coming progressively larger medially such that me-
dial scales are two to four times larger than lateral
ones. Circumorbitals present, not well differentiated
from supraoculars. Superciliaries eight to 13, ex-

tremely elongate medial scale occasionally present.
Palpebrals ovoid, slightly convex, interspersed with
numerous interstitial granules. Preoculars, subocu-
lars, and postoculars form an arc of six to 1 1 rect-
angular scales, second, third, or fourth scale not
elongate. Supralabials 13 to 18, usually slightly lon-
ger than high except anteriormost scale, which is
square or pentagonal. Lorilabials in two to three
rows, ovoid to rectangular, juxtaposed, separating
supralabials from suboculars and nasals. Aperture
of external auditory meatus rectangular or ovoid,
often constricted at or above the midpoint, approx-
imately two to four times higher than wide, with
small, strongly convex, somewhat conical auricular
scales lining anterior margin. Mental pentagonal,
one to 1.5 times wider than high, bordered laterally
by anterior infralabials and posteriorly by a pair of
large postmentals. Postmentals usually separated
from infralabials by a pair of sublabials, occasionally
only one sublabial or no sublabials present. Chin-
shields weakly differentiated or undifferentiated. In-
fralabials 11 to 17, square or wider than high, in-
ferior border convex. Gulars granular, strongly con-
vex and beadlike, each scale separated from adjacent
scales by numerous asymmetrically arranged inter-
stitial granules.

Dorsal scales in approximately 166 to 206 rows
midway between forelimb and hindlimb insertions.
Tail long, cylindrical to oval in females and juve-
niles over entire length, anterior one-half strongly
compressed laterally in adult males. Paired, median
row of subcaudals larger than adjacent subcaudals
and lateral caudals. Enlarged postanal scales in males
present.

Deep postfemoral dermal mite pocket present at
hindlimb insertion. Femoral pores 19 to 23, femoral
pores do not extend beyond angle of knee, separated
medially by 19 to 24 granular scales. Subdigital la-
mellae on fourth toe 19 to 24.

Coloration in Life. — Dorsal body coloration in
adult males is brown. The white component of the
dorsal pattern is composed of elongate white spots
and dashes on the body, with the tail, hindlimbs,
and forelimbs reticulated. Transverse body bars are
absent. Reticulations are always present on the su-
perficial mandibular and temporal regions. A broad
white or off-white caudal vertebral stripe is present.
The dorsal surface of the head is pale-colored, and
is conspicuously patternless. Olive green ventrolat-
eral coloration is present in adult males. The gular
coloration in adult males is generally slate gray with
an olive green tinge. A black central gular compo-

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

nent is present. The peripheral gular pattern is the
standard reticulate form.

Anterior and posterior collar markings are only
variably present with both sexes usually lacking pos-
terior collar markings and females often lacking both
the posterior and anterior collar components. When
present, the posterior collar markings are reduced
and do not approach one another middorsally. The
anterior collars are complete ventrally in adult males,
with black pigments extending through the gular
fold. A pair of black nuchal spots are not present
middorsally between the anterior collar markings.
Enlarged melanic axillary patches immediately pos-
terior to the forelimb insertion are variably present.
Large melanic inguinal patches are always present
in adult males. The femoral pores are generally off-
white to gray in color. Paired, melanic keels are
absent from the ventral surface of the caudal ex-
tremity.

Females are less vividly marked than males. The
head and gular markings are less vibrantly marked
and they lack male color pattern characteristics such
as the white dorsal caudal stripe and melanic in-
guinal patches, axillary patches, central gular patch,
and ventrally complete anterior collar marking. Fe-
males develop vivid orange or reddish lateral bars
during the gravid period. The tail is not vividly
colored in adult or subadult females of this species.

Size. — This species exhibits strong sexual dimor-
phism with males reaching larger adult size (maxi-
mum observed S VL = 1 20 mm) than females (max-
imum observed SVL - 104 mm).

Distribution (Fig. 48). — Restricted to Isla Angel
de La Guarda in the Gulf of California, Mexico.

Fossil Record.— None.

Natural History. — No published accounts are
available regarding the natural history of Crotaphy-
tus insularis. However, this species does not appear
to differ markedly with respect to its behavior and
ecology from its sister taxon, C. vestigium. Adults
were observed basking on isolated volcanic rocks
and a juvenile was basking on a talus slope com-
prised of smaller white stones. Individuals are wide-
ly spaced, which may be the result of extremely xeric
conditions with very scant vegetation. Adults of both
sexes and juveniles were active on 28 and 29 June
1991 and one female was observed with gravid col-
oration.

Illustrations. — A color photograph was provided
by Sprackland (1993).

Crotaphytus nebrius

Axtell and Montanucci, new combination
(Fig. 31 A)

Crotaphytus collaris nebrius Axtell and Montanucci, 1977:1; fig.

1. Type locality: “28°30'30''N-1 1 1°02'30"W” (14 Km by road

N. Rancho Cieneguita), Sonora, Mexico” (holotype: LACM

126617).

Etymology. — From the Greek nebrias, meaning spotted, like
a fawn. Named in reference to the fawn-like dorsal pattern of
large white spots on a pale tan field.

Diagnosis. — Crotaphytus nebrius can be distin-
guished from C. dickersonae, C. grismeri, C. bi-
cinctores, C. vestigium, and C. insularis by the ab-
sence in adult males of a laterally compressed tail,
enlarged dark brown or black inguinal patches that
extend between one-third and one-half the distance
between the hindlimb and forelimb insertions, and
a pale white dorsal caudal stripe. It can be further
distinguished from C. grismeri, C. bicinctores, C.
vestigium, and C. insularis by the presence of black
oral melanin. It can be distinguished from C. reti-
culatus and C. antiquus by its dorsal color pattern
of white spots on a pale tan field, rather than white
reticulations on a pale tan or brown field and the
absence of jet black femoral pores in males. It can
be further distinguished from C. reticulatus by the
presence in adult males of small dark brown or black
inguinal patches. It can be distinguished from C.
collaris by the presence in adult males of dark brown
or black pigmentation in the gular fold (= ventrally
complete anterior collar) and by the presence of burnt
orange ventrolateral abdominal coloration in breed-
ing males.

Variation (n = 20). — Rostral approximately four
times wider than high, usually rectangular in shape.
Rostral bordered by three to six postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by four to six internasals. Frontonasals oc-
casionally enlarged. Canthals three; five to eight
scales separate canthals of left and right sides. Su-
praorbital semicircles present with ten to 1 5 scales
per semicircle, median scales do not fuse to form
azygous frontals. Supraoculars flat or convex,
smooth, becoming progressively larger medially such
that medial scales are two to four times larger than
lateral ones. Circumorbitals present, not well dif-
ferentiated from supraoculars. Superciliaries eight
to 1 3, extremely elongate medial scale occasionally
present. Palpebrals ovoid, slightly convex, inter-

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

spersed with numerous interstitial granules. Preo-
culars, suboculars, and postoculars form an arc of
five to ten rectangular scales, second, third, or fourth
scale only rarely elongate. Supralabials 11 to 17,
usually slightly longer than high except anteriormost
scale, which is square or pentagonal. Lorilabials in
one to three rows, ovoid to rectangular, juxtaposed,
separating supralabials from suboculars and nasals.
Aperture of external auditory meatus rectangular or
ovoid, often constricted at or above the midpoint,
approximately two to four times higher than wide,
with small, strongly convex, somewhat conical au-
ricular scales lining anterior margin. Mental pen-
tagonal, one to 1.5 times wider than high, bordered
laterally by anterior infralabials and posteriorly by
a pair of large postmentals. Postmentals usually not
separated from mfralabials by sublabials; mental oc-
casionally contacted by one or two sublabials. Chin-
shields weakly differentiated or undifferentiated. In-
fralabials 13 to 17, square or wider than high, in-
ferior border convex. Gulars granular, strongly con-
vex and beadlike, each scale separated from adjacent
scales by numerous asymmetrically arranged inter-
stitial granules.

Dorsal scales in approximately 142 to 188 rows
midway between forelimb and hindlimb insertions.
Tail long, cylindrical or slightly laterally compressed
(oval) in both sexes and all age groups. Paired, me-
dian row of subcaudals larger than adjacent sub-
caudals and lateral caudals. Enlarged postanal scales
present in males.

Deep postfemoral dermal mite pocket present at
hindlimb insertion. Femoral pores 1 7 to 22, femoral
pores do not extend beyond angle of knee, separated
medially by 1 7 to 24 granular scales. Subdigital la-
mellae on fourth toe 17 to 20.

Coloration in Life. — Dorsal body coloration is
generally straw yellow, although this is subject to
some intraspecific variation with some individuals
dull tan in color. Contrary to Stebbins (1985), the
anterior portion of the head may bear yellow pig-
ments similar to those present in some populations
of C. collaris. The white component of the dorsal
pattern is composed of white spots on the body that
are often roughly three times larger middorsally than
they are laterally. Spots or a broken reticulum may
be present on the tail and hindlimbs, while the fore-
limbs are generally spotted or mottled. Transverse
body bars are absent. Reticulations may be absent
entirely, confined to the superficial mandibular and
temporal regions, or present on these regions as well

as the hindlimbs below the knee. A broad white or
off-white caudal vertebral stripe is lacking. The dor-
sal surface of the head is usually pale-colored, and
is conspicuously patternless. Burnt orange ventro-
lateral coloration may be present in males, partic-
ularly those from the western portion of the species’
distribution, and may be a form of breeding col-
oration. The gular coloration in males is generally
slate gray or dark brown, but may be overlain with
a yellow tint. A black central gular component is
not present. The peripheral gular pattern is highly
variable in this species, with the Tucson Mountains
population characterized by the standard reticulated
pattern, western populations characterized by
obliquely oriented, radiating white stripes, and the
remaining eastern and southern populations char-
acterized by white spots on a sky blue background.
Anterior and posterior collar markings are always
present and the posterior markings may contact
middorsally. The anterior collars are complete ven-
trally in adult males, with black pigments extending
through the gular fold. A pair of black nuchal spots
may be present middorsally between the anterior
collar markings. A pair of enlarged melanic axillary
patches are variably present immediately posterior
to the forelimb insertion. Small melanic inguinal
patches are always present in adult males. The fem-
oral pores are generally off-white to gray in color.
Paired, melanic keels are always present on the ven-
tral surface of the caudal extremity, except in the
Tucson Mountains populations where they are lack-
ing in two of the three specimens examined.

Females are less vividly marked than males. The
dorsal coloration is often browner than that of males.
The head and gular markings are less vibrantly
marked and they lack male color pattern character-
istics such as the melanic inguinal patches, axillary
patches, and ventrally complete anterior collar
marking. Females develop vivid orange or reddish
lateral bars during the gravid period. The tail is not
vividly colored in adult or subadult females of this
species.

Size. — This species exhibits strong sexual dimor-
phism with males reaching larger adult size (maxi-
mum observed SVL =112 mm) than females (max-
imum observed SVL = 98 mm).

Distribution (Fig. 49). — Crotaphytus nebrius oc-
curs in lowland desert and arid-tropical thornscrub
mountain ranges of the Sonoran Desert where it
appears to be allopatrically distributed with respect
to all other Crotaphytus. In southwestern Arizona,

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 49. — Geographic distribution of Crotaphytus nebrius. The cross-hatched area represents the distribution of C. dickersonae.

C. nebrius occurs throughout the north-south trend-
ing mountain ranges, with specimens known from
the Gila, Mohawk, Little Ajo, Ajo, Pozo Redondo,
Puerto Blanco, Sikort Chuapo, and Estrella moun-

tains, as well as the Buckeye Hills. They are also
known from a few mountain ranges further to the
east including the Quijotoa, Silverbell, and Tucson
mountains (C. collaris occurs on the opposite side

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

of the Tucson Valley in the Santa Catalina Moun-
tains). It is very likely that they occur in the re-
maining mountain ranges south of the Gila River,
although the Baboquivari Mountains may be in-
habited by C. collaris (Axtell and Montanucci, 1977).
Crotaphytus bicinctores generally skirts the northern
border of C. nebrius’ range on the north side of the
Gila River, but crosses the river at the Sentinel Plain,
a region uninhabited by C. nebrius, as no Sonoran
mountain ranges project northward into this area.

In Sonora, Crotaphytus nebrius occurs in the
transversely oriented foothills that follow the Unit-
ed States-Mexico border along Mexican Highway 2
(the Pinacate Region). The north-south trending
ranges of southwestern Arizona project northward
from these foothills and probably provide the cor-
ridor through which C. nebrius entered these moun-
tains. They have been collected from several moun-
tain ranges to the south and east in northern Sonora
including the Sierra Cubabi, Sierra La Gloria, Sierra
El Alamo, and Sierra El Rajon. One specimen is
known from either the Sierra Cibuta or Sierra El
Pinto (AMNH 73758, 25.6 km S Nogales), a more
eastern locality in the northern foothills of the Sierra
Madre Occidental. There is a relatively large gap in
the known distribution of the species between the
Caborca region (Sierra El Rajon) and the Hermosillo
region. However, a series of specimens are known
from the foothills between Hermosillo and the
Guaymas region. Finally, the remaining specimens
have been taken from the foothills of the Sierra
Madre Occidental, in a series of north-south trend-
ing valleys separated by presumably uninhabitable
densely vegetated mountain ranges. It is likely that
C. nebrius reached these localities by way of major
river drainages entering from the south, such as the
Rio Sonora and Rio Yaqui, as suitable open habitat
appears to be restricted to these drainage systems.

Populations of Crotaphytus nebrius are only nar-
rowly separated from those of C. bicinctores at two
localities and in both cases the barrier that prevents
contact is the Gila River. Crotaphytus nebrius occurs
on the northern edge of the Gila Mountains and is
separated from a population of C. bicinctores in the
Laguna Mountains approximately 0.4 km to the
north on the opposite side of the Gila River. Sim-
ilarly, C. nebrius occurs on the western margin of
the Buckeye Hills, while C. bicinctores occurs on the
extreme eastern margin of the Gila Bend Mountains
only a few hundred meters to the west on the op-
posite shore of the Gila River. Thus, C. nebrius may
be observed on the east side of the Gillespie Bridge

and C. bicinctores can be observed moments later
on the west side.

Several questions remain regarding the distribu-
tion of C. nebrius. First, C. nebrius occurs as far
north as 1 1.7 km N Huasabas and 19.5 km N Ba-
cadehuachi in the Sierra Madre Occidental, while
C. collaris is known from as far south as the Bavispe
Region, approximately 60 km to the north. It is
unknown whether this gap is real or an artifact of
collecting. The habitat in the Huasabas and Baca-
dehuachi regions appears to be marginal and the
presence of higher elevation mountains between this
area and the Bavispe region strongly suggests that a
contact zone does not exist here. However, this re-
mains to be substantiated with additional field stud-
ies. Second, a specimen of C. bicinctores was ob-
served by the author at Black Gap, Maricopa Coun-
ty, Arizona, a narrow pass on the western periphery
of the Sauceda Mountains through which Arizona
State Highway 85 passes. This observation was ex-
tremely surprising given that this area is apparently
well isolated from known C. bicinctores populations
north of the Gila Bend River and on the Sentinel
Plain. If C. bicinctores has an established population
at this locality, it is likely that C. nebrius and C.
bicinctores contact somewhere in the Sauceda or
Maricopa mountains. Several later attempts to find
C. bicinctores or C. nebrius at this locality were un-
successful.

Fossil Record.— V an Devender and Mead (1978)
referred a maxilla and dentary from late Pleistocene
deposits in the Tucson Mountains and Wolcott Peak,
Pima County, Arizona, to Crotaphytus collaris. Van
Devender et al. (1991) referred dentary, maxillae,
and tooth crown material from late Pleistocene de-
posits in Organ Pipe Cactus National Monument to
either C. collaris or C. insularis. Because the Tucson
Mountains and Organ Pipe Cactus National Mon-
ument are currently inhabited by C. nebrius, this
material probably should be referred to C. nebrius
on distributional grounds.

Natural History. — Nothing has been published re-
garding the natural history of this species but I have
made the following observations. Crotaphytus ne-
brius occurs in a diversity of habitats, although al-
ways in association with rocks. In the northern por-
tion of its range it may be found in extremely xeric
habitats characterized by granitic outcroppings or
volcanic flows. In the southern portion of its range,
it is occurs in rocky areas often with relatively dense
arid-tropical thornscrub vegetation. In these areas,
C. nebrius may be concentrated in arroyo bottoms

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

and less vegetated stream and river valleys. In the
northwestern portion of its range, the species is often
found perched on granitic rocks that lay in sandy
washes at the bases of rocky hillsides.

No observations have been made with respect to
the feeding habits of this species although it is likely
that arthropods and small lizards make up the bulk
of the diet as in other Crotaphytus species.

The activity period for the species may extend
between March and at least late September. Adult
and subadult males were observed on 1 9 March in
the Buckeye Hills, Maricopa County, Arizona, and
juveniles were observed north of Guaymas, Sonora,
Mexico, on 27 March. Between 15 and 19 April
1992, juveniles and subadults that apparently had
just emerged from hibernation (they were still en-
crusted with dirt) were observed in the western foot-
hills of the Sierra Madre Occidental and at Quijotoa,
Pima County, Arizona. On the same day that the
Quijotoa subadults were observed, adult males were
observed just north of Ajo (Pima County) and at
Mohawk, Yuma County, Arizona. Adults are active
at least as late as 1 1 August and recently hatched
neonates have been observed as late as 19 Septem-
ber. It seems likely that adults extend their activities
at least into September and juveniles into October
or November.

Reproductive behavior appears to be typical of
the genus. On 14 June 1991 mating was observed
in the Gila Mountains, Yuma County, Arizona. The
male was observed to grasp the female by a fold of
skin of the neck during coitus. The female offered
no resistance and thus appeared to be fully receptive.
Interestingly, the female bore fully developed gravid
coloration, which is consistent with observations
made by Montanucci ( 1 965) that this coloration may
not deter copulation in Gambelia silus, at least with
females that do not display rejection behavior. It
therefore seems likely that mating takes place pri-
marily in May or June. Recently emergent neonates
have been observed on 1 1 August in the Silverbell
Mountains, Pima County, Arizona, and on 19 Sep-
tember in the Gila Mountains. Neonates collected
in the Silverbell Mountains were as small as 44 mm
SVL and the individual collected in the Gila Moun-
tains was 42 mm SVL and still retained a small
portion of the umbilicus. Thus, neonates appear to
hatch out between July and/or August and Septem-
ber, at least in the northern portion of the range.

Illustrations.— A black-and-white photograph ap-
pears in Axtell and Montanucci ( 1 977). A color pho-
tograph of a gravid female was provided in Sprack-
land (1993).

Crotaphytus oligocenicus f Holman

Crotaphytus oligocenicus Holman, 1972:1613. Type locality:
“From early Oligocene, Cypress Hills Formation, north branch
of Calf Creek, in L. S. 4, Sec. 8, twp. 8, range 22, W. 3rd mer.,
elevation 3600 ft (1 100 m)” (holotype: Saskatchewan Museum
of Natural History number 1444).

Etymology’. —Named in reference to the time period during
which these lizards lived.

Distribution. — Known only from the type locality.
Remarks. — Crotaphytus oligocenicus f is an ex-
tinct species of Oligocene age known only from six
dentaries collected at the type locality. Because of
the fragmentary nature of the type material, it can-
not be determined whether this species shares any
of the crotaphytid synapomorphies presented here.
Thus, I agree with Estes (1983) in questioning
whether this species is in fact a crotaphytid. How-
ever, given that no data were discovered in this
analysis either supporting or rejecting the placement
of this species within Crotaphytidae, no taxonomic
rearrangements are herein suggested. A black-and-
white illustration of the holotype material (a right
dentary) is given in Holman (1972).

Crotaphytus reticulatus Baird
’ (Fig. 30C)

Crotaphytus reticulatus Baird, 1858:253. Type locality: Laredo
and Ringgold Barracks, Starr County, Texas— (Smith and Tay-
lor, 1950): “Laredo”; (Cochran, 1961) “Ringgold Barracks,
Montague County, Texas”; (Montanucci, 1976): “Fort Ring-
gold Military Reservation (= Ringgold Barracks), Starr County,
Texas” (lectotype Montanucci, 1976: USNM 2692A).
Crotaphytus ( Crotaphytus ) reticulatus— Weiner and Smith, 1965:
187.

Etymology. — From the Latin reticulatus, made like a net. In
reference to the net-like dorsal and gular pattern of white retic-
ulations present in this species.

Diagnosis.— Crotaphytus reticulatus can be dis-
tinguished from all other species of Crotaphytus ex-
cept C. antiquus by the presence of an adult color
pattern consisting of white reticulations, some of
which enclose black pigmentation, and the presence
of jet black femoral pores in males. It can be dis-
tinguished from C. antiquus by the dorsal coloration
of golden tan rather than dark brown and by the
presence of black pigments in only a subset of the
dorsal body reticulations rather than in all or nearly
all of them. It can be further distinguished from C.
collaris by the presence of dark brown or black pig-
mentation in the gular fold (= ventrally complete
anterior collar) in adult males. It can be further dis-
tinguished from C. antiquus, C. nebrius, C. dicker-
sonae, C. grismeri, C. bicinctores, C. insularis, and

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

C. vestigium by the absence in adult males of small
or large dark brown or black inguinal patches. It
may be further distinguished from C. dickersonae,
C. grismeri, C. bid net ores, C. insular is, and C. ves-
tigium by the absence in adult males of a strongly
laterally compressed tail, a white or off-white dorsal
caudal stripe, and a pale tan or white patternless
region on the dorsal surface of the head. It may be
further distinguished from C. grismeri, C. bicinc-
tores, C. insularis, and C. vestigium by the presence
of black oral melanin.

Variation (n — 17). — Rostral approximately four
times wider than high, usually rectangular in shape.
Rostral bordered by three to six postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by five to seven internasals. Frontonasals oc-
casionally enlarged. Canthals three; five to eight
scales separate canthals of left and right sides. Su-
praorbital semicircles present with ten to 1 5 scales
per semicircle, median scales do not fuse to form
azygous frontals. Supraoculars flat or convex,
smooth, becoming progressively larger medially such
that medial scales are two to four times larger than
lateral ones. Circumorbitals present, not well dif-
ferentiated from supraoculars. Superciliaries seven
to 13, extremely elongate medial scale occasionally
present. Palpebrals ovoid, slightly convex, inter-
spersed with numerous interstitial granules. Preo-
culars, suboculars, and postoculars form an arc of
seven to 1 2 rectangular scales, second, third, or fourth
scale not elongate. Supralabials 11 to 15, usually
slightly longer than high except anteriormost scale,
which is square or pentagonal. Lorilabials in two to
three rows, ovoid to rectangular, juxtaposed, sepa-
rating supralabials from suboculars and nasals. Ap-
erture of external auditory meatus rectangular or
ovoid, often constricted at or above the midpoint,
approximately two to four times higher than wide,
with small, strongly convex, somewhat conical au-
ricular scales lining anterior margin. Mental pen-
tagonal, one to 1.5 times wider than high, bordered
laterally by anterior infralabials and posteriorly by
a pair of large postmentals. Postmentals may or may
not be separated from infralabials by one or two
sublabials. Chinshields weakly differentiated or un-
differentiated. Infralabials ten to 1 5, square or wider
than high, inferior border convex. Gulars granular,
strongly convex and beadlike, each scale separated
from adjacent scales by numerous asymmetrically
arranged interstitial granules.

Dorsal scales in approximately 156 to 192 rows
midway between forelimb and hindlimb insertions.

Tail long, cylindrical to oval, sometimes more
strongly laterally compressed in adult males. Paired,
median row of subcaudals larger than adjacent sub-
caudals and lateral caudals. Enlarged postanal scales
absent in males.

Deep postfemoral dermal mite pocket absent.
Femoral pores 1 5 to 18, femoral pores do not extend
beyond angle of knee, separated medially by 14 to
20 granular scales. Subdigital lamellae on fourth toe
18 to 22.

Coloration in Life. — Dorsal body coloration in
adult males and females is golden tan. The white
component of the dorsal pattern is composed of a
white reticulum found over nearly the entire dorsal
surface of the animal, including the body, the tail,
all four limbs, and the superficial mandibular and
temporal regions. Many of the white reticulations
of the body (and occasionally the limbs) enclose
black pigments and these black-filled hexagons are
present in seven or eight transversely arranged rows.
Transverse body bars are absent. A broad white or
off-white caudal vertebral stripe is not present in
adult males. The dorsal surface of the head is not
pale colored, and may bear a mottled pattern. Olive
green or burnt orange ventrolateral coloration is
lacking. The gular coloration in adult males is gen-
erally slate gray or olive green and may be heavily
tinged with yellow when the male breeding colora-
tion is present. A black central gular component is
present in males. Anterior and posterior collar
markings are usually present in males, while only
the posterior collar markings (in the form of a trans-
verse series of black-filled reticulations) are often
present in females. In both sexes, the collar markings
appear to be more rudimentary than those of other
Crotaphytus and appear to represent modified rows
of transversely arranged black-filled hexagons from
which black pigments have escaped and run togeth-
er. When present, the posterior markings do not
contact middorsally. The anterior collar markings
are complete ventrally in adult males, with black
pigments extending through the gular fold. A pair
of black nuchal spots are generally present middor-
sally between the anterior collar markings. Enlarged
melanic axillary patches immediately posterior to
the forelimb insertion are lacking. Large melanic
inguinal patches are never present in adult males.
The femoral pore exudate of males is jet black.
Paired, melanic keels are absent from the ventral
surface of the caudal extremity. Females develop
vivid orange or reddish lateral bars during the gravid
period. The tail is not vividly colored in adult or
subadult females of this species.

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Size. — This species exhibits sexual dimorphism
with males reaching larger adult size (maximum ob-
served SVL = 122 mm) than females (maximum
observed SVL =118 mm). Montanucci (1971) in-
dicated that Crotaphytus reticulatus reaches a SVL
of 137 mm, a much larger size than was observed
in any of the material examined for this study.

Distribution (Fig. 45). — Crotaphytus reticulatus
occurs in the Tamaulipan Biotic Province of the
lower Rio Grande valley of southern Texas and ad-
jacent Mexico (Montanucci, 1971, 1976). Montan-
ucci (1971) provided a dot distribution map for the
species as well as a verbal description of its distri-
butional limits. Axtell (1989Z?) provided a detailed
dot distribution map for the species within the con-
fines of Texas. Montanucci (1971) stated that the
western limit of the species occurred at Muzquiz,
Coahuila, Mexico, which would suggest that the dis-
tributions of C. reticulatus and C. collaris overlap
over an extensive area. However, Axtell (198 1) found
that the locality data associated with the Muzquiz
specimen were erroneous. The questionable (“?”)
locality shown in Figure 45 from near the border
between Tamaulipas and San Luis Potosi, Mexico,
represents a locality given for C. reticulatus (AMNH
104448 — “rte. 101, 12 mi. SW jet. with side rd. to
Tula, 13 mi. NE San Luis Potosi state line”)- This
locality is dubious for C. reticulatus, but would not
be unexpected for C. collaris.

Fossil Record. — None.

Natural History. — Before Montanucci’s (1971)
study, very little was known about the natural his-
tory of this species and his publication stands as the
major contribution to this topic. Crotaphytus reti-
culatus differs in many respects from other Crota-
phytus, particularly in that it is much less reliant on
rocky habitats. Indeed, while this species will utilize
rocky habitats within its range, it is often found on
mesquite flats far from the nearest rocky habitat.
Montanucci (1971) noted that it is not found on
rocky outcroppings along the margins of bluffs (hab-
itat that one would expect other species of Crota-
phytus to inhabit), but that these outcroppings were
occupied by Sceloporus cyanogenys. Montanucci
(1971) refers to the preferred habitat of this species
as thombrush desert characterized by the following
plant taxa: mesquite ( Prosopis glandulosa ), several
species of Acacia, Mimosa, paloverde ( Cercidium
macrum), white brush ( Aloysia lycioides ), cenizo
( Leucophyllum frutescens), and prickly pear (Opun-
tia lindheimeri). Like other Crotaphytus, this species
prefers to bask above the surrounding substrate and

this is accomplished in rockless areas by perching
on fence posts (personal observation) or in the
branches of mesquite trees (Montanucci, personal
communication).

The natural history of Crotaphytus reticulatus
bears a number of similarities to that of Gambelia.
The utilization of flatland habitats with or without
the presence of rocks is one notable similarity. An-
other is associated with their escape behavior. When
alarmed, they often will run to the base of a nearby
bush where they flatten themselves to the ground
and remain motionless (Montanucci, 1971; personal
observation), a behavior that often is observed in
G. silus (Montanucci, 1965), G. wislizenii, and G.
copei. As in the latter three species, C. reticulatus
often will allow one to approach within one or two
meters without attempting escape.

The diet of Crotaphytus reticulatus is similar to
that of other Crotaphytus with arthropods (primar-
ily orthopterans and coleopterans) making up the
bulk of the diet, but with lizards ( Cnemidophorus
gularis, Eumeces), snakes ( Salvadora grahamiae ),
and rodents ( Peromyscus ?) occasionally taken (Klein,
1951; Montanucci, 1971). As has been observed in
a number of other Crotaphytus and Gambelia spe-
cies, plant matter (in particular Lycium berries) may
be consumed.

Montanucci (1971) discussed several additional
aspects of Crotaphytus reticulatus biology including
territoriality, reproduction, diel activity, seasonal
activity, hatching and growth, predators, parasites,
and injury.

Illustrations.— Line drawings of Crotaphytus re-
ticulatus were given in Cope (1900) and Burt (1935).
Black-and-white photographs were presented in
Smith (1946) and Montanucci (1971, 1974). Color
illustrations appear in Conant (1975) and Conant
and Collins (1991). Color photographs are found in
Behler and King (1979), Garrett and Barker (1987),
and Sprackland (1993).

Crotaphytus vestigium Smith and Tanner
(Fig. 32C)

Crotaphytus fasciatus Mocquard, 1899:303; pi. 13, fig. 1. Type
locality: “Cerro de las Palmas,” Baja California, Mexico (type:
none designated).

Crotaphytus fasciolatus— Mocquard (substitute name for Cro-
taphytus fasciatus Mocquard, 1899), 1903:209.

Crotaphytus insularis vestigium Smith and Tanner, 1972:29; fig.
1, 2. Type locality: “Guadelupe Canyon, Juarez Mountains,
Baja California” (holotype: BYU 23338).

Crotaphytus vestigium— Collins, 1991:43.

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

Etymology’. — From the Latin vestigium, a footprint, a track, a
trace. In reference to the reduced collars of this species (Tanner,
personal communication, 1993).

Diagnosis. — Crotaphytus vestigium can be distin-
guished from all other Crotaphytus except C. insu-
laris and C. reticulatus by the presence of widely
separated posterior collars. It can be distinguished
from all other species of Crotaphytus by the presence
of slender, white transverse dorsal body bars. It can
be further distinguished from C. reticulatus, C. col-
laris, C. nebrius, and C. dickersonae by the absence
of black oral melanin. It can be further distinguished
from C. reticulatus, C. collaris, and C. nebrius by
the presence in adult males of a strongly laterally
compressed tail, a white or off-white dorsal caudal
stripe, a pale tan or white patternless region on the
dorsal surface of the head, and enlarged dark brown
or black inguinal patches (rather than the small in-
guinal patches of C. nebrius and some C. collaris ).
It can be distinguished from C. antiquus and further
distinguished from C. reticulatus in the absence of
a dorsal pattern composed of a white reticulum with
some or all of the reticulations enclosing black pig-
mentation. It can be further distinguished from C.
grismeri by the absence of a greenish tint to the white
bar that separates the anterior and posterior collars,
by the hindlimb pattern consisting of white reticu-
lations or spots on a brown field (field occasionally
yellowish distal to the knee), by the presence of olive
green or burnt orange ventrolateral coloration, and
by its much larger maximum adult SVL. It can be
distinguished from C. insularis by its broader nasal
process of the premaxilla and its more strongly de-
veloped posterior collar.

Variation (n — 28). — Rostral approximately four
times wider than high, usually rectangular in shape.
Rostral bordered by two to five postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by three to five intemasals. Frontonasals oc-
casionally enlarged. Canthals three; five to seven
scales separate canthals of left and right sides. Su-
praorbital semicircles present, median scales rarely
fuse to form an azygous frontal. Supraoculars flat or
convex, smooth, becoming progressively larger me-
dially such that medial scales are two to four times
larger than lateral ones. Circumorbitals present, not
well differentiated from supraoculars. Superciliaries
nine to 12, extremely elongate medial scale occa-
sionally present. Palpebrals ovoid, slightly convex,
interspersed with numerous interstitial granules.

Preoculars, suboculars, and postoculars form an arc
of six to 1 1 rectangular scales, second, third, or fourth
scale not elongate. Supralabials ten to 18, usually
slightly longer than high except anteriormost scale,
which is square or pentagonal. Lorilabials in two to
three rows, ovoid to rectangular, juxtaposed, sepa-
rating supralabials from suboculars and nasals. Ap-
erture of external auditory meatus rectangular or
ovoid, often constricted at or above the midpoint,
approximately two to four times higher than wide,
with small, strongly convex, somewhat conical au-
ricular scales lining anterior margin. Mental pen-
tagonal, one to 1.5 times wider than high, bordered
laterally by anterior mfralabials and posteriorly by
a pair of large postmentals. Postmentals may or may
not be separated from mfralabials by one or two
sublabials. Chinshields weakly differentiated or un-
differentiated. Infralabials 1 1 to 17, square or wider
than high, inferior border convex. Gulars granular,
strongly convex and beadlike, each scale separated
from adjacent scales by numerous asymmetrically
arranged interstitial granules.

Dorsal scales in approximately 156 to 212 rows
midway between forelimb and hindlimb insertions.
Tail long, cylindrical to oval in females and juve-
niles over entire length, anterior one-half strongly
compressed laterally in adult males. Paired, median
row of subcaudals larger than adjacent subcaudals
and lateral caudals. Enlarged postanal scales in males
present.

Deep postfemoral dermal mite pocket present at
hindlimb insertion. Femoral pores 1 5 to 25, femoral
pores do not extend beyond angle of knee, separated
medially by 1 7 to 24 granular scales. Subdigital la-
mellae on fourth toe 15 to 25.

Coloration in Life. — Dorsal body coloration in
adult males is brown. The white component of the
dorsal pattern is composed of white spots and dashes
on the body, a reticulated tail and hindlimbs, and
forelimbs that are either reticulated, spotted, or
nearly patternless. Slender, transverse body bars are
present in both sexes. Reticulations are always pres-
ent on the superficial mandibular and temporal
regions. A broad white or off-white caudal vertebral
stripe is present. The dorsal surface of the head is
pale-colored, and is conspicuously patternless. Ei-
ther olive green or golden orange ventrolateral col-
oration is present in adult males, with the former
color present in individuals north of Bahia de San
Luis Gonzaga, Baja California, Mexico, and the lat-
ter color present in individuals from Bahia de Los
Angeles southward. The ventrolateral coloration of

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

individuals occurring between Bahia de San Luis
Gonzaga and Bahia de Los Angeles is not known.
The gular coloration in adult males is generally slate
gray or gun-barrel blue, with a black central gular
component. The peripheral gular pattern is the stan-
dard reticulate form. Anterior collar markings are
always present and posterior collar marks are only
rarely lacking. The posterior markings are widely
separated middorsally. The anterior collar markings
are complete ventrally in adult males, with black
pigments extending through the gular fold. A pair
of black nuchal spots are not present middorsally
between the anterior collar markings. Enlarged me-
lanic axillary patches immediately posterior to the
forelimb insertion are variably present. Large me-
lanic inguinal patches are always present. The fem-
oral pores are generally off-white to gray in color.
Paired, melanic keels are always present on the ven-
tral surface of the caudal extremity.

Females are less vividly marked than males. The
dorsal coloration is usually gray or greenish gray.
The head and gular markings are less developed and
male color pattern characteristics such as the white
dorsal caudal stripe, ventrally complete anterior col-
lar markings, and melanic inguinal patches, axillary
patches, and central gular spot are lacking. Gravid
females develop vivid orange or reddish lateral bars.
The tail is not brightly colored in adult or subadult
females of this species.

Size. — This species exhibits strong sexual dimor-
phism with males reaching larger adult size (maxi-
mum observed SVL = 125 mm) than females (max-
imum observed SVL = 98 mm).

Distribution (Fig. 48 ). — Crotaphytus vestigium in-
habits the peninsular ranges and adjacent rocky hab-
itats from the northern slope of the San Jacinto
Mountains in southern California to the southern
margin of the volcanic Magdalena Plain in Baja Cal-
ifornia Sur. In southern California and northern Baja
California, C. vestigium is limited to the eastern face
of the peninsular ranges. There is a gap in the pen-
insular ranges between the southern edge of the Si-
erra San Pedro Martir and the northern edge of the
Sierra La Asamblea and C. vestigium occurs on ei-
ther side of the peninsular ranges from this point
southward. Furthermore, its range extends north-
ward along the western side of the peninsular ranges
from this gap to a point at least as far north as the
vicinity of Rancho San Jose (Meling’s Ranch) and
even approaches the Pacific Coast at Mesa San Car-
los (Bostic, 1971). The known southern distribu-

tional limit of C. vestigium is 27.7 km (by road) S
of San Jose de Comondu (McGuire, 1991). It is
likely that the actual distributional limit is bounded
by the volcanic mesas that terminate near this lo-
cality. Crotaphytus vestigium apparently does not
inhabit the isolated Sierra Santa Clara and Sierra
Vizcaino on the Vizcaino Peninsula (Grismer et al.,
1994).

Fossil Record. — None.

Natural History. — Ye ry little has been written re-
garding the natural history of Crotaphytus vestigium.
Sanborn and Loomis (1979) discussed the display
patterns for this species and noted that it inhabits
rocky outcroppings on the more rugged portions of
the alluvial fans and mountain slopes at their San
Jacinto Mountains study site. Common plant spe-
cies at this locality included Larrea tridentata, En-
celia farinosa, and Ambrosia dumosa. Welsh (1988)
collected two individuals, one of which was found
on a rocky volcanic slope in central desert scrub and
the other on a granitic outcrop in coastal sage scrub.
Bostic (197 1) observed two individuals on Mesa San
Carlos, a table-topped mountain overlooking the
Pacific coast of Baja California approximately 350
km south of the United States-Mexico border. One
of these individuals was foraging among large ba-
saltic rocks along the edge of the mesa while the
other was seen basking on a large basaltic outcrop-
ping on top of the mesa proper.

Crotaphytus vestigium is a denizen of desert hill-
sides, alluvial fans, canyons, and lava flows, always
in association with rocks. They occur in some of the
most xeric habitats of North America such as the
eastern bases of the Sierra de Juarez and Sierra San
Pedro Martir where they may be observed basking
during the heat of the day. The rocky habitats in
which they occur generally are characterized by scant
vegetation. Common plant taxa with which C. ve’.s-
tigium is often associated include Fouquieria splen-
dens, F. digueti, Opuntia, Larrea tridentata, Pachy-
cormus discolor, Bursera, Ferocactus, Pachycereus
pringlei, Prosopis, and numerous additional xero-
philic species. When alarmed, this species can move
with great speed over complex rocky terrain by
bounding bipedally from one stone to the next, often
taking refuge beneath a larger rock.

The activity season for adult Crotaphytus vestig-
ium probably commences in March. Adults have
been observed as early as 1 April 1992 at the foot
of the Sierra La Asamblea, Baja California, and adult
males, gravid females, and subadults have been

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

found as early as 1 1 April 1992 on the lava flows
just south of Puertocitos, Baja California. A sub-
adult male observed in this area also had conspic-
uous orange bars similar to those of gravid females.
On 9 April 1993 adults of both sexes as well as
juveniles were observed at San Ignacio, Baja Cali-
fornia Sur. At this time, large males already bore
intense breeding coloration, while a large adult fe-
male appeared to have recently emerged from hi-
bernation as dried mud was still adhering to the
flanks and limbs.

Little is known about the predators of Crotaphy-
tus vestigium, although it is likely that coachwhip
snakes ( Masticophis flagellum ), raptors. Loggerhead
Shrikes ( Lanius ludovicianus), and Greater Road-
runners ( Geococcyx californianus), all of which are
common throughout the range of C. vestigium,
probably prey on this species. An American Kestrel
( Falco sparverius ) was observed near Rosarito, Baja
California, with a limp C. vestigium in its talons
and, thus, represents at least one known predator
on the species.

Illustrations. — Black-and-white photographs were
presented in Smith and T anner (1972), Axtell (1972),
and Jones (1993). A black-and-white illustration was
given in Mocquard (1899). Color photographs were
provided by Sprackland (1990, 1993) and McGuire
(1994).

Taxonomic Remarks. — In 1899, Mocquard de-
scribed Crotaphytus fasciatus from Cerro Las Pal-
mas, Baja California. It is clear from his description,
and from the accompanying figure, that this is a
juvenile Crotaphytus vestigium, and, as the name
fasciatus predates that of vestigium by 73 years, the
former name has priority. However, at the time of
Mocquard’s description, the name fasciatus was al-
ready in use as Hallowell (1852) had applied this
name to a specimen of G. wislizenii from the sand
hills at the lower end of Jornada del Muerte, New
Mexico. Apparently realizing his error, Mocquard
(1903) provided a substitute name for the Baja Cal-
ifornia species, giving it the name C.fasciolatus, but
by the time Mocquard had corrected his mistake,
C. fasciatus Hallowell had already been synony-
mized with C. wislizenii by Cope ( 1 900). Thus, C.
fasciatus Mocquard again became the senior syn-
onym for the Baja California species of collared liz-
ard. The name C. fasciatus has not since been ap-
plied to the Baja California population of Crota-
phytus (sensu stricto), largely because later workers
thought that Mocquard had described another syn-

onym of C. wislizenii. Thus, Van Denburgh (1922)
erroneously synonymized C. fasciatus Mocquard and
C. fasciolatus Mocquard with C. wislizenii. Only
Schmidt (1922) and Burt (19286) recognized that
Mocquard’s specimen was indeed a Crotaphytus
(sensu stricto). Over the following 50 years, the name
C. collaris continued to be applied to this population
and by the time it was recognized that the Baja
California population is a distinct form, the name
fasciatus Mocquard had long since been forgotten.
Because the name fasciatus has not been used for
more than 50 years and because the name vestigium
has become firmly entrenched in the herpetological
literature, an appeal should be made to the Inter-
national Code of Zoological Nomenclature to use
its plenary power to suppress the name C. fasciatus
in order to maintain taxonomic stability.

Gambelia Baird

Crotaphytus— Baird and Girard, 1852:69.

Leiosaurus, part— Dumeril, 1856:533.

Crotaphytus (Gambelia)— Baird, 1858:253. Type species (by

monotypy): Crotaphytus wislizenii Baird and Girard, 1852a.
Gambelia— Smith, 1946:158.

Definition. — Gambelia is defined as a node-based
name for the clade stemming from the most recent
common ancestor of Gambelia wislizenii and all
species that are more closely related to that species
than to Crotaphytus.

Etymology. —Named in honor of William Gambel, ornithol-
ogist and pioneer naturalist of western North America in the
mid- 1800s.

Coloration in Life.— There is much variation in
the color pattern of Gambelia, although much of
this is geographic variation within the wide-ranging
species G. wislizenii. Nevertheless, several compo-
nents of the color pattern are found in all Gambelia,
at least during some portion of ontogeny. For ex-
ample, the color patterns of neonates are very sim-
ilar in all three extant species. They are character-
ized by a series of transversely arranged, blood-red
dorsal spots that begin on the head and continue
onto the base of the tail. Each row of enlarged spots
is generally comprised of four spots. Enlarged blood-
red spots may extend onto the hindlimbs as well.
Each transverse series of enlarged spots is separated
by a pale or cream-colored transverse bar. The spots
and bars continue onto the tail where the spots pro-
gressively coalesce distally, forming dark bars. The
dark bars alternate with the pale bars giving the tail
a banded appearance, a pattern that remains

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

throughout ontogeny. Early in ontogeny, the blood-
red color of the dorsal spotting begins to fade to a
brown hue that is maintained into adulthood.

Another component of the juvenile pattern that
is consistent among extant Gambelia are the
obliquely oriented, radiating melanic bars present
on the head. These have a visually disruptive effect
and may play a role in camouflage (McCoy, 1967).
These head markings are lost early in ontogeny.

The gular pattern of Gambelia is relatively con-
sistent, with longitudinally arranged black streaks
present in both sexes throughout ontogeny. Gam-
belia silus differs slightly from G. copei and G. wis-
lizenii in that the streaks are usually fragmented
leaving spots or rhombs.

Most Gambelia are characterized by the presence
of brown dorsal spots that correspond to the blood-
red dorsal spots of juveniles. The spots vary in size,
density, and position within various populations and
species. The spots may be fragmented or may be
surrounded by ornamentation in the form of minute
white spots. Many Gambelia also retain the juvenile
crossbanding into adulthood and these crossbands
are in many cases offset paravertebrally.

The dorsal base color of Gambelia is generally a
pale shade of white, cream, or gray but may be dark
brown. The ventral coloration is generally white,
off-white, or a pale shade of gray or yellow.

All Gambelia lack sexual dichromatism, except
in the case of male breeding coloration (present only
in G. silus ) and vivid orange or red female “gravid
coloration,” which is present in all Gambelia. The
“gravid coloration” may be deposited in patches on
the sides of the head and on the thighs, in a single
or double row of spots along the flanks, and along
the ventral surface of the tail.

Size. — Gambelia silus exhibits sexual dimor-
phism with males larger than females, while females
attain much larger sizes than males in G. copei and
G. wislizenii.

Distribution.— Gambelia is found in the western
United States from central Idaho and eastern Ore-
gon southward in the Great Basin through western
Colorado and western Texas in the east, and through
the San Joaquin Valley and eastern deserts of Cal-
ifornia in the west; southward into Mexico to west-
ern Coahuila, northern Zacatecas, eastern and cen-
tral Chihuahua, central Sonora, and into the cape
region of Baja California.

Fossil Record. — Numerous Pleistocene fossils
have been referred to Gambelia, all of which were
considered to be G. wislizenii. At least one fossil was

found within the current distributional limits of G.
silus and may therefore represent this species
(Brattstrom, 1953).

Gambelia copei Yarrow
(Fig. 30B)

Crotaphytus copeii Yarrow, 1882:441. Type locality: “La Paz,
Cal.” (holotype: USNM 12663).

Crotaphytus copii— Garman, 1884:16.

Crotaphytus copei— C ope, 1887:34.

Crotaphytus wislizenii— Cope, 1900:255.

Crotaphytus wislizeni copei— Leviton and Banta, 1964:153.
Crotaphytus wislizeni neseotes Banta and Tanner (syn. fide Mon-
tanucci, 1978), 1968:186; fig. 1-5. Type locality: “Cedros Is-
land, west coast of Baja California Norte, Mexico” (holotype:
CAS 79872).

Etymology^. — Named in honor of Edward Drinker Cope, noted
American herpetologist and paleontologist.

Diagnosis. — Gambelia copei is diagnosed from G.
corona f by the absence of a broad, transversely con-
cave frontal bone, the presence of a frontoparietal
suture posterior to the posterior extent of the orbits,
and an elongate and slender nasal process of the
premaxilla. It is diagnosable from G. silus in its
absence of male breeding coloration, absence of sex-
ual dimorphism wherein males are larger than fe-
males (the reverse condition is present), absence of
notched zygosphenes and zygantra, and in the pos-
session of an elongate (rather than truncated) and
slender nasal process of the premaxilla. Gambelia
copei is not easily diagnosed from G. wislizenii, as
the primary character that supports the recognition
of separate species is their narrowly overlapping dis-
tributions (see comments below). Additional differ-
ences include the absence of spotting on the head
in all but one of 38 G. copei examined (SDSNH
18118, Bahia de San Francisquito, Baja California)
and its darker dorsal coloration. Adjacent popula-
tions of G. wislizenii are easily diagnosed from G.
copei as they are characterized by a pale dorsal col-
oration with numerous small punctations that are
asymmetrically arranged, extend well onto the head,
and continue well down onto the flanks.

Variation ( n = 21). — Rostral approximately four
times wider than high, usually rectangular in shape.
Rostral bordered by four to seven postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by six to seven internasals. Frontonasals oc-
casionally enlarged. Canthals four; posterior one or
two wider than high; seven to nine scales separate
canthals of left and right sides. Supraorbital semi-

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

circles absent. Supraoculars small, flat or convex,
smooth, becoming progressively larger medially such
that medial scales are two to four times larger than
lateral ones. Circumorbitals absent. Superciliaries
eight to 12, extremely elongate medial scale present.
Palpebrals ovoid, slightly convex, may be inter-
spersed with numerous interstitial granules. Preo-
culars, suboculars, and postoculars form an arc of
four to seven rectangular scales, second, third, or
fourth scale elongate. Supralabials 13 to 17, usually
slightly longer than high except anteriormost scale,
which is square. Lorilabials in two to four rows,
ovoid to rectangular, juxtaposed, separating su-
pralabials from suboculars and nasals. Aperture of
external auditory meatus rectangular or ovoid, often
constricted at or above the midpoint, approximately
two to four times higher than wide, with small,
strongly convex, somewhat conical auricular scales
lining anterior margin. Mental pentagonal, one to
1.5 times wider than high, bordered laterally by an-
terior infralabials and posteriorly by a pair of post-
mentals that may be enlarged. Postmentals almost
always separated from infralabials by sublabials on
at least one side. Chinshields weakly differentiated
or undifferentiated. Infralabials 12 to 17, square or
wider than high, inferior border convex. Gulars usu-
ally flat, but occasionally convex and beadlike; each
scale may be separated from adjacent scales by nu-
merous asymmetrically arranged interstitial gran-
ules.

Dorsal scales in approximately 160 to 200 rows
midway between forelimb and hindlimb insertions.
Tail long, cylindrical in both sexes and all age groups.
Paired, median row of subcaudals not larger than
adjacent subcaudals and lateral caudals. Enlarged
postanal scales present in males.

Deep postfemoral dermal mite pocket present at
hindlimb insertion. Femoral pores 20 to 3 1 , femoral
pores extend beyond angle of knee, separated me-
dially by ten to 18 granular scales. Subdigital la-
mellae on fourth toe 20 to 24.

Coloration in Life. — Individuals from southern
San Diego County, the Sierra de Juarez and Sierra
San Pedro Martir, and cismontane northwestern Baja
California generally are dark brown in coloration
with a pair of large paravertebral spots that are sep-
arated by broad, cream-colored transverse bars.
There is much lateral flecking; however, lateral spots
are lacking. Spots are nearly always absent from the
head. In southern populations, such as those in the
Vizcaino Desert, the base color of the dorsum is a
paler golden tan, the dorsal spots are fragmented,

and lateral spots may be present. In some southern
individuals, the dorsal spotting may be nearly in-
distinguishable, with the dorsum peppered with fine
pale speckling. This pattern may be more cryptic on
the fine aeolian sand characteristic of the Vizcaino
Desert (Grismer et al., 1994). The speckled pattern
of the southern individuals appears to be an onto-
genetic fragmentation of the color pattern charac-
teristic of northern individuals as subadults have
been examined with dorsal patterns very similar to
those from the northern portion of the peninsula.

Gravid coloration in G. copei is similar to that of
G. wislizenii, with orange or red spots often present
on the head and/or neck, in two rows of spots on
each flank, and on the ventral surface of the tail.
Red or orange pigments may be present on the thighs
as well. Males lack any form of breeding coloration.

A description of the dorsal pattern of G. copei
(pattern Cl) was provided in Montanucci (1978).

Size. —This species exhibits strong sexual dimor-
phism with females reaching larger adult size (max-
imum observed SVL = 126 mm) than males (max-
imum observed SVL = 120 mm).

Distribution (Fig. 50 ). — Gambelia copei occurs in
extreme southcentral California in the vicinities of
Cameron Comers (Mahrdt, 1973), Campo, and Po-
trero Grade southward through all but the San Fe-
lipe Desert region of northeastern Baja California
to the northern portion of the cape region, Baja
California Sur. The species is also found on the Pa-
cific islands of Isla de Cedros, Isla Magdelena, and
Isla Santa Margarita off of the west coast of the
peninsula. Gambelia copei occurs in the lower Col-
orado Desert region between El Huerfanito and Ba-
hia de San Luis Gonzaga and is also known from
the gulf coast desert region in the vicinities of Bahia
de Los Angeles and Punta San Francisquito. How-
ever, G. copei apparently does not inhabit the Gulf
Coast desert region between Santa Rosalia and the
vicinity of Loreto and may be excluded from this
region by the intervening Sierra San Pedro and Si-
erra de La Giganta. This species occurs in high den-
sities on the sandy plains of the Vizcaino Peninsula
and its distribution appears to be limited to the
western side of the peninsular ranges from this re-
gion to a point at least as far south as the southern
terminus of the Sierra de La Giganta. It is known
from as far south as 1 km N Rancho Tres Hermanos
(N ofTodos Santos) in the cape region of Baja Cal-
ifornia Sur.

The only published distribution map specific to
Gambelia copei (Banta and Tanner, 1968) is flawed

100

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

in a number of respects. First, the lower Colorado
Desert region between San Felipe and Puertocitos
is inhabited by G. wislizenii rather than G. copei.
Second, G. copei is not known from the eastern half
of the peninsula between Bahia de San Francisquito
and La Paz. Finally, G. copei is not known to range
throughout the cape region.

Gambelia copei is narrowly syntopic with G. wis-
lizenii over a zone of approximately 1 .6 km in Paseo
de San Matias, Baja California (denoted by a rect-
angular mark on Figure 50). The two species are
separated by a broad, transverse volcanic field that
extends from the Sierra San Felipe to the gulf coast
between Puertocitos and El Huerfanito, Baja Cali-
fornia. This rugged volcanic flow, which is 31.5 km
in width (by road), appears to act as an effective
dispersal barrier for Gambelia along the gulf coast.

On the provided dot distribution map (Fig. 50),
the question marks represent localities in Baja Cal-
ifornia Sur that are questionable because of impre-
cise locality data (CAS 18823 — San Andreas [San
Jorge]; MVZ 37260 — Medano Blanco, 37262 — sand
dunes 12 mi SE Venancio).

Fossil Record. — None.

Natural History.— Very little has been written re-
garding the natural history of Gambelia copei, al-
though it seems likely that it is similar to G. wisli-
zenii in most aspects of its biology. This species is
particularly common on the sparsely vegetated ae-
olian flats of the Vizcaino Peninsula, Baja California
Sur, where it is often observed basking on roadside
rocks, on the berms adjacent to graded dirt roads,
or moving about in open spaces between clumps of
vegetation. Gambelia copei is also found in more
xeric creosote scrub habitats in the general vicinities
of Paseo de San Matias, Bahia de San Luis Gonzaga,
and Bahia de Los Angeles, Baja California, and in
coastal sage scrub and oak woodland habitats on the
western slopes of the Sierra San Pedro Martir and
Sierra de Juarez (Welsh, 1988; personal observa-
tion). Where G. copei extends its range into extreme
southcentral California, it apparently occurs in rel-
atively densely vegetated chaparral.

Gambelia copei shares a number of behavioral
similarities with G. mslizenii and G. silus. For ex-
ample, all three share a habit of basking on small
stones and roadsides berms. Gambelia copei also
displays the familiar “freeze” behavior such that
when they are threatened, they run to the base of a
bush or thicket, flatten themselves to the ground,
and remain motionless (Tevis, 1944; personal ob-

servation). Like G. mslizenii, this species appears
to be a lizard predation specialist as evidenced by
the presence of Uta stansburiana and Callisaurus
draconoides in the stomach contents of museum
specimens. Banta and Tanner (1968) observed a Uta
stansburiana and a grasshopper in the stomach of
an adult female (CAS 8843) from Isla de Cedros.
Like its sister taxon G. mslizenii, females attain larg-
er sizes than males. Although rigorous ecological
data are lacking, G. copei appears to be nonterritorial
as in G. wislizenii (personal observation).

Although little is known of the predators of Gam-
belia copei, they are likely to include the coachwhip
snake {Masticophis flagellum) and patch-nosed snake
( Salvadora hexalepis) as well as other saurophagous
snake species, raptors, the Loggerhead Shrike ( Lan -
ius ludovicianus), the Greater Roadrunner ( Geococ-
cyx calif or nianus), as well as a number carnivorous
mammals such as the coyote ( Canis latrans ). Only
one predation event has been observed by the au-
thor, in which a Loggerhead Shrike was observed
carrying a nearly full-grown G. copei. The shrike
could only fly short distances with the relatively
large lizard and, when pursued, was forced to pin
the dead lizard on the spine of a mesquite ( Prosopis ).

Adult Gambelia copei have been observed as early
as 1 April 1993 in the vicinity of Catavina, on 9
April 1993 on the Vizcaino Peninsula, and on 10
April 1992 in Paseo de San Matias, indicating that
this species emerges from hibernation at a date sim-
ilar to that of G. wislizenii from southern California
(Miller and Stebbins, 1964; Tollestrup, 1979;
Mitchell, 1984). Although adult females were ob-
served in April, none were gravid, suggesting that
reproductive activity had not yet commenced. The
earliest that gravid females have been observed by
the author is 3 May 1 993 at the Paseo de San Matias
locality. Gravid females have also been seen on 27
June 1991 in the Sierra San Borja and 4 July 1991
in the Sierra Santa Clara. An emaciated female that
appeared to have recently deposited eggs also was
observed on 4 July in the Sierra Santa Clara, indi-
cating that mating probably took place in mid to
late June. Fitch (1970) examined 90 leopard lizards
from Baja California (but did not list localities, so
it is possible that some of the specimens were G.
wislizenii) and found two of two females collected
in March to be gravid, as well as six of nine collected
in June, and three of six collected in July. Thus, the
reproductive season is more extensive than my ob-
servations would indicate.

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McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

101

114 110

Fig. 50.— Geographic distribution of Gambelia copei. The small rectangular block in northern Baja California denotes the narrow zone
where G. copei and G. wislizenii occur together. The asterisks represent sight records by the author for G. copei near Bahia de San Luis
Gonzaga. The question marks along the Pacific coast of Baja California Sur indicate localities that must be considered questionable
because of imprecise locality data.

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BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Illustrations. — Black-and-white photographs of
adult lizards were provided in Banta and Tanner
(1968) and Montanucci (1978).

Taxonomic Remarks. -Gambelia copei and G.
wislizenii are easily distinguished on the basis of
their coloration (see diagnosis above). However,
geographic variation in the dorsal coloration of
Gambelia wislizenii is extensive and this alone is
not particularly compelling evidence for the recog-
nition of copei as a distinct species. The primary
motivation for this taxonomic rearrangement is the
occurrence of both forms in syntopy along a narrow
zone within Paseo de San Matias in northeastern
Baja California. Within Paseo de San Matias, in-
dividuals that are easily identified to species occur
together in the same microhabitat over a zone of
1.6 km without showing any obvious evidence of
intergradation. Aside from this narrow contact zone,
the distributions of G. copei and G. wislizenii are
widely separated.

Paseo de San Matias is a low elevation dispersal
corridor that connects the lower Colorado Desert
with the coastal region of northwestern Baja Cali-
fornia. Several desert species extend their ranges
westward toward the Pacific coast by way of this
corridor and some coastal species nearly reach the
desert by extending eastward (Welsh and Bury,
1984). It may appear as though G. copei and G.
wislizenii are geographic variants and that the pat-
tern change is the result of in situ selection where
the habitat changes from extremely xeric creosote
desert to more mesic mountainous terrain. How-
ever, typical G. copei occur in the lower Colorado
Desert region in the vicinity of Bahia de San Luis
Gonzaga, documenting that the distinctive color
pattern of G. copei is not another G. wislizenii pat-
tern type that appears only in mesic habitats. Gam-
belia copei in the Bahia de San Luis Gonzaga region
are approached by G. wislizenii in the vicinity of
Puertocitos, where they are separated by a trans-
verse volcanic field that is 31.5 road km in width.
This lava field extends from the peninsular ranges
to the edge of the Gulf of California and appears to
be a dispersal barrier for Gambelia. Because the
color pattern differences noted above are main-
tained in these populations, which occur in essen-
tially identical habitats that are separated only by
the lava field, the notion that the G. copei and G.
wislizenii color pattern differences are the result of
in situ selection is unlikely. Nevertheless, because
this taxonomic decision is based only on differences
in coloration that are relatively subtle, on a single

osteological character that differs in frequency (the
presence of a well-developed tubercle on the an-
terolateral margin of the postorbital was present in
all G. copei examined [n = 8], whereas in G. wisli-
zenii, the tubercle usually is absent [present in four
of 49 specimens]), and on presumed reproductive
isolation in this region, the recognition of G. copei
as a full species is considered tentative. Electropho-
retic analyses of the Paseo de San Matias popula-
tions are planned in order to determine if fixed al-
lelic differences can be detected that are consistent
with the dorsal color pattern data.

Montanucci (1978) considered the populations of
Gambelia on Isla Tiburon and coastal Sonora be-
tween Puerto Libertad and Bahia Kino to be
con(sub)specific with copei. Although there are no-
table similarities between certain individuals from
the coastal Sonoran region and those from Baja Cal-
ifornia (particularly in CAS 17050 from the south-
eastern end of Isla Tiburon), they differ in that the
Sonoran lizards have spots that continue onto the
dorsal surface of the head, whereas G. copei nearly
always lack this spotting. While some individuals
from coastal Sonora clearly resemble those of Baja
California, the majority examined here were char-
acteristic of those of the remaining portions of So-
nora.

Gambelia coronal Norell

Gambelia corona Norell, 1989:1 1; fig. 10. Type locality: LACM
locality 7058, Vallecito Badlands, Anza-Borrego Desert State
Park (holotype: LACM 42880).

Etymology. — From the Latin corona, a crown, in reference to
the distinctive characteristics of the frontal and frontoparietal
suture.

Diagnosis. — Gambelia corona t is distinguished
from other Gambelia by the presence of the fron-
toparietal suture anterior to the posterior extent of
the orbits. It is further distinguished from Gambelia
copei and G. wislizenii by the presence of a trans-
versely concave frontal bone.

Distribution. — Known only from the type locality.
Remarks. — Gambelia corona f is an extinct spe-
cies known only from a fossilized skull and man-
dibles. Black-and-white photographs of dorsal and
lateral views of the skull were provided by Norell
(1989).

Gambelia silus Stejneger

Crotaphytus silus Stejneger, 1890:105. Type locality: “Fresno,
Cal.” (holotype: USNM 11790A).

Crotaphytus wislizenii— Cope, 1900:255.

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McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

103

Gambelia wislizenii silus— Smith, 1946:164; pi. 31.

Crotaphytus ( Gambelia ) wislizeni silus— Weiner and Smith, 1965:

187.

Gambelia silus— Montanucci, Axtell, and Dessauer, 1975:339.
Gambelia sila— Jennings, 1987:1 1.

Etymology. — From the Latin silus, snub-nosed, in reference to
the blunt snout of this species.

Diagnosis. — Gambelia silus is diagnosed from G.
corona\ by the presence of a frontoparietal suture
that is posterior to the posterior border of the orbits.
It is diagnosed from G. wislizenii and G. copei by
the presence of territoriality, male breeding color-
ation, vertebrae with notched zygosphenes and zyg-
antra, sexual dimorphism wherein males are larger
than females, and in its truncated snout.

Variation (n = 15). — Rostral approximately four
times wider than high, usually rectangular in shape.
Rostral bordered by six to eight postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by six to nine internasals. Frontonasals oc-
casionally enlarged. Canthals four; posterior one or
two wider than high; six to ten scales separate can-
thals of left and right sides. Supraorbital semicircles
absent, although slightly enlarged scales correspond-
ing to the supraorbital series occasionally evident.
Supraoculars small, flat or convex, smooth, becom-
ing progressively larger medially such that medial
scales are two to four times larger than lateral ones.
Circumorbitals absent. Superciliaries eight to 13,
extremely elongate medial scale present. Palpebrals
ovoid, slightly convex, may be interspersed with
numerous interstitial granules. Preoculars, subocu-
lars, and postoculars form an arc of five to eight
rectangular scales, second, third, or fourth scale
elongate. Supralabials 13 to 16, usually slightly lon-
ger than high except anteriormost scale, which is
square. Lorilabials in one to four rows, ovoid to
rectangular, juxtaposed, separating supralabials from
suboculars and nasals. Aperture of external auditory
meatus rectangular or ovoid, often constricted at or
above the midpoint, approximately three to four
times higher than wide, with small, strongly convex,
somewhat conical auricular scales lining anterior
margin. Mental pentagonal, one to 1.5 times wider
than high, bordered laterally by anterior infralabials
and posteriorly by a pair of enlarged postmentals.
Postmentals separated from infralabials by subla-
bials on at least one side. Chinshields weakly dif-
ferentiated or undifferentiated. Infralabials 12 to 16,
square or wider than high, inferior border convex.
Gulars convex and beadlike; each scale separated

from adjacent scales by numerous asymmetrically
arranged interstitial granules.

Dorsal scales in approximately 156 to 182 rows
midway between forelimb and hindlimb insertions.
Tail long, cylindrical in both sexes and all age groups.
Paired, median row of subcaudals not larger than
adjacent subcaudals and lateral caudals. Enlarged
postanal scales present in males.

Deep postfemoral dermal mite pocket present at
hindlimb insertion. Femoral pores 1 5 to 20, femoral
pores do not extend beyond angle of knee, separated
medially by 17 to 25 granular scales. Subdigital la-
mellae on fourth toe 16 to 20.

Coloration in Life. — The dorsal base color ranges
from pale tan, light or dark gray, or brown and the
ventrum is white or yellowish. The dorsum is marked
with seven to ten broad, pale transverse bars that
may or may not be offsetting. Dark spots are often
present between the pale crossbars and generally
extend onto the temporal region of the head. The
crossbars occasionally may be fragmented into light
spots and a vertebral stripe may be present (Mon-
tanucci, 1965). Spots and crossbars similar to those
of the back are generally present on the limbs and
tail, although the crossbars may be absent from the
forelimbs. The tail becomes banded distally as de-
scribed in the generic account.

The posterior of the thigh and the underside of
the tail in juveniles is suffused with yellow pigments.
Males in certain parts of the range (particularly the
foothills surrounding the San Joaquin valley) de-
velop a breeding color composed of either a bright
rusty red suffusion of the abdomen and the ventral
and dorsal surfaces of the hindlimbs and tail or a
bright salmon color that extends over the entire ven-
tral surface of the body and limbs, sometimes in-
cluding the gular region as well (Montanucci, 1965).
Occasionally, individuals may develop this color-
ation only laterally (Montanucci, 1970). Gravid col-
oration in this species is similar to that of G. copei
and G. wislizenii in that the orange or red pigments
are deposited on the lateral surfaces of the head and
flanks, on the under surface of the tail, and occa-
sionally on the thighs. However, this pattern differs
from that of G. copei and G. wislizenii in that the
pigments are generally deposited in a single row
along each flank, rather than in two rows (Montan-
ucci, 1970).

The dorsal pattern of Gambelia silus was de-
scribed more fully in Van Denburgh (1922), Smith
(1946), and Montanucci (1965, 1970).

Size. — This species exhibits strong sexual dimor-

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BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

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phism with males reaching larger adult size (maxi-
mum observed SVL - 120 mm) than females (max-
imum observed SVL =111 mm; Tollestrup, 1979,
1982).

Distribution (Fig. 51 ). — Gambelia silus is restrict-
ed to the San Joaquin valley of California and its
surrounding foothills. They range between “the old
town of Carnegie in Corral Hollow,” San Joaquin
County, in the north to the Cuyama Valley and base
of the Tehachapi Mountains in the south. The spe-
cies apparently does not contact G. wislizenii pres-
ently, although Montanucci (1970) identified an iso-
lated population of putative hybrid origin between
the two species in the Cuyama River drainage sys-
tem southwest of the southern end of the San Joa-
quin valley. Although G. silus and G. wislizenii are
isolated from one another, Gambelia wislizenii ap-
proaches G. silus in the Cuyama valley drainage
where G. wislizenii occurs above 1 1 00 m and G.
silus occurs below 790 m (Montanucci, 1970).

Fossil Record.— No fossil specimens have been
referred to this species, although Brattstrom (1953)
considered measurements of two maxillae taken
from McKittrick, Kern County, California, a local-
ity within the current distributional confines of
Gambelia silus, to conform more closely to extant
G. wislizenii than to G. silus. However, examination
of his figures renders this observation suspect as
neither fossil has a complete nasal process. On dis-
tributional grounds, it would appear more likely that
these specimens represent G. silus. Because the ma-
terial has not been reexamined here, the reference
to G. wislizenii is considered questionable.

Natural History. — Montanucci (1965, 1967, 1970)
and Tollestrup (1979, 1982, 1 983) studied the ecol-
ogy of Gambelia silus and all of the comments pro-
vided here are taken from these references unless
otherwise noted. According to Montanucci (1965),
the species inhabits sparsely vegetated plains, alkali
flats, low foothills, canyon floors, large washes, and
arroyos. They prefer open habitat and are absent or
rare in areas with dense vegetation or tall grass. As
is the case with G. wislizenii, the species appears to
be most common in areas with abundant rodent
burrows. Common vegetational associates include
grasses ( Stipa ), saltbush ( Atrip/ex ), and iodinebush
( Al/enrolfea occidentals).

In contrast with Gambelia wislizenii [and presum-
ably G. copei ), G. silus is highly territorial and males
from many, but not all, populations develop rusty
red coloration during the breeding season (Montan-
ucci, 1965; Tollestrup, 1979, 1982). The activity
season commences in late March or early April and

extends through late September, although some ju-
veniles may remain active into October given fa-
vorable weather conditions (Montanucci, 1965;
Tollestrup, 1979). The mating season occurs pri-
marily in late April and May, although Germano
and Williams ( 1 992) observed gravid females as late
as mid-July, and young hatch in late July or early
August (Montanucci, 1965; Tollestrup, 1979, 1983).
Clutch size is smaller than that of G. wislizenii, with
a range of two to six and a mean of 2.90 (Tollestrup,
1979, 1982) to 3.30 (Montanucci, 1970). Germano
and Williams (1992) documented that as many as
four clutches may be deposited per reproductive
season.

Gambelia silus shares a number of behavioral
similarities with G. copei and G. wislizenii. All three
are often observed basking on small roadside rocks
and the berms along the edges of graded dirt roads.
“Freeze” behavior (Montanucci, 1965), wherein
threatened individuals run to the base of a nearby
bush, flatten themselves to the ground, and remain
motionless (presumably as a means of avoiding de-
tection) is also a shared behavior.

Montanucci (1965) indicated that Gambelia silus
feeds primarily upon locusts (Orthoptera), cicadas
(Homoptera), and small lizards, including Uta
stansburiana, Phrynosoma coronatum, Cnemidoph-
orus tigris, and Sce/oporus magister. Germano and
Williams (1994) observed that G. silus eat young
conspecifics, as well. Tollestrup (1979) found no ev-
idence of lizard predation at her southern San Joa-
quin valley study sites and noted the following ar-
thropod prey items: orthopterans, coleopterans, hy-
menopterans, dipterans, homopterans, lepidopter-
ans, and spiders. Regional or seasonal variation may
explain the discrepancies in food preferences found
in these studies.

Montanucci (1965) noted predation on Gambelia
silus by several avian species including Loggerhead
Shrikes ( Lanius ludovicianus), American Kestrels
{Falco sparverius ), Burrowing Owls {Athene cuni-
cularia ), and Greater Roadrunners {Geococcyx cal-
ifornianus). Prarie Falcons {Falco mexicanus ) are
also known to capture this species (Germano and
Carter, 1995). Montanucci (1965) also observed
predation by the coachwhip snake {Masticophis fla-
gellum) and the gopher snake ( Pituophis melano-
leucus). Other potential predators include the spot-
ted skunk {Spi/ogale putorius) and the ground squir-
rel {Spermophilus beecheyi), both of which con-
sumed G. silus when captured together in barrel
traps, as well as the coyote {Canis latrans ), badger
{Taxidea taxus), glossy snake {Arizona elegans), long-

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McGUIRE — SYSTEM ATICS OF CROTAPH YT1D LIZARDS

105

nosed snake ( Rhinocheilus lecontei ), and common
kingsnake ( Lampropeltis getula).

Remarks.— Gambelia silus is now extinct over
much of it historical range due primarily to habitat

degradation associated with agricultural develop-
ment of the San Joaquin valley. As of 1990, only
seven percent of the San Joaquin valley had not been
altered by agricultural and urban development

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BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

(Steinhart, 1990). As a result, this species is a fed-
erally and state listed endangered species.

Illustrations. — Montanucci (1965) provided a line
drawing of the snout squamation; black-and-white
photographs were provided by Van Denburgh
(1922), Smith (1946), and Pickwell (1972); color
illustrations were given in Smith and Brodie (1982)
and Stebbins (1985); color photographs were pro-
vided in Behler and King (1979) and Steinhart
(1990).

Gambelia wislizenii Baird and Girard
(Fig. 30 A)

Crotaphytus wislizenii Baird and Girard, 1852:69. Type locality:
“near Santa Fe,” New Mexico (holotype: USNM, now lost or
destroyed); invalid holotype (Yarrow 1882a): USNM 2770;
invalid lectotype (Tanner and Banta 1963): USNM 2685.
Crotaphytus gambelii Baird and Girard (syn. fide Cope, 1 900),
1852:126. Type locality: “Not precisely known. . .California”
(holotype: USNM 2722).

Cro/ap/ty/M5/a5c/a/a5Hallowell(syn. fide Cope, 1900), 1852:207.
Type locality: “Sand hills, at the lower end of the Jornada del
Muerte, New Mexico” (holotype: USNM 2736).

Leios. [aurus] fasciatus—'Dnmenl, 1856:533.

L. [eiosaurus] hallowellii Dumeril (substitute name for L.fascia-
tus Hallowell, 1852), 1856:533.

Crotaphytus {Gambelia) wislizenii— Baird, 1858:253.

Gambelia wislizenii— Smith, 1946:158; fig. 57, 68; pi. 30.
Crotaphytus ( Gambelia ) wislizeni punctatus Tanner and Banta,
1963: 1 38; fig. 1-5. Type locality: “Yellow Cat Mining District
approximately 10 miles south of U.S. Highway 50-6, Grand
County, Utah” (holotype: BYU 20928).

Crotaphytus {Gambelia) wislizeni— Weiner and Smith, 1965: 186;
fig. 1-6.

Crotaphytus wislizenii neseotes— Banta and Tanner (syn. fide
Montanucci, 1978), 1968:186; fig. 1-5. Type locality: “Cedros
Island; west coast of Baja California Norte, Mexico” (holotype:
CAS 79872).

Gambelia wislizeni— Montanucci, Axtell, and Dessauer, 1975:
339.

Crotaphytus wislizeni maculosus— Tanner and Banta, 1977:230;
fig. 2-4. Type locality: “approximately 200m W of the lookout
point along Nevada Highway 33, west side of Pyramid Lake,
Washoe County, Nevada” (holotype: BYU 32685).

Etymology. —Named in honor of Dr. Frederick Adolphus Wis-
lizenus, an army surgeon, who collected the original type speci-
men.

Diagnosis. — Gambelia wislizenii is distinguished
from G. corona^ by the absence of a broad, trans-
versely concave frontal bone, the presence of a fron-
toparietal suture posterior to the posterior extent of
the orbits, and an elongate and slender nasal process
of the premaxilla. It is diagnosable from G. silus in
its absence of male breeding coloration, absence of
sexual dimorphism wherein males are larger than
females (the reverse condition is present), absence

of notched zygosphenes and zygantra, and in the
possession of an elongate (rather than truncated) and
slender nasal process of the premaxilla. For a di-
agnosis distinguishing G. wislizenii and G. copei, see
discussion under the G. copei taxonomic account.

Variation ( n = 20). — Rostral approximately four
times wider than high, usually rectangular in shape.
Rostral bordered by five to eight postrostrals. Re-
maining snout scales irregularly arranged, an en-
larged middorsal series may be present. Nasals sep-
arated by six to nine internasals. Frontonasals oc-
casionally enlarged. Canthals four; posterior one or
two wider than high; seven to nine scales separate
canthals of left and right sides. Supraorbital semi-
circles absent. Supraoculars small, flat or convex,
smooth, becoming progressively larger medially such
that medial scales are two to four times larger than
lateral ones. Circumorbitals absent. Superciliaries
seven to 13, extremely elongate medial scale pres-
ent. Palpebrals ovoid, slightly convex, may be in-
terspersed with numerous interstitial granules. Preo-
culars, suboculars, and postoculars form an arc of
four to seven rectangular scales, second, third, or
fourth scale elongate. Supralabials 12 to 17, usually
slightly longer than high except anteriormost scale,
which is square. Lorilabials in one to four rows,
ovoid to rectangular, juxtaposed, separating su-
pralabials from suboculars and nasals. Aperture of
external auditory meatus rectangular or ovoid, often
constricted at or above the midpoint, approximately
two to four times higher than wide, with small,
strongly convex, somewhat conical auricular scales
lining anterior margin. Mental pentagonal, one to
1.5 times wider than high, bordered laterally by an-
terior infralabials and posteriorly by a pair of post-
mentals that may be enlarged. Postmentals almost
always separated from infralabials by sublabials on
at least one side. Chinshields weakly differentiated
or undifferentiated. Infralabials 12 to 17, square or
wider than high, inferior border convex. Gulars usu-
ally flat, but occasionally convex and beadlike (es-
pecially in southern portion of range); each scale
may be separated from adjacent scales by numerous
asymmetrically arranged interstitial granules.

Dorsal scales in approximately 158 to 224 rows
midway between forelimb and hindlimb insertions.
Tail long, cylindrical in both sexes and all age groups.
Paired, median row of subcaudals not larger than
adjacent subcaudals and lateral caudals. Enlarged
postanal scales present in males.

Deep postfemoral dermal mite pocket present at
hindlimb insertion. Femoral pores 1 5 to 25, femoral

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McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

107

pores extend beyond angle of knee, separated me-
dially by 14 to 25 granular scales. Subdigital la-
mellae on fourth toe 18 to 25.

Coloration in Life. — The dorsal pattern of G. wis-
lizenii is extremely variable, with several color
morphs that are more or less confined to specific
geographic regions. These pattern classes conform
to the subspecies wislizenii, punctatus, and macu-
losus (Montanucci, 1978; although he recognized an
additional unnamed pattern class as well) that are
not recognized here. They differ most notably in the
size of the dorsal spots (large in the maculosus pat-
tern class, intermediate in wislizenii, and small in
punctatus), as well as in the character of the dorsal
transverse bars. The dorsal spots are often scattered
over the dorsum irregularly, extend well down onto
the flanks, and continue onto the dorsal and lateral
surfaces of the head. The dorsal base color for most
individuals is white, cream, or gray, although some
individuals apparently may approach the brown col-
oration of northern G. copei (Montanucci, 1978).

Gravid coloration in G. wislizenii is similar to
that of G. copei with orange or red spots often pres-
ent on the head and/or neck, in two rows of spots
on each flank, and on the ventral surface of the tail.
The red or orange pigments occasionally may extend
onto the thighs. Males lack any form of breeding
coloration.

A more detailed description of geographic vari-
ation in the dorsal pattern of Gambelia wislizenii is
provided in Montanucci (1978).

Size. — This species exhibits strong sexual dimor-
phism with females reaching larger adult size (max-
imum observed SVL = 144 mm) than males (max-
imum observed SVL =119 mm; Tollestrup, 1979,
1982).

Distribution (Fig. 52). — Gambelia wislizenii oc-
curs in the western United States and northern Mex-
ico, ranging from eastern Oregon and southern Ida-
ho in the north, at least as far south as central Sonora
in the west, and southern Coahuila or northern Za-
catecas in the east. This species extends westward
well beyond the limits of the lower Colorado Desert
in southern California where it has been collected
at Temecula, near Vail Lake, and at Arlington in
Riverside County. However, a specimen purport-
edly collected at Arcadia, Los Angeles County
(FMNH 203919), seems suspect. The species ap-
pears to be absent from the high elevation moun-
tains of eastern Arizona and adjacent western New
Mexico. Its distribution also appears to be limited
in Texas, with a number of specimens known from

the sandy northern portion of the Texas panhandle
and from the Chihuahuan Desert habitats between
Big Bend National Park and El Paso. It is unclear
whether G. wislizenii is continuously distributed in
the western portion of Texas between Reeves, Ward,
and Crane counties and the southern portions of
Brewster and Presidio counties. Specimens are rel-
atively few from most of northern Mexico, but it
appears that G. wislizenii is completely excluded
from the higher portions of the Sierra Madre Oc-
cidental of eastern Sonora and western Chihuahua.
Gambelia wislizenii and G. copei occur together in
a narrow zone of syntopy in northern Baja California
which is denoted in Figure 52 by an oblong oval
marking (for a more extensive discussion of this
zone of syntopy, see the G. copei account above).
The two northern Oregon localities shown on Figure
52 are old records from The Dalles, Wasco County,
and Hat Rock, Umatillo County. The symbol “?”
shown on Figure 52 represents a record from Che-
ney, Spokane County, Washington. The northern
Oregon and Washington records should be consid-
ered questionable until verified by additional field
work.

Fossil Record. —Numerous Pleistocene fossils
have been referred to this species (Estes, 1983) in-
cluding a pair of maxillae that may be more properly
referred to Gambelia silus (see G. si/us account for
comments).

Natural History. — There is extensive literature as-
sociated with the natural history and ecology of
Gambelia wislizenii. The reader is referred to the
following papers for a more detailed discussion of
this topic: McCoy, 1967; Montanucci, 1967, 1970,
1978; Turner et al., 1969; Tanner and Krogh, 1974a,
1974/?; Essghaier and Johnson, 1975; Parker and
Pianka, 1976; Tollestrup, 1979, 1982, 1983; and
Mitchell, 1984. This widespread species occurs in a
number of habitat types, although it is found pri-
marily on desert flats and lower foothills character-
ized by sparse vegetation. Throughout much of its
range in the Sonoran, Mojave, Great Basin, and
Chihuahuan deserts it is found in flatlands in as-
sociation with creosote bush ( Larrea tridentata ) as
well as other xerophilic plants. In the Pyramid Lake
region of northwestern Nevada, it is found in as-
sociation with filaree storksbill (Erodium cicutar-
ium ), mormon tea ( Ephedra nevadensis), four-wing
saltbush ( Atriplex canescens ), and Grayia spinosa
(Snyder, 1 972). Tollestrup (1979, 1982, 1983) stud-
ied G. wislizenii near California City, California,
where the dominant shrub was creosote bush {Ear-

108

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Fig. 52. — Geographic distribution of Gambelia wislizenii. The elongate ovoid marking in northern Baja California represents the narrow
zone in which G. wislizenii and G. copei occur together. The “?” denotes a questionable locality record from Cheney, Spokane County,
Washington.

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

109

rea tridentata ), and other major components of the
vegetation included saltbush (Atrip/ex), Haplopap-
pus, Lycium andersonii, and Dalea. McCoy (1967)
discussed the ecology of this species in the Colorado
River valley, Mesa County, Colorado, where it was
found in association with greasewood ( Sarcobatus
venniculatus) and big sage (Artemisia tridentata). In
southeastern Arizona, the species was found on sand
dunes with sand sage (Artemisia filifolia) and indigo
bush (Dalea sp.) and on bajadas characterized by
cat-claw acacia (Acacia constricta), jimmyweed
(Haplopappus taenuisecta), Opuntia, and Agave
(Mitchell, 1984). Near the northeastern limits of its
range (1 1.5 mi S Monahans, Ward County, Texas),
Tinkle (1959) found them on sandy flatlands in as-
sociation with mesquite (Prosopis), creosote bush
(Larrea tridentata). Acacia, and dwarf shin oak
(Quercus havardii). Montanucci (1970) found G.
wislizenii restricted to the high elevation (above 3600
ft) pinyon-juniper woodland habitats of the Cuyama
and Lockwood valleys, southern California, near the
hybrid zone between this species and G. silus. How-
ever, the pinyon-juniper zone is thought to be sub-
optimal habitat for G. wislizenii and they are often
absent from such areas (Tanner and Jorgenson, 1 963;
McCoy, 1967). Gambelia wislizenii appears to be
most common on sparsely vegetated flatlands with
large numbers of rodent burrows (Tanner and Banta,
1963; McCoy, 1967; Nussbaum et al., 1983).

Unlike Crotaphytus and Gambelia silus, G. wis-
lizenii lacks territoriality (McCoy, 1967; Montan-
ucci, 1970; Tollestrup, 1979, 1982, 1983) and there
is often much overlap in home ranges (Tollestrup,
1979, 1983). Females may even nest communally
(Parker and Pianka, 1976). Females attain much
larger size than males and appear to consume a high-
er proportion of vertebrate prey (Parker and Pianka,
1976; Tollestrup, 1979, 1982, 1983). Southern pop-
ulations reach larger adult sizes than more northern
populations which Parker and Pianka (1976) again
linked to an increased emphasis on vertebrate prey.
Gambelia wislizenii are ambush predators, often
resting in the shadows at the base of a bush before
dashing out to capture passing prey items (Tolles-
trup, 1979, 1983). They are able to move with great
speed and have been observed to leap as high as 0.6
m to capture flying insects (Franklin, 1914). Known
prey items include arthropods, especially orthop-
terans, as well as coleopterans, lepidopterans, hy-
menopterans, hemipterans, homopterans, dipter-
ans, isopterans, neuropterans, and arachnids

(Knowlton and Thomas, 1936; McCoy, 1967; Sny-
der, 1972; Tanner and Krogh, 1974a, 19746; Essgh-
aier and Johnson, 1975; Parker and Pianka, 1976;
Tollestrup, 1979; Mitchell, 1984). Vertebrate prey
include the lizards Callisaurus draconoides, Cne-
midophorus tessellatus, C. tigris, Uta stansburiana,
Phrynosoma platyrhinos, Sceloporus graciosus, S.
undulatus, smaller G. wislizenii, and small snakes,
as well as the pocket mouse Perognathus longimem-
bris (Taylor, 1912; Richardson, 1915; Camp, 1916;
VanDenburgh, 1922; Knowlton and Thomas, 1936;
Banta, 1967; McCoy, 1967; Snyder, 1972; Tanner
and Krogh, 1974a, 19746; Parker and Pianka, 1976;
Tollestrup, 1979, 1983; Pietruszka et al., 1981;
Crowley and Pietruszka, 1983). As has been re-
ported for several Crotaphytus species (i.e., C. bi-
cinctores, C. vestigium), Lycium berries are often
consumed and may even represent a preferred food
item during parts of June and July (Tanner and
Krogh, 1974a). Turner et al. (1969) observed in-
dividuals climbing into Lycium bushes to eat the
berries, indicating that this plant material is not
consumed inadvertently. Jorgensen and Orton
(1962) collected two G. wislizenii in traps baited
with oatmeal and found oatmeal in the stomach
contents of both.

Gambelia wislizenii shares a number of behav-
ioral similarities with G. copei and G. silus. All three
are often observed basking on small roadside rocks
and the berms along the edges of graded dirt roads.
“Freeze” behavior (Brooking, 1934; McCoy, 1967)
wherein threatened individuals run to the base of a
nearby bush, flatten themselves to the ground, and
remain motionless (presumably as a means of
avoiding detection) is also a shared behavior. A be-
havior present in G. wislizenii but not yet noted in
other Gambelia is vocalization (Taylor, 1912; Jor-
gensen et al., 1 963; Wever et al., 1 966; Crowley and
Pietruszka, 1 983). Wever et al. ( 1966) described the
sound emitted as “vocal cries of a wailing or moan-
ing character.” The ability to vocalize, although ex-
tremely unusual within iguanians, has also been not-
ed in C. bicinctores (Smith, 1974) suggesting that all
crotaphytids may possess this ability.

Accounts of predation on Gambelia wislizenii are
rare in the literature. Tollestrup (1979) observed a
failed predation attempt on an adult female by a
Prairie Falcon (Falco mexicanus). Tollestrup (1979)
considered the following species to be potential
predators at the California City study site: the coach-
whip snake (Masticophis flagellum), sidewinder

110

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

( Crotalus cerastes ), Mojave rattlesnake ( Crotalus
scutulatus). Loggerhead Shrike ( Lanius ludovici-
anus ), raptors. Burrowing Owl ( Speotyto cunicular-
ia), badger ( Taxidea taxus), coyote (Canis latrans ),
and kit fox ( Vulpes macrotis). To this list can be
added G. wislizenii, which commonly preys on
smaller individuals of its own species and a number
of saurophagous snakes that occur within its range,
such as the patch-nosed snake ( Salvadora sp.), the
common kingsnake ( Lampropeltus getula), the go-
pher snake ( Pituophis melanoleucus), the glossy snake
{Arizona eiegans), and the long-nosed snake ( Rhin -
ocheilus lecontei).

The length of the activity season of Gambelia wis-
lizenii varies latitudinally. Northern and northeast-
ern populations (western Colorado, Utah, north-
western Nevada, and Ward County, Texas) may not
emerge from hibernation until early or even late
May (Tinkle, 1959; McCoy, 1967; Snyder, 1972;
Parker and Pianka, 1976). Adults enter hibernation
in early August and, thus, may have activity seasons
less than three months in length (McCoy, 1967).
Individuals from southern populations emerge from
hibernation in late March or early April (south-
eastern Arizona, vicinity of California City, Joshua
Tree National Monument) and enter hibernation in
late August to late October (Miller and Stebbins,
1964; Tollestrup, 1979; Mitchell, 1984). Reproduc-
tion appears to be concentrated in late May and early
June in the California City and southeastern Ari-
zona populations and after these dates gravid fe-
males were not observed (Tollestrup, 1979, 1982;
Mitchell, 1984). In Utah and western Colorado,
gravid females were observed between early June
and early July, indicating that the reproductive sea-
son is pushed back by a few weeks in more northern
populations (McCoy, 1967; Parker and Pianka,
1976). Clutch size also varies from population to
population, with mean clutch sizes ranging between
5.15 (Robison and Tanner, 1962) and 7.3 (McCoy,
1967; Mitchell, 1984). Most studies have found no
evidence of multiple clutch production (McCoy,
1967; Tanner and Krogh, 1974a; Parker and Pian-
ka, 1976; Tollestrup, 1979, 1982; Mitchell, 1984),
although Turner et al. (1969) observed second
clutches in a southern Nevada population.

Gambelia wislizenii develop vibrant orange or
reddish gravid coloration shortly before ovulation
(as do all crotaphytid species). This coloration is
maintained throughout the gravid period and is lost
soon after parturition. The fecal matter of females
that are losing their gravid coloration may be heavi-

ly saturated with similar orange pigments and this
may provide a clue to the yet-to-be-identified pig-
ment type responsible for this coloration.

Illustrations. —Numerous photographs and illus-
trations have been published. Detailed black-and-
white illustrations of the entire animal were pro-
vided by Baird and Girard (1852c), Hallowell (1852),
Baird (1859), and Stebbins (1954); ventral head
squamation (Stebbins, 1954); head, limb, and pre-
anal squamation by Cope (1900); skull, pelvic and
pectoral girdles by Weiner and Smith (1965); an-
terior body and head musculature by Robison and
Tanner (1962); black-and-white photos were pre-
sented by Van Denburgh (1922), Tanner and Banta
(1963, 1977), Pickwell (1972), Montanucci (1978),
and Nussbaum et al. (1983); color illustrations by
Stebbins (1985) and Conant and Collins (1991); co-
lorized photo by Ditmars (1920); color photographs
were provided by Leviton (1971), Behler and
King (1979), Hammerson (1986), and Garrett and
Barker (1987).

Taxonomic Remarks. —The subspecies Gambelia
wislizenii punctatus and G. w. maculosus often are
considered to be synonyms of G. w. wislizenii and
in their descriptions, broad intergrade zones were
identified (Tanner and Banta, 1963, 1977). Fur-
thermore, Montanucci (1978) showed that the G. w.
maculosus, G. w. punctatus, and G. w. wislizenii dor-
sal pattern classes occur sporadically throughout the
range of G. wislizenii. Based on these data, G. w.
maculosus and G. w. punctatus are here considered
to be pattern classes and are synonymized with G.
wislizenii.

No official holotype specimen of Crotaphytus wis-
lizenii was designated by Baird and Girard (1852a)
and this created some confusion when later workers
attempted to rectify the situation. Tanner and Banta
(1963) designated a lectotype (which they referred
to as a holotype) for C. wislizeni after recognizing
that Yarrow (1882a) had incorrectly designated
USNM 2770 as the type specimen, and that the
original specimen figured by Baird and Girard
(1852c) from near Santa Fe, New Mexico, had been
lost or destroyed. The specimen of Crotaphytus wis-
lizenii (USNM 2770) designated by Yarrow (1882a)
was collected by H. Baldwin Mollhausen in Colo-
rado probably in 1853-1854 after C. wislizenii had
already been described (Tanner and Banta, 1963)
and therefore could not have represented the orig-
inal type specimen described by Baird and Girard
(1852a). The designation of a lectotype requires that
the original description of the species was based on

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

a series of syntypes, rather than a single holotype.
In their description, Baird and Girard (1852a) stat-
ed: “Head proportionally narrow and elongated; ce-
phalic plates and scales on the back very small: yel-
lowish brown, spotted all over with small patches
of deeper brown or black. Caught near Santa Fe, by
Dr. Wislizenius (sic); specimens of the same species
sent in by Lieut. Col. J. D. Graham, collected be-
tween San Antonio and El Paso del Norte.” Thus,
the description of the species appears to be based
on the specimen from near Santa Fe, whereas the
other specimens were referred to the species after-
ward. Therefore, according to the International
Commission of Zoological Nomenclature (1985), it

1 1 1

is inappropriate to designate a lectotype for the spe-
cies. Furthermore, except under “exceptional cir-
cumstances,” a neotype is not to be designated ei-
ther. “Exceptional circumstances,” such as when a
neotype is necessary in the interests of stability of
nomenclature, clearly are not evident at present.
Therefore, USNM 2685 (collected between San An-
tonio and El Paso del Norte), which was designated
as the lectotype by Tanner and Banta ( 1963), should
not be recognized as either a lectotype or a neotype.
If the designation of a neotype should become nec-
essary, it should be collected in the immediate vi-
cinity of Santa Fe, New Mexico.

KEY TO THE SPECIES OF CROTAPHYTUS AND GAMBELIA

A key to the species of Crotaphytus is not difficult
to produce for adult males because most species are
easily distinguished on the basis of conspicuous col-
or pattern characteristics. A key for adult females
and juveniles of both sexes is more difficult because
many of the characteristics that distinguish species
are present only in adult males. Adult male Cro-
taphytus are easily distinguished from females by
the presence of conspicuous gular coloration, larger
femoral pores with a greater quantity of exudate,
and often by the presence of enlarged postanal scales.
A number of additional sexually dichromatic fea-
tures may also be employed depending on the spe-
cies in question (see taxonomic accounts). With re-
gard to Gambelia, the formulation of a key is dif-
ficult for both sexes and all age classes due to vari-
ation in the coloration of G. wislizenii and G. silus
and the absence of distinctive features of squama-
tion. With a few notable exceptions, all species of
Crotaphytus and Gambelia are allopatrically dis-
tributed with respect to their congeners. Thus, ge-
ography is usually a reliable means for determining
species identifications when morphology fails. For-
tunately, where geographic overlap occurs, the spe-
cies in question are easily distinguished. Note: The
key to juvenile Crotaphytus does not include C. an-
tiquus for which no specimens are available.

Key to the Species of Crotaphytus
(Adult Males)

1. Dorsal pattern comprised of white or pale gray net-like
reticulations on a golden tan or brown dorsal base color,

femoral pores jet black (Fig. 30C, D) 2

la. Dorsal pattern composed of white spots and/or dashes,
with or without white transverse bars, on a brown, blue.

green, tan, or straw yellow dorsal base color; femoral
pores off-white or gray (Fig. 31, 32) 3

2. Dorsal coloration golden tan, groin patches absent (Fig.

30C, 33) reticulatus

2a. Dorsal coloration brown, groin patches present (Fig. 30D)

antiquus

3. Anterior collar markings incomplete ventrally (do not

pass through the gular fold (Fig. 33) collaris

3a. Anterior collar markings complete ventrally (Fig. 34,

35) 4

4. Tail round or nearly so in cross section without an off-

white vertebral stripe; small melanic inguinal patches
are present but confined to immediate vicinity of groin
(Fig. 31 A, 34) nebrius

4a. Tail strongly compressed laterally with a white or off-
white vertebral stripe; large melanic inguinal patches
extend half way to the forelimb insertion or more (Fig.

3 1 B, 32A-D, 35) 5

5. Dorsal coloration aquamarine to cobalt blue; black oral

melanin present (Fig. 3 1 B) dickersonae

5a. Dorsal coloration dark brown; black oral melanin absent
(Fig. 32A-D) 6

6. Posterior collar markings absent or extremely reduced;
white component of dorsal pattern composed of irreg-
ularly arranged, elongate, wavy white lines (Fig. 32D)
insular is

6a. Posterior collar markings present; white component of
dorsal pattern composed of white spots and/or dashes,
with or without regularly arranged white transverse bars
(Fig. 31A-C; 32A, B) 7

7. White dorsal transverse bars present (Fig. 32C); olive
green or yellow-orange ventrolateral breeding coloration
present; posterior collar markings widely separated dor-

sa*'y vestigium

7a. White dorsal transverse bars absent, olive green or yel-
low-orange ventrolateral breeding coloration absent;
posterior collar markings in contact or narrowly sepa-
rated dorsally g

8. Granular ventrolateral reticulations present; pale orange
or peach-colored transverse bands incorporated into
brown dorsal base coloration; white bar that separates

1 12

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

anterior and posterior collar markings lacks green tint;
hindlimb brown with a white or off-white reticulate pat-
tern over entire dorsal surface bicinctores

8a. Granular ventrolateral reticulations absent; white bar
that separates the anterior and posterior collar markings
with a pale green tint; hindlimb spotted proximally but
patternless from just above the knee to the distal ter-
minus grismeri

Key to the Species of Crotaphytus
(Adult Females)

1. Dorsal pattern comprised of white or pale gray net-like

reticulations, at least some of which surround gray or
black pigments, on a golden tan or brown dorsal base
color 2

la. Dorsal pattern composed of white spots and/or dashes,
with or without white transverse bars, on a pale brown,
bluish, greenish, tan, or straw yellow dorsal base color
(Fig. 3 1C) 3

2. Postfemoral mite pockets absent; at least three of the

scales of the right and left supraorbital semicircles in
contact reticulatus

2a. Postfemoral mite pockets present; supraorbital semi-
circles either separated by a continuous row of scales or
with one or rarely two scales of the supraorbital semi-

circles in contact antiquus

3. Black oral melanin present 4

3a. Black oral melanin absent 5

4. Antehumeral mite fold lacking; tail bright lemon yellow
(Fig. 3 1C; note: this feature may prove to be variable)
dickersonae

4a. Antehumeral mite pocket present (Fig. 28); tail not bright

lemon yellow collaris or nebrius

5. Posterior collar markings absent; anterior collar mark-
ings usually absent insularis

5a. Anterior and posterior collar markings present 6

6. White dorsal transverse bars present vestigium

6a. White dorsal transverse bars absent 7

7. Subadult females with orange tail; subadult and adult

females with three melanic spots outlined in white along
the lateral trunk surface grismeri

7a. Subadult females without orange tail; melanic spots out-
lined in white usually absent from lateral trunk surface
bicinctores

Key to the Species of Crotaphytus
(Juveniles)

1. Postfemoral mite pockets absent reticulatus

la. Postfemoral mite pockets present (Fig. 29) 2

2. Antehumeral mite pocket absent dickersonae

2a. Antehumeral mite pocket present (Fig. 28) 3

3. Black oral melanin present collaris or nebrius

3a. Black oral melanin absent 4

4. A thin, pale tan dorsal caudal stripe is present and ex-
tends anteriorly onto the dorsal pelvic region . . . grismeri

4a. A pale tan dorsal caudal stripe is lacking 5

5. Paired melanic keels on ventral surface of caudal ex-
tremity . . vestigium or bicinctores (variable in bicinctores )

5a. Paired melanic keels on ventral surface of caudal ex-
tremity lacking

insularis or bicinctores (variable in bicinctores )

Key to the Species of Gambelia
(Adults of Both Sexes)

1. Reddish male breeding coloration present; snout trun-

cated; gular pattern in both sexes consists of grayish or
black linearly arranged spots silus

la. Male breeding coloration absent; snout elongate; gular
pattern in both sexes consists of longitudinally oriented
black streaks 2

2. Dorsal spotting extends onto the temporal region of the

head and often to the terminus of the snout; dorsal base
coloration off-white or pale tan (Fig. 30A) wislizenii

2a. Dorsal spotting does not extend onto the dorsal surface
of the head; dorsal base coloration dark brown or golden
tan (Fig. 30B) copei

Acknowledgments

I would like to thank the following individuals and institutions
for allowing me to examine specimens under their care: Philip
Damiani, Darrel Frost, and Charles Meyers, American Museum
of Natural History (AMNH); Jack Sites, Monte L. Bean Life
Science Museum, Brigham Young University (BYU); Jacques
Gauthier and Jens Vindum, California Academy of Sciences
(CAS); Ellen Censky and the late C. J. McCoy, Carnegie Museum
of Natural History (CM); William Duellman, Adrian Nieto, and
John Simmons, The University of Kansas Museum of Natural
History (KU); Robert Bezy and John Wright, Natural History
Museum of Los Angeles County (LACM); Harry Greene, Uni-
versity of California Museum of Vertebrate Zoology (MVZ); Os-
car Flores-Villela, Museo de Zoologia “Alfonso L. Herrera,”
Universidad Nacional Autonoma de Mexico (MZFC); Gregory
Pregill, San Diego Natural History Museum (SDSNH); Richard
Etheridge, San Diego State University (SDSU); David Canna-
tella, Texas Memorial Museum (TNHC); Charles Lowe, Uni-
versity of Arizona Department of Zoology (UAZ); Deborah Bak-

ken and Steven Sroka, University of Illinois Museum of Natural
History (UIMNH); Arnold Kluge and Greg Schneider, The Uni-
versity of Michigan Museum of Zoology (UMMZ); Ronald
Crombie, Kevin de Queiroz, Ronald Heyer, Addison Wynn, and
George Zug, National Museum of Natural History (USNM); and
Carl Lieb and Robert Webb, Laboratory for Environmental Bi-
ology, The University of Texas at El Paso (UTEP). In addition,
Richard Etheridge (REE), L. Lee Grismer (LLG), Bradford Hol-
lingsworth (BDH), Ernest Liner (EL), and Jay Savage (JMS) al-
lowed me to examine specimens from their personal collections.

For assistance in the field I would like to thank Alfonso Del-
gadillo-Espinoza, Richard Etheridge, Jerry Feldner, Marty Feld-
ner, Erik Gergus, Jesse Grismer, L. Lee Grismer, Bradford Hol-
lingsworth, Mario Mancilla-Moreno, Fernando Mendoza-Qui-
jano, Sharon Messenger, Richard Montanucci, David Orange,
Walter Schmidt-Ballardo, Eric Snow, and John Wiens. Kevin de
Queiroz, Richard Etheridge, L. Lee Grismer, Paula Mabee, Shar-
on Messenger, Steve Poe, Gregory Pregill, John Wiens, and an

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

113

anonymous reviewer provided valuable criticism of the manu-
script. I thank Richard Montanucci for helpful discussions as
well as the use of his extensive slide collection. John Huelsenbeck
graciously provided the program that allowed me to recompute
values specific to my data set.

Financial support critical to the completion of this project was
provided by the San Diego State University Department of Bi-
ology, the San Diego State Univeristy Mabel Myers scholarship

fund, the Society of Sigma Xi, the Theodore Roosevelt Memorial
Fund of the American Museum ofNatural History, the San Diego
Herpetological Society, and the California Academy of Sciences.

Scientific collecting permits were provided by the states of
Arizona and Texas. 1 am greatly indebted to Oscar Flores-Villela,
Arturo Gonzales-Alonso, Erik Mellink, and Fernando Mendoza-
Quijano, for obtaining permits (numbers 01303 and A00-700-
(2) 01480) that allowed for collecting in Mexico.

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Appendix 1

Specimens Examined

Museum acronyms follow Leviton et al. (1985)
except for the following nonstandard abbreviations:
BDH (collection of Bradford D. Hollingsworth), CES
(Centro Ecologio de Sonora, Hermosillo, Mexico),
EL (collection of Ernest Liner), JAM (collection of
Jimmy A. McGuire), JMS (collection of Jay M. Sav-
age), LLG (collection of L. Lee Grismer), MZFC
(Museo de Zoologia “Alfonso L. Herrera,” Univ-
ersidad Nacional Autonoma de Mexico), REE (col-
lection of Richard Etheridge), and UABC (Univ-
ersidad Nacional Autonoma de Baja California, En-
senada, Mexico). The following abbreviations de-
note the form of preparation for each specimen: D
(complete dry skeleton), S (skull only), P (preserved
specimen), ARAB (alizarin red, alcian blue stained
specimen), and H (hemipenis prepared by wax in-
jection). Locality data are presented for all ingroup
taxa examined but not for outgroup taxa.

Crotaphytidae

C. antiquus. — MEXICO: COAHUILA: CM 140199-140200;
TNHC 53152-53154, 53157, 53160-53161 (P), 53155-53156,
53158-53159 (D), MZFC 6750-6756 (P)-Sierra de San Lor-
enzo, approximately 0.25 mi. W of the pueblo of Santa Eulalia.

Crotaphytus bicinctores. —UNITED STATES: ARIZONA:
Coconino County: SDSNH 19479 (P)- Williams, 33053 (P)-5
mi. W Kane Ranch, 358 1 2 (P)-Coconino, Lee’s Ferry. Mojave
County: USNM 1 15677 (D)-Rampart Cave. Maricopa County:
REE 292 1 (D)— 6.3 mi. N Sentinel, 2922 (D)-2.3 mi. N Sentinel,

2923 (D), SDSNH 68624 (P)-7.0 mi. N Sentinel, 2924 (D) —
3.2 mi. N Sentinel; SDSNH 68623 (P)— 5.8 mi. N Sentinel, 68637-
39 (P) — Extreme E slope Gila Bend Mtns. on W shore Gila River
at jet. Old U.S. 80 and Gila River (W side Gillespie Bridge).
Yuma County: LLG 1397-99 (P) — Trigo Mtns., 12 mi. W Palo
Verde. REE 2931 (D)— Nr. Yuma Proving Grounds; SDSNH
16731 (P) — Castle Dome, 17602 (P)— Kofa Mtns., Wilbank
Ranch, 22351 (P)— Sentinel, 26911 (P)— Plamosa Mtns., 33301
(P) — Dublin, 68625 (P)— Dome Valley Solid Waste Transfer Site,
Co. 7th St., 1.0 mi. E Ave. 20E, NW of Wellton, 68626, SDSU
1723 (P)-S slope Laguna Mtns., 0.3 mi. NW Hwy 95 on rd. to
N.R. Adair Park (and shooting range). CALIFORNIA: Imperial
County: REE 2928-30 (D), SDSU 1 721-22 (P)-S end Chocolate
Mtns., jet. Ogilby Rd. and Hwy 86, REE 2925-27 (D)— jet. Palo
Verde Mtns. and Hwy 78, 2933 (D)— Black Mtn., 2.8 mi. SSE
Hwy 78 on Black Mountain Rd., 2934 (D), SDSNH 68627-28
(P, H), 68629-36 (P) — Chocolate Mtns., Black Mountain, Black
Mountain Rd. Inyo County: AMNH 108970-71 (D) — 9 mi. NE
Big Pine, ca 6000’; SDSNH 15878-79 (P)— Death Valley, Fur-
nace Creek, 15880-81 (P)— Death Valley, Stovepipe Wells, 15988
(P) — Argus Mtns., 3 mi. E Junction Ranch, 19475-77, 22218-
19 (P)— Ballarat, 22220 (P) — Emigrant Pass, 34113 (P)— 8 mi.
SE Keeler, 341 14 (P) — 8 mi. W Panamint Spring, 341 15 (P)—
Wildrose Station, 34305 (P) — Independence, Mazurka Canyon,
38255-56 (P)— Panamint Mtns., Wildrose Station. Kern County:
JMS 832 (S)— Twin Buttes nr. Mojave; REE 1570 (D) — 2 mi. S
Castle Butte. Riverside County: SDSNH 39751 (P) — 3 mi. E
Shaver’s Summit, 39752 (P)— foot of Fanhill Canyon, 40139
(P)_4 mi. NE Whitewater. San Bernardino County: REE 2932
(D)-Ord Mtns; SDSNH 2459-61 (P)— Victorville, 4407 (P)-
US Rt. 1 1 nr. California-Nevada line, 5874 (P)— Kramer Hills,
1 1087 (P) — N Fort Lytle Creek, 29091 (P)— Mountain Pass, 29229
(P)_7 mj. NE Cronise, 29664 (P)— Providence, Mtns., Cedar
Canyon, 38703 (P) — 20-50 mi. W Needles, 39874 (P)— Pipe Can-

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yon. IDAHO: Owyhee County: SDSNH 1 444 — 45 (P) — ID, Owy-
hee Co., Hot Springs S Bruneau. NEVADA: Clark County: JMS
203 (S) — Nr. Las Vegas. Lincoln County: USNM 18324 (D) —
25 mi. E Panaca, nr. Utah line. Storey County: LLG 1400-01
(P)— Carson City. Washoe County: JMS 197 (S) — White Mt.,
Truckee Meadows, 198 (S)— E side Truckee Meadows. UTAH:
Millard County: SDSNH 661-62 (P)-20 mi. NW Delta, 26704
(P) — 10 mi. S Kanosh. Washington County: SDSNH 24982-83
(P)— Zion Nat. Park, 24984 (P)-St. George, 25506-07 (P)-7
mi. NW Santa Clara, 25508-09 (P) — Beaver Dam Mtns., 25644-
46 (P)— Toquerville, 25647 (P)- Leeds, 25648-52 (P)-Rock-
ville; UIMNH 27723 (S)- Springdale, 93994-95 (S)-Nr. St.
George (nr. A Z border). No data: SDSNH 12244-45 (P).

C collaris. — MEXICO: CHIHUAHUA: CM 59531 (P)-40
mi. E Julimes, 59532 (P)— 1 8 mi. NE Aldama; KU 49628 (D)—
Vado de Fusiles, 157873 (D), SDSNH 49753 (P)— 22 km S Es-
tacion Moctezuma, KU 157874 (D), SDSNH 49755 (P)-30.6
mi. S jet Mex. Hwys 45 and 49; REE 1213 (D)— 20 mi. SW
Chihuahua, 1214 (D)-6 mi. W Camargo; SDSNH 47932 (P)—
Moctezuma, 47937^12 (P)— 1 1-20 mi. N Chihuahua, 49754 (P)—
1 1.6 mi. N jet. Mex. Hwys 45 and 49, 49756 (P)— 12.7 mi. N
jet. Mex. Hwys 45 and 49; UIMNH 48295 (S)— 27.7 mi. SCiudad
Delicias. COAHUILA: CM 42936 (P)— 8.6 mi. SW Cuatroci-
enegas de Carranza, N side San Marcos Mtn., 42938 (P)— 4 mi.
N Cuatrocienegas de Carranza, Rio Canon, 42939 (P) — 5 mi. N
Cuatrocienegas de Carranza, W slope Sierra del Muerto, 42940
(P) — 5 mi. N Cuatrocienegas de Carranza, N end Rio Canon,
42941 (P) — E edge Cuatrocienegas Basin, along Hwy. 13.5 mi. E
Cuatrocienegas de Carranza, 42942 (P)— Rancho San Fernando,
80 km SW Cuatrocienegas de Carranza; KU 147299 (D)— Mo-
tacorona; REE 2944 (D)— 1 7.3 mi. E Viesca; SDSNH 49744 (P)—
15.4 mi. S and 1.3 mi. W Sabinas, 49745 (P) — 15.4 mi. S and
0.6 mi W Sabinas, 49746 (P) — 0.9 mi. SE Motacorona, 49747
(P) — 7.4 mi. N Ahuichila, 49748 (P) — 5.8 mi. N Ahuichila, 49749
(P) — 21.5 mi. SW Viesca, 49751 (P)— 1 5.4 mi. S Sabinas, 6 mi.
W, 49752 (P)— 15.4 mi. S Sabinas, 3 mi. W, 56752 (P)— 15.4
mi. S and 4.8 mi. W Sabinas; UIMNH 43224-25 (S)— 15.6 mi.
E Cuatro Cienagas; SDSU 2061 (P, H)— 4.3 mi. N Bahia de
Ahuichila, 2062 (P) — 22.6 mi. S Viesca, 2063 (P)— 4.8 mi. N
Bahia de Ahuichila, 2064 (P) — 1.3 mi. N Bahia de Ahuichila,
2065 (P)— 15.1 mi. E Viesca. NUEVO LEON: CM 42943 (P)-
2.7 mi. S Villa Garcia; SDSNH 56750 (P)— 27.9 mi. N Mina.
ZACATECAS: SDSNH 5675 1 (P>— 1 . 1 mi. W Tecolotes. UNIT-
ED STATES: ARIZONA: Cochise County: AMNH 735 1 8, 74752,
75657 (D) — Portal. Coconino County: AMNH 82297 (D)— 11
mi. NNW Cedar Ridge; SDSNH 2087 (P)— 1 6 mi. N Flagstaff,
9010, 29231 (P)— Canyon Diablo, 25503-05, 25639-40, 29131
(P) — Meteor Crater, 29645 (P)— Two Guns, 32529, 32658, 34466
(P), JMS 200 (S), UIMNH 34337 (S)- Wupatki Nat. Monument,
JMS 202 (S)— The Citadel, Wupatki Nat. Monument; SDSNH
40958-59 (P)-1000 yds from Meteor Crater; UIMNH 27727
(D)— Wupatki Nat. Monument, nr. Citadel (4 mi. from Hwy 89).
Gila County: SDSNH 27751 (P)— Sierra Ancha Mtns. Pima
County: USNM 220214 (D)— Continental. Yavapai County:
AMNH 84489, 85381, 85625 (D) — vicinity of Stanton. AR-
KANSAS: Brown County: SDSNH 40963-66 (P)-7 mi. N Har-
rison. County undetermined: USNM 220216 (D) — Red River.
COLORADO: Delta County: CM 39257-39258 (P)— 14 mi. NW
Delta, Escalante Canyon. Fremont County: SDSNH 62106-13
(P) — Wet Mountain Project. Garfield County: JAM 3 1 5 (ARAB),
REE 2871, 2874, 2879, (D) SDSU 1735, 2108 (P)— 17.9 mi. N
Hwy 70 via Hwy 139, REE 2878 (D)— 18.5 mi. N jet. Hwys 139
and 70 via Hwy 139. Mesa County: CM 42932 (P)— Stovepipe

Canyon, 2 mi. W, 1 7 mi. N Fruita, 42933 (P) — Colorado National
Monument, mouth E Monument Canyon, 44747 (P)— Colorado
National Monument. Montezuma County: CM 67094-67097
(P)— Bridge Canyon. San Miguel County: CM 42931 (P) — Dis-
appointment Gap Spring (= Gypsum Gap). KANSAS: Cowley
County: SDSNH 10982 (P)-7 mi. NE Winfield, 2 1 859-63 (P)-
2 mi. NE Winfield. Douglas County (?): REE 1797, 1823-24
(D)— nr. Lawrence. County undetermined: REE 1836, 1857 (D)—
Kansas. NEW MEXICO: Colfax County: JMS 189 (S)— 1 .5 mi.
N Chico post office, 7200'. Dona Ana County: REE 2945 (D) —
Organ Mtns., 1 .7 mi. S Hwy 82/70 on Baylor Canyon Dr., 2946-
48 (D)— Organ Mtns., 5.1 mi. S Hwy 82/70 on Baylor Canyon
Dr., 2949 (D)— Organ Mtns., 5.0 mi. S Hwy 82/70 on Baylor
Canyon Dr.; SDSU 2059 (P)-Organ Mtns., 4.1 mi. S Hwy 82/
70 on Baylor Canyon Dr. Eddy County: SDSU 2067 (P) — Carls-
bad. Graham County: JMS 20 1 (S) — 9. 1 mi. ENE San Jose along
new paved road to Clifton (1951). Hidalgo County: CM 75544-
75551 (P)— ST 9, 3-5 mi. W Animas. Rio Arriba County: SDSNH
9007-08 (P)— Dixon, 57854 (P) — El Cobre Canyon. San Juan
County: AMNH 108314(D), SDSNH 20044 (P)-Chaco Canyon
Nat. Monument. San Miguel County: JMS 190 (S) — 10 mi. E
Sanchez, 192 (S) — 3.9 mi. NE Trementina. Torrance County:
JMS 191 (S) — Manzano. OKLAHOMA: Cherokee County:
SDSNH 52752-57 (P)— Tenkiller Ferry Reservoir. Jackson
County: JAM 556 (P), REE 2951-52 (D)-Altus. TEXAS: Brew-
ster County: SDSU 2058, 2066 (P) — 2.3 mi. W Study Butte via
Hwy 170. USNM 217271 (D)— specific locality unknown. Palo
Pinto County: JMS 40, 195-96 (S)— Palo Pinto. Pecos County:
JMS 194 (S)— Ft. Stockton. Presidio County: SDSU 2060 (P)—
the River Road at the Teepees (W of Study butte). Reeves County
(?): REE 2950 (D)— Pecos region. Shackelford County: Fort Grif-
fin. Travis County: SDSU 2068-7 1 (P)— Milton Reimer’s Fishing
Ranch, 0.9 mi. from FM 3238 off Hwy 7 1 . UTAH: Grand Coun-
ty: REE 2869, 2877 (D), SDSU 1734 (P, H)-33 mi. N jet Hwy
191 (NE Moab) via Hwy 128, REE 2870, 2875-76 (D), SDSU
2105-07 (P)— 32.2 mi. Njct Hwy 191 (NE Moab) via Hwy 128;
SDSU 2109 (P) — 29 mi. NE Moab on Utah Hwy 128.

C. dickersonae. — MEXICO: SONORA: AMNH 78949 (PI-
SE side Tiburon Island between Monument Pt. and red Bluff;
BYU 2425, 39995 (P)— 23 mi. N Kino Bay near coast, 2426,
2433, 3164, 3166-69, 3172 (P) — Punta Perla, NE end Tiburon
Island; CAS 14008-12 (P)-Isla Tiburon, SE end. 53265 (P), JMS
208 (S)— Tiburon Island; REE 2774-77, 2787-88, 2904-05 (D),
SDSU 1720, 23 1 8 (P), 2319 (P, H)— 1 .2 mi. N Bahia Kino Nuevo
via rd. to Punta Chueca, REE 2777-86 (D), SDSU 1718 (P)—
Isla Tiburon, El Corralito, Appx. 3 km N of S end of island;
SDSNH 47936 (P)— 10 mi. N Bahia Kino; SDSU 1719 (P) — Isla
Tiburon, Appx. 5 km N El Corralito (S end of island); UAZ 704-
OS, 30226 (P)— 6.5 mi. by rd. NW Desemboque, 9625-26 (P)—
Isla Tiburon, Ensenada Blanca, 16578 (P)— Bahia Kino, Mtn.
NW Caverna Seri, 20144 (P)— Punta Cirio, 7.0 mi. by rd. S
Puerto Libertad, 42569 (P) — Punta Cirio, Sierra Bacha, SE Lib-
ertad; USNM 238243-46 (P) — 11.5 mi. N Punta Chueca, 238247-
48 (P), 238249 (P, H)— 4 mi. N Bahia Kino, 248142-43 (P)—
Isla Tiburon, S end, 248 1 74-80 (P) — 3 mi. N Bahia Kino (Nuevo).

C. grismeri. —MEXICO: BAJA CALIFORNIA: Sierra de Los
Cucapas: CES 067-624 (P), 067-627-29 (P), 067-25 (P, H); MZFC
6647-51 (D); UABC 1 15-19 (P) — Canon David, appx. 2 km W
Mex. Hwy 2 on the rd. to the Sulfur mine (turnoff at km 49 S
Mexicali); USNM 37625 (P) — Volcano Lake.

C. insularis. — MEXICO: BAJA CALIFORNIA: CAS 14002
(P) — Isla Angel de La Guarda, SE end, 2 1 948^49 (P)— Isla Angel
de La Guarda, nr. small bay opposite Bay of Los Angeles (appx.

122

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

29°6 N, 113°12'W), 22712 (P) — Isla Angel de La Guarda: nr.
small bay on SW shore, opp. Bay of Los Angeles (appx. 29°6'N,
1 13°12'W), 50873-79, 86754-55, 86783-84, 148650—52; REE
2793-97 (D), SDSU 1732 (P. H), 1733 (P)— Isla Angel de La
Guarda, N end; SDSNH 19971, 19773-75, 50664, 53064 (P)-
Isla Angel de La Guarda.

C. nebrius. — MEXICO: SONORA; AMNH 73715 (S)-Guay-
mas, 73758 (P) — 1 6 mi. (via road) S of Nogales, 75682-83 (P)—
Punta San Carlos, 7 mi. N Guaymas, 80852 (P)— 2.3 mi. (road)
NEGuaymas; BYU 40930-31 (P)— 8 mi. N Guaymas; CAS 12774
(P) — 31 mi. SW Moctezuma; KU 1 52639-42 (P)- 139.4 km NW
Caborca on Mex. Rt. 2, 176402 (P)— 6.4 km S Guaymas; JMS
205 (S)— 10 mi. S Hermosillo; LACM 8798 (P)— 59.5 mi. E San
Luis, 8799 (P)-84.1 mi. E San Luis; MVZ 10163-65 (P)-Sierra
Alamo, 30 mi. W Caborca, 136687-88 (P) — 1 .9 rd. mi. N Ba-
cadehuachi, 136689-90 (P)— ca 4.1 rd. mi. NW Nacori Chico;
REE 370-71 (D)— nr. Pitiquito, 404-07 (D), 40 mi. W Sonoita,
2771-73 (D) — appx. 5 mi. N San Carlos Nuevo; SDSNH 49008
(P)— N bay at Guaymas; SDSU 2072 (P) — 66.6 mi. W Sonoita,
2073 (P)— 3.5 mi ENE Huasabas, 2074 (P)— 5.2 mi. ENE Huas-
abas. UNITED STATES: ARIZONA: Maricopa County: SDSNH
68657-58 (P) — Buckeye Hills Recreation Area, above picnic area
offBuckeye Hills Dr., 68659-61 (P)— Extreme W slope of Buck-
eye Hills on E side Gila River at jet. Old U.S. 80 and Gila River
(E side Gillespie Bridge). Pima County: CAS 81420 (P)— 20 mi.
S Ajo, Alamo Canyon, Organ Pipe Nat. Monument; KU 121460
(P) — Gates Pass, Tucson Mtns. W Tucson; MVZ 76641 (P),
UIMNH 5898 (S)— Ajo Mtns., Alamo Canyon, Organ Pipe Cac-
tus Nat. Monument; REE 2937-38 (D)— SE edge Tucson Mtns.,
nr. end Sarasota Dr., 2939-41 (D)— Little Ajo Mtns., 2.9 mi. W
Hwy 85 on entrance rd. to Ajo Air Force Station; SDSNH 68640-
41 (P)— Ajo Mtns., ca 1.5 mi. S of Why, 68642-44 (P) — Quijotoa,
68645 (P), 68646 (P, H)-0.9 mi. S Why, 68647 (P) — 4. 1 mi. N
Hwy 86 on rd. to Hickiwan, 68648—49 (P)— Silverbell Mtns.,
20.4 mi. (by rd.) W Tucson Mtns. by way of Avra Valley Rd.
Pinal County (?): KU 14860 (P)-20 mi. SW Phoenix. Yuma
County: REE 2925 (D)—W face Gila Mtns., on Hwy 8, 4 mi. E
Foothills Dr.; SDSNH 68650, 68652-54, SDSU 1724-25 (P)—
W slope of Gila Mtns., ca 2 mi. N Hwy 8, SDSNH 68651 (P)—
N slope Gila Mtns., 0.25 mi. S of RR tracks on S side Hwy 95
(at mile marker 39), 68655-56 (P)— Mohawk Mountains, N side
Hwy 8.

C. reticulatus. — MEXICO: COAHUILA: SDSNH 56753 (P)-
11.1 mi. S Villa Union. NUEVO LEON: EL 4138 (P)— 5.9 mi.
SSW 0. 9-2.0 mi. NW Cerralvo along Rancho los Robles rd. to
Picacho Mtns, 4816 (P)— 6.2 mi. SW Cerralvo at Rancho Los
Montemayores; JMS 211 (S)— between General Teran and El
Carbendo; UIMNH 3983 (S), 3984 (P)— 14 mi. E Cadereyta,
Reynosa-Monterrey rd. TAMAULIPAS: 4 1 30 (P) — Tamaulipas,
9.9 mi. SW Mier. UNITED STATES: TEXAS: County undeter-
mined: KU 128993 (P)— 7 mi. S Chacon Creek on Hwy 83 and
8 mi. NE on road to La Gloria Ranch. Dimmit County: KU
1 26948—52 (P) — 26 mi. SCarrizo Springs on Hwy 186, San Pedro
ranch. Maverick County: EL 3250. 1-50.2 (P) — 1 mi. E Eagle Pass
on Manges Ranch; KU 481 (P) — Eagle Pass, 143567-69 (P)— 1
mi. E Eagle Pass off U.S. Rt. 277, 147257 (P), 147266-76 (S),
1 47277-78, 1 57875-76 (D)- 1 mi. E Eagle Pass, Manges Ranch;
SDSNH 46884-86 (P) — 2 mi. E Eagle Pass, 56754-55 (P) — 1 mi.
E Eagle Pass. McMullen County: CM 64677 (P) — 4. 1 mi. W jet.
St. Hwy. 16 and FM 624 (ca 22 mi. SSW Tilden). Starr County:
KU 9092 (P) — Arroyo El Tigre, ca Rio Grande City, 1 3202 (P)—
Rio Grande City, 15388 (P)-23 mi. NW Rio Grande City;

UIMNH 20336 (S)— Arroyo Los Alamos, 3 mi. SE Rio Grande
City. Webb County: CM 52334-35 (P)— 40 mi. WNW Laredo
on FM 1472; EL 4748 (P) — 21.8 mi. W Mirando City on Texas
Rt. 359; KU 61 447-49 (P)-40 mi. NW Laredo, 121487, 121489,
121491 (P) — 5.2 mi. E jet. Hwys 44 and 83, 121488 (P) — 10 mi.
S Laredo, 126940-47, 126953-56, 126958 (P)-40 mi. WNW
Laredo on FM 1472, Trevino Ranch, 128990 (P) — 2 1 mi. NW
1-35, ca Laredo on FM 1472, 128992 (P)— 23 mi. NW 1-35, ca
Laredo on FM 1472, 7 mi. NE on El Chapote Rd.; REE 2906
(D)— 37.0 mi. NNW Laredo on FM 1472, 2907 (D)-41.8 mi.
NNW Laredo on FM 1472, 2908 (Dj-25.3 mi. NNW Laredo
on FM 1472, 2909 (D)-34.4 mi. NNW Laredo on FM 1472,
2910 (D) — 36.0 mi. NNW Laredo on FM 1472, 2911 (D)- 19.6
mi. NNW Laredo on FM 1 472, 29 1 2 (D)-35.7 mi. NNW Laredo
on FM 1472, 2913 (D)-22.6 mi. NNW Laredo on FM 1472;
SDSNH 41333 (P) — about 10 mi. S Laredo. Zapata County: KU
13203 (P)— San Ignacio.

C. vestigium. — MEXICO: BAJA CALIFORNIA: CAS 14000-
01 (P) — Vicinity Bahia de Los Angeles, 154267 (P) — 7 km W (by
rd.) of Bahia de Los Angeles; JMS 207 (S) — El Marmol, 210 (S),
SDSNH 43226 (P)— Sierra de Juarez, Camillas Canyon; REE
2806 (D)— 1.5 mi. N Bahia de San Luis Gonzaga, 2807-08 (D)—
Sierra Las Pintas, 2810 (D)— 10 km W Bahia de Los Angeles,
2814 (D)— 1 km W Bahia de Los Angeles, 2815 (D)— 1.5 km S
of hwy to Bahia de Los Angeles at km marker 56, 2822 (D) — 46
km W int. Mex. Hwys 3 and 5 on Hwy 3, 2823 (D)— Sierra San
Felipe, Campo La Roca, 18.5 mi. S San Felipe, 2824 (D)— 20
mi. NW San Felipe, int. powerlines and Sierra San Felipe, 2936
(D)— 28.5 mi. N Bahia de Los Angeles; SDSNH 17052 (P)-S
base of Sierra de Juarez, 17667 (P) — San Borja, 24391-92 (P) —
San Jose, 26754 (P)— E side Sierra San Pedro Martir, Canon del
Cardones, 37815 (P)— 1 mi. NW San Felipe, 41612 (P)— appx.
2.5 mi. W Bahia de Los Angeles, 45978 (P) — SE Mesa de San
Carlos, 52950-5 1 (P) — Bahia de Los Angeles, 1 .8 mi. S of V.S.E.
Field Station; SDSU 1726-27 (P)— 5 km E El Parador on rd. to
Bahia de Los Angeles, 1728 (P) — W base Sierra La Asamblea,
appx. 20 mi. N El Parador. BAJA CALIFORNIA SUR: CAS
18822 (P)-BCS, 9 mi. W San Ignacio, 146684 (P)-Santa Ague-
da, 147683 (P)— 29.1 mi. S (by rd.) Mulege on Mex. Hwy 1,
154268-70, 154272 (P), 154271 (P, H)-Santa Agueda; REE
2809 (D)— 9.7 mi ESan Isidro, 281 1 (D)— 16 km S Mulege, 2812
(D)— 2 km E San Jose de Magdelena, 2813 (D)— 1 km E San
Jose de Magdelena, 2816-17 (D) — km marker 76 N Loreto, 2818
(D)-Km 28 E Mex. Hwy 1 on rd to San Francisco de La Sierra,
2819 (D)— 7.6 mi. E San Isidro, 2820 (D)— 5.4 mi. E San Isidro,
2821 (D) — 3.0 mi. E San Isidro, 2825 (D)— 17.2 mi. S by rd. of
San Jose de Comondu, 2826 (D)— 1 3.2 mi. S by rd. of San Jose
de Comondu; SDSU 1729 (P)— 10.6 mi. S San Jose de Comondu,

1 730 (P)— Rd. to San Francisco de La Sierra. UNITED STATES:
CALIFORNIA: Imperial County: JAM 41 (ARAB)-Inkopah
Trail, 2 mi. E Jacumba; REE 2935 (D) — Mountain Springs, N
side westbound Hwy 8. Riverside County: BYU 2422, 2430,
2432, 2435, 2438 (P) — Chino Canyon, W Palm Springs. San
Diego County: CAS 7930 (P)— Palm Canyon, 62794-95 (P) —
San Felipe Creek, 62875 (P)- Mason Valley; JAM 617-18 (P)-
VallecitosCo. Park, McCain Pit; JMS 199 (S)-Sentenac Canyon,
204 (S) — 3.5 mi. E Jacumba, 209 (S)— Borrego Mtn. No data:
SDSNH 19788-92 (P).

Gambelia copei. — MEXICO: BAJA CALIFORNIA: MVZ
31794-95 (P)— 3 mi. W Canyon de Llanos, ca 10 mi SW Alaska
(= Rumarosa), 31839 (P) — 6 mi. W Alaska (= Rumarosa), 140759
(P) — Sierra San Pedro Martir, 2 mi. SW Paseo de San Matias;

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

123

REE 2800 (D)-1.0 km N San Borja; SDSNH 4071 (P)-San
Jose, San Telrno River, 4143 (P) — 3 mi. E. San Telmo, 5078-
80, 26752-53 (P)-San Jose, 5264, 15969 (P)-Isla de Cedros,
S. end, 7249, 17411, 24340-42 (P)-Isla de Cedros, 18118 (P)—
Bahia de San Francisquito, 18945-46 (P)— Valle de Trinidad,
19787 (P)— 40 mi. W Bahia de Los Angeles, 27693-94 (P)— Isla
de Cedros, canyon N middle canyon, 27965 (P) — Isla de Cedros,
Middle Canyon, 41613 (P)— Mouth of Arroyo de Rosario, 42622
(P) — 2 mi. N. San Simon, 43007 (P) — 8 mi, E. El Rosario, 45916
(P)-NE Mesa de San Carlos. BAJA CALIFORNIA SUR: CAS
56105 (P)— Isla Santa Margarita, 147738-39 (P)-1.3 mi. NE
Punta Abreojos, 147750 (P)— SE Sierra Santa Clara; REE 2798
(D)— km 24.5 on rd. to Punta Abreojos, 2799 (D) — Sierra Santa
Clara, 2801 (D)— jet. rds. to Puerto Nuevo and Bahia Tortuga,

2802 (D)— km 57 W of Mex. Hwy 1 on rd. to Punta Abreojos,

2803 (D)— Sierra Santa Clara, Rancho Santa Clara, 2804 (D)—
Sierra Santa Clara, 1.0 mi. S Rancho San Ramon, 2805 (D)—
km 30.25 on rd. to Punta Abreojos; SDSNH 1 7470 (P) — El Arco,
Miraflores Rancho. UNITED STATES: CALIFORNIA: San Di-
ego County: CAS 40302, 57865 (P)— Campo, 62964 (P) — Potrero
Grade; SDSNH 55251 (P)— 1.5 mi. NE Cameron Comers.

G. coronaf. —UNITED STATES: CALIFORNIA: San Diego
County: LACM 7058/42880 (S)— Anza Borrego Desert State Park.

G. silus. — CALIFORNIA: Fresno County: CAS 22713 (D),
227 14 (D, H)— in dry Panoche Creek bed, mouth of canyon on
W side San Joaquin Valley (about 120°39'W, 36°38'N), 20 mi.
by rd. WSW Mendota, 23250 (H)— nr. foothills, 3 mi. SE mouth
of Panoche Canyon and 16.5 mi. SW Mendota, next to pole line
rd., “Staggeredrock trap station,” 141318-19 (D)— 20.2 mi. S jet.
Cal Hwys 33 and 1 80, and 1 .7 mi. W on dirt rd. (nr. three Rocks);
KU 121493 (P), 121751 (S)-Bundgard Ranch, 10 mi. ESE Men-
dota, 121 500 (P) — 8 mi. ESE Mendota ca Double C Ranch, 121504
(P), 121752-53 (S) — 9 mi. ESE Mendota at Double C Ranch,
121507 (P)— 121520, 121526-27 (P)-2 mi. SWjct. Interstate 5
and Shields Ave. on Panoche Plain, 121524 (P), 121510 (S)—
Mouth of Little Panoche Creek on Levy-Zentner Ranch, 121754
(S) — 2 mi. S jet. Shields Ave. and Little Panoche Rd., 12175 5—
56 (S) — 2 mi. SSE jet. Shields Ave. and Little Panoche Rd.,
1 2 1 758-60, 121762 (S)- 1 mi. NW Three Rocks, 1 5 mi. S Men-
dota, 121764 (S) — Levy-Zentner Ranch, 1 mi. E mouth Little
Panoche Creek, 121765 (S) — 3 mi. N Mercey Hot Springs along
Little Panoche Creek, 121766 (S) — 2 mi. S jet. Interstate 5 and
Shields Ave, 121767-68 (S)— Levy-Zentner Ranch, Little Pa-
noche Wash. Fresno County (?), 2 mi. S turnoff to Little Panoche
Ranch on Little Panoche Rd., 121511 (P), 121757 (S) — Little
Panoche Ranch turnoff on Little Panoche Rd. Kern County: KU
121769-75 (S) — Blackwell’s Comer, 30 mi. W Wasco, jet Hwys
33 and 46; SDSNH 16055-59 (P)-3 mi. N McKittrick, 42434-
35 (P) — W end Greenhorn Mtns, 46339 (P) — Bakersfield. Kings
County: JMS 206 (S) — 2 mi. S Kettleman City; SDSNH 31697
(P)— Wheeler Ridge Post Office. Madera County: KU 121605,
121610, 121615-16 (P)— 8 mi. E Firebaugh, 121623 (P)-4 mi.
E Firebaugh on Rd. 9, 121748, 121750 (S) — 8 mi. E Firebaugh
off Ave. 7 1/2, 121749 (S) — 12 mi. E Firebaugh; SDSNH 46888-
89, 49758-59 (P) — 5.9 mi. E Firebaugh. Merced County: KU
121631-34, 121636-38 (P)— 4.5 mi. NWjct. Hwy. I 52 and Hwy.
59, Red Top, 121 644 — 46, 121648 (P) — 10 mi. SW Los Banos on
Arburua Rd., 1 2 1 647 (P) — 9 mi. SW Los Banos on Arburua Rd.,
121649 (P)— Wjct. Arburua and Langdon Rds., 121650-5 1 (P)—
8.7 mi. S Los Banos off Mercy Springs Rd., 121652 (P) — 1 0 mi.
SW Los Banos, W jet. Arburua and Langdon Rds. San Benito
County: CAS 22724-25 (D)— in and about the dry wash, SE end

Panoche Valley; KU 121537 (P)-2 mi. N jet. Little and Big
Panoche Rds. San Luis Obispo County: CAS 23 1 95 (H) — Carrizo
Plain, dry creek at N end of false valley between Panorama Hills
and the Temblor Mtns., 13 mi. at 235 degrees from Simmler;
KU 121657 (P)— 0.3 mi. W and 0.2 mi. S jet. CA Rts. 33 and
166, 121658 (P) — 1.7 mi. E jet. CA Rts. 33 and 166, 121659
(P) — Cuyama Valley at jet. CA Rts. 33 and 166, 121662 (P)—
7.8 mi. N jet. Soda Lake Rd. and CA Rt. 33, 121664 (P) — 7.5
mi. N jet. Soda Lake Rd. and CA Rt. 33, 121671 (P) — 7 mi. W
Maricopa.

G. wislizenii. — MEXICO: BAJA CALIFORNIA: BYU 23336
(P) — 5 mi. N. San Felipe, 34513 (P) — 3 mi. S. San Felipe (by rd.
to Puertocitos), 34514 (P)— 2.9 mi. S. San Felipe (by rd. to Air-
port), 34515 (P) — 4 mi. W. San Felipe (at trash dump); CAS
90256 (P)— San Felipe-Ensenada Rd. (Mex. Hwy. 3), 6.8 mi. W.
of San Felipe-Mexicali Hwy (Mex. Hwy 5), 119100 (P)— Mouth
of Guadalupe Canyon; LACM 94813 (P) — Arroyo Matomi,
132230 (P)— N. end Laguna Salada, 132231 (P) — 3 mi. N. Pozo
Penara, Laguna Salada; MVZ 9589 (P)— E. base San Pedro Martir
Mountains, El Cajon Canyon, 50017 (P)— Punta San Felipe,
182117 (P) — 5.8 mi. N. San Felipe (via Mex. Hwy. 5). CHI-
HUAHUA: UIMNH 6672-73 (S) — 28.7 mi. S Samalayuca, 40408
(S)— sand dunes 35 mi. S Juarez, 43373-75 (S) — 6.8 mi. S Sa-
malayuca, 43383 (S) — 0.3 mi. E Carillo. COAHUILA: EL 3129
(P) — 5.2 mi. S. Cuatrocienegas de Carranza along Rio Mesquites;
UIMNH 43378 (S) — 7 mi. E Matamoros. DURANGO: UIMNH
43379 (S) — 13.5 mi. S Tlahualilo. SONORA: CAS 15347 (P)-
1.5 mi. W Altar, 15356 (P)— 4.7 mi. SSE La Playa, 17049-50
(P) — Isla Tiburon, SE end of island, 104451 (P)— Isla Tiburon,
SW end; REE 2789-91 (D)— Isla Tiburon, appx. 2 mi. N El
Corralito (S end of island); SDSNH 38251 (P)-3 mi. NE Punta
Penasco, 38252 (P)— 16 mi. NE El Papalote, 38253 (P) — 18.5
mi. NE El Papalote, 38254 (P)— 1 2 mi. NE Punta Penasco, 38605
(P)-El Papalote, 38606 (P)- 1 mi. NE El Papalote, 38888 (P)-
12 mi. NE Punta Penasco, 40601 (P)— 24 mi. N Punta Penasco,
49009 (P)— 36 mi. E. San Luis. UNITED STATES: ARIZONA:
Coconino County: SDSNH 6030-32 (P)— Grand Falls of Little
Colorado River, 32560 (P)— Nr. Jacob Lake, 35813-14 (P) — 3
mi. SW Navajo Bridge. Maricopa County: JMS 187 (S)— Wick-
enburg. Yuma County: REE 810 (D)— Yuma County. Undeter-
mined: USNM 220224 (D) — Arizona. CALIFORNIA: Imperial
County: REE 1029, 1172 (D)-Glamis, 2915 (D)-Salton City;
SDSNH 1879 (P) — 5 mi. E. Holtville, 7143 (P) — 4 mi. N. Kane
Spring, 7847 (P)— Kane Spring, 10937 (P) — Mountain Spring,
11346 (P)— Coyote Wells, 13352 (P) — 4 mi. N. Bard, 13911,
20967 (P) — Gray’s Well, 1 8596 (P) — 6 mi. N. Truckhaven, 28762
(P)-Niland. 36541 (P)-Ocotillo, 39735 (P)-5 mi. E San Di-
ego-Imperial Co. line, 49002 (P)— 17.5 mi. W. Calexico, 49003
(P) — 3 mi. E. Coyote Wells. Kem County: USNM 18298 (D)—
Kernville. San Bernardino County: CAS 190054 (H) — Kelbaker
Rd., 2.6 mi. SE Baker; JMS 41 (S) — 29 Palms; REE 1571 (D)-
17 mi. ESE Lucerne Valley, 2916-17 (D), SDSNH 68662, 68664
(P)— Hinkley, Hinkley Rd, REE 2918-20 (D), SDSNH 68663,
SDSU 2282 (P)— Johnson Valley, Camp Rock Rd; SDSNH 23636
(P)— Stoddard Well. San Diego County: JMS 21, 186 (S)— Clark
Dry Lake, 1 84 (S)— Borrego Valley, 185-1,2 (S)-Split Mountain,
188 (S) — 14 mi. E Benson’s Dry Lake. County undetermined:
REE 496, 550 (D) California. IDAHO: Ada County: SDSNH
1450-51 (P) — Ada Co., foothills N. of Boise. Elmore County:
SDSNH 1452 (P)-S. of Cleft. NEVADA: Nye County: UIMNH
93992-93 (S) — 1 5 mi. N Mercury. Storey County: REE 2914
(D)— Carson City. Washoe County: UIMNH 3166 (S)— 20 mi.

124

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

N Reno. 3167-68 (S) — 5 mi. S Sutcliffe, Pyramid Lake, USNM
220226 (D) — Sutcliffe, Pyramid Lake. County undetermined:
Nevada, camp 1 2. NEW MEXICO: Luna County: EL 5 1 76 (P)-
4.2 mi. S., 0.6 mi. E. Deming on Rock Hound State Park road.
UTAH: Javier County: JMS 1 83 (S) — 2 mi. W Monroe. San Juan
County: CAS 141349 (H)— 10.8 rd. mi. N Montezuma Creek.
No locality: JMS 700 (D).

Chamaeleonidae

Brookesia kersteni: REE 532 (D). B. stumpffi: REE 1911 (D).
Hydrosaunis amboiensis: REE 2068 (D), 2080 (D); SDSNH 47009
(D). H. pustulatus: CAS 11000-01 (P), 28171 (P), 62377 (P),
85642 (P). Leiolepis belliana: REE 1680 (D), 1906 (D), 1908 (D),
1993 (D), 2505 (D); SDSU 2587-90 (P). Physignathus cocincinus:
SDSNH 67845 (D), 68062 (D). P. lesueurii: KU 69303 (S, P),
69304 (P); REE 1364 (D), 1722 (D), 1849 (D). Uromastyx acan-
thinurus: CAS 135162 (P), 1 35 166-67 (P); KU 94507 (S, P); REE
318 (D), 450 (D); SDSNH 62665 (D). U. aegyptius: SDSU 2584
(P). U. asmussi: CAS 154357 (P). U. benti: SDSNH 68121 (D).
U. geyrii: CAS 135006-16 (P). U. hardwickii: REE 1339 (D),
1 840 (D); SDSU 2573-78 (P). U. loricatus: CAS 86379 (P), 86463
(P), 120480 (P). U. macfadyeni: SDSU 2580 (P). U. microlepis
(synonymized with U. aegyptius by Moody, 1987): CAS 97834-
35 (P); SDSNH 55288 (D); SDSU 2585-86 (P). U. ocellatus:
SDSU 2582-83 (P). U. philbyi: C AS 139537 (P), 141997-98 (P);
SDSU 2579 (P). U. thomasi: CAS 190887 (P); SDSU 2581 (P).

Corytophanidae

Basiliscus basiliscus: KU 84956 (D), 93452-54 (D); REE 2015
(D). B. plumifrons: KU 25660 (P), 91784 (P), 96637 (P), 180368
(P); REE 427 (D), 2014 (D); SDSNH 57098 (D), 57100 (D);
SDSU 2093 (P). B. vittatus: REE 49 (D), 555 (D), 637 (D), 1601
(D), 1729 (D), 1757 (D), 1759 (D); SDSU 2095-96 (P). Cory-
tophanes cristatus: KU 59602 (P); SDSNH 62345 (D), 67849-
50 (D); SDSU 2098-2100 (P). C. hernandezi: KU 24068 (P),
24070-71 (P), 24073 (P); REE 1 176 (D), 1800 (D); SDSNH 68090
(D). C. percarinatus: KU 93456 (S), 184183-84 (P), 187149-50
(P), 190773 (D). Laemanclus longipes: KU 27529 (P), 59608 (P),
187739 (P); SDSNH 64542 (D), 67835 (D), 68086 (D). L. ser-
ratus: KU 70226 (P), 70267 (P), 74910 (D), 75532 (P); REE 619
(D); SDSU 2095 (P).

Hoplocercidae

Enyalioides laticeps: KU 125967 (D), 147929-34 (P), 147937
(P), 147939-42 (P), 152497-98 (P); REE 76 (D); SDSU 2116-
17. E. oshaughnessyi: KU 122116 (P), 147183 (P); REE 1957
(D). E. praestabilis: KU 122117 (P), 140394 (P), 147184 (P),
169854 (P).

Iguanidae

Brachylophus fasciatus: REE 1019 (D), 1866 (D), 1888 (D);
SDSNH 55601 (D), 55603 (D); SDSU 2591-93 (P). Dipsosaurus
dorsalis: JAM 287 (D), 345-51 (D); SDSU 2594-600 (P).

Opluridae

Chalaradon madagascariensis: KU 187757 (P), 187762-63 (P),
187765 (P), 187756 (S); REE 455 (D), 457 (D), 547 (D); SDSU
2123-29. Oplurus cuvieri: JAM 281 (D); KU 1 87666-68 (P); REE
558 (D), 620 (D), 1835 (D). O. cyclurus: CAS 86739 (P). O.
fierinensis: KU 187769 (P), 187770 (S,P), 187771—72 (P). O.
quadrimaculatus: REE 658 (D); SDSU 2120-22 (P). O. saxicola:
CAS 13958 (P), 14439 (P), 86724 (P); SDSU 2119 (P).

Phrynosomatidae

Callisaurus draconoides: JAM 88 (D), 184 (D), 202 (D), 361
(D). Petrosaurus mearnsi: JAM 285 (D), 288-90 (D), 295 (D);
REE 35 1 (D), 557 (D); SDSU 2253 (P). P. repens: SDSNH 1 7484
(P), 45985 (P). P. thalassinus: REE 575 (D), 765 (D); SDSNH
17484 (P), 32922 (P), 44516 (P), 45985 (P). Phrynosoma asio:
REE 1489 (D), 1580 (D), 1676 (D); SDSU 2308-09 (P). P. co-
ronatum: REE 310 (D), 390 (D), 527 (D), 609 (D), 1438-39 (D),
1786 (D), 1999 (D); SDSNH 1 6042^43 (P); SDSU 2305-07 (P).
P. ditmarsi: SDSU 2278 (P). P. douglassi: REE 1109-11 (D),
1 118(D), 1372 (D); SDSU 2283-84 (P). P. orbicular e: REE 1104
(D), 1181 (D), 1725 (D), 1920 (D), 1931 (D). Uma exsul: REE
2880-81 (D); SDSU 2274-77 (P). U. inornata: KU 90961 (D),
95849 (D); REE 263-64 (D), 602 (D),1538 (D); SDSNH 2754
(P), 48486 (D). U. notata: JAM 172 (D), 235-37 (D), 239-41
(D); SDSU 2558-63 (P). U. scoparia: BDH 117 (D); CAS 42135
(S); REE 509 (D), 551 (D), 2867 (D); SDSNH 7556 (P), 7658
(P), 38419 (P). Urosaurus auriculatus: SDSNH 34853 (P), 34859
(P), 34861 (D), 34866 (P). U. bicarinatus: SDSNH 7371 (P),
10154 (P), 28513 (P). U. clarionensis: SDSNH 22514 (P), 22529
(P), 28507 (P). Uta nolascensis: CAS 14244 (P), 14247-48 (P).
U. palmeri: SDSNH 46492-94 (P), 46496 (P). U. squamata: CAS
52343 (P), 52351 (P), 52359 (P). U. stansburiana: JAM 265 (D),
284 (D), 301 (D), 366 (D); REE 274-75 (D), 1877-78 (D); SDSNH
3374 (P), 60800-1 10 (P), 60800-187 (P), 60800-418 (P); SDSU
2525-30 (P).

Polychrotidae

Anisolepis grilli: REE 1952 (D); SDSU 2130-31 (P). Chamae-
leolis chamaeleonides: CAS 1 46 1 0 (P); KU 245644 (P). C. porcus:
KU 245645. Enyalius bibronii: MCZ 163783 (P). E. bilineatus:
MCZ 5567, 84034, 144556, 163776, 163777 (P); REE 1678 (D),
1958 (D). E. boulengeri: MCZ 163780 (P), 163781 (D). E. bras-
iliensis: MCZ 3317, 3322, 4251, 163778-79 (P); REE 1960 (D).
E. catenatus: CAS 16101 (P); MCZ 163782 (P); REE 1961 (D).
E. iheringii: MCZ 6315, 163786-87 (P); REE 1959 (D); SDSU
2222-23 (P). E. perditus: MCZ 163788 (D), 163789 (P). E. pictus:
MCZ 82873 (P), 163784 (D), 163785 (P); SDSU 222 1 (P). Phen-
acosaurus heterodennis: SDSU 2224-25 (P). P. richteri: SDSU
2226-27, 2240 (P). Polychrus acutirostris: KU 73436-38 (P);
MZUSP 568 (D), 4412 (D), 4448 (D), 4543 (D); SDSU 2236-37
(P). P. femoralis: KU 142682 (P), 218381 (P). P. guttarosus: KU
25170 (P), 76074 (P), 113495 (P); SDSU 2235 (P). P. liogaster:
KU 133872-73 (P). P. marmoratus: JMS 1 16-1 17; REE 346 (D),
2283 (D), 2496 (D), 2498 (D), 2863 (S); SDSU 2231-34 (P).
Pristidactylus casuhatiensis: MCZ 162924 (D). P. torquatus: CAS
85234 (D); MCZ 33586 (D); REE 2766-68 (D); SDSU 2249-51
(P). Urostrophus vautieri: CAS 13883 (P); REE 2507 (D); SDSU
2522 (P).

Tropiduridae

Ctenoblepharys adspersus: LACM 49147 (D); MVZ 85415-16
(P); REE 25 1 3 (D). Leiocephalus carinatus: REE 1469 (S), 1 805-
06 (D), 1816 (D); SDSNH 67957-58 (P); SDSU 1996-97 (P). L.
greenwayi: REE 1814 (D). L. inaguae: KU 242855 (P), 242859
(P), 242865 (P), 242868 (P). L. macropus: REE 1819 (S); SDSNH
65959-60 (P), 65989 (D), 66002 (P), 66004-05 (D), 66012 (P).
L. melanochlorus: KU 243460 (P), 243463 (P), 243470 (P), 243474
(P); REE 1802 (D). L. pratensis: KU 244861-62 (P), 244864 (P),
246145 (P). L. psammodromus: KU 244836 (P), 244838-39 (P),
244843 (P); REE 1813 (D). L. schreibersi: KU 245006-08 (P);
REE 1808 (D); SDSNH 64665 (D), 64668-69 (D), 64672 (P),

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

125

64675 (P), 66967 (P), 66970 (P); SDSU 1998 (P). Microlophus
duncanensis: CAS 1 2202 (D). M. grayi: CAS 1 1 620 (D). M. stolz-
manni: KU 134701 (P), 134712 (P), 134743-44 (P). M. there-
sioides: KU 162010-1 1 (P), 162015-16 (P). M. tigris: KU 163750-
52 (P), 163757 (P). Phymaturus palluma: REE 2306 (D), 2309
(D), 2311 (D), 2313 (D), 2326 (D); SDSU 1946-51 (P). P. pa-
tagonicus patagonicus: REE 247 1-72 (D); SDSU 1980 (P). P. p.
payuniae: REE 233 1-33 (D), 2336 (D), 2339 (D), 2360 (D); SDSU

1981-84 (P). P. p. somuncurensis: REE 2433-36 (D), 2439 (D);
SDSU 1780-84 (P). P. p. zapalensis: REE 2451-53 (D); SDSU
1986-90 (P). P. punae: REE 2356-7 (D), 2383-85 (D); 1978-79
(P). P. sp.: SDSU 1991-95 (P). Plesiomicrolophus koepckeorum:
KU 163604 (P), 163606-07 (P), 212665 (P). Stenocercus guenth-
eri: SDSNH 49472 (P). Uranoscodon superciliosus: KU 128214
(P), 128215 (D), 128216 (P), 128218 (P), 130218 (P), 135269
(D); REE 2589 (D); SDSNH 65497 (D); SDSU 2110 (P).

126

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Appendix 2
Data Matrix

The symbols a-y represent frequency ranges within which the derived character state was observed in any particular terminal taxon

(see Table 1). “?” = missing or unknown.

1 2 3 4 5

6 7 8 9 0

tiiii

1 2 3 4 5

11112
6789 0

2 2 2 2 2

1 2 3 4 5

2 2 2 2 3

6 7 8 9 0

3 3 3 3 3

1 2 345

3 3 3 3 4
6789 0

4 4 4 4 4

1 2 3 4 5

Ancestor

aaaa?

aa??a

aa?aa

a??a?

?a??a

aaOaa

?aa? ?

a?aaa

cl 3. EL 3, cL

G. copei

yyayy

yyaay

ypayy

ayaaa

yaayy

yaOyy

Cwaaa

yaaah

ydyyy

G. corona t

a?a?y

?aaa?

?y ? ? ?

a?aaa

?y??y

ya0?y

Dya? ?

?a???

99999

G. situs

fyaya

ydaac

ayaym

axaay

ya?w?

yaOyy

Anaaa

yauaa

ukyyy

G. wislizenii

yyayy

ycaax

yyayy

awaaa

yaayy

yaOyy

Bvaaa

Q3.8.3.6

xfyyc

C. bicinctores

babya

yayyy

aayya

aaayy

ay?aa

bylya

Lkyyy

ayayy

byyde

C. antiquus

agmya

yayys

aayya

aaayy

ayyaa

aylya

Fsysy

gyaay

ayyym

C. collaris

abaya

yayyy

aayya

avayy

axyba

cylya

Gkyyy

ayaay

asyaa

C. dickersonae

aayya

yayyy

aayya

aayyy

ayyaa

dylya

Isyyy

ayayy

ayyai

C. grismeri

faaya

yayyy

aayya

akayy

ay?aa

aylya

Jkyyy

ayayy

auyfp

C. insularis

yaaya

yayyy

aayya

yaayy

ayyaa

yyiya

Kayyy

ayayy

ayyfa

C. nebrius

aaaya

yayyy

aayya

aaayy

ayyda

bylya

Hsyyy

ayaay

axyaa

C. reticulatus

aaaya

yayyy

aayya

aeayy

ayyca

cy2ya

Eqyyy

ayaay

awqay

C. vestigium

baaya

yayyy

aayya

jaayy

ayyba

gyiya

Mkyyy

ayayy

axydc

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

127

Appendix 2— Extended

4 4 44 5

6 7 8 9 0

5 5 5 5 5

1 2 34 5

5 5 5 5 6
6789 0

6 6 6 6 6

1 2 3 4 5

6 6 667
67 89 0

7 7 7 7 7

1 2 3 4 5

77778
6789 0

8 8 8 8

12 3 4

8 888 9
67 89 0

9 9 9 9 9

1 2 34 5

999

678

yaaaa

aaaa?

?aa?a

aaaaa

aa??a

aa???

aa?a?

??a0

?aa??

99999

???

aaaay

ayyay

aayay

ayaaa

aaOaa

ya???

aa?a?

?yaO

(04)

a?a??

99999

???

9 9 9 7 9

99999

????

99999

???

yaaaa

ayaay

aayaa

ayaya

aaOaa

ya,? ? ?

aa?a?

?yaO

aaa??

99999

???

yaaaa

ayyay

aayay

ayaaa

aaOaa

ya???

aa?a?

?yaO

ayall

11111

Ill

ayayy

vaaya

yyyya

yaaay

yy2yL

ayay2

ayyay

aasO

yay44

44444

444

ayayy

yaaya

yyyya

??aya

yyiyy

yyay ( 012 )

yyayy

aaaO

ya???

99999

???

gtayy

eaaya

yyyya

yaaaa

ya2yh

yyaa( 01 )

thaaa

aac ( 03 )

(345)

yay66

66666

666

ayyyy

yaaya

yyyya

yayay

ya2yy

yyayi

ayyay

aaa3

yay22

22222

222

ayayy

yaaya

yyyya

yaaay

ya2yy

ayay2

ayyay

aaaO

yay??

99999

???

apayy

yaaya

yyyya

yaaay

ya4ya

ayyy3

ayyay

aapl

yay??

99999

???

awayy

yaaya

yyyya

yaaaa

ya2yy

yyayO

gyaaa

xas2

yay55

55555

555

avayy

aaaya

yyaya

yaaaa

yalaa

yyyy(Oi)

ta?yy

aaaO

aay77

77777

777

ayayy

yaaya

yyyya

yaaay

ya3yy

ayyy3

ayyay

aau( 12 )

yay33

33333

333

128

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Appendix 3

Outgroup Data Matrix

Species that exhibited more than one character state were assigned state V (variable) in this data matrix. “?” = missing or unknown.

1 2 3 4 5

67 89 0

11111

1 2 34 5

11112
6789 0

2 2 2 2 2

1 2 34 5

2 2 2 2 3

67 89 0

3 3 3 3 3

1 2 3 4 5

3 3 3 3 4

6 7 89 0

Brookesia stumpffi

0?10?

000??

?0100

0110?

01??1

00000

?0???

????!

Chamaeleo kersteni

0?00?

001??

?0000

0110?

0???1

00000

?0???

????!

Hydrosaurus amboiensis

0000?

10110

00000

0010?

?01?0

00200

?0?01

??001

H. pustulatus

99999

????1

Leiolepis belliana

0000?

00110

00011

0110?

011?0

10000

?0?00

V?001

Physignathus cocincinus

0000?

10110

?0000

0110?

001?0

00000

?0???

??001

P. lesueurii

0000?

10110

00010

0111?

001?0

00000

?0?01

0?001

Uromastyx acanthinurus

0000?

voovo

00000

0111?

101?1

01000

?0???

??oov

U. aegyptius

99999

U. asmussi

99999

????1

U. benti

0000?

00010

00000

0?11?

1?1?1

00000

?0???

??001

U. gevrii

99999

????!

U. hardwickii

0?00?

?0000

00000

Oil??

001?1

00000

?0?0?

??001

U. loricatus

99999

????1

U. mafadyeni

99999

????1

U. microlepis

0000?

00010

00000

0111?

101?1

01000

?0???

??001

U. ocellatus

99999

????1

U. philbyi

99999

9 9 9 9 9

????!

U. thomasi

99999

????1

Chamaeleonidae

0000?

00110

00000

0110?

001??

00000

?o?o?

0?001

Basiliscus basiliscus

0000?

10110

00000

0000?

10100

00000

?001?

1?100

B. plumifrons

0000?

10110

00000

0010?

10100

00000

?001?

1?100

B. vittatus

0000?

101?0

00000

0010?

101?0

00000

?001?

1?100

Corytophanes cristatus

0000?

101V0

?0000

0010?

?0100

00000

?0V1?

1?101

C. hernandezi

ovoo?

10110

?ovoo

0V10?

000?0

00000

?00??

1?101

C. percarinatus

0000?

10110

?ovoo

0110?

0?100

00000

?01??

??101

Laemanctus longipes

0000?

101V0

00000

0010?

vovoo

00000

?001?

1?101

L. serratus

0000?

10110

00000

0100?

00100

00000

?0V1?

??101

Corytophanidae

0000?

101?0

00000

0010?

?0100

00000

?001?

1?10?

Enyaliodes laticeps

0000?

V0110

oooov

0000?

V0100

00000

?00?1

0?000

E. oshaughnessyi

0000?

10110

00000

0000?

001?0

00000

?00?1

0?000

E. praeslabilis

99999

Hoplocercidae

0000?

10110

00000

0000?

00100

00000

?00?1

0?000

Brachvlophus fasciatus

00001

00110

00000

0010?

voooo

00000

?0111

V?101

Dipsosaurus dorsalis

V0001

ooovo

voooo

0000?

?0000

00000

?0001

0?000

Iguanidae

00001

00?10

00000

00?0?

?0000

00000

?0??1

o??oo

Chalaradon madagascariensis

0000?

ooovo

1V100

ovvo?

V0010

00000

?0001

0?000

Opiums cuvier i

0000?

00110

10100

0000?

100?0

10010

?0001

0?000

O. cyclurus

99999

????0

0. fierinensis

0000?

00010

10000

0000?

00110

01100

?0?1?

1??00

O. quadrimaculatus

0000?

00??0

10100

00???

?00?0

00000

?10??

??000

0. saxicola

99999

????0

Opluridae

0000?

00?10

10?00

0000?

?0?10

???00

??0?1

??ooo

Callisaurus draconoides

?????

99999

????0

99999

???01

0?000

Petrosaurus mearnsi

1000?

00000

01V01

ovoo?

10111

00001

?0?10

0?000

P. repens

P. thalassinus

9 9 9 9 9

99999

0000?

00010

oovoo

ovoo?

1101?

0000?

?0?11

0?000

Phrynosoma asio

P. coronatum

0001?

?00?0

10100

0000?

00010

V0100

?0?00

1?001

0000?

00010

10100

0000?

10011

010?0

?0?0?

??001

P. ditmarsi

P. douglassi

P. orbicu/are

99999

???01

0000?

?0000

00?00

0100?

10011

ovvoo

?0???

??001

0000?

00010

10100

0100?

1001?

oov?o

?0???

??001

Uma exsul

0001?

00000

00101

0000?

10010

00000

?0?11

v??oo

U. inornata

0001?

00000

0010V

ovoo?

10010

ovooo

?0?11

0?000

1996 McGUIRE-SYSTEMATICS OF CROTAPHYTID LIZARDS 129

Appendix 3— Extended

44444 44445 55555 55556 66666 66667 77777 77778 88888 88889 99999 999

12345 67890 12345 67890 12345 67890 12345 67890 12345 67890 12345 678

??0?? ????? ????? ????? ????? ????? ????? ????? ????? 0???? ????? ???

100?0 00??? ????? ????? ????? ????? ????? ????? ????? 0???? ????? ???

1?0?? ??101 00?00 ??0?? ????0 00??0 00??? 00?0? ????? 0???? ????? ???

?00?V 00000 00??1 000?0 0?000 00??0 00??? 00?0? ??0?? 0???? ????? ???

1?0?1 00??? ????? ????0 ???0? ????? ?0??? 0???? ??0?? 0?0?? ????? ???

100?V V011? 00??0 100?? ??ooo 00??0 00??? oo?o? ??0?? 0?0?? ????? ???

?01?0 10V11 00?01 VOO?? ????0 00??0 00??? 00?0? ??0?? ??0?? ????? ???

??1?? ??011 00?01 000?? ????0 00??0 00??? 00?0? ??0?? ??0?? ????? ???

??1?? ??111 00?01 000?? ????0 00??0 00??? 0???? ??0?? ??0?? ????? ???

??1?0 ?0??? ????? ????? ????? ????? ????? ????? ????? ??0?? ????? ???

??1?? ??1?1 00001 ?00?? ????0 00??0 00??? 00?0? ?00?? ??0?? ????? ???

?01?0 10111 00?01 000?? ????o 00??0 00??? 01?0? ??o?? ??o?? ????? ???

??1?? ??101 00001 000?? ????0 00??0 00??? 0?00? ??0?? ??0?? ????? ???

??1?? ? ? 1 1 1 00?01 000?? ????0 00??0 ?0??? 00?0? ??0?? ??0?? ????? ???

??1?0 10011 00?01 000?? ????o 00??0 00??? oo?o? ??o?? ??0?? ????? ???

??1?? ??101 00001 000?? ????0 00??0 ?0??? 00?0? ??0?? ??0?? ????? ???

??1?? ??111 00?01 100?? ????0 00??0 ?0??? 00?0? ????? ??0?? ????? ???

??1?? ??V11 00?01 000?? ????0 00??0 ?0??? 00?0? ??0?? ??0?? ????? ???

100?0 00??1 0000? ?oo?o o?ooo 00??0 00??? oo?o? ??0?? 000?? ????? ???

000?1 00??? ????? ????0 ??0?? ????? ?0??? 0???? ????? 000?? ????? ???

000?1 00111 0???? 000?? ?oooo 00??0 00??? 00??? ??0?? 000?? ????? ???

000?1 00011 0???0 000?0 ?0000 00??0 ?0??? 00??? ??0?? 000?? ????? ???

0?0?0 00101 o???v ooo?i ??ooo 00??0 00??? 00??? ??o?? o?o?? ????? ???

010?V 00011 0???? ?00?? ??000 00??0 ?0??? 00??? ??0?? 0?0?? ????? ???

0?0?? 00V01 0???1 ?00?? ??000 00??0 ?0??? 00??? ??0?? 0?0?? ????? ???

0?0?V 00001 o???o ?oo?? ??ooo 00??0 00??? 00??? ??o?? 0?0?? ????? ???

000?1 00011 0???0 000?? ??000 00??0 ?0??? 00??? ??0?? 0?0?? ????? ???

000?1 00?11 o???o 000?? ?oooo 00??0 00??? 00??? ??o?? 000?? ????? ???

00000 00101 voiov ?oo?i ????o oo??o 00??? oo?o? ??o?? 0???? ????? ???

00000 00111 oo?oi ?oo?? ????o oo??o ?o??? oo?o? ??o?? ????? ????? ???

0?0?? ??111 00?01 ?00?? ????0 00??0 ?0??? 00?0? ??0?? ????? ????? ???

00000 001?1 0010? ?00?1 ????o 00??0 00??? oo?o? ??o?? ????? ????? ???

00000 0000? 0000? ?oo?o o?ooo oo??o ?o??? o??o? ??0?? 000?? ????? ???

00000 V0110 00001 ?01?0 00000 00?00 00??? oo?o? ??o?? 000?? ????? ???

00000 00??0 0000? ?o??o 00000 00??0 00??? oo?o? ??0?? 000?? ????? ???

00000 0001V o??oo ooi?o ????o 00??0 00??? 00??? ??0?? ?0??? ????? ???

00000 100V0 0??01 001?? ??o?o 00??0 ?1??? 00??? ??o?? ????? ????? ???

0?0?? ??011 0??00 ?01?? ??0?0 00??0 ?1??? 00??? ??0?? ????? ????? ???

0?0?? ??01V 0??0V 001?? ????0 10??0 ?0??? 00??? ??0?? ????? ????? ???

000?0 ?0010 0??0? 00??? ??0?0 00??0 ?0??? 00??? ??0?? ????? ????? ???

0?0?? ??010 0??00 ?01?? ????0 00??? 00??? 00??? ??0?? ????? ????? ???

00000 ?001? 0??0? 001?0 ??0?0 ?0??0 0???? 00??? ??0?? ?0??? ????? ???

?0000 01??? ????? ????0 00000 00?10 00??? 00?0? ??0?? 000?? ????? ???

0?000 10?10 10000 000?0 00000 00?00 00??? 00?0? ??0?? 100?? ????? ???

????? ??010 10000 ?00?0 ?0000 00?10 ?1??? 01?0? ??0?? 1?0?? ????? ???

0?000 10010 10000 000?0 ?00?0 00?10 01??? 01?0? ?00?? 1?0?? ????? ???

?oooo 00?01 00?00 ?00?? ??0?0 00??0 00??? oo?o? ??0?? 0???? ????? ???

??000 00101 00?00 100?1 00000 00?00 00??? oo?o? ??0?? 0?0?? ????? ???

??0?? ???01 00?00 000?? 00000 00??0 00??? 00?0? ??0?? 1???? ????? ???

?0000 00?01 00000 000?1 00000 00?00 00??? oo?o? ??0?? 0?0?? ????? ???

?0010 00??? ????? ??0?1 ??0?0 00??? 00??? 00?0? ??0?? ????? ????? ???

ooooo moo 00000 000?0 ??0?0 00?00 00??? 01?0? ??0?? 000?? ????? ???

0000V 11110 0000V 000?0 00000 00?00 00??? 00?0? ??0?? 000?? ????? ???

130

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Appendix 3 — Continued

1 2 3 4 5

6 7 8 9 0

11111

1 2 34 5

11112

67 8 9 0

2 2 2 2 2

1 2 34 5

2 2 2 2 3
6789 0

3 3 3 3 3

1 2 34 5

3 3 3 3 4

67 89 0

U. notata

0001?

00010

00101

0000?

10010

00000

?0?V1

0??00

U. scoparia

0001?

00010

?010V

ovoo?

10010

00000

?0?11

0?000

Urosaurus auriculatus

000??

00010

10000

o?oo?

1?01?

11000

?0???

??000

U. bicarinatus

99999

???00

U. clarionensis

99999

???00

Uta nolascensis

99999

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U. palmeri

99999

???oo

U. squamata

99999

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U. stansburiana

vooo?

00000

00101

OVOO?

V1010

00000

?o?oo

1?000

Phrynosomatidae

0000?

00000

0010?

o?oo?

1?010

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?0??0

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Anisolepis grill i

0000?

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?0000

0000?

0110?

01000

?00??

??001

Chamaeleolis chamaeleonides

99999

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C. porcus

99999

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Enyalius bilineatus

0000?

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00000

0010?

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1?101

E. boulengeri

0000?

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00100

0000?

0010?

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E. brasiliensis

0000?

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01100

0110?

1000?

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0?000

C. catenatus

0000?

?0010

?0100

0?10?

0010?

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E. iheringii

0000?

10010

00100

0010?

1010?

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E. perditus

0000?

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?0100

0000?

0010?

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?10??

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E. pictus

0000?

?0??0

?1100

0????

?010?

00?00

?10??

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Phenacosaurus heterodermis

99999

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P. richteri

99999

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Polychrus acutirostris

0001?

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?0000

0100?

VV01?

010V0

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P. femoralis

99999

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99999

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P. guttarosus

99999

???1?

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P. liogaster

99999

???1?

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P. marmoratus

000V?

00110

00000

0100?

V001?

01000

?0001

0?101

Pristidactylus casuhatiensis

0000?

?0011

00010

00?1?

1110?

01000

?0???

???00

P. torquatus

ooov?

00110

0V010

??11?

1110?

01000

?V001

0?000

Urostrophus vautieri

0000?

00?10

01000

0010?

0100?

01000

?1???

???01

Polychrotidae

000??

00?10

00000

0??0?

?1???

01000

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0?00?

Ctenoblepharys adspersus

0010?

00010

00?00

ovoo?

1100?

00000

?0???

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Leiocephalus carinatus

0010?

00100

ov?oo

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11010

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L. green way i

0000?

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00?00

0100?

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L. inaguae

99999

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L. macropus

001V?

?0000

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L. melanochlorus

0010?

00100

01?00

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L. pralensis

99999

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L. psammodromus

0000?

00000

00?00

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0?010

00000

?oo??

??0?0

L. schreibersi

ovvo?

00100

00?00

ovoo?

00010

00000

?0?11

o???o

Microlophus duncanensis

?000?

00000

?0100

0?0??

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?0???

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M. grayi

0111?

oo??o

00?0?

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?101?

10000

?0???

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M. stolzmanni

99999

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M. theresioides

?????

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M. tigris

?????

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Phvmaturus palluma

vooo?

00010

ov?oo

OVOO?

00000

?0000

1?000

P. patagonicus patagonicus

oovo?

ooovo

?0?00

0000?

voooo

10000

?0?10

1?000

P. p. payuniae

oovv?

oooov

00?00

0000?

ovooo

10000

?0?00

1?000

P. p. somuncurensis

oovo?

000?0

00?00

ovoo?

voooo

10000

?0?00

1?000

P. p. zapalensis

ovoo?

00000

00?00

ovoo?

vvooo

10000

?o??o

1?000

P. punae

vooo?

00010

01?00

0100?

?0000

voooo

?00?0

1?000

P. sp.

99999

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P/esiomicroloph us koepckeoru m

?????

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Stenocercus guentheri

?????

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Uranoscodon superci/iosus

ooov?

V0010

00000

OVOO?

00V1V

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o?voo

Tropiduridae

00?0?

000?0

00?00

0?00?

??0?0

00000

?oo??

??000

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

131

Appendix 3 — Extended— Continued

4 4 4 4 4

1 2 3 4 5

4 4 4 4 5
6789 0

5 5 5 5 5

1 2 3 4 5

5 5 5 5 6

6 7 8 9 0

6666 6

1 2 3 4 5

6 6 667

6 7 8 9 0

77777

1 2 34 5

77778
6789 0

88888

1 2 34 5

8 8 8 8 9
67 89 0

9 9 9 9 9

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999

678

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132

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Appendix 4

Step Matrices for Manhattan Distance Frequency Approach

Given below are the step matrices employed in the coding of character 31 (number of premaxillary teeth) and in the reanalysis of
the Montanucci et al. (1975) allozyme data set using the Manhattan distance frequency approach (Wiens, 1995). Each step matrix is
labeled by enzyme and given in the same sequence as presented in Montanucci et al. (1975). Only ten of the 27 original allozyme loci
held informative character state changes. The ten included loci are coded as characters 89-98 in the data matrix given in Appendix B.
The matrix presented at the bottom of the appendix gives the character “states” that were incorporated into the actual data matrix
(Appendix B).

31. Number of Premaxillary Teeth:

100

(Note: 1: Gambelia silus, 2: G.

wislizenii, 3: G. copei,

, 4: G. corona, 5: Crotaphytus reticulatus, 6: C. antiquus,

7: C. col laris, 8:

C. nebrius,

9: C. dickersonae, 10:

C. grismeri, 1 1 : C. insularis,

12: C. bicinctores, 13: C. vestigium)

89. H-LDH

100

90. a-GPD

91. 6-GPD

92. ICDs

100

1 1
15
1 1
11

100

93. ICDm

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

133

Appendix A — Continued

1 1

94. GOTs

100

95. Pro

96. EST1

100

97. Hbpf

98. Tr

100

G. wislizenii

1111111111

C. dickersonae

2222222222

C. vestigium

3333333333

C. bicinctores

4444444444

C. nebrius

5555555555

C. collaris

6666666666

C. reticulatus

7777777777

134

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Appendix 5

Character Transformations for Each Stem of the
Single Most Parsimonious Tree
Characters 1-27, 29-30, 32-67, 69-74, 76-83, 86-88 with a
maximum of 24 steps; characters 28, 68, 75, and 84-85 with a
maximum of one step; characters 3 1 and 89-98 with a maximum
of 100 steps. PAUP does not calculate consistency indices for
characters coded using step matrices. Therefore, “n/a” appears
in the Cl column for characters 89-98 (allozyme characters cod-
ing using Manhattan distances in step matrices). Arrows with
double lines indicate unambiguous changes, i.e., those occurring
in all optimizations. Arrows with single lines indicate changes
that do not occur in all optimizations.

(ACCTRAN optimization):

Branch

Char-

acter

Steps

Change

HYPANC -*• node A

0.774

a «-» b

1.000

a <=> y

1.000

a <=* y

0.462

a <=> x

1.000

a <=> y

0.453

a <=> c

1.000

a «=> y

0.429

a <=> q

0.774

a <-> e

0.585

a <=* k

0.750

a <=> y

0.247

a <=> y

0.500

a - y

0.500

a ** y

node A node B

0.421

a — * f

0.774

b =5 y

0.889

a — * c

0.727

a=?y

1.000

a =» m

0.462

e — * x

1.000

a y

0.857

C — * w

1.000

a -* y

0.462

c =1 y

1.000

a=£y

0.632

a=3y

0.960

a =3 u

0.436

a=J y

0.800

a-^y

1.000

a =? y

1.000

a -* y

1.000

a =3 y

1.000

a -* y

node B node C

1.000

a =5 y

1.000

a -* y

1.000

m — 1 ► y

1.000

y =? a

0.857

w — » y

n/a

A=£C

0.444

q =» w

0.960

u — » X

0.585

k-*f

1.000

a -* y

1.000

a -*■ y

1.000

a — y

Appendix 5 — Continued

Branch

Char-

acter

Steps

Change

node C =» node D

0.421

f=£y

node D =» G. cocci'

0.889

c =? y

0.462

x =3 y

0.727

y p

0.462

x^y

0.774

e ^ h

0.960

x y

0.585

f=» d

node D =» G. wislizenii

0.462

x — » w

n/a

C=t B

0.444

w — * V

0.632

y — * q

0.247

y=?c

node C => G. coronaf

0.421

f —*■ a

0.889

c — » a

0.490

a=G

0.444

w^ly

node B => G. silus

0.889

c =» d

0.462

X — * c

0.444

q -* n

1.000

a u

0.774

e — » a

0.500

a y

node A =» node E

1.000

a -*• y

1.000

a -* y

0.462

x =i y

1.000

a — y

1.000

a =5 y

0.490

a =» y

1.000

a ~ * y

1.000

a =? y

1.000

0 — 1

n/a

A — > L

1.000

a y

0.800

a ~ * y

1.000

a -*> y

1.000

a -► y

0.774

e=? y

0.585

k =» w

0.649

a ^ v

1.000

a ~ * y

1.000

a — y

1.000

a y

1.000

a ~ * y

1.000

a=J y

1.000

a -*• y

1.000

a =5 y

1.000

a =! y

0.800

0^ 1

1.000

a=J y

0.558

a =» t

1.250

0^ 1

1.000

a=J y

100

n/a

1 2

n/a

1 — ► 6

n/a

1 -> 2

n/a

1 -> 2

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

135

Appendix 5 — Continued

Branch

Char-

acter

Steps

Change

Branch

Char-

acter

Steps

Change

n/a

1 -»■ 7

1.000

2 =8 3

n/a

1 -» 6

1.000

0=8 1

100

n/a

1 — 3

n/a

2 — 1

node E = 8 node F

0.857

c =8 b

n/a

4 — »• 3

n/a

LUH

n/a

6 -*• 1

0.247

y -*■ i

node L =8 C. insularis

0.421

b=8y

0.889

a =5 e

1.000

j y

0.800

1 — » 2

0.462

g=J y

1.000

a =8 y

n/a

M =8 K

0.393

a =5 h

0.444

k =8 a

1.000

a =8 h

0.436

d =8 f

1.250

1 -> 4

0.247

c =8 a

1.000

a=Jy

0.649

y=£ P

node F =8 node G

0.462

e =8 a

0.800

3 — ► 4

0.857

b — >• a

0.393

1 =8 a

0.462

c =5 b

0.465

s — p

0.444

q =8 s

node L =8 C. vestigium

0.857

a =8 b

0.585

w =| y

0.585

y-^x

0.649

v=8y

0.393

l — *• y

0.889

e=J y

0.465

s =8 u

0.393

h =8y

node J =8 C. grismeri

0.421

b =8 f

1.000

h=?y

0.462

a =8 k

n/a

6 — 1

0.462

b ^ a

n/a

7 -»« 5

n/a

L=8 J

node G =3 node FI

0.774

b — » a

0.585

y =8 u

0.558

t=8g

0.436

d =8 f

node H =8 node I

n/a

H =8 L

0.247

i =8 p

1.000

a=8y

node I =8 C. dickersonae

0.649

a =8 y

1.000

a=8y

1.000

a =8 y

1.000

0— 1

0.462

b =8 d

0.558

g=2a

n/a

L =8 I

1.000

a=8y

1.000

a =8 y

node I =8 node J

0.421

a =5 b

1.000

a ^ y

0.444

s =8 k

1.000

0=83

0.436

a =5 d

1.250

4 =8 3

0.500

y=s a

100

n/a

1 =8 2

1.000

1 -*• 2

n/a

1 =82

100

n/a

2^3

n/a

5 — » 2

100

n/a

2 — ► 3

n/a

6=82

n/a

5 — ► 4

n/a

1 =8 2

node J =8 node K

0.247

i =5 e

n/a

3 =8 2

0.393

y — *■ 1

node H =8 C. nebrius

0.857

a =8 d

0.465

a =J s

0.585

y — > x

node K =8 C. bicinctores

0.649

a =5 b

0.247

i =8 a

0.960

a =3 b

0.649

y — » w

0.889

y=£ v

0.500

y =8 a

0.500

a =5 y

1.000

a =8 x

n/a

3 — » 4

0.465

a =8 s

n/a

6 =84

1.000

0=82

n/a

1 =8 4

1.250

4=8 2

100

n/a

3 =84

n/a

2=85

node K =8 node L

1.000

a=8j

n/a

1 =8 5

0.462

b=8g

1 1

n/a

1 =8 5

n/a

L=8M

n/a

6 =8 5

0.247

e =8 c

node H =8 C. collaris

0.462

e — » v

0.800

2 — > 3

0.490

y — *■ x

0.500

a=8y

n/a

H =8 G

136

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Appendix 5 — Continued

Branch

Char-

acter

Steps

Change

Branch

Char-

acter

Steps

Change

0.444

q =3 k

0.462

c=3y

0.585

w — * s

1.000

a =£ y

0.247

i => a

0.632

a =3 q

0.800

a ~ g

0.960

a ^ u

0.649

v — ► t

0.750

q ->y

1.000

y =i a

0.436

a=J y

0.500

y =3a

0.800

a -* y

0.465

a c

1.000

a y

n/a

2 — ► 6

1.000

a -> y

n/a

1 =£ 6

0.500

a -*■ y

n/a

1 =3 6

1.000

a =£ y

n/a

7=J 6

1.000

a ~ y

100

n/a

3 6

node B =» node C

1.000

a =3 y

node F =» C. antiquus

0.774

b=J g

1.000

y =?a

0.649

a^m

1.000

a — y

0.462

y s

n/a

A=U

0.462

b =* a

0.444

n =5 v

n/a

H =£ F

node C =» node D

0.421

a =! y

0.800

y =s s

0.889

a — » c

0.632

a=£g

0.462

c * X

0.436

a =S y

1.000

a->y

0.247

i — * m

1.000

m — 5

0.500

a =5 y

0.857

w — ► y

0.500

a y

0.774

a — » e

0.800

2 — » 1

0.960

u * X

0.558

t=*y

1.000

a -► y

0.500

a=£y

1.000

a — y

node E =£ C. reticulatus

0.774

b — » a

node D => <7. cope/

0.889

c=iy

1.000

1 -» 2

0.462

x =5 y

n/a

L=?E

0.727

y =5 p

0.750

y — Q

0.462

W=J>

0.500

y — * a

0.444

V — » w

0.500

a — y

0.632

q -* y

0.500

a =5 y

0.774

e =» h

100

n/a

2 — > 7

0.960

x =? y

n/a

6 7

0.585

f=J d

n/a

6 =? 7

0.247

i -»■ y

n/a

1 =J 7

node D :=* G. wislizenii

n/a

C => I

(DELTRAN optimization):

0.247

i c

Char-

1.000

a — » y

Branch

acter

Steps

Change

node C =3 G. coronal

0.490

a =s y

HYPANC =i node A

1.000

a ~ y

0.444

v =£ y

1.000

a <=> y

node B =» G. silus

0.421

a — » f

0.462

a *-* c

0.889

a ^ d

1.000

a => y

0.462

w — » >

0.462

a - c

0.632

q y

1.000

a <=> y

1.000

a ^ u

0.444

a <=> n

0.585

f-» k

0.585

a <=> f

0.247

i -► y

0.750

a - q

0.500

a =5 y

0.247

a «-» i

node A =* node E

1.000

a -* y

0.500

a *=> y

1.000

a -*• y

node A node B

0.774

a =3 y

0.462

c^y

0.727

a =5 y

1.000

a — y

1.000

a=*m

1.000

a=J y

0.462

e — * w

0.490

a =» x

1.000

a - > y

1.000

a — y

0.857

c — * w

1.000

a=J y

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

137

Appendix 5 — Continued

Branch

Char-

acter

Steps

Change

n/a

A — » L

1.000

a=£y

0.800

a -*y

1.000

a -* y

1.000

a — y

0.774

a =3 y

0.585

f =3 s

0.649

a =5 t

1.000

a -> y

1.000

a ~ y

1.000

a =3y

1.000

a -> y

1.000

a=3y

1.000

a -*> y

1.000

a =3 y

1.000

a =3 y

1.000

a=3y

0.558

a =3 1

1.000

a =3 y

n/a

1 -» 6

n/a

1 — 6

n/a

1 -* 2

n/a

1 -> 2

n/a

1 -» 6

100

n/a

1 -► 3

node E =3 node F

0.857

c=3b

1.000

0^ 1

n/a

L =3 H

0.750

q — y

0.889

a ^ e

0.500

a -» y

0.800

0 — ► 2

1.000

a=£y

0.393

a =3 h

1.000

a =3 h

1.250

0 — * 4

1.000

a =3 y

100

n/a

1 — 2

node F =3 node G

0.462

e4a

0.490

x-*y

0.462

c =3 b

0.444

n =3 s

0.585

S =3 X

0.649

t =3 w

0.889

e =S y

0.393

h y

1.000

h =J y

node G =3 node H

0.558

t=5g

n/a

6 — 1

node H =3 node I

0.857

b — » a

n/a

H =3 L

1.000

a =3 y

0.649

w — > y

1.000

a =5 y

0.558

g=J a

1.000

a=£y

node I =3 node J

0.421

a =3 b

0.444

s =3 k

Branch

Char-

acter

Steps

Change

0.436

a =3 d

0.500

y =? a

1.000

0 — » 2

n/a

2 -> 5

node J node K

0.247

i =3 e

0.465

a =3 p

100

n/a

2 — »• 3

100

n/a

2 — > 3

1 1

n/a

5 — *■ 4

node K =3 C. bicinctores

0.649

a =3 b

0.960

a =3 b

0.585

x * y

0.889

y v

0.500

a =3 y

0.393

y-i

0.465

p -» s

n/a

3 — ► 4

n/a

6 — » 4

n/a

6=34

n/a

1 =3 4

100

n/a

3 =3 4

node K =3 node L

1.000

a =5 j

0.462

b=J g

n/a

L =5 M

0.247

e =3 c

0.500

a =3 y

1.000

2=5 3

1.000

0=5 1

node L4C. insularis

0.421

b=5y

1.000

J =5y

0.462

g=f y

n/a

M =3 K

0.444

k =3 a

0.585

x * y

0.436

d =3 f

0.247

c =3 a

0.649

y=3p

0.800

2 — » 4

0.393

y=5a

node L =3 C. vestigium

0.857

a =3 b

0.800

2 — ► 3

0.465

P =5 u

n/a

6 — > 3

n/a

4 — ► 3

n/a

6 — ► 3

node J =3 C. grismeri

0.421

b =5 f

0.462

a =5 k

0.462

b =3 a

n/a

L=3 J

0.585

x =5 u

0.436

d=5f

0.247

i =3 p

node I =3 C. dickersonae

0.649

a=3y

1.000

a=5y

0.462

b=3d

n/a

L=5 1

0.585

x * y

1.000

a=5y

138

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Appendix 5 — Continued

Char-

Branch

acter

Steps

Change

1.000

a =5 y

1.000

0^ 1

1.000

0=5 3

1.250

4 =S 3

n/a

6 — » 2

100

n/a

1 =1 2

n/a

1 =5 2

n/a

6 =5 2

n/a

1 =5 2

n/a

3 =5 2

node H ^ C. nebrius

0.857

b=5 d

0.247

i =5 a

0.500

y =^a

1.000

a ^ x

0.465

a =5 s

1.000

0=5 2

1.250

4 =5 2

n/a

6 =5 5

n/a

1 =5 5

n/a

1 =5 5

n/a

2 — ► 5

n/a

6=5 5

node H =5 C. collaris

0.774

a — » b

0.462

e — »• v

n/a

H =5 G

0.444

n ^ k

0.247

i =5 a

0.800

a^g

1.000

y =* a

0.500

y =5 a

0.465

a =5 c

n/a

1 =5 6

n/a

1 =5 6

n/a

2=56

100

n/a

3 =5 6

node F =5 C. antiquus

0.774

a =5 g

0.649

a =5 m

0.462

y=5s

0.857

b — ► a

0.462

b =5 a

n/a

H =5 F

0.800

y =5 s

0.632

a =5 g

0.585

x — y

0.436

a =5 y

0.247

i — * m

0.649

w — * y

0.500

a =5 y

0.500

a =5 y

0.800

2 -> 1

0.558

t =5 y

0.500

a =5 y

node E =5 C. reticulatus

0.490

x — y

1.000

0 — >• 2

n/a

L =5 E

0.444

n — q

0.585

s — » w

0.247

i — y

Char-

Branch acter

Steps

Change

0.649

t -> V

0.800

0^ 1

0.500

a-^y

0.500

a =5 y

1.250

0^ 1

100

n/a

1 -»• 7

n/a

6=5 7

n/a

6 — ► 7

n/a

2 — ► 7

n/a

6 =5 7

n/a

1 =5 7

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

139

Appendix 6

List of Character State Changes by Character
Characters 1-27, 29-30, 32-67, 69-74, 76-83, 86-88 with a
maximum of 24 steps; characters 28, 68, 75, and 84-85 with a
maximum of one step; characters 3 1 and 89-98 with a maximum
of 100 steps. PAUP does not calculate consistency indices for
characters coded using step matrices. Therefore, “n/a” appears
in the Cl column for characters 89-98 (allozyme characters cod-
ing using Manhattan distances in step matrices). Arrows with
double lines indicate unambiguous changes, i.e., those occurring
in all optimizations. Arrows with single lines indicate changes
that do not occur in all optimizations.

(ACCTRAN optimization):

Character change lists:

Character

Steps

Changes

0.421

node Aa^f node B

node C f =4 y node D

node C f — * a G. corona\

node I a =4 b node J

node L b =5 y C. insularis

node J b =4 f C. grismeri

0.774

node A b - a HYPANC

node Ab4y node B

node Gb->a node H

node G b g C. antiquus

node E b — » a C. reticulatus

0.649

node K a =4 b C. bicinctores

node I a 4 y C. dickersonae

node G a =4 m C. antiquus

1.000

node Ay»a HYPANC

1.000

node B a =4 y node C

1.000

node Ay«a HYPANC

0.889

node A a — » c node B

node D c =4 y G. copei

node C c — * a G. coronal

node B c =4 d G. silus

1.000

node Aa-^y node E

1.000

node Aa^y node E

0.462

node Ax a HYPANC

node D x 4 y G. copei

node B x — » c G. silus

node Ax4y node E

node G y =5 s C. antiquus

1 1

1.000

node Ba-»y node C

0.727

node A a =5 y node B

node Dy4p G. copei

1.000

node A a — » y node E

1.000

node A y <=> a HYPANC

1.000

node AaTm node B

node B m — » y node C

1.000

node K a =4 j node L

node L j =4 y C. insularis

0.462

node Ae^x node B

node D x 4 y G. copei

node D x -* w G. wislizenii

node F e =4 a node G

node J a =5 k C. grismeri

node F e — ► v C. collaris

1.000

node I a =» y C. dickersonae

1.000

node A a =4 y node E

1.000

node By^a node C

Appendix 6 — Continued

Character change lists:
Character CI

Steps

Changes

1.000

node Aa-*y node B

0.490

node Ca=*yG. coronaf

node A a =4 y node E

node F y — ♦ x C. collaris

1.000

node A a — *■ y node E

0.857

node Ac-*w node B

node Bw-»y node C

node Ec=»b node F

node Fb-*a node G

node L a =4 b C. vestigium

node H a =4 d C. nebrius

1.000

node Aa-^y node B

0.462

node Ac « a HYPANC

node Ac4y node B

node Fc=»b node G

node Kb4g node L

node L g =4 y C. insularis

node J b => a C. grismeri

node I b =4 d C. dickersonae

node G b =4 a C. antiquus

1.000

node A a =5 y node E

1.000

node A 0 — » 1 node E

node E 1 — » 2 C. reticulatus

1.000

node Ay « a HYPANC

1.000

node A a => y node B

n/a

node B A =4 C node C

node D C =4 B G. wislizenii

node A A — * L node E

node E L =5 H node F

node H H =+ L node I

node K L => M node L

node L M => K C insularis

node J L =* J C. grismeri

node 1 L => I C. dickersonae

node G H =* F C. antiquus

node F H =» G C. collaris

node E L 4 E C. reticulatus

0.444

node A q <=> a HYPANC

node Bq4w node C

node D w — » v G. wislizenii

node Cw4y G. coronal

node B q — » n G. silus

node F q =4 s node G

node I s =4 k node J

node L k 4 a C. insularis

node F q =4 k C. collaris

1.000

node Aa4y node E

0.800

node A a — * y node E

node G y =4 s C. antiquus

1.000

node A a — » y node E

0.632

node Aa4y node B

node D y — » q G. wislizenii

node G a 4 g C. antiquus

1.000

node Aa-»y node E

1.000

node B a 4 u G. Silus

1.000

node H a =4 y node I

0.774

node A e - a HYPANC

node D e =4 h G. copei

140

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Appendix 6 — Continued

Character change lists:
Character Cl

Steps

Changes

Character change lists:
Character Cl

Steps

Changes

node Be^aG. si/us

0.500

node Ba=»yG silus

node Ae4y node E

node G a =» y C. antiquus

0.960

node A a =» u node B

1.000

node H a => y node I

node B u — » x node C

1.000

node A a =1 y node E

node D x =» y G. copei

0.500

node K a =5 y C. bicinctores

node K a =1 b C. bici net ores

node G a 4 y C. antiquus

0.585

node Ak«a HYPANC

0.800

node A 0 — * 1 node E

node B k — » f node C

node E 1 — ► 2 node F

node D f 4 d G. copei

node K2-»3 node L

node A k =£ w node E

node L 3 — » 4 C. insularis

node Fw4y node G

node G 2 —* 1 C. antiquus

node L y — » x C. vestigium

1.000

node E a =1 y node F

node J y =1 u C. grismeri

0.393

node Ea4h node F

node H y — * x C. nebrius

node F h =» y node G

node F w — > s C. collaris

node J y — *• 1 node K

0.750

node Ay«a HYPANC

node L 1 =» a C. insularis

node E y — ► q C. reticulatus

node L 1 — » y C. vestigium

0.436

node A a =5 y node B

0.500

node Ay»a HYPANC

node I a ^ d node J

node I y => a node J

node L d =» f C. insularis

1.000

node Aa=>y node E

node J d =4 f C. grismeri

0.500

node Ka4y node L

node G a =» y C. antiquus

node E a — » y C. reticulatus

0.247

node Ay w a HYPANC

1.000

node F y => a C. collaris

node D y => c G. wislizenii

1.000

node H 0 — » 1 node I

node E y — * i node F

node I 1 — *• 2 node J

node J i =5 e node K

node K2=>3 node L

node Ke4c node L

0.558

node Aa=»t node E

node L c 4 a C. insularis

node G t=»g node H

node J i =» p C. grismeri

node H g^a node I

node H i => a C. nebrius

node G t =5 y C. antiquus

node G i — * m C. antiquus

1.000

node Ea=»h node F

node F i =» a C. collaris

node F h ^4 y node G

0.800

node Aa-*y node B

1.000

node Ha=>y node I

node F a —* g C. collaris

0.500

node G a 4 y C. antiquus

0.649

node Aa^v node E

node E a =5 y C. reticulatus

node F v =» y node G

0.500

node H y =» a C. nebrius

node L y =+ p C. insularis

node F y =» a C. collaris

node Hy^wC. nebrius

1.000

node H a =» x C. nebrius

node F v — » t C. collaris

1.000

node Aa->y node B

1.000

node I a => y C. dickersonae

0.465

node J a=>s node K

1.000

node Aa^y node E

node L s — » p C. insularis

1.000

node Aa->y node E

node L s => u C. vestigium

0.889

node Ea4e node F

node H a =5 s C. nebrius

node Fe4y node G

node F a =» c C. collaris

node K y => v C. bicinctores

1.000

node K 0 =» 1 node L

1.000

node A a =4 y node B

node 1 0 3 C. dickersonae

1.000

node Ba-^y node C

node H 0 =5 2 C. nebrius

1.000

node A a =4 y node E

1.250

node A 0 — * 1 node E

1.000

node Aa-*y node B

node E 1 — » 4 node F

1.000

node A a — » y node E

node 1 4 =4 3 C. dickersonae

1.000

node A a =4 y node E

node H 4 2 C. nebrius

0.500

node A y -» a HYPANC

1.000

node E a => y node F

node E y — * a C. reticulatus

1.000

node Ba^y node C

1.000

node A a — *■ y node E

1.000

node A a =5 y node E

1.000

node Ba->y node C

n/a

100

node A 1 — » 2 node E

1.000

node Aa4y node E

100

node I 2 — » 3 node J

1.000

node Aa4y node B

node K 3 — » 4 C. bicinctores

1.000

node I a 4 y C. dickersonae

100

node E 2 — » 7 C. reticulatus

1996

McGUIRE— SYSTEM ATICS OF CROTAPHYTID LIZARDS

141

Appendix 6 — Continued Appendix 6 — Continued

Character change lists:
Character Cl

Steps

Changes

Character change lists:
Character Cl

Steps

Changes

n/a

node A 1 — » 6 node E

node D x =4 y G. copei

node F 6 — » 1 node G

node A c 4 y node E

node E 6 ^ 7 C. reticualtus

node G y =4 s C. antiquus

n/a

node A 1 — » 2 node E

1 1

1.000

node C a — * y node D

node K 2 — ► 1 node L

0.727

node Aa4y node B

node H 2 4 5 C. nebrius

node D y 4 p G. copei

node F 2 — » 6 C. collaris

1.000

node A a — * y node E

n/a

100

node I 1 =» 2 C. dickersonae

1.000

node Ay«a HYPANC

node H 1 =4 5 C. nebrius

1.000

node Aa4m node B

node F 1 =» 6 C. collaris

node Cm-»y node D

n/a

node I 1 4 2 C. dickersonae

1.000

node Ka4j node L

node H 1 4 5 C. nebrius

node L j =4 y C. insularis

node F 1 =» 6 C. collaris

0.462

node Ae-»w node B

n/a

node A 1 — » 2 node E

node Dw4yC. copei

100

node I 2 — ► 3 node J

node Bw-^x & silus

n/a

node A 1 — ► 7 node E

node F e ^ a node G

node F 7 — » 5 node G

node J a 4 k C. grismeri

1 1

node I 5 — » 4 node J

node F e — * v C. collaris

node K4^3 node L

1.000

node I a 4 y C. dickersonae

node I 5 — » 2 C. dickersonae

1.000

node A a =4 y node E

node F 7 =4 6 C. collaris

1.000

node By4a node C

n/a

node A 1 — » 6 node E

1.000

node Aa-*y node B

node K 6 4 4 C. bicinctores

0.490

node C a 4 y G. coronaf

node K 6 — » 1 node L

node A a =» x node E

node I 6 =» 2 C. dickersonae

node Fx-»y node G

node H 6 4 5 C. nebrius

node E x — » y C. reticulatus

node E 6 =1 7 C. reticulatus

1.000

node Aa-*y node E

n/a

node K 1 4 4 C. bicinctores

0.857

node Ac^w node B

node I 1 42 C. dickersonae

node C w — * y node D

node E 1 =4 7 C. reticulatus

node E c =4 b node F

n/a

100

node A 1 — » 3 node E

node Hb->a node I

100

node K 3 4 4 C. bicinctores

node L a 4 b C. vestigium

node I 3 =» 2 C. dickersonae

node H b 4 d C. nebrius

100

node F 3 4 6 C. collaris

node Gb^aC. antiquus

(DELTRAN optimization):

1.000

node B a — >■ y node C

Character Cl

Steps

Changes

0.462

node Ac»a HYPANC

0.421

node C a =4 y node D

node Ac4y node B

node B a — » f G. silus

node Fc4b node G

node I a =» b node J

node K b =4 g node L

node L b 4 y C. insularis

node L g =4 y C. insularis

node J b =4 f C. grismeri

node J b 4 a C. grismeri

0.774

node Aa4y node B

node I b 4 d C. dickersonae

node G a 4 g C. antiquus

node G b =4 a C. antiquus

node F a — * b C. collaris

1.000

node A a =4 y node E

0.649

node K a 4 b C. bicinctores

1.000

node E 0 — » 1 node F

node I a =4 y C. dickersonae

node E 0 —* 2 C. reticulatus

node G a =4 m C. antiquus

1.000

node Ay « a HYPANC

1.000

node A y - a HYPANC

1.000

node Aa4y node B

1.000

node Ba4y node C

n/a

node B A =4 C node C

1.000

node Ay « a HYPANC

node D C 4 B G. wislizenii

0.889

node Ca-*c node D

node A A — * L node E

node D c 4 y G. copei

node E L ^4 H node F

node B a 4 d G. silus

node H H 4 L node I

1.000

node Aa-»y node E

node K L 4 M node L

1.000

node Aa->y node E

node L M 4 K C. insularis

0.462

node Ac«a HYPANC

node J L 4 J C. grismeri

node C c — * x node D

node I L =4 I C. dickersonae

node G H 4 F C. antiquus

142

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY

NO. 32

Appendix 6 — Continued Appendix 6 — Continued

Character change lists:
Character Cl

Steps

Changes

node FH^GC. collaris

node E L =1 E C. reticulatus

0.444

node An«a HYPANC

node Bn4v node C

node D v — > w G. copei

node Cv=*y6. corona^

node F n =» s node G

node I s k node J

node L k =5 a C. insularis

node F n ^ k C. collaris

node E n — » q C. reticulatus

1.000

node A a =* y node E

0.800

node Aa-^y node E

node G y ^ s C. antiquus

1.000

node Aa->y node E

0.632

node Aa=»q node B

node D q -» y G. copei

node B q — *• y G. silus

node G a 4 g C. antiquus

1.000

node A a — » y node E

1.000

node B a =£ u G. silus

1.000

node H a =5 y node I

0.774

node Ca-*e node D

node D e h G. copei

node Aa4 y node E

0.960

node Aa^u node B

node Cu-*x node D

node D x ^ y 6. copei

node K a ^ b C. bicinctores

0.585

node Af«a HYPANC

node D f =» d G. copei

node B f — * k G. silus

node Af=»s node E

node Fs4x node G

node K x — * y C. bicinctores

node L x — » y C. insularis

node J x =» u C. grismeri

node I x — * y C. dickersonae

node G x — ► y C. antiquus

node E s — w C. reticulatus

0.750

node A q - a HYPANC

node Aq->y node B

node Eq->y node F

0.436

node A a =5 y node B

node I a =1 d node J

node L d =» f C. insularis

node J d =» f C. grismeri

node G a ^ y C. antiquus

0.247

node A i " a HYPANC

node D i — *■ y G. copei

noe D i =5 c G. wislizenii

node B i — > y G. silus

node J i =3 e node K

node K e =1 c node L

node L c =5 a C. insularis

node J i =2 p C. grismeri

noe H i =* a C. nebrius

node G i — » m C. antiquus

Character change lists:
Character Cl

Steps

Changes

node F i => a C. collaris

node E i — » y C. reticulatus

0.800

node Aa-*y node B

node F a — » g C. collaris

0.649

node A a =» t node E

node Ft=»w node G

node H w — » y node I

node L y => p C. insularis

node Gw^yC. antiquus

node E t — * v C. reticulatus

1.000

node I a 4 y C. dickersonae

1.000

node Aa->y node E

1.000

node Aa->y node E

0.889

node Ea=>e node F

node F e =5 y node G

node Ky=>vC. bicinctores

1.000

node A a =* y node B

1.000

node C a — » y node D

1.000

node Aa=>y node E

1.000

node A a — > y node B

1.000

node Aa-»y node E

1.000

node Aa=>y node E

0.500

node Aa^y node B

node Ea-*y node F

1.000

node Aa-*y node E

1.000

node C a — » y node D

1.000

node Aa=*y node E

1.000

node A a =» y node B

1.000

node I a => y C. dickersonae

0.500

node B a =» y G. silus

node G a =» y C. antiquus

1.000

node H a =5 y node I

1.000

node A a => y node E

0.500

node K a y C. bicinctores

node G a ^ y C. antiquus

0.800

node E 0 — * 2 node F

node L 2 — * 4 C. insularis

node L 2 — » 3 C. vestigium

node G 2 — *T C. antiquus

node E 0 — » 1 C. reticulatus

1.000

node Ea=»y node F

0.393

node Ea=>h node F

node Fh=>y node G

node K y — ► 1 C. bicinctores

node L y => a C. insularis

0.500

node Ay ^ a HYPANC

node I y =» a node J

1.000

node Aa=»y node E

0.500

node Ka^»y node L

node E a — » y C. reticulatus

1.000

node F y =* a C. collaris

1.000

node I 0 — *• 2 node J

node K2=»3 node L

node I 0 — > 1 C. dickersonae

0.558

node A a => t node E

node Gt=»g node H

node H g =» a node I

node G t =* y C. antiquus

1996

McGUIRE — SYSTEM ATICS OF CROTAPHYTID LIZARDS

143

Appendix 6 — Continued

Character change lists:
Character Cl

Steps

Changes

Character change lists:
Character Cl

Steps

Changes

1.000

node Ea4h node F

node L 4 — » 3 C. vestigium

node Fh=>y node G

node H 2 -> 5 C. nebrius

1.000

node Ha4y node I

node F 2 4 6 C. collaris

0.500

node G a 4 y C. antiquus

node E 2 — » 7 C. reticulatus

node E a 4 y C. reticulatus

96 n/a

node A 1 — * 6 node E

0.500

node H y 4 a C. nebrius

node K 6 4 4 C. bicinctores

node F y 4 a C. collaris

node L 6 — ► 3 C. vestigium

1.000

node H a 4 x C. nebrius

node I 6 =4 2 C. dickersonae

1.000

node Aa-*y node B

node H 6 4 5 C. nebrius

0.465

node J a =5 p node K

node E 6 =4 7 C. reticulatus

node K p — » s C. bici net ores

97 n/a

node K 1 4 4 C. bicinctores

node L p 4 u C. vestigium

node 114 2 C. dickersonae

node H a 4 s C. nebrius

node E 1 4 7 C. reticulatus

node F a 4 c C. collaris

98 n/a

100

node A 1 — * 3 node E

1.000

node K04 1 node L

100

node K 3 4 4 C. bicinctores

node I 0 4 3 C. dickersonae

node I 3 4 2 C. dickersonae

node H 0 4 2 C. nebrius

100

node F 3 4 6 C. collaris

1.250

node E 0 — » 4 node F

node I 4 4 3 C. dickersonae

node FI 4 4 2 C. nebrius

node E 0 — * 1 C. reticulatus

1.000

node E a =4 y node F

1.000

node D a — » y G. wislizenii

Appendix 7

1.000

node Aa4y node E

Scleral Ossicle Data

n/a

100

node E 1 — > 2 node F

Scleral ossicle numbers and patterns of overlap were assessed

100

node J 2 — »• 3 node K

in the listed specimens. All crotaphytids examined match the

node K 3 — » 4 C. bicinctores

apparently plesiomorphic iguanian condition in which ossicles

100

node E 1 -* 7 C. reticulatus

1 , 6, and 8 are positive and 4, 7, and 1 0 are negative (Underwood,

n/a

node A 1 — » 6 node E

1970; de Queiroz, 1982). Only

one set of scleral ossicles (one eye)

node G 6 — *• 1 node FI

was examined in the specimens followed by asterisks.

node E 6 4 7 C. reticulatus

n/a

node A 1 — » 6 node E

Crotaphytus :

node K 6 — > 4 C. bicinctores

bicinctores

REE 2931, 2932, 2934

node L 6 — » 3 C. vestigium

antiquus

TNHC 53155*, 53156, 53159

node I 6 — * 2 C. dickersonae

collaris

REE 2875, 2944, 2952*

node H 6 =4 5 C. nebrius

dickersonae

REE 2777,

2904, 2905

node E 6 —* 7 C. reticulatus

grismeri

MZFC 6648, 6649, 6650*

n/a

100

node I 1 =4 2 C. dickersonae

insularis

REE 2794-

■2796

node H 1 4 5 C. nebrius

nebrius

REE 2937,

2941, 2942, 2943

node F 1 =4 6 C. collaris

reticulatus

REE 2910, 2911, 2913*

n/a

node I 1 =4 2 C. dickersonae

vestigium

REE 2820, 2825, 2826

node H 1 =4 5 C. nebrius

Gambelia:

node F 1 4 6 C. collaris

copei

REE 2798, 2802. 2804

n/a

node A 1 — » 2 node E

silus

CAS 22713

1, 22742*, 141328*

100

node J 2 — *■ 3 node K

wislizenii

REE 2789*

, 2790. 2791. 2792. 2916'. 2917.

n/a

node A 1 — * 2 node E

29182, 2919. 2920

node 12 — *5 node 1

Ossicles 1 and 14 of the right scleral ring are partially overlapping.

1 1

node J 5 — *• 4 node K

2 Ossicles 1 and 1 4 of the right scleral ring and 1 3 and 14 of the'left ring are partially
overlapping.

ISSN 0145-9058

BULLETIN

OF CARNEGIE MUSEUM OF NATURAL HISTORY

TAXONOMY AND EVOLUTION OF LATE
CRETACEOUS LIZARDS (REPTILIA: SQUAMATA)

FROM WESTERN CANADA

GAO KEQIN and RICHARD C. FOX

DUMBER 33

PITTSBURGH, 1996

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