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McGUIRE-SYSTEMATICS 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 Croraphytus bicinc-
(ores 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, 19 16; 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 Sceloporus. Cnernidophorus,
Phrynosoma, and Xantusia vigilis (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 (1 980) studied the reproductive biology
of C. bicinclores 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 (1 974) 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.
Illustrarions.-A detailed black-and-white illus-
tration ofthe entire animal was provided in Stebbins
(1954); line drawings of the head squamation were
included in Bun (1 928b: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 (1 972), Smith and Tanner (1 972),
and Nussbaum et al. (1983); color photographs were
given by Behler and King (1979) and Sprackland
(1990, 1993).
Croraphyius collaris Say
Agama collaris Say, 1823:252. Type locality: not given; Arkansas
Tenitory (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 Temtory"; (Stejneger and Barbour. 19 17): "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. 1989~): Verdigris
River near its union with the Arkansas River. Oklahoma.
Croraphyrus collaris- Holbrook, 1842:79; pl. 10.
Leiosaurus collaris-Dumkril, 1856:532.
Croraphyrus baileyi Stejneger (syn. fide Cope, 1900), 1890: 103;
fig. 1.2. Type locality: "Painted Desert, Little Colorado River,
Arizona" (holotyp: USNM 1582 1).