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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 16 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
OF CROTAPHYTID LIZARDS
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 Gat?jbelia is very different
from that of Crotaphytlrs. The pattern is composed
oflongitudinally 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 Garnbelia and in both sexes, which
is in contrast to the Crotaphyttts 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 Melanic Asillary Parches (Character
83).-Enlarged melanic axillary patches are variably
present in Crotap/tytus bicinctores, C. collaris. C.
instilaris, C. nebrius, and C. rtestigium. They are
absent from C. antiqlrlrs. C. dickersonae. C. gris-
meri, and C. reticttlatus, although in C. reticttlatus
and C. antiqutcs, black-filled reticulations may occur
in the same axillary position as the melanic spots
seen in other Crotaphyttis. Axillary patches are not
a fixed feature in any Crotaph.vtus 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. Utua essul, and Leiocephalus rnacropus
(within Leiocephalus, axillary patches are variable
within L. macropus, but present in male L. lunarus,
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. Crotaphylus insularis, and C. ves-
tigium, as well as some male C. collaris and C. ne-
brius. The coloration present in C. insularis, C. ne-
brim, and C. vestigitrtn 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