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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 hindlimbs
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 compressed
tails (C. bicinctores, C. dickersonae. C. grismeri,
C. insularis, and C. vestigium), a pale white
or cream stripe runs down the dorsal surface of the
tail (Fig. 3 1 B, 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, 3 1 A-D, 32A-D, 33-35). -All male Crotaphytus,
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 reticulations
surrounding bla~k pigment. This is a condition
very similar to that seen in adult C. reticrtlatus
and C. antiquus of both sexes. The extent and placement
of the reticulated pattern varies considerably
between species resulting in somewhat bewildering
interspecific variation. Nevertheless, a pair of discrete
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 condition
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 abdominal
reticulations were not observed in the outgroup
taxa; therefore, their presence is treated as the
derived state.
In Crotaphytus, there are two common dorsal pattern
types, reticulation and spotting. It seems likely
that spots are formed when reticulations have become
fragmented. For example, in large C. vestig-
OF CROTAPHYTID LIZARDS
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 patteni 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. reticuiatus 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 (1 972)
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 apriori
assumptions were made regarding the order of trans-
formation. Because Crotaphytus and Garnbelia are