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4 2 BULLETIN CARNEGIE MUSE .UM OF NATURAL HISTORY NO. 32
appear to be unusually small, no attempt was made
to polarize this character because adequate comparative
material was not available.
Sexual Dimorphism (Character 60).-Most iguanian
lizards are sexually dimorphic with males
reaching larger SVLs than females (Fitch, 198 1).
This condition is exhibited in all Crotaphytus (Burt,
1929; Axtell, 1972; Fitch, 1981; McGuire, 1994;
personal observation) as well as Gambelia silus (Tol-
Iestrup, l 979, 1 982), while females are much larger
than males in G. ~vislizenii (Tollestrup, 1979, 1982)
and G. copei (Banta and Tanner, 1968). Sexual dimorphism
in which males are larger than females
appears to be the ancestral state for the families
Chamaeleonidae (Parcher, 1974; Fitch, 198 l), Iguanidae
(Fitch, 198 1; Gibbons, 1981; Carothers, 1984),
Opluridae (Blanc and Carpenter, 1969), Phrynosomatidae
(Fitch, 198 I), and Tropiduridae (Dixon and
Wright, 1975; Fitch, 1981; Cadle, 1991; Etheridge,
1992, 1994, 1995; Pregill, 1992; R. Etheridge, personal
communication, 1994). The ancestral state is
equivocal for Hoplocercidae (Duellman, 1978),
Corytophanidae (Fitch, 1981), and Polychrotidae
(Lazell. 1969; Fitch, 198 1; Frost and Etheridge, 1989;
Etheridge and Williams, 1991; Schwartz and Henderson,
199 1). Although the data regarding sexual
dimorphism in iguanians are somewhat fragmentary,
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. rvislizenii
(females larger than males) is treated as the derived
state.
Gravid artd Subadult Coloration (Characters 6 1,
62; Fig. 3 1 C, D).- All female crotaphytids display
red or orange dorsal banding or spotting when grav-
id. Although Frost and Etheridge (1989) suggested
that graGid coloration may be a synapomorphy for
the family, the presence ofgravid 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. hicinctores. C. dick-
ersonae, C. gristtteri. C. insularis, C. nebrius, C. re-
ticulatus, and C. vestigiurn. 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 Gatnbelia 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 1 B, 3 l C, 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.
Gatttbelia silus juveniles have yellow pigmenta-
tion in the form ofa 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. antiqulcs that was observed and