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4 8 BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY NO. 32
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 sometimes
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 ancestral
state in all but Opluridae (collars present in
0. cuvieri and 0. cyclurus). Therefore, the presence
of white-bordered collars is treated as the derived
state.
Additional variation occurs in C. bicinctores, C
anfiquus, 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. irtsularis and C. vesfigiurn,
the posterior collars are broadly separated
(Fig. 32C, D). The condition in C. reticirlarrrsis more
difficult to interpret because of the weak development
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.
Fig. 34.-Ventral view of an adult male Crotaphytus nehrircs.
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 condilion 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-
tiqtrus, 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 67551, 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