Download Full Document - Mountain Boomer Music!

BULLETIN CARNEGIE MUSEUM OF NATURAL HISTORY NO. 32
Fig. 11.-Ventral view of the skull of Crotaphytur dickrsonae
(REE 2777, adult male. SVL = 116 mm). Scale = 5 mm.
(Leiolepis belliana, Physignathus lesueurii). There-
fore, the presence of a tubercle is considered to be
the derived state and represents a synapomorphy
for Crotaphytidae.
There is also variation in the angle of the jugal
where it serves as the ventrolateral border of the
orbit. In Crotaphytus, the medial face of the jugal
is oriented dorsolaterally at about a 45-degree angle
over most of its length. In G. wislizenii, G. copei,
and 15 of 3 1 G. silus, the medial face becomes pro-
gressively more vertical anteriorly until it articulates
with the palatine, lacrimal, and prefrontal. As a re-
sult, the region of articulation of the three bones in
Gambelia wislizenii, G. copei, and some G. silus is
box-like because the jugal meets the palatine and
prefrontal at perpendicular angles. In Crotaphytus
and some G. silus, the jugal meets the prefrontal in
a smooth, rounded arc. The box-like condition of
the ventrolateral border of the orbit was approached
only in Petrosaurus mearnsi. Uta stansburiana. Uma
(but not Callisaurus, Cophosaurus, or Holbrookia
rnaculata), one of two Enyalioides laticeps, and Lei-
olepis belliana and is therefore considered to be the
derived state within Crotaphytidae.
PALATE
Vorners (Character 16; Fig. 1 1, 12). -In Crota-
phytus insularis and C. vestigium, a separate pair of
small bones, here termed extravomerine bones, may
be present posteromedially where the vomers and
palatines meet (Fig. 12). These medially contacting
bones appear to be the result of secondary ossifi-
cation centers in the vomers. In many specimens,
this additional bone is present on one side only and
the region where the bone is absent is filled in by
the vomer from that side. Extravomerine bones are
present in all five C. insularis available for study,
although it is found on the right side only in one
specimen (REE 2797). It is also found on at least
one side in ten of 27 C. vestigium. Extravomerine
bones are not present in the outgroup taxa examined
here and no evidence has been discovered docu-
menting their presence in other lizard species.
Therefore, the presence of either one or two extra-
vomerine bones is considered to be the derived state.
Palatines (Character 17; Fig. 6, 1 1, 12).-In Cro-
raphytus, the dorsal surface of the maxillary process
usually bears the palatine foramen (Fig. 6), which
may be situated in the suture of the maxillary pro-
cess and the prefrontal or completely within the
palatine. In one C. collaris (USNM 2202 16), the
foramina were located entirely within the palatine
processes of the prefrontals. A well-developed,
transversely oriented canal, associated with the in-
termediate palatine branch of nerve VII (Oelrich,
1956), projects medially from the palatine foramen
(Fig. 6). In Gambelia, a palatine foramen is only
rarely evident (five of 43 G. tvislizenii, zero of eight
G. copei, two of 30 G. silus), although the canal, and
presumably the intermediate palatine branch of
nerve VII, are present. Instead of passing through
the prefrontal and palatine bones, the tube passes
through the connective tissue medial to the palatine
process of the prefrontal along the lateral border of
the orbitonasal fenestra. The absence of a palatine
foramen in the great majority of Gambelia appears
to be the result of the narrower palatine process of
the prefrontal found in this taxon, rather than the
absence or rerouting of the intermediate palatine
branch of nerve VII. Some variation was observed