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1996 McGUIRE-SYSTEMATICS OF CROTAPHYTID LIZARDS 5 5
external nares, (I) overlap nasal process of the
premaxilla anterior to posterior extent of ex-
ternal nares.
4. Prefrontals (P): (0) not in contact with jugals,
(1) contact jugals.
5. Cranium (U): (0) vaulted, (1) not vaulted.
6. Postorbitals (P): (0) weakly overlapped dorsally
by frontal and parietal, (I) strongly overlapped
dorsally by frontal and parietal.
7. Tubercle on anterolateral portion of postorbi-
tals (P): (0) absent, (I) present.
8. Posterior border of parietal roof (P): (0) ap-
proximately twice as wide as narrowest portion
of frontal bone (unconstricted), (I) equal in
width or only slightly wider than narrowest por-
tion of frontal bone (constricted).
9. Supratemporal processes (in lateral view) (P):
(0) tapered, rapidly narrowing dorsoventrally at
their midpoints; (1) not tapered, remain broad
over entire length.
10. Supratemporals (P): (0) broadly exposed on the
lateral surface of the supratemporal process of
the parietal, (1) lies in a groove on ventral sur-
face of supratemporal process of parietal.
1 I. Septomaxillae (P): (0) wide, (I) narrow.
12. Suture of maxillae with premaxilla (P): (0) not
saddle-shaped, no process of the maxilla over-
laps the lateral border of the premaxillary base;
(1) saddle-shaped, a process of the maxilla over-
laps lateral border of premaxillary base.
13. Shape of maxilla-palatine articulation (U): (0)
low arch, (1) triangular.
14. Jugal+ctopterygoid tubercle (P): (0) absent, (1)
present.
15. Angle of jugal along anteroventral border of
orbit (P): (0) approximately 45 degrees, (1) ap-
proximately 90 degrees (box-like condition).
16. Extravomerine bones (P): (0) absent, (1) at least
one present.
17. Palatine foramen (U): (0) present, (1) absent.
18. Transverse process of the pterygoid with (U):
(0) weakly developed ventral process, (I)
strongly developed ventral process.
19. Paraoccipital processes project posteriorly (P):
(0) to level of occipital condyle, (1) well beyond
occipital condyle.
20. Angle of the quadrate process of the pterygoid
(U): (0) approximately 18 degrees, (1) approx-
imately 26-3 1 degrees.
2 1. Posterior projection of ectopterygoid crest (U):
(0) present, (I) absent.
22. Posterior projections of parabasisphenoid (P):
(0) reach the sphenoccipital tubercles; (1) ter-
minate at, or anterior to, the base of the sphen-
occipital tubercles.
23. Anterior extent of angular (U): (0) never reaches
the fourth dentary tooth (counting forward from
the posteriormost tooth) and rarely extends an-
teriorly beyond the posteriormost tooth, (I) ex-
tends at least to the fourth tooth (counting for-
ward from the posteriormost tooth) and usually
beyond.
24. Posterior mylohyoid foramen (U): (0) equal with
apex of coronoid, (1) posterior to apex of cor-
onoid.
25. Posterolingual process of the coronoid (P): (0)
oriented vertically, (1) angled posteroventrally
at approximately 45 degrees.
26. Bony shelf extending between medial process
of surangular and ramus of mandible (P): (0)
absent, (1) present.
27. Lateral process of surangular (P): (0) absent or
present as a weakly elevated ridge, (1) present
as a large protuberance.
28. Ridge on lateral surface of surangular (P, UO):
(0) absent, (I) moderately developed, (2) strong-
ly developed such that the dorsal surface of the
mandible is concave.
29. Tympanic crest (P): (0) forms lateral border of
retroarticular process, (1) curves posteromedi-
ally.
30. Maxillary and dentary teeth (P): (0) stout, either
straight or slightly recurved; (1) long, slender,
and more strongly recurved.
3 1. Number of premaxillary teeth (U, UO): (0) five,
(I) six, (2) seven, (3) eight, (4) nine.
32. Palatine teeth (P): (0) absent, (1) present.
33. Pterygoid tooth patch (P): (0) follows margin of
interpterygoid vacuity, (1) curves posterolater-
ally.
HYOID APPARATUS
34. Ceratohyals (U): (0) without hook-like process-
es on proximal, medial edge; ( I ) with hook-like
processes on proximal, medial edge.
35. Length of second ceratobranchials (U): (0) ap-
proximately one-half length of ceratohyals, (1)
more than two-thirds length of ceratohyals.
36. Second ceratobranchials (P): (0) in contact me-
dially, (I) widely separated.
37. Skull rugosity at some point in ontogeny (U):
(0) absent, (I) present.