20 University of California Publications in Zoology 



shaped*, or with a posterior midsagittal crest (Y-shaped)*; parietal foramen present, on 

 frontoparietal suture or within frontal*; outUnes of osseous labyrinth indistinct (moderately 

 distinct in Dipsosaurus); supratemporal situated primarily on posteromedial surface of 

 supratemporal process of parietal*; lacrimal present; postfrontal present; septomaxilla with 

 a large posterodorsal shelf*; epipterygoid present; Meckel's groove closed and fused 

 between anterior end of splenial and mandibular symphysis*; angular present; splenial 

 present; coronoid with large lateral process overlapping dentary; three to eleven 

 premaxillary teeth (most species with a mode of seven); premaxillary teeth without lateral 

 cusps, bicuspid, or tricuspid; crowns of posterior marginal teeth flared, with three to 

 many* cusps; palatine teeth absent*; pterygoid teeth present or absent*; second 

 ceratobranchials long* or short, adpressed or separated* medially; 14 scleral ossicles. 



AXIAL SKELETON: vertebral neural spines tall or short*; zygosphenes and zygantra 

 well developed*; mode of 24 or 25* presacral vertebrae; caudal autotomy septa present or 

 absent*; less than 25* to more than 70 caudal vertebrae; some caudal vertebrae with two 

 pairs of transverse processes that diverge from one another*; first rib usually borne on fifth 

 cervical vertebra; usually four pairs of free (cervical) ribs on fifth through eighth presacral 

 vertebrae; usually four pairs of sternal ribs on ninth through twelfth presacral vertebrae; 

 one* or two pairs of xiphistemal ribs attached to 13th and usually 14th presacral vertebrae; 

 all post-thoracic presacral vertebrae usually bear unfused ribs; postxiphistemal inscriptional 

 ribs attached to corresponding bony ribs, with zero to three pairs meeting midventrally to 

 form continuous chevrons. 



APPENDICULAR SKELETON: clavicles with or without* flattened lateral shelf; dorsal 

 ends of clavicles articulate with suprascapulae; clavicular fenestrae usually absent (except in 

 Conolophus); scapular fenestrae usually present* (variably reduced or absent in 

 Amblyrhynchus and Sauromalus); posterior coracoid fenestrae present* or absent; lateral 

 arms of interclavicle form angles of 45° to 90° with posterior process; posterior process of 

 interclavicle extending posterior to lateral corners of sternum or not*; sternal fontanelle 

 present but small (approximately equal to interclavicle in width) or absent*; phalangeal 

 formula of manus 2:3:4:5:3; phalangeal formula of pes 2:3:4:5:4. 



NONSKELETAL ANATOMY: superciliary scales quadrangular and non-overlapping to 

 elongate and strongly overlapping (Etheridge and de Queiroz, 1988); subocular scales all 

 subequal and quadrangular to one greatly elongate (Etheridge and de Queiroz, 1988); 

 interparietal scale small; transverse gular fold present (weakly developed in 

 Amblyrhynchus); pendulous dewlap present* or absent; gular crest present* or absent; 

 middorsal row of enlarged scales present or absent*; subdigital lamellae keeled, without 

 setae; femoral pores present in one or two rows; preanal pores absent; scale surface with 

 honeycomb pattern (Etheridge and de Queiroz, 1988); scale organs lacking elongated 

 spines (Etheridge and de Queiroz, 1988); nasal passage S-shaped, with concha present 

 (Stebbins, 1948); colon with transverse valves or folds (Iverson, 1980). 



