Phylogenetic Systematics oflguanine Lizards 



47 



oc 



FIG. 21. Ventral views of the neurocrania of (A) Sauromalus varius (RE 451), (B) Ctenosaura 

 hemilopha (RE 325), (C) Iguana iguana (RE 1006), and (D) Cyclura nubila (RE 337), showing differences 

 in the width of the parabasisphenoid and the size of its posterolateral processes. Scale equals 1 cm. 

 Abbreviations: bo, basioccipital; bs, parabasisphenoid; eo, exoccipital-opisthotic; oc, occipital condyle; 

 pro, prootic; ps, parasphenoid rostrum; sot, spheno-occipital tubercle. 



basipterygoid prcx;esses, giving the ventral outline of the braincase roughly the shape of an 

 hourglass (Fig. 21A,B). In contrast, the cristae ventrolaterales of Iguana are widely 

 separated, extending in almost straight lines from the basipterygoid processes posteriorly to 

 the spheno-occipital tubercles and giving the ventral outline of the braincase the shape of a 

 box (Fig. 21 C). Cyclura is variable in this character, though all species have relatively 

 broad parabasisphenoids (Fig. 2 ID) compared to those of most other iguanines. C. 

 carinata has the narrowest basisphenoid, while that of C. pinguis is at least as wide as that 

 of some Iguana delicatissima; other species are intermediate. In at least some of those 



