Phylogenetic Systematics of I guanine Lizards 



169 



FIG. 58. Geographic distribution oi Iguana (from Elheridge, 1982). 



6. Thin midsagittal processes on anterodorsal surfaces of caudal centra relatively small 

 and confined to anterior fifth of caudal sequence (62-B). This character occurs also in 

 Brachylophus, in which it is interpreted as convergent. 



7. Coeliac artery arises posterior to mesenteric arteries, between mesenteric arteries, or 

 continuous with mesenteric arteries rather than anterior to them (78-B). This character also 

 occurs in some Sauromalus, in which it is interpreted as convergent. It needs to be 

 checked in larger samples. 



8. Snout covered by large, platelike scales (82-B). This character also occurs in some 

 Cyclura and may be a synapomorphy of a more inclusive group. 



9. Large dewlap present (88-B). This character also occurs in Brachylophus and in 

 Ctenosaura bakeri and C palearis, in which it is interpreted as two separate instances of 

 convergence. 



10. Gular crest of enlarged scales present (88-B). 



In addition, the following derived characters occur in only some Iguana: 



1. Frontal wider than long (8-B). This character occurs also in Amblyrhynchina and in 



Cyclura cornuta, in which it is interpreted as two separate instances of convergence. 



Within Iguana it occurs only in /. delicatissima and appears to be a synapomorphy of that 



taxon. 



