Phylogenetic Systematics of I guanine Lizards 



171 



FIG. 59. Geographic distribution of Cyclura (from Schwartz and Carey, 1977). 



Definition: The most recent common ancestor of Recent Cyclura (carinata, collei, 

 comma, cychlura, nubila, pinguis, ricordii, and rileyi) and all of its descendants. 



Distribution: The Bahama Islands; Cayman Islands; Mona and Anegada islands; and 

 Cuba, Hispaniola, and Jamaica, and their nearby islets (Fig. 59). Cyclura is nearly extinct 

 on Jamaica (Woodley, 1980) and has become extinct on Navassa Island in historical times 

 (Thomas, 1966). 



Diagnosis: Members of this taxon can be distinguished from other iguanines by the 

 following synapomorphies: 



1. Modal number of premaxillary teeth greater than seven (43-44-C). This character 

 applies only to populations; its presence or absence cannot always be inferred from the 

 condition in a single organism. 



2. Presence of toe combs formed by enlargement of anterior keels of subdigital scales 

 and fusion of their bases (92-B). Ctenosaura defensor also possesses enlarged and fused 

 subdigital keels, which are interpreted as convergent; however, in this taxon, they occur 

 only under the first phalanx of digit III. In Cyclura the enlarged and fused subdigital keels 

 occur under the first phalanx of digit II and the first and second phalanges of digit III. 



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



