Phylogenetic Systematics of I guanine Lizards 



147 



FIG. 54. Geographic distribution of Ctenosnura (from Peters and Donoso-Barros, 1970; H. M. Smith, 

 1972; Etheridge, 1982). 



Etymology: (Greek) Ktenos, comb, + sauros, lizard, referring to the dorsal crest of 

 enlarged scales. 



Definition: The most recent common ancestor of the extant species of Ctenosaura 

 (acanthura, baked, clarki, defensor, hemilopha, palearis, pectinata, quinquecarinata, and 

 similis) and all of its descendants. 



Distribution: Lowlands of Mexico and Central America from southeastern Baja 

 California and the middle of Sonora in western Mexico and near the Tropic of Cancer in 

 eastern Mexico southward through most of Central America to central Panama, as well as 

 Isla de Providencia, Isla de San Andres, the Tres Marias Islands, and various offshore 

 islands in the eastern Pacific, the western Caribbean, and the Sea of Cortez (Fig. 54). 



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

 following synapomorphies: 



1 . Premaxillary process of maxilla curves dorsally; premaxillary teeth set higher than 

 maxillary teeth (16-B). This character is not present in small specimens. 



