150 University of California Publications in Zoology 



quinquecarinata were allocated to Enyaliosaurus, but no justification was provided 

 for the revival of the genus. Duellman (1965: 599), followed Smith and Taylor in 

 recognizing the validity of Enyaliosaurus, placed erythromelas in the synonymy of 

 defensor, provided a key to the species, and suggested that: "Enyaliosaurus 

 doubtless is a derivative of Ctenosaura, all species of which are larger and have 

 relatively longer tails and less well-developed spines than Enyaliosaurus." Meyer 

 and Wilson (1973) referred Ctenosaura bakeri to Enyaliosaurus, but Wilson and 

 Hahn (1973: 114-5) returned bakeri to Ctenosaura, commenting that: "John R. 

 Meyer is currently studying the problems of the relationship of the species now 

 grouped in Enyaliosaurus to those now grouped in Ctenosaura. He (pers. comm.) 

 advised us that he considers the two genera inseparable, and that bakeri appears to 

 be closely related to both palearis (now in Enyaliosaurus) and similis (now in 

 Ctenosaura)." In addition, Ernest Williams of Harvard University has informed me 

 (pers. comm.) that based on an unpublished study of the group by him and Clayton 

 Ray, he does not believe the recognition of Enyaliosaurus is warranted. At the 

 present time the problem of the relationships of Ctenosaura and Enyaliosaurus are 

 under study by Diderot Gicca of the Florida State Museum. (Etheridge, 1982:9-10) 



More recently, Gicca (1983) recognized the genus Enyaliosaurus. 



Evidence for the monophyly of Ctenosaura in the broad sense of Bailey (1928) has 

 been presented above. An evaluation of the monophyletic status of Ctenosaura in the 

 narrow sense, and of Enyaliosaurus, required a phylogenetic analysis using the species of 

 both as basic taxa. In this analysis, I have used primarily characters recognized by 

 previous workers, in particular, Bailey (1928), Smith and Taylor (1950), and Ray and 

 Williams (unpubl.). When possible, all characters were checked on specimens. My 

 analysis is based on the following 19 characters representing a minimum of 23 

 phylogenetic transformations. The polarities of these characters were determined using 

 Amblyrhynchina, Iguanina, Sauromalus, Dipsosaurus, and Brachylophus as outgroups. 

 The character-state codes are as follows: 0, ancestral; 1, derived; 2, further derived; etc. 

 Letter codes are used for characters whose polarities were considered undeterminable. 



1. Maximum snout-vent length: (0) greater than 190 mm; (1) less than 190 mm. 

 Maximum snout-vent lengths for the various taxa are as follows: acanthura = 215 mm 

 (MCZ 16074, Bailey, 1928; 315 mm according to Ray and Williams, unpubl., but they 

 include pectinata in acanthura); bakeri = 210 mm (USNM 25324, Bailey, 1928); clarki = 

 154 mm (UMMZ 112711, Duellman and Duellman, 1959); defensor = 155 mm (HM 3420, 

 Bailey, 1928); hemilopha = approximately 400 mm (H. M. Smith, 1972; the largest 

 specimen that Bailey [1928] presents data for is AMNH 2073 with a snout- vent length of 

 260 mm); palearis = 254 mm (CAS 69308, A. Bauer, pers. comm.); pectinata = 305 mm 

 (MCZ 2726, Bailey, 1928); quinquecarinata = 169 mm (Hidalgo, 1980; Gicca, 1983); and 

 similis = 489 mm (Fitch and Hackforth-Jones, 1983). A cutoff of 190 mm was chosen, 

 partly because of an apparent gap and partly because all other species of Iguanini reach 

 greater maximum snout- vent lengths than this. 



