Phylogenetic Systematics of I guanine Lizards 143 



the sister group of all other iguanines. The weaker tendency of Brachylophus to develop 

 fourth cusps on the posterior marginal teeth might be taken as further evidence in favor of 

 the latter hypothesis, but the character is variable in Brachylophus and has reversed several 

 other times within iguanines. At least three other characters might be used to support one 

 or the other of these alternative hypotheses, but these characters must be used with caution 

 because their polarities are unclear. These are: (1) the lack of a notch separating 

 zygosphenes from prezygapophyses in Dipsosaurus (character 56); (2) the absence of 

 circular colic valves in Brachylophus (character 80); and (3) the low number of colic valves 

 in Dipsosaurus (Iverson, 1982). Camp (1923) noted another character in which all 

 iguanines except Dipsosaurus share what appears to be a derived condition (Conolophus 

 was not examined): a high degree of separation of the M. mylohyoideus anterior 

 superficialis. Because of this contradictory information, I have chosen to leave the 

 relationships among Dipsosaurus, Brachylophus, and the monophyletic group consisting 

 of the remaining iguanines (Iguanini) unresolved. I am not aware of any characters 

 suggesting that Dipsosaurus and Brachylophus are sister taxa. 



Brachylophus Wagler 1830 



Type species (by monotypy): I guana fas data Brongniart 1800. 



Etymology: (Greek) Brachys, short, + lophos, a crest. The name presumably refers to 

 the relatively short scales of the dorsal crest in B.fasciatus, the type species. 



Definition: The most recent common ancestor of B.fasciatus and B. vitiensis and all of 

 its descendants. 



Distribution: Numerous islands in the Fiji Islands group, Tongatapu in the Tonga 

 Islands group, and lies Wallis northeast of Fiji, all in the southwestern Pacific Ocean (Fig. 

 53). 



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

 following synapomorphies: 



1. Lateral process of palatine behind infraorbital foramen contacts jugal (23-B). This 

 character occurs in all iguanines except Dipsosaurus and some specimens of Sauromalus, 

 and may be a synapomorphy of a more inclusive group. 



2. Infraorbital foramen located entirely within palatine bone, may or may not be 

 connected to lateral edge of palatine by suture (24-B). This character also occurs in some 

 Amblyrhynchus, some Ctenosaura, and some Sauromalus, in which it is interpreted as 

 convergent. 



3. Anterior inferior alveolar foramen located entirely within dentary (34-35-B). This 

 character occurs only in Brachylophus within Iguaninae, but does not occur in all 

 specimens. 



