42 University of California Publications in Zoology 



edge of the palatine is generally present (condition 2). Sauromalus obesus is similar to 

 Amblyrhynchus and Ctenosaura in this regard, but specimens of S. ater, S. hispidus, and 

 S. varius exhibit condition 4, in which the maxilla contributes to the ventral rim of the 

 foramen, rather than condition 2 (samples of other species of Sauromalus are too small 

 upon which to base generaUzations). 



Brachylophus and Dipsosaurus are unique among iguanines in the positions of their 

 infraorbital foramina, though at different ends of the morphological spectrum. In 

 Brachylophus, the infraorbital foramen is entirely within the palatine. A suture extending 

 from the foramen to the lateral edge of the maxillary process of the palatine (condition 2) 

 was observed in all four B. vitiensis examined but was absent (condition 1) in over half of 

 the specimens of B.fasciatus. Dipsosaurus is the only iguanine that commonly exhibits 

 condition 5, in which the infraorbital foramen emerges between palatine and maxilla. In 

 some specimens, a small posteriorly or laterally directed process is present at the medial 

 edge of the foramen; in others it is absent. When present, the process is smaller than that 

 seen in other iguanines (some Sauromalus) in which this process fails to contact the jugal 

 laterally. 



Because of the high intrageneric variation in the position of the infraorbital foramen, I 

 recognized three characters each with one apomorphic state rather than one character with 

 four or five: one for the size of the portion of the palatine immediately posterior (or 

 posteromedial) to the infraorbital foramen, a second for the presence or absence of contact 

 between this part of the palatine and the jugal, and a third for whether or not the infraorbital 

 foramen lies entirely within the palatine. 



The infraorbital foramina of the four outgroups examined in this study generally differ 

 from any of those seen in iguanines. Basiliscines and morunasaurs exhibit a condition 

 similar to that described above as condition 4, but the process of the palatine at the medial 

 edge of the infraorbital foramen is directed posteriorly rather than laterally (Fig. 17F). 

 Chalarodon and some Oplurus possess condition 5, while other Oplurus possess the 

 condition described for basiliscines and morunasaurs. Individual crotaphytines may also 

 exhibit the basiliscine-morunasaur condition, but in other individuals the infraorbital 

 foramen is located between palatine and jugal as in some iguanines. In the latter case, 

 however, the contact of the posteriorly directed process of the palatine with the jugal results 

 from extensive medial development of the jugal, rather than from lateral extension of the 

 process of the palatine as in iguanines. 



The differences between iguanines and the four outgroups indicate either that some 

 morphological change occurred between the most recent common ancestor of iguanines and 

 their closest relatives among these four outgroups or that no living iguanine species is 

 characterized by the condition that was present in the most recent common ancestor of the 

 group (though some individual specimens may be). Nevertheless, differences between 

 iguanines and the outgroups are minor enough that the polarities of all three characters can 

 be assessed. Because no iguanines possess the same morphology of the infraorbital 

 foramen seen in the outgroups, no iguanine is scored plesiomorphic for all three characters. 



