Phylogenetic Systematics oflguanine Lizards 



29 



pmx 



FIG. 11. Dorsal view of the skull of Amblyrhynchus cristatus (MVZ 67721), showing the short, wide 

 frontal and the wedge-shaped orbital borders. Scale equals 1 cm. Abbreviations: fr, frontal; ju, jugal; mx, 

 maxilla; na, nasal; par, parietal; pmx, premaxilla; prf, prefrontal; ptf, postfrontal; pto, postorbital; sq, 

 squamosal; st, supratemporal. 



while Conolophus, Cyclura cornuta, and Iguana delicatissima are intermediate between 

 Amblyrhynchus and the other iguanines. In C. cornuta and /. delicatissima reduction in 

 frontal length may be related to enlargement of the fenestrae exonarinae, although Cyclura 

 pinguis, which has large bony external nares, has a frontal that is about as wide as it is 

 long. 



The width of the frontal between the orbits exhibits substantial intergeneric variation in 

 iguanines, but the pattern of variation is obscured by correlation of this feature with size. 

 Small species and juveniles of large species have relatively large orbits and concomitantly 



