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FIG. 53. Geographic distribution oi Brachylophus (from Gibbons, 1981; Etheridge, 1982). 



4. Labial process of coronoid moderately large (36-B). The enlarged labial coronoid 

 process of Amblyrhynchus and Conolophus is interpreted as convergent. 



5. Second ceratobranchials much longer than first ceratobranchials (52-53-C). The 

 long second ceratobranchials oil guana iguana are interpreted as convergent. 



6. Zygosphenes separated from prezygapophyses by a deep notch (56-B). This 

 character occurs in all iguanines except Dipsosaurus, and may be a synapomorphy of a 

 more inclusive group. 



7. Caudal autotomy septa absent (60-B). Although the outgroup evidence is 

 equivocal, I have assumed that the presence of caudal autotomy, and the intravertebral septa 

 that facilitate it, are primitive for iguanines. The absence of caudal autotomy septa in 

 Amblyrhynchus and Conolophus on the one hand and in Iguana delicatissima on the other 

 are interpreted as convergent. 



8. Midsagittal processes on dorsal surfaces of caudal centra anterior to neural spine 

 relatively small and confined to anterior fifth of caudal sequence (62-B). This character 

 also occurs in Iguana, in which it is interpreted as convergent. 



9. Anterior postxiphistemal inscriptional ribs enlarged and members of at least one pair 

 united midventrally to form continuous chevrons (63-C). Midventrally continuous 

 chevrons formed by the first pair of postxiphistemal inscriptional ribs occur in various 

 other iguanines but not invariably within species, as in Brachylophus. Unlike other 



