A Molecular Phylogeny of Agamid Lizards

appear as the sister group of the Agamidae, which are monophyletic. Uromastyx and Leiolepis represent early sidebranches. The remaining agamids separated into a western and one or more eastern clades during the lower Tertiary. Within the western clade, Trapelus and Agama s.s. are monophyletic, but Stellio is diphyletic. The Palaearctic Stellio s.s. is the sister group of Phrynocephalus, whereas the Ethiopian Stellio atricollis group seems to be more closely related to Pseudotrapelus. Judging from branch lengths in the best fitting Wagner tree, a uniform average evolutionary rate of albumin can be attributed to most lineages, except Acanthosaura, Calotes, and Gonocephalus, which show a marked increase in their albumin evolution, and Uromastyx, which has a comparatively slowly evolving albumin. T HE only phylogenetic analysis of the family Agamidae to date is Moody's (1980) thesis, based primarily on internal anatomy. Moody also changed the intrafamilial taxonomy by subdividing the large collective genus Agama into six genera: Agama, Stellio, Trapelus, Pseudotrapelus, Brachysaura, and Xenagama. These genera may be called the Agama group. Together with its supposed sister taxon, Phrynocephalus, this group makes up the western radiation of the Agamidae, whereas Uromastyx was considered by Moody as a member of a primitive agamid