. Advances in herpetology and evolutionary biology : essays in honor of Ernest E. Williams. Williams, Ernest E. (Ernest Edward); Herpetology; Evolution. Use of the Comparative Approach • Hall 655 PHRYNOSOMA (15 S p.) UMA (4 S p.) CALLISAURUS (1 Sp.) BOLBROOKIA (4 Sp.) First cervical ri b 1ost. SCELOPORUS (54 sp.) SATOR (2 Sp.) UROSAURUS (10 Sp.) UTA (9 sp.) Clavicles develop hooks Frontals covered anteriorly in some c. d. g. Lacrimal and postfrontal lost Frontals covered anteriorly Interclavicle median process shortened a. Sternal fontanella increased in size b. Sternal ribs reduced to 3 / A.
. Advances in herpetology and evolutionary biology : essays in honor of Ernest E. Williams. Williams, Ernest E. (Ernest Edward); Herpetology; Evolution. Use of the Comparative Approach • Hall 655 PHRYNOSOMA (15 S p.) UMA (4 S p.) CALLISAURUS (1 Sp.) BOLBROOKIA (4 Sp.) First cervical ri b 1ost. SCELOPORUS (54 sp.) SATOR (2 Sp.) UROSAURUS (10 Sp.) UTA (9 sp.) Clavicles develop hooks Frontals covered anteriorly in some c. d. g. Lacrimal and postfrontal lost Frontals covered anteriorly Interclavicle median process shortened a. Sternal fontanella increased in size b. Sternal ribs reduced to 3 / A. B. C. D. E. F. G. PETROSAURUS (incl. STREPTOSAURUS) (4 Sp.) Sternal fontanella of moderate size Sternal ribs 4 Lacrimal ana postfrontal present Frontals exposed anteriorly Five pairs of cervical ribs Clavicles without hooks Interclavicle median process lon^. Figure 2. Phylogenetic relationships and numbers of species of the sceloporine genera. Phylogeny based on Presch (1969: 286), after Etheridge (1964). Primitive character states designated by capital letters. Small letters indicate derived character states. Species numbers are from Smith and Taylor (1950). By 1966 taxonomic revisions changed Holbrookia to 3 species, Petrosaurus to 3, Phrynosoma to 14, and Sceloporus to 57. oporus had more opportunities for speci- ation simply because it is an older radia- tion cannot reasonably explain the strik- ing species diversity. The conclusion from these data showed that the species diversity of Sceloporus was extraordi- nary compared to other North American genera, and particularly to their close relatives. Hunsaker continually reminded me that this anomaly presented a fascinating problem to be explained. However, no opportunities in biogeography or special- izations in ecology or morphology ex- plained why Sceloporus, instead of some combination of the related genera, should have achieved such a striking proliferation of species. The anomalous species diversity most likely was a r
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Keywords: ., bookauthorharvarduniver, bookcentury1900, booksubjectherpetology
