Using the polymerase chain reaction, portions of nuclear and mitochondrial ribosomal RNA genes will be sequenced from 41 phrynosomatid species. The sequence data will be combined with data sets based on more traditional characters, and the expanded data set used to infer the phylogenetic relationships among the 10 genera. Also, from the large number of species of Sceloporus that will be examined, the monophyly of this diverse genus will be tested and the relationships among the Sceloporus species groups will be determined. Once a hypothesis of phyrnosomatid relationships is obtained, questions pertaining to the evolution of various morphological, karyological, and behavioral phenotypes will be addressed. The status of the morphological characters used in phylogenetic analyses will be reinterpreted and the extent of homoplasy assessed. Inferences will be made as to whether similar behavioral repertoires are the result of common ancestry or convergent evolution. From the molecular phylogeny a better assessment of the mode and pattern of phrynosomatid karyotypic evolution will be gained. The extent of centric fusion and fission within Sceloporus will determined and the homology of particular karyotypes will be tested. Finally, the sequence data generated will contribute to the growing sequence database for ribosomal RNA genes, allowing better models for the evolution of these genes to be formulated.
