Evolution of the lizard family Phrynosomatidae as inferred from diverse types of data

Abstract

The phylogenetic relationships within the iguanian lizard family Phrynosomatidae are inferred from diverse types of data (i.e., mitochondrial rDNA, osteology, coloration, scalation, karyology, and behavior). All 10 currently recognized genera (Callisaurus, Cophosaurus, Holbrookia, Petrosaurus, Phrynosoma, Sator, Sceloporus, Uma, Urosaurus, and Uta) are included in the phylogenetic analyses. The phylogenies inferred from the separate analyses of the DNA sequence data (779 bp; 162 informative characters; 40 species) and non-DNA data (155 informative characters; 59 species) share 26% (10) of their respective clades. Four of the congruent clades (i.e., sand lizards + Phrynosoma, Petrosaurus, Urosaurus, Uta) are strongly supported (-70% bootstrap) in both of the separate analyses while five others are strongly supported in only one, but not both, of the separate analyses. All conflicting hypotheses leading to the taxonomic incongruence (e.g., Sceloporus group interrelationships) are weakly supported (<70% bootstrap) in one or both of the separate analyses. Combining the DNA and non-DNA data for phylogenetic analysis results in a single shortest tree. Overall, the phylogeny from the combined analysis shares more clades in common with the hypotheses inferred from the separate DNA analysis (74%) than with the separate analysis of the non-DNA data (53%). The intergeneric relationships inferred from the combined analysis are more similar to recently published hypotheses based on morphological data, except the Sceloporus group is paraphyletic. Although phrynosomatid intergeneric relationships are well resolved by the combined analysis of the DNA and non-DNA data, the relationships among most genera are nevertheless weakly supported by the separate and combined analyses. This weak support is most likely the result of rapid speciation. The monophyly of the speciose genus Sceloporus (exclusive of Sator) is supported by the separate non-DNA and combined analyses. The inclusion of numerous incomplete taxa (19 species lacking DNA data) in the combined analysis did not decrease resolution among the complete taxa (40 species with DNA and non-DNA data), but the addition of the incomplete taxa did affect the relationships among the complete taxa. Overall, the DNA data are more homoplastic than the non-DNA data, but the degree of character incongruence exhibited within the different partitions and/or sources of the DNA and non-DNA data sets varies greatly.