Dissertation Research: Phylogenetic Relationships, Biogeography, and Phylogeography of Plethodontid Salamanders of the Genera Pseudotriton, Gyrinophilus, and Stereochilus

University Of Texas At Arlington, Arlington TX

Investigators

Abstract

The objectives of this research are to investigate relationships of red, mud, spring, and many-lined salamanders (Pseudotriton, Gyrinophilus, and Stereochilus), evaluate the factors that have determined their geographic distributions, and assess species boundaries in the group. Specimens from throughout the ranges of these species will be examined using both molecular and morphological data. DNA markers will also be developed that will allow reliable identification of larvae of the red and mud salamanders (Pseudotriton); these are important components of many aquatic systems but are extremely difficult to distinguish based on morphology. Plethodontid salamanders are model organisms for a wide variety of ecological and behavioral studies, but very little is known about phylogenetic relationships and species boundaries within and among the genera Pseudotriton, Gyrinophilus and Stereochilus. Preliminary mitochondrial DNA sequence data suggest greater species diversity than previously thought. Nuclear sequences will also be examined to test phylogenetic hypotheses based on the mitochondrial data. Pseudotriton ruber exhibits genetic homogeneity throughout the Appalachians but considerable diversity in the lowlands, suggesting a higher degree of gene flow in highland populations of this species than that observed for any other plethodontids. This study will allow tests of hypotheses regarding high- versus low-elevation centers of diversification in plethodontids, and has broader implications for understanding of historical biogeography, patterns of biodiversity, and conservation in eastern North America. This work will also result in a major taxonomic revision of the Pseudotriton/ Gyrinophilus/