Dissertation Research: A Molecular Phylogenetic Study of Geographic Genetic Variation and Speciation in Salamanders of the Eurycea bislineata species complex

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For stream-associated organisms with limited dispersal abilities, the historical connections among streams generate predictions about genetic interactions among populations and routes of dispersal between drainage systems. We use the temporal and spatial variation present in mitochondrial gene lineages to investigate the relationship between the geological history of stream drainages and geographic genetic fragmentation in plethodontid salamanders of the Eurycea bislineata species complex. Plethodontid salamanders of the Eurycea bislineata species complex are common in streams throughout the Interior Lowland, Appalachian Highland, Piedmont and Coastal Plain physiographic provinces of eastern North America. Intensive research on the plethodontid salamander fauna of eastern North America has uncovered high levels of genetic structuring among populations and numerous cryptic species in this group, whose endemism and species diversity are greater in the southern Appalachian Mountains than any other region in the United States. Our research provides insight into the historical factors affecting diversification in this species-rich group of vertebrates. At a broader level, this research has implications for understanding factors that generate and maintain biodiversity in stream-associated organisms of eastern North America.