Abstract

The Southern Appalachians are unique in the high diversity of salamanders that occur there. The genus Plethodon encompasses the terrestrial woodland salamanders that occur only in North America. This genus is the most diverse group of salamanders with 77 species currently described. Within this genus is the Plethodon glutinosus species complex, where several new species have been recently described, including the Gray-cheeked salamanders. Allozyme data have shown that there are four distinct Gray-cheeked salamander species comprising the Plethodon montanus species complex in Western North Carolina. These are the Northern Gray-cheeked (P. monatnus), Southern Gray- cheeked (P. metcalfi), Blue Ridge Gray-cheeked (P. amplus), and South Mountain Gray-cheeked (P. meridianus) salamanders. The little-understood geographic ranges of these species are the main distinction between them, though not much is currently known about the genetic relationships among these four species nor where each lineage actually occurs. Using samples collected by labmates, I isolated the mitochondrial gene ND2 from salamander tail tips of the four species via DNA extraction and PCR techniques and sent out for Sanger sequencing. I then constructed a series of phylogenetic trees to reveal the evolutionary history and relationships among these four species. This information helps us have a clearer idea of how closely related these species are, their unique evolutionary histories, and give us a better understanding of the current range of each species. These data also add to our understanding of the broader process of speciation in woodland salamanders. Importantly, we found that currently suggested species ranges do not correspond to mitochondrial lineages, and I offer a revision of the geographic range for each of these four species.

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