Systematics, Phylogeography, and Population Genetics of the Plethodontid Salamander Genus Gyrinophilus. The genus Gyrinophilus consists of four spring/cave-associated species ranging throughout the Appalachian Highlands and portions of the Interior Low Plateau. Two species, the Tennessee Cave Salamander (G. palleucus) and (G. gulolineatus), are paedomorphic stygobites inhabiting subterranean streams of eastern and middle Tennessee, northern Alabama, and northwest Georgia. The West Virginia Spring Salamander (G. subterraneus) is known only from a cave in Greenbrier Co., West Virginia, while the Spring Salamander (G. porphyriticus) is found from the Appalachian Highlands in New England southwestward to Alabama and Mississippi. Recent genetic work suggests that the two stygobitic forms are sister species derived from a porphyriticus-like ancestor that inhabited southern sections of the Cumberland Plateau. Additionally, Gyrinophilus appears to be a relatively young group dating back to the mid-Pliocene. My current research focuses on understanding the intra- as well as interspecific phylogeography of members of the genus and determining the validity of described species and subspecies. Using phylogenetic and population genetics methods, my goals are to examine the effects of Pleistocene glaciation on the evolution of troglomorphic characters within the genus and to examine the extent, if any, of gene flow between subterranean and between subterranean and epigean populations of Gyrinophilus.
Systematics, Phylogeography, and Population Genetics of the Southern Cavefish (Typhlichthys subterraneus). The Southern Cavefish, Typhlichthys subterraneus, has a distinct distribution inhabiting two main regions: the Interior Low Plateau of middle Tennessee, northern Alabama, northwest Georgia, and Kentucky and the Ozark Plateau of central and southeast Missouri and northeast Arkansas. Although the cavefish has a wide distribution, it is protected in every state throughout its range. Little work has been conducted regarding the phylogenetic relationships of known populations. Current research focuses on the phylogenetic relationships and phylogeography among populations, estimating their effective population sizes, and defining and estimating the ages of distinct lineages within the species.
Phylogeny and Evolution of Troglomorphic Characters in the Family Amblyopsidae. The family Amblyopsidae is comprised of six species that range from epigean (Chologaster cornuta) to stygophilic (Forbesichthys agassizii) to stygobitic (Typhlichthys subterraneus, Amblyopsis rosae, A. spelaea, and Speoplatyrhinus poulsoni). Characters such as eye structure, pigmentation, fin length, and number and size of sensory papillae very among the six species and offer an opportunity to study the transition towards subterranean existence.
Distribution and Natural History of Cave-associated Amphibians. Although the Appalachian Highlands and Interior Low Plateau support more stygobitic and troglobitic species than all other karst regions in the continental United States, only three species of amphibians are considered obligate cave-dwellers. Comprehensive inventories have been conducted on these species. However, few studies have focused on the non-obligate cave-associated species of amphibians within the eastern United States. My former advisor at MTSU, Brian Miller, and myself have documented nearly two dozen species of amphibians from caves in Tennessee, Alabama, and Georgia over the past three years. Regrettably, caves and other subterranean haunts largely have been overlooked by biologists as suitable habitat for reproduction or inhabitation for many amphibian species. Our research focuses on examining the distribution and extent of subterranean use by amphibians throughout the karst regions of the eastern United States.
Distribution and Natural History of Amphibians and Reptiles of Tennessee. Tennessee is home to over one hundred species of salamanders, frogs, snakes, lizards, and turtles. Although diverse, surprisingly little is known about the distributions and natural history of several of these species. Brian Miller and myself are interested in determining the distribution of several species that have not been sufficiently sampled throughout the state, and in doing so, are gathering natural history. Ultimately, I’d like our efforts to culminate in a book in the format of “The Amphibians and Reptiles of Arkansas” and the upcoming Georgia herp book.
Conservation and Natural History of the Streamside Salamander (Ambystoma barbouri) in Middle Tennessee. The Streamside Salamander, Ambystoma barbouri, has only recently been identified in the Central Basin of middle Tennessee. Although populations have been studied from other portions of the salamander’s range, information regarding the distribution, natural history, and status of populations in Tennessee is lacking. Continued deforestation and land development associated with urban sprawl from the city of Murfreesboro threaten extant populations. Ongoing studies with Brian Miller at MTSU aim to provide a basis for the development of conservation plans by state and local agencies for the species.