A grant has been awarded to Dr. Paul Chippindale and Mr. Ronald Bonett of the University of Texas at Arlington to examine phylogenetic relationships, genetic variation, and biogeographic and phylogeographic history of aquatic plethodontid salamanders of the Eurycea multiplicata/Typhlotriton spelaeus complex. This group occurs only in the Interior Highlands of the south-central U.S. (Ouachita Mountains and Ozark Plateau), an area with high faunal diversity and many endemic species. Preliminary data indicate that the transforming surface-dwellers Eurycea m. multiplicata and E. m. griseogaster, the nontransforming species E. tynerensis, and the enigmatic cave-dweller Typhlotriton spelaeus share a recent common ancestor and have undergone a major radiation in the region. Numerous undescribed species appear to be present. Mitochondrial and nuclear DNA sequences, allozymes, and morphology will be used to reconstruct relationships, and the diverse life history strategies and morphologies in the group will be examined in a phylogenetic context. In collaboration with the Joint Genome Institute, entire mitochondrial genomes will be sequenced for 19 members of the complex plus outgroups to further assess relationships and species diversity.
This work will provide an understanding of the factors that have shaped biodiversity and species distributions in the Interior Highlands, and likely will result in recognition of several new species. Such an approach is fundamental for conservation of these salamanders and the sensitive stream and cave habitats in which they occur. This research will involve tests of biogeographic hypotheses regarding geological and climatic events that have structured the complex, and will provide a framework within which to trace life-history and morphological change. This represents one of the first applications of entire mitochondrial genome sequences to such problems, will have wide-ranging implications for studies of phylogeny and biodiversity, and will identify portions of the mitochondrial genome that are most informative at a variety of phylogenetic scales.
