B.A., Zoology, Miami University 1982.
M.S., Zoology, Miami University 1985.

Research Interests:

The geologically recent rise of the Isthmus of Panama and the impact of this event on the animals and their gene pools forms the basis of my collaborative research efforts. I address this with two systems; i) the isthmus as a bridge between South and Central America and its significance to tungara frogs; and, ii) the isthmus as a marine barrier between the eastern Pacific and Caribbean shrimp fauna.

Molecular phylogenies are under construction for the tungara frog, with concurrent studies of female selection on male mating calls and population genetics. Allozyme, mating call and mtDNA results to date from more than thirty populations across a 5,000 km transect from Mexico to Venezuela will be supplemented with nuclear gene sequences in target areas. By comparing the phylogenetic relationships of the taxa in a historical and geographical perspective, this will allow us to test several other hypotheses including historical barriers to gene flow, rates of molecular evolution and rates of behavioral character change.

The snapping shrimp genus Alpheus, has more than 100 species and hosts the taxonomically deepest sampling to date of "geminate" species pairs ("twins" formed by the rise of the ishtmus), with fifteen pairs and their related species. We currently have morphological, reproductive behavioral, allozyme and mtDNA data and anticipate collecting nuclear gene sequences in the near future. Our work indicates that many of the "species" are actually sibling or cryptic species complexes, so the actual number of species may be much higher than previously thought.

Selected Publications:

1993. (with N. Knowlton, L. A. Solorzano, D. E. K. Mills and E. Bermingham) Divergence in proteins, mitochondrial DNA, and reproductive compatibility across the Isthmus of Panama. Science 260: 1629-1632.

(In press) (with M. J. Ryan and A. S. Rand) Allozyme and advertisement call divergence in the tungara frog, Physalaemus pustulosus. Evolution.

(In press) (with N. Knowlton) Species of marine invertebrates: a comparison of the biological and phylogenetic species concepts. In: Claridge, M. F., H. A. Dawah, and M. R. Wilson (eds.), Species: The Units of Biodiversity. Systematics Association Special Volume, Chapman and Hall, London.

(In press) (with K. Summers, E. Bermingham, S. S. McCafferty and L. Dahlstrom) Phenotypic and mitochondrial DNA divergence in three species of dart-poison frogs with contrasting parental care behaviour. Journal of Heredity.

Current Position:

www.lab.si.edu/