The Science Seminar Series: Novemeber 15, 2007

Comparative Phylogeography of Pygmy Sunfishes (Elassomatidae): A Test of the Interglacial Refugia Hypothesis

Michael Sandel, University of Alabama,

Dept. of Biological Sciences & Department of Geography

Place: Powell Hall
Time: 4:00 -5:00pm

The Southeastern United States has long been recognized as an area of exceptional biological diversity. Aquatic communities of this region are especially remarkable, housing the greatest diversity of fishes, amphibians, turtles, crayfishes, snails, bivalves, and aquatic insects within North America. Historical ecology, which explains how and why biological diversity is generated and maintained, has largely been ignored in these communities. The Southeastern Coastal Plain has a unique history, having been repeatedly inundated by marine highstands during the last 64 million years. Within the last several million years, these high sealevels have likely influenced the geographic distribution of extant freshwater species. This study examines genetic variation within three freshwater fishes found only in the Southeastern Coastal Plain. This variation is analyzed using phylogenetic and population genetic methods, in order to detect the phylogeographic signal of historical marine inundation upon freshwater populations. The results of this study explicate the role of historical sealevel change in promoting and maintaining biodiversity in the Southeastern Coastal Plain.