STRANGE, Rex; Southeast Missouri State University: Historical Biogeography of the Stripetail Darter, Etheostoma kennicotti (Osteichthyes: Percidae), and the origin of the upper Cumberland River Fish Fauna

The stripetail darter (Etheostoma kennicotti kennicotti) occurs in headwater tributaries of the lower Ohio River, including the Green and Tennessee rivers. Another subspecies, E. kennicotti cumberlandicum, is endemic to the upper Cumberland River (UCR). Neither subspecies occurs in the lower (below the Falls) Cumberland River. The favored hypothesis for this biogeographic pattern holds that species entered the UCR through the capture of a tributary of an adjacent drainage. An alternative hypothesis holds that these populations may be relictual and were present in the basin before the formation of Cumberland Falls. I tested these hypotheses by examining the phylogenetic relationships among mitochondrial cytochrome b sequences taken from stripetail darters collected throughout the species� distribution. Mitochondrial haplotypes found in the UCR are sister to haplotypes found in the adjacent Tennessee River. However, the Tennessee River haplotypes form a monophyletic group, and the haplotypes taken from sites closest to the UCR do not form a close relationship with E. kennicotti cumberlandicum. The implication of the data I collected is that E. kennicotti was present in the UCR before the formation of the Falls, and was not transferred from another drainage by stream capture.