The objectives of this proposal are to test the evolutionary relationships among selected species of the genus Etheostoma and to test the monophyly of this genus relative to its closest relatives, Percina and Crystallaria. These genera comprise the second largest group of North American freshwater fishes and the majority of species in the family Percidae. Etheostoma is the largest genus (114 species compared to 34 species of Percina and one species of Crystallaria). However, the monophyly of the genus is not well established and numerous problems exist concerning the relationships among the 18 subgenera. Polymerase chain reaction and direct sequencing protocols will be used to amplify and sequence parts of the 12S ribosomal gene (800 base pairs) and a segment of the cytochrome-b genes (450 base pairs) of 15 species of Etheostoma, four species of Percina, and two outgroups, Crystallaria asprella, and Stizostedion canadense. This will allow me to perform a preliminary test of the monophyly of Etheostoma, explore the possibility that some Etheostoma are actually more closely related to Percina, and arrive at some preliminary conclusions regarding the relationships among selected species groups of Etheostoma. Phylogenetic analysis employing several parsimony criteria will be used to test alternate hypotheses of relationship. Resolution of the relationships among darters will lead to a better understanding of the origin and diversification of the North American freshwater fish fauna and enhance our ability to study the speciation, historical ecology, and comparative behavior of this speciose group.
