Intraspecific phylogeography of Percina evides (Percidae : Etheostomatinae): an additional test of the Central Highlands pre-Pleistocene vicariance hypothesis

North America exhibits the most diverse freshwater fish fauna among tempera te regions of the world. Species diversity is concentrated in the Central H ighlands, drained by the Mississippi, Gulf Slope and Atlantic Slope river s ystems. Previous investigations of Central Highlands biogeography have led to conflicting hypotheses involving dispersal and vicariance to explain the diversity and distribution of the freshwater fish fauna. In this investiga tion predictions of the Central Highlands pre-Pleistocene vicariance hypoth esis are tested with a phylogeographic analysis of the percid species Perci na evides, which is widely distributed in several disjunct areas of the Cen tral Highlands. Phylogenetic analysis of complete gene sequences of mitocho ndrially encoded cytochrome b recover three phylogroups, with very low leve ls of sequence polymorphism within groups. The two western phylogroups are monophyletic with respect to the eastern phylogroup. The recovery of two mo nophyletic lineages with an eastern and western distribution in the disjunc t highland areas is a pattern expected from vicariance, but is not predicte d by the Central Highlands pre-Pleistocene vicariance hypothesis. The recov ery of very limited mitochondrial DNA polymorphism and lack of phylogeograp hic structuring across the entire range of the eastern clade, very shallow polymorphism between the disjunct Missouri River and upper Mississippi Rive r populations, and lack of sequence polymorphism in the upper Mississippi R iver populations, support a hypothesis of dispersal during or following the Pleistocene. The present distribution of P. evides is best explained by bo th vicariant and dispersal events.