Molecular Systematics And Speciation Of The Gilt Darter (Percina evides) In The St. Croix River Drainage: Final Report

Systematics and evolutionary history of the widespread gilt darter (Percana evides) was investigated with complete sequences of the mitochondrial encoded cytochrome b gene. Most disjunct populations throughout the gilt darter's range were sampled to assess the taxonomic status of populations in the upper Mississippi River of Minnesota and Wisconsin. Two major lineages were recovered in phylogenetic analysis, a western clade containing upper Mississippi River and Ozark populations, and a clade containing all populations east of the Mississippi River. The phylogeography of P. evides is discussed and the populations in Minnesota are hypothesized to have resulted from post-Pleistocene dispersal from the Ozarks. The upper Mississippi populations are not morphologically distinct from the Ozark populations; however, these populations are morphologically and genetically divergent from eastern populations and represent an undescribed species. The conservation implications of phylogeography of P. evides is discussed.