A systematic study of Etheostoma longimanum and Etheostoma podostemone (Pisces, Percidae)

Abstract

The purpose of this study was to clarify the systematic relationships between Etheostoma longimanum, an endemic of the James River system, and Etheostoma podostemone, an endemic of the Roanoke River system. Twenty-nine morphological characters were compared between the two species, using Ginsberg's criteria and sample comparison diagrams as indicators of divergence. These two forms were shown to be separable on Ginsberg's specific or intermediate specific level in seven morphological characters, Subspecific differences were found to occur in seven other characters. These differences, as well as additional qualitative differences, are interpreted by the writer as evidence that E. longimanum and E. podostemone represent valid species. Allopatric speciation from E. olmstedi stock is postulated.