Systematics and biogeography of snubnose darters, genus Etheostoma (Teleostei: Percidae) from the black warrior river system Alabama

Abstract

Members of the Etheostoma chermocki species group, formerly known only as the Warrior snubnose darter, were examined from throughout their ranges for products of 44 presumptive gene loci. Polyallelic loci support the specific recognition of E. chemocki and indicate that E. bellator is actually a composite of three distinct evolutionary species diagnosable on the basis of both fixed allelic products and significant allele frequency differences. Based on other studies, these species are also diagnosable using traditional morphological characteristics. Eheostoma bellator is the most widely distributed species, while the two new species are endemic to the upper Sipsey and Locust forks of the Black Warrior River system. Phylogenetic evaluation of 30 variable loci and all possible bifurcating trees indicate that the E. chermocki species group is not a monophyletic assemblage. Rather, some species of the group are more closely related to E. simoterum and E. ramseyi in the Tennessee and Alabama river drainages, respectively. Diversification within the Etheostoma chemrocki species group was probably associated with the complex break-up of the Appalachian River System, once connecting the upper Tennessee River and rivers of the current Mobile Basin, and drainage exchanges between the Locust Fork of the Black Warrior River and the adjacent Cahaba or Coosa rivers.