Systematics of the Etheostoma cinereum (Teleostei: Percidae) species complex (subgenus Allohistium)

We examined geographic variation within the Ashy Darter, Etheostoma cinereum, of the mitochondrially enconded cytochrome b gene (cyt b) and nuclear recombination activation gene 1 (RAG1) as well as pigmentation, 6 meristic variables, and 20 morphometric variables for patterns indicative of speciation within the complex. Four geographically disjunct entities were identified by at least one of the datasets corresponding to the Cumberland, Duck, Elk, and upper Tennessee river systems. Monophyly of cyt b and RAG1 sequences, modal meristic differences, moderate morphometric divergence, and unique pigmentation in specimens from the Cumberland River suggest this entity represents an evolutionary species under many different species concepts and is described herein as Etheostoma maydeni. Other populations exhibit varying degrees of divergence in the different datasets and have conflicting relationships in phylogenetic analyses using cyt b and RAG1 sequences, leaving the evolutionary history and taxonomic status of the Duck, Elk and upper Tennessee populations unclear.