Mitochondrial cytochrome b sequences support recognition of two cryptic species of plains killifish, Fundulus zebrinus and Fundulus kansae

The current literature treats the plains killifish as a single species (Fun dulus zebrinis). However, a recent range-wide survey of generic variation d etected two distinct groups. The presence of the two groups suggests that t ile plains killifish may actually rep resent two species (F. zebrinus and F . kansae, as has bren proposed in prior taxonomic treatments. Previous mole cular studies within the genus Fundulus have relied upon the mitochondrial cytochrome b gene. I generated a set of cytochrome b sequences in order to compare the phylogenetic support for the putative: species E: zebrinus and F: kansae with that round in other accepted sister species of Fundulus. Bot h neighbor-joining and maximum parsimony analyses recovered two clades of p lains killifish that were strongly supported by a variety of measures inclu ding branch lengths, decay indices and bootstrap proportions. The strength of support fur the putative F. kansae and F. zebrinus clades was comparable to, or better: than, similar measures for six other sister species pairs o f Fundulus. While the molecular data supported the recognition of two speci es of plains killifish, the groups recognized were not ill agreement with t he range descriptions previously proposed for the two species.