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

Brian R. Kreiser, University of Southern Mississippi

Abstract

The current literature treats the plains killifish as a single species (Fundulus zebrinis). However, a recent range-wide survey of generic variation detected two distinct groups. The presence of the two groups suggests that the plains killifish may actually rep resent two species (F. zebrinus and F. kansae, as has bren proposed in prior taxonomic treatments. Previous molecular 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. Both neighbor-joining and maximum parsimony analyses recovered two clades of plains killifish that were strongly supported by a variety of measures including 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 of Fundulus. While the molecular data supported the recognition of two species of plains killifish, the groups recognized were not ill agreement with the range descriptions previously proposed for the two species.