Molecular Systematics of the Cyprinid Genus Campostoma (Actinopterygii: Cypriniformes): Disassociation between Morphological and Mitochondrial Differentiation

Campostoma are ubiquitous across North America, yet relationships among members of the genus are poorly understood. Here we present phylogenetic hypotheses based on analyses of DNA sequence data from the mitochondrial cytochrome b gene. All analyses consistently recovered nine clades of comparable topological structure. Differentiation of the recovered clades did not follow currently accepted taxonomic boundaries, and was not consistent with previously hypothesized relationships among recognized species and subspecies. Rather, the recovered clades corresponded to broad geographic divides and to areas known either to have high rates of endemism or to represent discrete biogeographic provinces, indicating that clades not corresponding to recognized taxa represent additional diversity within the group. This result provides evidence of morphological similarity among genealogically divergent lineages, and supports several disputed descriptions of putative Campostoma taxa based on subtle variation in morphology. At least nine lineages could be recognized as distinct taxa to provisionally resolve differences among prior systematic accounts of Campostoma evolutionary diversity.

Fig. 1

Distribution of recognized species in the genus Campostoma (the entire distribution of C. ornatum is not identified in this depiction) and sample locations of specimens according to cytochrome b clade with suggested allocations. Specimens from one location in the Roanoke River drainage, noted as a red and black square, were recovered in two clades.

Fig. 2

Relationships resolved by Bayesian analysis (left) and parsimony analysis (right). Numbers above branches on left side are posterior probabilities; on right, jackknife support. Only support values of posterior probabilities ≥90 are shown on the left, and jackknife support values ≥85 are shown on the right.

Fig. 3

Phylogram recovered in Bayesian analysis. Numbers above branches are posterior probabilities. Currently accepted and suggested (in parentheses) allocations to taxa are given to the right of the tree.

Contributor Notes

Associate Editor: J. W. Armbruster.

¹ Molecular Ecology Research Branch, National Exposure Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268, Present Address: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, Louisiana 70118, E-mail: mjblum@tulane.edu. Send reprint requests to this address.

² Department of Biology, Saint Louis University, St. Louis, Missouri 63103.

³ Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487.

Received: 25 Apr 2006

Accepted: 02 Oct 2007