Carolina Redhorse-a new species of Moxostoma (Cypriniformes: Catostomidae) from North Carolina and South Carolina, USA.

Recognized as an undescribed species since the mid-1990s, the Carolina Redhorse is herein described as Moxostoma carolinasp. nov. The Carolina Redhorse is distinguished from all other species described in the genus Moxostoma by the number of caudal peduncle scales, the texture and angle of the lower lip, and by pigmentation and tuberculation patterns. It is morphologically similar to M. erythrurum, although the two species are allopatric and phylogenetic analysis of the COI mitochondrial gene supports the Carolina Redhorse as a distinct evolutionary lineage. The Carolina Redhorse is rare, localized, and endemic to lower Piedmont streams and run-of-river reservoirs in North Carolina and South Carolina. Characteristics of five of the species with which the Carolina Redhorse is sympatric and M. erythrurum are discussed, and a dichotomous key is provided.