Co-occurrence and Hybridization between Necturus maculosus and a Heretofore Unknown Necturus in the Southern Appalachians

Abstract

Abstract.— The only mudpuppy (Caudata: Proteidae) known to occur in the Tennessee Valley of the Interior Highlands and Southern Appalachians is the Common Mudpuppy (Necturus maculosus). Necturus maculosus is not known to co-occur with any other congeners. Here, we report evidence that an additional Necturus occurs in the Hiwassee River, a tributary of the Tennessee River, in eastern Tennessee. Some specimens from the Hiwassee River are clearly identified as N. maculosus, but others resemble the Neuse River Waterdog (N. lewisi), known from only the Tar-Neuse river system draining to the Atlantic Ocean on the opposite side of the Appalachian Mountains. Concordance between color pattern, mitochondrial DNA, and four nuclear loci demonstrate that these two co-occurring forms represent distinct lineages rather than color variants within a single, panmictic population. A few mismatched genotypes (7 of 32 individuals in total) suggest rare hybridization and backcrossing. Phylogenetic analyses indicate that the ne...