Genetic Relationships of the Eastern Large Plethodon of the Ouachita Mountains

Abstract

An electrophoretic study of 23 genetic loci in 20 samples of Plethodon ouachitae and P. caddoensis, species endemic to the Ouachita Mountains of Arkansas and Oklahoma, indicates that there is a third member of the group, as genetically different from the two named species as they are from each other. It is described as a new species, Plethodon fourchensis. The three species are also differentiated by color pattern characters and by size. Genetic variation at four localities in a narrow hybrid zone between P. ouachitae and P. fourchensis is analyzed. A comparison of the genetic relationships of the three endemic Ouachita Mountain species with sympatric P. glutinosus from nine localities and with P. yonahlossee from two localities in the southern Appalachian Mountains indicates that they are more closely related to P. glutinosus than they are to P. yonahlossee. No genetic evidence of hybridization between P. ouachitae and P. glutinosus is found.