Morphological Variation in the Cryptic SpeciesDesmognathus quadramaculatus(Black-bellied Salamander) andDesmognathus folkertsi(Dwarf Black-bellied Salamander)

Abstract

Abstract Plethodontid salamanders in general and the genus Desmognathus in particular exhibit extreme morphological conservatism and rampant homoplasy so that cryptic lineages are common. In spite of this, multivariate morphometric analysis has proven a useful tool in detecting subtle morphological differences among cryptic forms. We used this technique to investigate subtle differences in morphology among populations of Desmognathus quadramaculatus (Black-bellied Salamander) and its cryptic congener, Desmognathus folkertsi (Dwarf Black-bellied Salamander). We found significant morphological variation among five populations of D. quadramaculatus but not between two populations of D. folkertsi. We also determined there to be a significant, albeit weak, correlation between genetic distance and morphological (Mahalanobis) distance. Given the relationship between genetic and morphological distance, the high morphological variation within D. quadramaculatus, relative to that within D. folkertsi, is not surpris...