Sympatric Occurrence of Two Species of the Two-Lined Salamander (Eurycea bislineata) Complex

Genetic analyses of contact zones between closely related taxa are critical to an understanding of reproductive isolation between species. We evaluated allelic frequencies and external morphology from one such contact zone between two members of the Eurycea bislineata complex (i.e., E. cirrigera and E. wilderae). We found that, within this zone of contact, these presumed species had significantly different frequencies of alleles at three loci. In addition, these sympatric forms were significantly different in lateral mottling pattern, tail color, and length of tail stripe. These morphological patterns were identical to those used to describe the original subspecies E. b. cirrigera and E. b. wilderae. Evidence from this zone of contact supports the hypothesis that these forms are separate species. Moreover, there is evidence of ecological and/or reproductive character displacement among these species when in sympatry.