Until 1989, the Streamside Salamander (Ambystoma barbouri) was considered conspecific with the Small-mouthed Salamander (Ambystoma texanum). Although they have distinct natural histories, particularly reproductive behaviors, individuals of these two species are nearly indistinguishable from each other. The similarity in appearance typically is not an issue because the two species are largely allopatric and geography can be used to determine which species is present. However, several narrow zones of contact (i.e. parapatry) have been reported from Kentucky, Indiana, and Ohio, and identifying an individual to species in these zones requires an examination of the dentition in postmetamorphic individuals. We used scanning electron microscopy to examine the gross morphology of teeth from adult Streamside Salamanders and adult Smallmouth Salamanders from middle Tennessee. Our observations of tooth morphology do not differ from those of these two sibling-species from other regions of their range. The lingual cusps of teeth on the upper jaw (premaxillae and maxillae) of Streamside Salamanders are short and rounded; whereas, cusps of these teeth in Small-mouthed Salamanders are long and narrow. Tooth morphology can be used to identify postmetamorphic individuals of each of these species from middle Tennessee.
Key Words.— Central Basin, Eastern Highland Rim, labial cusps, lingual cusps, sibling species, teeth, tooth morphology