Abstract
A darter endemic to the Guadalupe River System in Texas is described as a new subspecies apristis of Hadropterus scierus. Its characters contrast with those of typical H. scierus and with those of the two other species of the same genus known to inhabit Texas waters, H. shumardi ? and H. maculatus. The two samples of H. s. apristis studied can be separated from each of 11 samples of H. s. scierus on apparently reliable grounds. Despite intersample variability, three morphologic groupings occur: The two samples of apristis, nine samples from Texas and the Red River system in Oklahoma, and the Wabash River sample. The Arkansas River sample is intermediate between the latter two. Jordan and Gilbert''s name serrula is not resurrected for the second morphologic grouping because the distinctions of the single northern sample may not hold up when other samples are studied.

This publication has 2 references indexed in Scilit: