Abstract
Pseudomystus sobrinus, a new species of bagrid catfish, is described from small coastal streams draining the eastern slope of the Annam Cordillera in central Vietnam. Pseudomystus sobrinus resembles P. siamensis and P. bomboides; all three species are distinguished from congeners by their color pattern of strongly contrasting brown and yellow/cream vertical bands on the body. Pseudomystus sobrinus differs from P. siamensis in having a slightly bulbous snout, shorter adipose-fin base (14.7–19.9% SL vs. 21.3–27.2) and pectoral-fin spine (15.4–18.3% SL vs. 17.8–23.4), and from P. bomboides in having a shorter maxillary barbel (not reaching beyond opercle vs. reaching beyond base of pectoral-fin spine) and one (vs. two) brown bands on the caudal fin.