Garra waensis, a new cyprinid fish (Actinopterygii: Cypriniformes) from the Nan River Basin of the Chao Phraya River system, northern Thailand.

A new cyprinid fish, Garra waensis, is described from the Wa River, a tributary of the Nan River of the Chao Phraya River system in northern Thailand. The species is distinguishable from its congeners by the combination of the following characters: the absence of barbels; 7 branched dorsal fin rays; 31-37 lateral-line scales; 10-12 circumpeduncular scales; a small and broad head (head length [HL] 22.7-26.1% in standard length, head depth 56.1-64.9% HL, head width 74.0-85.0 % HL); a weakly developed proboscis in front of nostrils; the presence of reddish-orange spots (white or dull yellowish white in preserved specimens) on the side of the body; and a dark mid-lateral stripe running from the upper edge of the gill opening to the caudal peduncle and expanding into a large anteriorly-pointed triangular blotch at the end of the body (in preserved condition). A vomero-palatine organ of the species is also described in detail for the first time for Asian species of Garra. The genus Placocheilus is treated as a junior synonym of Garra.