Identity and type locality of R. mutabilis. There are two reasons for poor taxonomic understanding of R. mutabilis. The first one is that the precise location of the type locality of the species in Guizhou Province remains uncertain. The type locality was given as ‘Yunkiang’ in the original description by Lin (1933), but no present river in Kweichow ( = Guizhou) has been known by this name. Lin’s ‘Yunkiang’ means the ‘Yun–Jiang’ in Chinese, and the present Yun–Jiang is a tributary draining to the Liu–Jiang of the Pearl River drainage in Guangxi Province. Wu (1989) ever maintained that the ‘Yunkiang’ was the Rong–Jiang in Guizhou Province, but without further elaboration. Despite the current treatment of R. mutabilis as a valid species, it has not been recorded from Guizhou Province since its original description. The second, and more important, reason is that little is known about the whereabouts of the type specimens of Epalzeorhynchus mutabilis (Lin 1933). Its original description stated that the type material was stored in the museum of Sun Yat-Sen University, but it can not be traced. In Böhlke’s (1953) catalogue of the type specimens of recent fishes in the Natural History Museum of Stanford University, the holotype of this species was given as CAS-SU 35261 (122.5 mm SL), which was said to have been received from Lingnan University Natural History Museum (see Kottelat 2001). On the basis of this specimen, Bǎnǎrescu (1986) provided a redescription of E. mutabilis, but placed it in Crossocheilus. From Kottelat’s (2001) point of view, there is no evidence that the holotype of R. mutabilis is CAS-SU 35261.