The Malayan Cyprinoid fishes of the family Homalopteridae

INTRODUCTION The Homalopteridae comprise small, loach-like fishes that occur in rapids, riffles and other fast-flowing parts of streams and rivers throughout the mainland of Malaya. In his monographic study, Silas (1953) reported six species from Malaya, viz., Homaloptera Zollingeri Bleeker, H. wassinki Bleeker, H. orthogoniata Vaillant, H. tweediei Herre, H. leonardi Hora and Neohomaloptera johorensis Herre, while Tweedie (1952) recorded H. ocellata Van der Hoeven and I described H. ogilviei Alfred (1967). In the present account, the earlier records of H. zollingeri, H. wassinki and H. ocellata are relegated to synonymy. Nine species, all of the genus Homaloptera Van Hasselt, are described, including a new record and two new species. Fowler's characterisation of the sub-genera Homalopteroides Fowler (1905) and Homaloptera (sensu stricto) has been accepted here. While also accepting this division, Silas (1953) however diminished the distinction between the two sub-genera by characterising Homaloptera as with the origin of the dorsal fin opposite or in front of that of the ventral fins. This appears to be due to the fact that he inadvertently followed Hora (1941: 61) in including H. tweediei in this sub-genus, although the dorsal origin in the species is behind that of the ventrals. Herre (1944) added the monotypic sub-genus Neohomaloptera, which Silas (1953) raised to the rank of a genus. Except for the presence of four pairs of barbels, as against three in Homaloptera, and the lower pectoral fin ray count, I do not find the other diagnostic features mentioned by Silas sufficiently distinctive. Neohomaloptera is accordingly afforded only sub-generic rank. All the local species have at least part of the ventral surface, between the