A REVISION OF THE SOUTHEAST ASIAN CATFISH GENUS SILURICHTHYS (TELEOSTEI: SILURIFORMES: SILURIDAE)

Abstract

The taxonomy of the catfish genus Silurichthys is revised, and eight species are now recognised. A neotype for S. hasseltii is designated. Three new species are described: S. citatus from the Kapuas basin in western Borneo, S. gihhiceps from the Barito basin in southern Borneo and S. marmoratus from northwestern Borneo. Silurichthys leucopodus Fowler, 1939, is considered a subjective junior synonym of S. schneideri Volz, 1904. The usefulness of the taxonomic characters used by previous authors to differentiate the various Silurichthys species is examined. The extent of the gape shows considerable infraspecific variation and of little taxonomic value. The number of anal-fin rays is a useful taxonomic character, but only if used with other meristic data such as the number of vertebrae. Some infraspecific variation in colour exists, mainly due to individuals becoming paler and less mottled at night, but nevertheless, colour can still be used as a secondary character in separating some species. The shapes of the head and caudal fin were found to be new and useful characters separating the species. The presence of sexual dimorphism is recorded in the genus for the first time: mature males are smaller than females and have prominent posterior serrae on the pectoral spine and articulated segments of the first pectoral-fin element. The shape and number of these serrae are also diagnostic for some species