A grotesque variant of Silurus asotus (Teleostei: Siluridae) from Hongshuihe River basin, Guizhou, China

One grotesque catfish specimen was collected in Zhangjiang River (upper reach of a secondary tributary of Hongshuihe River) in Libo County, Guizhou Province, China. This specimen bears surprising character of four dorsal fins, which have not appeared in any other silurid fishes. But other morphological characters, such as two pairs of barbels, lower jaw projecting beyond upper jaw, the first dorsal fin with one un-branched ray and 4 branched rays, mouth cleft shallow, anterior spine margin of pectoral spine prominently serrated, vomerine tooth band continuous across midline, show much similarities with that of Silurus asotus. This result supports that this variant originated from S. asotus for some special causations. The present study provided description and comparison with S. asotus.