Pterocryptis gangelica Peters, 1861

Heok Hee Ng & Bosco P. - L. Chan, 2005, Revalidation and redescription of Pterocryptis anomala (Herre, 1933), a catfish (Teleostei: Siluridae) from southern China., Zootaxa 1060, pp. 51-64 : 60

[[ Pterocryptis gangelica Peters, 1861 ]]

We treat the nominal species Pterocryptis gangelica Peters, 1861 and Silurus afghana Guenther, 1864 , both of which are known from the Brahmaputra and Ganges River drainages in the northern part of the Indian subcontinent as conspecific. Pterocryptis material from northern India is poorly represented in collections and we could not distinguish between the small amount of material identified as either of the two nominal species. Kobayakawa (1989) diagnosed P. afghana as possessing tubercles on the snout, but our examination shows that tubercles are present on the snouts of all Pterocryptis species, although the tubercles are often small and may be obscured by a thick layer of congealed mucus in preserved material. Furthermore, the tubercles are easily damaged (e.g. when we attempted to remove the layer of congealed mucus by rubbing), making it more difficult to study this character. In summary, it is possible that tubercle shape may be useful in diagnosing Pterocryptis species, but its worth could not be fully assessed in our study. We note, however, that tubercle shape has been used as diagnostic characters in other catfish groups, most notably in sisorids (Mo & Chu, 1986) and mochokids (Roberts, 1989; Ng, 2004); its utility as a diagnostic character for silurids warrants further investigation. The tubercles presumably enlarge during breeding, as is the case with other ostariophysans (Wiley & Collette, 1970), but we do not understand enough of the biology of these fishes to be fully certain.