Erethistoides Hora, 1950

Alfred W. Thomson & Lawrence M. Page, 2006, Genera of the Asian Catfish Families Sisoridae and Erethistidae (Teleostei: Siluriformes)., Zootaxa 1345, pp. 1-96 : 17-19

Erethistoides Hora, 1950

Fig. 7

Erethistoides Hora, 1950 : 190. (Type species: Erethistoides montana Hora, 1950 , by original designation). Gender masculine.

Diagnosis: No thoracic adhesive apparatus; serrations on anterior margin of pectoral spine directed toward tip of spine distally and away proximally; slender body; smooth to granulate anterior margin on dorsal spine; moderate gill openings; papillate upper lip; 9-11 anal rays.

Erethistoides is diagnosed from all other erethistids by having the anterior margin of the pectoral spine with serrations directed toward the tip of the spine distally and away from the tip proximally (Fig. 6c). It is further distinguished from Erethistes by its more slender body (Fig. 7), from Ayarnangra by having 9-11 anal-fin rays (vs. 13-16), from Conta , Caelatoglanis and Pseudolaguvia by the absence of a thoracic adhesive apparatus and by having moderate gill openings (vs. narrow and restricted to the pectoral-fin base in Conta , and wide and nearly meeting on the venter in Caelatoglanis and Pseudolaguvia ). It is further distinguished from Conta by having a smooth to granulate (vs. serrated) anterior margin on the dorsal spine, and from Caelatoglanis by having a papillate (vs. plicate) upper lip and a more slender body.

Description: Dorsal fin with strong spine, 5 rays; pectoral fin with strong spine, 6 rays; 6 pelvic-fin rays; 9-11 anal-fin rays. Depressed, triangular head; elongate, compressed body (Fig. 7). Skin tuberculate or smooth. Eyes small to moderate, dorsolaterally and situated in posterior half of head. Jaw teeth villiform, in bands; palatal teeth absent. Maxillary barbel longer than head, with well-developed membrane. Gill openings moderate, extend onto venter; branchiostegal membranes broadly fused to isthmus. Pectoral girdle with long coracoid process. Pectoral-fin spine serrated anteriorly and posteriorly. Dorsal spine smooth to anteriorly, serrated posteriorly. No thoracic adhesive apparatus. Paired fins non-plaited.

Remarks: Ng (2005c) questioned the utility of the pectoral spine morphology as a useful diagnostic character for Erethistoides , noting that some of the serrations on the anterior edge of the pectoral spine in some specimens of Erethistes filamentosa are directed toward the tip of the spine distally (as in Erethistoides ). Additionally, he identified four apomorphies diagnosing Erethistoides : 1) neural spines of the first eight postWeberian vertebrae strongly depressed, inflated posteriorly, and depressed in a groove formed by the prezygapophyses of the vertebrae immediately posterior; 2) an enlarged maxilla that is almost as long as the palatine; 3) a fan-shaped mesethmoid lacking distinct cornua (shared with Ayarnangra ); 4) a strongly overhanging snout with premaxillary tooth plate completely exposed when mouth is closed (shared with Ayarnangra ).

Distribution: Brahmaputra and Meghna drainages, northern India and Nepal (Ng & Edds 2005a).