Gagata Bleeker, 1858

Alfred W. Thomson & Lawrence M. Page, 2006, Genera of the Asian Catfish Families Sisoridae and Erethistidae (Teleostei: Siluriformes)., Zootaxa 1345, pp. 1-96 : 29-30

Gagata Bleeker, 1858

Fig. 10

Gagata Bleeker, 1858 : 204, 206. (Type species: Pimelodus gagata Hamilton, 1822 , by absolute tautonymy). Gender feminine.

Callomystax Guenther, 1864 : 218. (Type species: Pimelodus gagata Hamilton, 1822 , by being a replacement name. Unneeded replacement for Gagata Bleeker, 1858 . Gender masculine.

Diagnosis (based, in part, on Roberts & Ferraris 1998): Compressed head; eyes on side of head; depressed snout; small conical teeth in lower jaw; branchiostegal membranes broadly fused to isthmus; no serrations on anterior margin of pectoral spine; no welldeveloped maxillary barbel membrane; outer and inner mental barbels close together with their origins nearly parallel, in a transverse line; short nasal and maxillary barbels; palatal teeth absent.

Gagata is distinguished from Nangra by having the branchiostegal membranes broadly fused to the isthmus (vs. free from the isthmus), a compressed (vs. depressed) head, lateral (vs. dorsolateral) eyes, absence of palatal teeth, maxillary barbels extending only to the pectoral-fin base (vs. extending to the pelvic-fin base.) and nasal barbels shorter than the eye diameter (vs. longer, reaching at least to the eye). Gagata is distinguished from Gogangra , Bagarius and Sisor by having a compressed (vs. depressed) head, and by having the outer and inner mental barbels close together with their origins nearly parallel (vs. widely separated, origin of the inner barbels anterior in Gogangra and Bagarius , and origin of the inner barbels posterior in Sisor ). Gagata is further distinguished from Gogangra by having the branchiostegal membranes broadly fused to the isthmus (vs. free from the isthmus). Gagata is further distinguished from Bagarius by having the branchiostegal membranes broadly fused to the isthmus (vs. free from the isthmus), and by having the dentition in the lower jaw consisting of only small conical teeth (vs. dentition markedly heterodont), and by lacking a well-developed maxillary barbel membrane. Gagata is further distinguished from Sisor by lacking serrations on the anterior margin of the pectoral spine (vs. serrations on both anterior and posterior margins of pectoral spine), no series of bony plates on the dorsum, no spine in the adipose fin, the uppermost caudal-fin ray not greatly elongated (vs. greatly elongated, more than half the length of the body), and no well-developed maxillary barbel membrane.

Description: Dorsal fin with 1 spine, 6 branched dorsal rays; pectoral fin with 1 spine, 7-10 branched rays; 6 pelvic-fin rays; 8-16 anal-fin rays (8-14 branched); 17 principal caudal rays. Head compressed; snout depressed; eyes large, lateral; teeth finely conical, in few rows, absent from upper jaw in some species. Palatal teeth absent. Maxillary barbel extending only to level of pectoral-fin base, without well-developed membrane at base. Base of maxillary barbel stiff. Branchiostegal membranes fused to isthmus; coracoid process not visible externally. Pectoral-fin spine smooth anteriorly, serrate or granulate posteriorly. Dorsal spine smooth anteriorly and posteriorly. No thoracic adhesive apparatus. Paired fins non-plaited.

Distribution: Indus drainage in Pakistan and India, east and south (including peninsular India) to the Tenasserim drainages, Myanmar (Roberts & Ferraris, 1998; Mirza et al.,1999).