Chitala chitala (Hamilton, 1822)
Species overview
The genus Chitala is the genus within the Notopteridae with the greatest number of species, which, however, are quite difficult to identify, because there is "No single character known that will distinguish all specimens of C. chitala from all other species" (Roberts, 1992: 367). The upper profile of the head is excessively concave and continues in an as well excessively convex outline of the back, characters which are even more obvious with age - size of the fish. C. chitala is rather inconspicuously colored.
Size observed: up to 150 cm..
Taxonomic description
-Body typically "knife shaped", laterally compressed.
-Head above eyes much lower than greatest body depth, its upper profile exsessively concave, outline of back above gill cleft more than two times as deep as upper profile of head above eyes; curvature of back hump like, outline of underside of body rather straigth.
-Mouth terminal, its edge extending clearly beyond posterior rim of eye.
-Eye large.
-Preopercle with scales of same size as scales of body, opercular cleft long, round.
-Pectoral fin reaching to origin of anal fin, pelvic fin small.
-Dorsal fin with short base, feather like.
-Base of anal fin long, 116-121 fin-rays, merging in caudal fin (15-16 fin rays) without obvious boundary, fin-rays of anal rather long, maximum length shortly anterior to caudal. 80-83 vertebrae.
-Coloration, the ground colour is brown to velvety blackish-brown, countershaded; old specimens tend to become silvery. Usually most stages have a series of four to six small, round - but never ocellated - spots close to the end of the body, and a series of pale transverse bars or streaks on the back, silvery or golden in life. A spotted variety with small dark spots scattered on the body is relatively rare. Another variaty may have small dark spots at the end of the anal fin and none on the body.
Type locality
Mystus chitala : >rivers of Bengal and Behar<, no type specimen or drawing.
Notopterus maculatus : not indicated.
Distribution
According to Roberts (1992) natural range apparently only Indus, Ganges, Brahmaputra and Mahadani basins. Records from other regions may be due to the difficulty to identify and separate the four species in question.