Morphological differentiation of closely resembling ariid species, Arius venosus and A. sumatranus

In Indian waters ariids (Siluriformes/ Ariidae) are represented by 9 genera and 25 valid species. The genus Arius is the most diverse with eight species reported from Indian waters which can be categorised in two broad groups. One having elongated teeth patches with globular teeth comprising of five species- A. jella, A. maculatus, A. gagora, A. malabaricus and A. arius is clubbed under maculatus complex. Other group included species like A. subrostratus, A. sumatranus and A. venosus having smaller teeth patches with villiform teeth (non-maculatus complex) (Dhanze and Jayaram. 1982). The non-maculatus complex does not contribute much to the commercial fishery barring A. subrostratus which forms minor fishery along southwest coast of India. A. subrostratus can be easily differentiated from rest of the con-generic members by smaller barbels and long snout with small mouth.