Organs of adhesion in some mountain-stream teleosts of India: Structure-function relationship

Abstract

The sub-Himalayan streams and rivers of India are known to be inhabited by a number of teleost fishes specialized for living in rapids (Day, 1958; Jayaram, 1981). Ecologically, these are perennial shallow-water bodies, characterized by having low water temperature, high turbulent current and sandy-rocky substratum (Das and Nag, 2004). In order to thrive against the adverse habitat situations, many species show a number of unique adaptive specialisations. One notable morphological feature shown by them is an adhesive organ (AO), by which the species adhere to submerged rocks and stones of streams. The AO is ventral in position and located either at the thoracic region behind the opercular openings or encircling the mouth opening. In mountain-stream catfishes (Sisoridae), additional adhesive devices are present on the ventral surface of the paired pectoral and pelvic fins. In these fishes, the skin of the outer rays of those fins is formed into a series of alternate ridges and grooves (Hora, 1922, 1930). © 2009 Springer Science+Business Media B.V.