Morphology of adhesive surfaces in the sisorid catfish, Glyptothorax sinense sikkimensis

Abstract

This paper deals with the surface morphology and structure of suctorial mouthparts, expanded paired fins and adhesive organ (AO) in a mountain stream catfish Glyptothorax sinense sikkimensis of India, as studied by scanning electron microscopy. It possesses type I taste buds on its barbels and lips. There are scattered unculiferous plaques on the lower lip and horny tubercles on outer fin rays, and knob like microstructures between fin rays of both paired fins. The thoracic region bears a prominent AO, which has 8-10 unculiferous ridges arranged parallel to the body axis, separated by many non-unculiferous grooves. The latter may act as the major attachment sites and function as a suction cup. A combined action of the adhesive devices with their unique surface specializations enables the fish for better anchorage to sandy-rocky substratum of glacier-fed, rapid mountain streams. The plaques on lower lip and horny tubercles and knob like substructures in fin rays perhaps help in additional anchorage support to the major AO located at the thoracic area.