Morphological adaptation of the buccal cavity in relation to feeding habits of the omnivorous fish Clarias gariepinus: A scanning electron microscopic study

The surface architecture of the buccal cavity of the omnivorous fish Clarias gariepinus was studied in relation to its food and feeding habits. The buccal cavity of the present fish was investigated by means of a scanning electron microscope. This cavity may be distinguished into the roof and the floor. Papilliform and molariform teeth which are located in the buccal cavity are associated with seizing, grasping, holding of the prey, crushing and grinding of various food items. Three types of taste buds (Types I, II & III) were found at different levels in the buccal cavity. Type I taste buds were found in relatively high epidermal papillae. Type II taste buds were mostly found in low epidermal papillae. Type III taste buds never raise above the normal level of the epithelium. These types may be useful for ensuring full utilization of the gustatory ability of the fish. A firm consistency or rigidity of the free surface of the epithelial cells may be attributed to compactly arranged microridges. These structures protect against physical abrasions potentially caused during food maneuvering and swallowing. Furthermore, protection of the epithelium from abrasion is enhanced with mucous cell secretions which lubricate ingested food items.