Observations on the Pharyngeal Teeth of Two Hill-Stream Fishes, Schizothorax richardsonii (Gray) and Barilius bendelisis (Ham-Buch) in Relation to Food and Feeding Habits

摘要

The present paper furnishes an account of the pharyngeal bone and teeth of two hill-stream cyprinids, S. richardsonii and B. bendelisis. Carps are commonly characterized by the presence of pharyngeal teeth but their jaws are edentulous. Pharyngeal teeth in relation to food and feeding habit have been studied in a number of fishes by many workers. The pharyngeal teeth are borne on the inferior pharyngeal bone which represents the ceretobranchial of 5th arch. The other components viz. hypobranchial, epibranchial and pharyngobranchial of the 5th arch are absent. These teeth may be villiform, caniniform, molariform in nature and prevent regurgitation of food or act as rasping organ. Ecological conditions in the hill-streams have brought about various interesting modifications in the morphology of torrential fishes. The chief modifications are those associated with the feeding apparatus which includes mouth aperture, jaw teeth, gill rakers, pharyngeal teeth etc. The present paper furnishes a detail account of the pharyngeal bone along with teeth of S. richardsonii and B. bendelisis.