DENTIGEROUS BONES AND DENTITION IN THE HEMIRAMPHID FISH DERMOGENYS PUSILLUS (ATHERINIFORMES, TELEOSTEI)

Structure and arrangement of the teeth were studied in the hemiramphid Dermogenys pusillus, using scanning electron microscopy as well as cl eared and stained specimens. The teeth of the jaws are small, monocusp id, and tilted towards the esophagus. They are arranged along the late ral edges of the premaxillas and dentaries. Each premaxilla bears addi tional teeth on an osseous bar extending from rostro-lateral to medio- lingual. The dentition of both dentaries curves slightly within the ca vity of the mouth and gently tapers off laterorostrad just beyond the tip of the upper jaw The part of the lower jaw which typically protrud es beyond the upper jaw, is without teeth. One dorsal and two lateral tooth-bearing bony plates (tooth plates) are found in the pharyngeal r egion. Their teeth are largely irregular in arrangement. The teeth on the two lateral plates are small and monocuspid, whereas the dorsal an d the ventral tooth plate possess additional strong bi- and tricuspid teeth. The teeth of the jaws and of the pharyngeal region obviously ha ve a bony pedicel (''attachment bone'') which is asymmetric in all tee th. An elastic suture connects the cone of dentine with the bony pedic el. The special construction of the teeth and their arrangement on the various dentigerous bones will be discussed with respect to their fun ction in catching prey.