The Dentition and Feeding Mechanism in Adults of the Southern Hemisphere Lamprey Geotria australis Gray

Abstract

AbstractScanning electron micrographs of the teeth and sections and dissections of the head have been used to describe the functional interrelationships between the dentition and associated cartilages, muscles and ligaments in adults of the southern hemisphere lamprey Geotria australis. These studies, together with manipulation of the piston and oral disc in living specimens, elucidated the probable feeding mechanism in this species. The main cutting action appears to result from a scissoring movement brought about by the rapid interlocking of the three sharp and stout cusps of the transverse lingual lamina with large grooves on the rear face of the supraoral lamina. The movement of excised flesh back through the oral passage to the pharynx would be facilitated by the action of the pair of strongly cuspid longitudinal lingual laminae. The unique oral disc teeth of G. australis are apparently adapted to allow the disc to slide forward over the host and yet restrict any tendency to slip backwards.