A Unigue Jaw Mechanism in the Echidna, Tachyglossus aculeatus (Monotremata)

Abstract

The specialized tongue of the echidna functions in both capturing and grinding food. These processes can occur simultaneously because the echidna opens and closes its mouth by rotating the mandibles about their own long axes. This action translates the curvature of the attached rami into a downward movement commencing from a point just posterior to the corner of the mouth. Orthal hinge movements of the mandible are prevented by short ligaments which attach the horizontal ramus to the maxilla, and the position of the jaws is unchanged.