The predentary bone and its significance in the evolution of feeding mechanisms in ornithischian dinosaurs

This study aims to re‐evaluate these hypotheses as well as provide in‐depth qualitative comparative descriptions of predentary bone morphology in ornithischian genera throughout all subclades, including heterodontosaurids, thyreophorans, ornithopods, and marginocephalians. Descriptions evaluate overall shape of the predentary, its articular surfaces contacting the rostral ends of the dentaries, and the morphology of the rostral extent of the dentaries and their midline symphysis. Functionally relevant morphologies in each predentary morphotype are accentuated for further speculation of feeding mechanisms. Three predentary morphotypes are described throughout ornithischian subclades and each plays a unique role in feeding adaptations. Most notably, the predentary likely evolved as a midline axial point of the mandibular symphysis for simultaneous variable movement or rotation of the mandibular corpora in many, but not all, taxa. This simultaneous movement of the hemimandibles would have aided in feeding on both sides of the jaw at once. The function of the predentary as well as other jaw adaptations is discussed for genera throughout all subclades, focusing on both general shape and joint morphology. This article is protected by copyright. All rights reserved.

Source: The Anatomical Record Part B: The New Anatomist - August 3, 2016 Category: Anatomy Authors: Ali Nabavizadeh, David B. Weishampel Tags: Full Length Article Source Type: research