Summary

Abstract

Ornithopods were the most diverse of Mesozoic herbivores. The way their jaw systems worked has been investigated several times in the past, but only on isolated taxa. The present work analyzes jaw mechanics in approximately fifty species which fall into all five ornithopod families Following detailed arthrologic descriptions of the majority of cranial joints in these species, three-dimensional kinematic modeling was used to explore available jaw mechanics hypotheses in the literature and many that were not, in order to test each against actual tooth wear represented in ornithopod specimens. From these kinematic analyses, ornithopod jaw systems can be divided into three fundamentally different mechanisms, all constructed on isognathy and bilateral occlusion.