Meeting Abstract
Crocodyliforms evolved a series of key features responsible for their Mesozoic adaptive radiation. Among these is the pterygoid buttress, the characteristic hypertrophied pterygoid flange in the skull. Although historically approached simply as a palatal element, the buttress forms a prominent articulation with the mandible here referred to as the pterygomandibular joint. We will present lines of evidence from anatomy, development, biomechanics, and the fossil record that show the joint is part of a dual craniomandibular joint system evolved early in suchian evolution and the key factor that stabilized the mandible and released the lineage to evolve high bite forces and robust skulls. The crocodyliform pterygomandibular joint bears resemblance to the eutherian temporomandibular joint as both joints possess sesamoid-like fibrocartilages within evolutionarily-conserved muscle attachments. Thus, crocodyliforms and mammals convergently evolved dual craniomandibular joint systems with similar joint morphologies albeit at different locations. These new findings enable significant new insights into cranial biomechanical modeling, skeletal development and vertebrate evolution.
