Meeting Abstract

P3.103  Friday, Jan. 6  Mobility of the mandibular symphysis during feeding in lizards MONTUELLE, S.J.*; WILLIAMS, S.H.; Ohio University Heritage College of Osteopathic Medicine; Ohio University Heritage College of Osteopathic Medicine

In jawed vertebrates, the lower jaw is comprised of two hemimandibles that are united in the anterior midline by the mandibular symphysis. In lizards, the symphysis exhibits variable morphology in the extent of connective tissue density, symphyseal width and the morphology of Meckel’s cartilage (i.e., fused anteriorly or unfused). Because of these differences, previous studies have suggested functional differences in the role of the mandibular symphysis during feeding. Here, we investigate symphyseal mobility during prey capture and processing in lizards that differ in the morphology of their mandibular symphysis. We compare the intra-mandibular movements in a lizard species characterized by an un-fused Meckel’s cartilage, Gerrhosaurus major, with one characterized by a fused Meckel’s cartilage, Pogona vitticeps. Both species, however, have dense connective tissue in the symphyseal joint. We use high speed fluoroscopy in lateral and dorsoventral views to reconstruct the movements of the two hemimandibles in three dimensions. Our observation indicates that despite an unfused Meckel’s cartilage, the hemimandibles of G. major do not move independently during feeding. These results suggest that fiber density may be more important for restricting movements of the hemimandibles than Meckel’s cartilage in lizards.