Meeting Abstract

P1.105  Thursday, Jan. 3  An Examination of Durophagy and Associated Craniodental Traits in Varanus niloticus Using Finite Element Analysis HALL, J. T.; FARKE, A. A.*; Stony Brook University; Stony Brook University theropods@gmail.com

Ontogenetic dietary changes in Nile monitor lizards, Varanus niloticus, have been observed in wild populations. Juvenile V. niloticus are generalized carnivores, eating opportunistically. Adults have a more specialized durophagous diet, predominately eating snails, crabs and mussels. These dietary changes are accompanied by marked changes in jaw and tooth morphology. Juvenile mandibles are relatively slender and elongate, with low coronoid processes, and pointed, recurved teeth that are serrated and laterally compressed. Adult mandibles have relatively shortened tooth rows, high coronoid processes, and are bowed out ventrally near the posterior teeth. Adult teeth are molariform, blunted and rounded at the base, lacking serrations. These morphological changes have been suggested as adaptations for the durophagous diet of adults. To test this hypothesis, nine 2D finite element models of V. niloticus representing an ontogenetic sequence were created from digital photographs. The models were constrained at the quadratomandibular joint and posterior four teeth and loaded at the attachment sites of the bodenaponeurosis (jaw adductor tendon) and the M. pterygoideus to simulate forces acting on the jaws during biting. Models were scaled to the same size, and the same forces were placed on each to examine differences in stress patterns between the ontogenetic stages. The juvenile specimens showed higher magnitudes of stress than the adult specimens. High stresses in the juvenile were distributed over much of the jaw while the highest stress magnitudes in adults were localized near the coronoid where the bodenaponeurosis inserts. This supports the hypothesis that the adult morphology is an adaptation for absorbing forces associated with a durophagous diet.