Meeting Abstract

P3.92  Sunday, Jan. 6  Enamel thickness as an indicator of feeding behavior in crocodyliforms HOLLIDAY, CM; SELLERS, KC*; Univ. of Missouri; Univ. of Missouri kcsty5@mail.missouri.edu

Many craniodental features are known to be under selective pressures; thus, insights into dental anatomy may shed light on feeding evolution. Tooth size, complexity, and enamel thickness provide information on dietary adaptations in living and fossil taxa. Fossil crocodyliforms display a wide diversity in dental forms, including the conical teeth of the predatory Alligator, giant molars of durophagous species, and the complicated cusps of putatively herbivorous, chewing species. However, enamel thickness of these specimens remains unmeasured and little is understood about the evolution of internal dental features in crocodyliforms. To test the hypothesis that enamel thickness varies among crocodyliforms with potentially different feeding habits, we investigated the enamel thickness of teeth of different ontogenetic stages and locations in Alligator mississippiensis, and then the molariform teeth of two protosuchians, the stem eusuchian Iharkutosuchus, the extinct globidont alligatorid Allognathosuchus, and finally the extant squamate Dracaena. Measurements of enamel thickness, enamel-dentine junction length, and volumes were obtained from analysis of microCT data. Crocodyliform enamel thickness is substantially lower than that recorded for primates. Iharkutosuchus, with the most complex cusp morphology, has the relatively thickest enamel, whereas the other taxa possess similar enamel thicknesses, even the megadont Allognathosuchus. This suggests that crocodyliform enamel thickness may track with derived chewing behaviors and dietary regimes. More data are necessary to better understand the ontogenetic and phylogenetic patterns of the dentition as it relates to diet and the feeding apparatus.