Meeting Abstract
P1.143 Tuesday, Jan. 4 Dental Microwear Analysis as a Predictor of Feeding Types in Predatory Mesozoic Marine Reptiles POYNTER, Jeremy M*; ADAM, Peter J; Northwest Missouri State University; Northwest Missouri State University j.poynter@gmail.com
Extinct members of the predatory marine reptile guild constitute a paraphyletic group that includes ichthyosaurs, plesiosaurs, pliosaurs, and mososaurs. These fast swimming predators dominated many ecological niches in Mesozoic oceans and evolved numerous feeding strategies to exploit a diverse pelagic prey base that included heavily armored ammonites and belemnoids, as well as softer-bodied bony fishes, sharks, and other marine reptiles. Previous work by Judy Massere revealed that the diverse dentition of marine reptiles can be used to predict their feeding tactics and diets. Using (primarily) tooth morphology Massare identified seven major feeding strategies among predatory marine reptiles: crushing, crunching, smashing, piercing I, piercing II, generalist, and cutting types. Tooth microwear, commonly used to assess diet in other groups, has not been studied in fossil marine reptiles. We examined microwear in representatives of different feeding types to establish if quantitative measures of pits and scratches on teeth were correlated with feeding types predicted by Massere. Sampled genera include Plesiosaurus, Ichthyosaurus, Clidastes, Tylosaurus, Globidens, Ectenosaurus, and Platecarpus. Polyvinylsiloxane molds were taken of selected teeth, followed by generation of die stone casts that were examined using a digital reflective microscope at a magnification of 200X. Data for maximum, minimum, and mean pit diameter and scratch density, depth, and width were collected along basal-apical transects of lingual tooth surfaces. Preliminary results indicate that tooth microwear may be useful for distinguishing more extreme feeding strategies (e.g., smashing versus piercing) but that functionally similar strategies (e.g., piercing I and II) cannot be discriminated.
