Investigating gut contents of the leptocleidian plesiosaur Umoonasaurus demoscyllus using micro-CT imaging

Abstract The holotype of Umoonasaurus demoscyllus (AM F.99374) is one of the most complete plesiosaur skeletons ever discovered in Australia. It preserves a gastric mass in the pectoral girdle region that has not yet been documented in detail. Here, we use high resolution micro-computed tomography (micro-CT) to image the gut contents of this specimen. These comprise 17 vertebrae from an unidentified teleost, together with at least 60 rounded gastroliths averaging about 5 mm in maximum length. Our study demonstrates the potential for 3D tomographic imaging to investigate Mesozoic marine reptile diets and ecology. Joshua M. White [Joshua.white@anu.edu.au], Research School of Physics, Department of Materials Physics, Australian National University, Canberra, ACT 2601, Australia; Australian Museum Research Institute, 1 William Street, Sydney, New South Wales 2010, Australia. Aleese Barron [aleese.barron@anu.edu.au], Research School of Physics, Department of Materials Physics, Australian National University, Canberra ACT, 2601, Australia; School of Archaeology and Anthropology, Banks Building, Australian National University, Canberra, ACT 2601, Australia. Matthew R. McCurry [matthew.mccurry@austmus.gov.au], Australian Museum Research Institute, 1 William Street, Sydney, New South Wales 2010, Australia; Earth and Sustainability Science Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales 2052, Australia; Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA. Tim Denham [tim.denham@anu.edu.au], School of Archaeology and Anthropology, Banks Building, Australian National University, Canberra, ACT 2601, Australia.