Investigating the diet of Umoonasaurus demoscyllus using micro-CT imagery

Presented by Joshua White

PhD Candidate, The Australian National University

Supervisors: Matthew McCurry (AM, UNSW), Prof Tim Denham (ANU)

The holotype of Umoonasaurus demoscyllus (AMF 99374) is one of the most complete Mesozoic marine reptile remains in the world. First discovered in Coober Pedy, South Australia in 1987 it became part of the Australian Museum’s Palaeontology collection in 1993 after a crowd funded donation successfully kept the fossil in Australia. In addition to the near complete skeleton, there are also preserved stomach contents in the gastric region of the holotype that have not previously been described in detail. Here, I use high resolution micro-computed Tomography (micro-CT) imaging techniques to provide the first detailed documentation of the stomach contents of this specimen.

The stomach contents contained 17 vertebrae from an unidentified teleost fish and approximately 60 well rounded gastroliths with an average length of 5 mm. Our study provides the first insight into the internal structure of the stomach contents associated with the holotype. Additionally, our study demonstrates the potential of using 3D penetrative scanning techniques to investigate the diets of extinct marine Mesozoic tetrapods and other extinct taxonomic groups.