Is Agrosaurus macgillivrayi Australia's oldest dinosaur?

WA Museum Records and Supplements | Updated 9 years ago

Abstract - The holotype and only known specimen of the prosauropod Agrosaurus macgillivrayi Seeley, 1891 probably comes from the Late Triassic Durdham Down locality near Bristol, England. Originally it was reported as being from the northeast coast of Australia. Firsthand examination of the most plausible northeast Australian source for such a fossil, outcrops of the Jurassic Helby Beds exposed on the east coast of Cape York Peninsula, have demonstrated that the rock in that unit was quite unlike that associated with the holotype. Gross and trace element comparisons between possible fossil bone fragments from the Helby Beds and the holotype also showed them to be quite different. On the other hand, similar comparisons between the holotype and fossil bone from Durdham Down showed them to be quite comparable, as were the rocks and microvertebrates there and the ones associated with the holotype. Furthermore, A. macgillivrayi is probably a junior synonym of Thecodontosaurus antiquus Morris, 1843 from Durdham Down.