Abstract
The anterior half of the right mandible of a dugong is described from the early Pliocene Loxton Sands of the Murray Basin in South Australia. This is the oldest dugong fossil known in Australia, and, although not identifiable, is possibly antecedent to or the oldest representative of the genus Dugong. Its provenance so far from the Equator supports other evidence for global warming and high sea-levels during the late Cenozoic.