Neohelos stirtoni - Diprotodontid (Marsupial) partial skull

Neohelos stirtoni belonged to an extinct family of giant wombat-like marsupials called Diprotodontidae. There are two types of diprotodontids, currently based on the shape of the third premolar. Species that belong to the sub-family Diprotodontiae are characterised by having 1-3 cusps present on the third premolar, as opposed to members of Zygomatuinae, which have 4-5 cusps. Other than this small difference, all members of Diprotodonitdae are extremely similar in body shape and diet, but vary in weight and size. The largest is the 3 tonne Diprotodon optatum and one of the smallest is approximately 60kg, Nimbadon lavarackorum.
Neohelos stirtoni belonged to the subfamily Zygomaturinae and occupied most northern parts of Australia, including Riversleigh World Heritage Fossil Area, Queensland and Bullock Creek, Northern Territory. Neohelos was approximately the size of a small cow and lived during the early to middle Miocene (23-11 Ma) of Australia. Unfortunately, all members of diprotodonitds, like other types of megafauna, went extinct approximately 40,000 years ago. The cause of this extinction event is still hotly debated among palaeontologists.