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Museum Victoria | Collections & Research | Education | What's On |
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What is a Fossil? | Invertebrate Fossils | Dinosaurs | Ice Age Animals | Victoria's Fossils |
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Diprotodontids
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The Diprotodontids
The diprotodontids are perhaps the best known of the Australian Megafauna. There were a number of species of these large herbivorous marsupials, varying from animals about the size of a sheep that existed 15 million years ago, to several more recent and much larger species. Diprotodon optatum, which evolved about a million years ago and may have become extinct as recently as 15,000 years ago, has the distinction of being the largest marsupial ever. It was the size of a rhinoceros—three metres long, almost two metres high at the shoulder, and weighing as much as two tonnes. It had pillar-like legs and broad footpads, a little like those of an elephant. Diprotodon optatum was quite widespread throughout inland Australia prior to the last glacial peak about 18,000 years ago. Inland Australia was somewhat less arid at that time, and supported extensive grasslands. The last Ice Age brought increasingly dry conditions to the inland, and this may have caused the extinction of Diprotodon soon after. Fossils of Diprotodon and other animals are plentiful in the dry inland lakes of South Australia, and may be evidence that the last of the Diprotodons retreated into the lakes as they dried up. The articulated cast skeleton on display at Melbourne Museum is based on a skeleton that was collected from Lake Callabonna in inland South Australia.
The skulls of diprotodontids were huge but quite hollow. Fossil skulls therefore tend to be rather fragile. The two Diprotodon skulls on display at Melbourne Museum are both from Victoria, and are the best specimens ever found. A third, smaller skull of an earlier Diprotodontid, Neohelos stirtoni is from the Northern Territory and is about 10 million years old. An articulated skeleton of Zygomaturus tasmanicus, which was a close relative of Diprotodon, is featured in Melbourne Museum's exhibition. The Zygomaturus species were somewhat smaller than Diprotodon, and probably favoured the forested areas of south-eastern and south-western Australia, while Diprotodon was more suited to the open grasslands of the interior. The adult Zygomaturus was about 2.5 metres long and about 1 metre high at the shoulder, with a weight of 300-500 kilograms. The specimen on display is one of a number of skeletons of Zygomaturus found preserved in Mowbray Swamp near Smithton in north-west Tasmania in 1912. Exhibits at Melbourne Museum:
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