Extinct giant wombat over twice the size of modern wombats, actually part of wombat family unlike Diprotodon

Palaeontologists have found Australia’s true giant wombat.

Diprotodon is an extinct megafauna species that is often referred to as Australia’s ‘giant wombat’. While Diprotodon were definitely giant, being the largest marsupials of all time, the car-sized animals were only distantly related to wombats. They were actually in a completely different family.

Now Griffith University researchers have shed light on a large species that does belong to the same family as modern wombats.

The fossil skull of the animal was found in a cave in Rockhampton, Queensland. The remains are estimated to be around 80,000 years old. The species is described in a paper published in Papers in Paleontology.

“The extinct megafauna of Australia never ceases to amaze and intrigue not just Australians, but people all over the world,” says lead author, Associate Professor Julien Louys. from Griffith.

“Although one of the most charismatic of the giant mammals to go extinct, Diprotodon is commonly referred to as a ‘giant wombat’. But this is incorrect as Diprotodon belongs to an entirely different family – equivalent to saying a hippo is just a giant pig,” Louys explains.

Read more: Unearthing Australia’s ancient birds of prey

Ramsayia magna. Credit: Eleanor Pease.

But Louys explains that Ramsayia magna, which lived in Australia during the late Pleistocene (about 2,580,000 to 11,700 years ago) was a true giant wombat.

“There were however, true giant wombats,” Louys says. “These have traditionally been poorly known, but the discovery of the most complete skull of one of these giants, Ramsayia, has provided us with an opportunity to reconstruct what this creature looked like, where and when it lived, and how the evolution of giant wombats took place in Australia.”

While the skull and jaw bones of R. magna were found in the early 2000s, it was only later analysis that it was confirmed to be a specimen from a previously described, but very poorly understood, species.

Extinct giant wombats from the Vombatidae family are rarer than fossil diptrotodontids. But the new analysis sheds some light on what Ramsayia was like.

Read more: 100-million-year-old fossil dug up in Australian outback might be a new species

Louys says it had extensive cranial sinuses – previously unseen in wombats. “This indicates that the wombat had a large, rounded skull for the attachment of specific and strong chewing muscles. The giant wombat also possessed a ‘premaxillary spine’, an indication that it had a large, fleshy nose.”

The endocranial view of the excavated skull. Credit: Griffith University.

The study also gives an insight into broader giant wombat evolution, though the reason Ramsayia went extinct is still a mystery.

“In this paper, we show that all true giant wombats evolved large body sizes first, then individually became quite specialised to eat different types of grasses. We also dated this species as being about 80,000 years old. This is the first date for this species and is much earlier than human arrival in Australia, although we still don’t know exactly when or why this species became extinct.”

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