Scientists have concluded a seven-year study into 130-kilogram giant wombats — comparable in size to "really large sheep" — that lived in central Queensland about 80,000 years ago.
A team led by Griffith University's Australian Research Centre for Human Evolution excavated and studied the extinct megafauna species after a skull was found at Johannsen’s Cave north of Rockhampton in the early 2000s.
Team leader Julien Louys said Ramsayia magna was one of three giant wombats scientists were aware of.
"They're closely related to the modern wombats but they're much larger than the current species," Dr Louys said.
"[There are] about a dozen specimens across the entirety of the continent of Australia, so it's incredibly rare."
The team's research is published today in the Papers in Palaeontology scientific journal.
How giant wombats compare to modern wombats
Dr Louys said many of Australia's extinct megafauna were unable to be dated due to their age, but a combination of techniques had allowed the team to gauge the age of the giant wombat fragments.
"We were able to tell that the fossil was probably around 80,000 years old," he said.
The palaeontologist said with previously discovered parts of jaws and teeth, researchers knew little about the "gentle giants" and how their evolution progressed in Australia.
"With this particular specimen, we've actually got most of the skull preserved," he said.
"We're able to determine not just what it looked like, but most likely what it ate, and we've made some inferences into some of its behavioural adaptations."
Along with the findings were the shape of the giant wombat's head, its rounded skull, and its large fleshy nose.
"[It] contrasts remarkably with the modern wombats, which have a much flatter skull," Dr Louys said.
"We think that this giant wombat, with a more dome skull, perhaps wasn't living in burrows like the modern wombat does."
It's the real deal
The researcher said there were three different types of giant wombats that existed in Australia, but all of them likely "evolved once" with gigantism.
"Once these giant wombats became giant, then they became even more specialised, focusing on different aspects of the environment, of the grasses that were around in Australia at the time," Dr Louys said.
He said another extinct megafauna species called Diprotodon was often incorrectly referred to as a giant wombat.
"It doesn't actually belong to the wombat family; it's about as closely related to wombats as a cow is to a hippo," he said.
"What we found with this particular specimen [in central Queensland] is it actually is a true wombat — it is part of the wombat family."
'Puts Rockhampton on the map'
Rockhampton man Noel Sands was with a researcher when the fossil was "discovered by accident".
"We found a small piece of the wombat, which I didn't know what it was at the time," he said.
Mr Sands has since volunteered alongside the experts studying the giant wombat fossil, which he said was found in the wall of the cave mined for guano in the late 1890s to about 1930.
"The rest of the wombat, and who knows what other material, would have been mined out by the guano miners going back to the early part of the 20th century," he said.
Mr Sands has volunteered, collecting fossils with the Queensland Museum since 1998.
"I'm just a plain, ordinary person with no technical ability, but I've got the huge privilege of going out and helping them find these things," he said.
While the finding "puts Rockhampton on the map", Mr Sands urged the public to seek appropriate national parks permits when exploring.
Where is the fossil now?
The fossil is part of the Queensland Museum collection, but Dr Louys said it could one day be put on display.
"In the meantime, we are going to continue our research on various different fossil marsupials, wombats included," he said.
He said it was important to continue exploring the caves in the tropical north of Australia because there was "so little known".
"Most of the fossils that we have come from the south and the south east," he said.
"Who knows what else we're going to find, what other fantastic remains are waiting to be discovered. It's just amazing.
"We're really just scratching the surface with this."
