A prehistoric fossil, hiding in plain sight in museum storage for more than a century, has revealed that giant echidnas once roamed Victoria.
The Owen’s giant echidna, Megalibgwilia owenii, lived during the Pleistocene, a geological epoch that began 2.5m years ago. It grew to about 1 metre long and weighed up to 15kg – about twice the size of Australia’s modern echidnas.
Specimens of the extinct monotreme have previously been found across Australia, from Western Australia to Tasmania – but they had been mysteriously absent from the fossil record in Victoria.
That changed when Tim Ziegler, the collection manager of vertebrate palaeontology at the Museums Victoria Research Institute, came across a skull fragment in “a tray of unsorted fossils” that had been excavated in 1907 from Foul Air Cave, in the Buchan cave complex in East Gippsland.
“I remember plucking out this one bone fragment, which isn’t much longer than your finger,” Ziegler said. “It was just one among many – I think it had probably been mistaken for a hind limb of a small kangaroo.”
But Ziegler noticed the symmetry of the fossil, the arch of a palate, and “internal spaces that would have been where air passed through when it was breathing. These basic features said to me: this is an echidna beak, and it’s huge.”
Ziegler first noticed the fossil in the collection in 2021, but further work – including 3D scans of modern and fossil echidna specimens held in museum collections around the country – was needed to confirm the discovery.
“I knew what I was looking at in an instinctive sense, but then the job is to document it, to demonstrate it and to prove it,” he said.
Using historical archives, Ziegler confirmed the specimen had been collected by museum officer Frank Spry in an expedition to Foul Air Cave more than a century earlier.
The Owen’s giant echidna was likely a similar size to the long-beaked echidnas, Zaglossus, which today live in the tropics of New Guinea.
“But its skeleton is much more robust than that comparably sized animal. Its bones, particularly in the limbs, have deeper, more prominent muscle scars and larger attachments for ligaments that showed it was using much greater force when it interacted with the landscape,” Ziegler said.
“We can imagine either digging for buried larvae, larger prey of beetles, or bogong moths, for example, or … tearing tree bark to access this food.”
The identification of the Buchan specimen fills in a 1,000km gap in the species’ known distribution.
“The earliest … collected fossils are from New South Wales in the 1860s,” Ziegler said. “Since then, they’ve been located in south-west Western Australia, at the Mammoth Cave, for example, [and] in the Naracoorte region in South Australia.”
Giant echidna fossils have also been found in Tasmania, “which, at the time that this animal was living, was in all likelihood connected by a land bridge”.
For Ziegler, the discoveries of the fossils in historically temperate and forested habitat invited the question: why weren’t the animals also roaming ice age Victoria?
“It turns out they were there all along. And we just needed the right moment to recognise their presence.”
The research was published in Alcheringa: An Australasian Journal of Palaeontology.
