Giant echidnas weighing 15kg roamed Victoria – and the evidence was hiding in plain sight | Mammals
A prehistoric fossil hidden in plain sight in museum storage for more than a century has revealed that giant echidnas once roamed Victoria.
Owen’s giant echidna, Megalibgwilia OveniiHe lived during the Pleistocene, a geological epoch that began 2.5 million years ago. Reached a length of about 1 meter and a weight of up to 15 kg; this was about twice the size of Australia’s modern echidnas.
Specimens of the extinct monotreme have previously been found throughout Australia, from Western Australia to Tasmania; but these were mysteriously missing from the fossil record in Victoria.
That changed when Tim Ziegler, collections manager for vertebrate paleontology at the Victoria Museum Research Institute, came across a skull fragment in “a tray of unclassified fossils” excavated in 1907 at Foul Air Cave in the Buchan cave complex in East Gippsland.
“I remember removing this single piece of bone that wasn’t much longer than your finger,” Ziegler said. “It was just one of many things; I think it was probably mistaken for the hind leg of a small kangaroo.”
But Ziegler noticed the fossil’s symmetry, the palatal arch, and “the internal spaces through which air passes as it breathes. These key features told me: This is an echidna beak, and it’s very big.”
Ziegler first noticed the fossil in the collection in 2021, but more studies were needed to confirm the discovery, including 3D scans of modern and fossil echidna specimens held in museum collections across the country.
“I instinctively knew what I was looking at, but the job is to document, show and prove it,” he said.
Using historical archives, Ziegler confirmed that the sample was collected by museum officer Frank Spry on an expedition to Foul Air Cave more than a century ago.
Owen’s giant echidna was likely similar in size to the long-beaked echidnaZaglossus, Today they live in the tropics of New Guinea.
“But its skeleton is much more robust than that of this similarly sized animal. Its bones, especially in its limbs, have deeper, more pronounced muscle scars and larger attachments for ligaments, indicating that it used much more force when interacting with the landscape,” Ziegler said.
“We can imagine digging for buried larvae, larger prey of insects or swamp moths, or tearing through tree bark to get to this food.”
The identification of the Buchan specimen fills a 1,000-kilometer gap in the species’ known distribution.
“The oldest fossils collected are from New South Wales in the 1860s,” Ziegler said. “They have since been found in the southwestern part of Western Australia, for example in Mammoth Cave. [and] “In the Naracoorte region of South Australia.”
Giant echidna fossils were also found in Tasmania; “When this animal lived, it was probably connected to here by a land bridge.”
According to Ziegler, the discovery of fossils from historically temperate and forested habitats raised the question: Why didn’t animals also roam ice age Victoria?
“It turns out they were there all along. And we needed the right moment to recognize their presence.”
The research was published on: Alcheringa: Australasian Journal of Paleontology.
