Paleontologists announced the discovery of an extinct Australian mammal resembling a 300-pound wombat in new research published in the journal Scientific Reports.
If you’re struggling to picture a wombat, imagine a stocky, short-limbed ball of burrowing marsupial fluff, as Joshua Sokol helpfully describes for the New York Times. (Humans find wombats so adorable that Maria Island National Park in Tasmania had to issue a special advisory asking visitors to stop petting them, trying to take selfies with them and generally attempting to squeeze them for ever and ever.)
The next crucial step to imagining this 25-million-year-old animal is to take the trundling wombat you’ve conjured and make it the size of a black bear, which is the living animal that study co-author Mike Archer, a paleontologist at the University of New South Wales, used to approximate the new species’ size in a statement.
The big-boned creature was named Mukupirna nambensis for the words muku (“bones”) and pirna (“big”) of the indigenous Dieri and Malyangapa languages spoken near where the fossil was unearthed.
The find included a partial skull and skeleton that revealed Mukupirna would have been an herbivore well-suited to digging like wombats, though judging by its size it was probably not a full-blown burrower.
“Mukupirna clearly was an impressive, powerful beast, at least three times larger than modern wombats,” says lead study author Robin Beck, a paleontologist at the University of Salford, in the statement. “It probably lived in an open forest environment without grasses, and developed teeth that would have allowed it to feed on sedges, roots, and tubers that it could have dug up with its powerful front legs.”
While wombats are its closest living relatives, Mukupirna has such unfamiliar features that researchers placed it in its very own, newly created family of marsupials, according to the statement.
“The form of the teeth is unlike any that we've ever seen in any other group of marsupials," Archer tells Anna Salleh of the Australian Broadcasting Corporation. Compared to wombats, Archer tells ABC that Mukupirna had dainty chompers with thin enamel that suggest its diet consisted of softer, more nutritious foliage than the tough grasses favored by wombats today.
The Mukupirna fossil was first collected in 1973 at Australia’s Lake Pinpa, a remote, dried-up salt lake to the east of the Flinders Ranges in South Australia, according to the statement. When researchers started working on it again about ten years ago, they realized it could be something of a missing link within the vombatiforms—an evolutionary group that includes wombats and koalas.
Gavin Prideaux, a palaeontologist from Flinders University who was not involved in the research, tells ABC that while it’s been understood for some time that wombats and koalas are each other's closest living relatives, the substantial differences between them also suggest their evolutionary paths diverged long ago.
Speaking with ABC, Prideaux says Mukupirna could help fill in the evolutionary gap between the two marsupials. "It's got attributes that shows it's very clearly not a wombat, but it's halfway to being a wombat," he says.
Within the extinct vombatiforms, Mukupirna’s big-boned heft wasn’t even particularly unusual. Amy Woodyatt and Rob Picheta of CNN report that the researchers found that members of the group evolved body weights of 220 pounds or more no fewer than six times in the past 25 million years. The very largest one, according to the statement, was a vombatiform named Diprotodon, thundered across the outback weighing more than two metric tons until at least 50,000 years ago.