The modern koala is about three feet tall and weighs about 50 pounds with claws and teeth, fluffy ears and a fluffy white pouch. You could cuddle one – experts suggest they’d prefer if you didn’t – but you wouldn’t want to carry it around all day.
Now imagine that same koala, or one very similar, weighs a much more manageable (and potentially cuter) six pounds.
Researchers from Flinders University in Adelaide, Australia, believe that such a creature, called Lumakoala blackae, once made its home in the country’s Northern Territory some 25 million years ago, and most likely spent its days snacking on tender leaves and the occasional insect.
Their research, based on the discovery of fossilized molars at the Pwerte Marnte Marnte fossil site in the Australian outback, was published this month in the journal Scientific Reports.
It is often wrongly thought that marsupials only live in Australia. While Australia has an impressive array of particularly charismatic examples – platypuses, Tasmanian devils, kangaroos, koalas, wombats, wallabies and bandicoots, to name a few – these make up roughly 70 percent of the world’s population, with the remaining 30 percent comes from the world population. America.
Sometime between 65 and 50 million years ago, Australian marsupials, known as diprotodontians, set out on a different evolutionary track than marsupials elsewhere in the world. The details of exactly how this happened are unclear: There is, researchers note, a “gap of about 30 million years” in the fossil record that obscured the first half of diprotodontic evolution, tens of millions of years ago, when continental boundaries were completely different from those of today.
This stealthy, cat-sized koala could be the missing link, Arthur Crichton, a PhD student at Flinders University who led the study, said in a statement.
“It was suggested in the past that the enigmatic Thylacotinga and Chulpasia” – two other species of ancient marsupials – “could be closely related to marsupials from South America,” he said.
“However, the discovery of Lumakoala suggests that Thylacotinga and Chulpasia could actually be early relatives of Australian herbivorous marsupials such as koalas, wombats, kangaroos and possums.”
The fossilized remains found at the site near Alice Springs were previously thought to resemble some of those previously found in South America, said Robin Beck, who co-authored the paper with Mr Crichton research.
Instead, Dr. Beck, also in a statement: “These Tingamarran marsupials are less mysterious than we thought, and now appear to be ancient relatives of younger, more well-known groups such as koalas.” Tingamarra is an extinct genus of small mammals from Australia.
He added: “It shows how finding new fossils like Lumakoala, even if it’s just a few teeth, can revolutionize our understanding of the history of life on Earth.”
In fact, koalas of all sizes appear to have spread across prehistoric Australia, Gavin Prideaux, a paleontologist at Flinders University and co-author of the study, said in a statement.
“So far there are no reports of koalas ever being in the Northern Territory; now there are three different species at one fossil site,” said Dr. Prideaux. “Although we have only one koala species today, we now know that there were at least seven from the late Oligocene – along with giant koala-like marsupials called ilariids,” he said, referring to a period about 30 million years ago .
The smallest koalas are especially attractive. But their largest relatives, the ilariids, could have been quite a terrifying proposition, weighing an estimated 440 pounds, about the size of a piano.