Mukupirna means "big bones" in Dieri and Malyangapa language, and is the name of a 150kg prehistoric wombat-like marsupial found encased in clay on a dry salt lake floor. It has been called out as being one of the best-preserved marsupials of its time.
A part of the skull, and most of the skeleton, was a part of a recent study to understand the mammal better. However, it was found in South Australia's Lake Pinpa back in 1973 by a team of international scientists including UNSW Science Professor Mike Archer.
"It was an extremely serendipitous discovery because in most years the surface of this dry lake is covered by sands blown or washed in from the surrounding hills," said Professor Archer.
"But because of rare environmental conditions prior to our arrival that year, the fossil-rich clay deposits were fully exposed to view. And this unexpected view was breathtaking."
Professor Archer said the found full skeletons of "many new and exotic kinds of mammals."
"These animals ranged from tiny carnivorous marsupials about the size of a mouse right up to Mukupirna, which was similar in size to a living black bear. It was an amazingly rich fossil deposit full of extinct animals that we'd never seen before."
One of these was the Mukupirna, at least three times the size of a modern-day wombat.
"We found it by probing the dry flat surface of the Lake with a thin metal pole, like acupuncturing the skin of Mother Earth," said Professor Archer.
"We only excavated downwards into the clay if the pole contacted something hard below the surface – and in this case it turned out to be the articulated skeleton of a most mysterious new creature.
The recent study has revealed new secrets about Mukupirna, which has been dubbed "gentle giant". Its teeth show it was a herbivore, feeding on roots and tubers, and it was likely to have been a "scratch-digger" as opposed to a burrower like modern wombats.
The scientists looked at how body size has evolved in Mukupirna, wombats, koalas and their relatives, known as vombatifom marsupials. They saw those who weighed 100 kg or more evolved at least six times over the last 25 million years. The largest known vombatifom marsupial was the 50,000-year-old Diprotodon, weighing in at over 2 tonnes.