Paleontologists have identified a giant wombat-like marsupial that lived 25 million years ago (oligocene epoch) in what is now Australia. Named Mukupirna nambensisThe prehistoric creature was at least five times larger than living wombats and so different that researchers had to create a new family to accommodate it.
An artist’s impression of Mukupirna nambensis living in central Australia that was much greener 25 million years ago. Image credit: Peter Schouten.
The fossilized remains of Mukupirna nambensis – a partial skull and most of the skeleton – were found in 1973 on the clay floor of Lake Pinpa in northeast South Australia by an expedition led by Dr. Richard Tedford of the American Museum of Natural History.
“It was an extremely fortuitous discovery because in most years the surface of this dry lake is covered by sand washed away or washed away by the surrounding hills,” said Professor Mike Archer, a scientist at the PANGEA Research Center at the University of New Wales. from the south. .
“But due to the rare environmental conditions before our arrival that year, the fossil-rich clay deposits were left fully exposed to view. And this unexpected sight was impressive. “
“On the surface, and just below, we find skulls, teeth, bones and, in some cases, articulated skeletons of many types of new and exotic mammals. In addition, there were the teeth of extinct lung fish, skeletons of bony fish, and bones of many types of waterfowl, including flamingos and ducks. ”
“These animals ranged from tiny mouse-sized carnivorous marsupials to Mukupirna nambensis it was similar in size to a live black bear. It was an incredibly rich fossil deposit full of extinct animals that we had never seen before. “
Mukupirna nambensis It weighed between 143 and 171 kg, similar in size to a black bear, and was probably a strong digger.
An analysis of evolutionary relationships shows that the ancient animal is more closely related to wombats, but has several unique characteristics.
“Mukupirna nambensis It was clearly an impressive and powerful beast, at least three times larger than modern wombats, “said Dr. Robin Beck, a researcher at the University of Salford.
“He probably lived in an open forest environment with no grass, and developed teeth that would have allowed him to feed on sedges, roots, and tubers that he could have dug with his powerful front legs.”
“Mukupirna nambensis it reveals a fascinating mix of features and provides evidence of a close link between wombats and an extinct group of marsupials called wynyardiids, “said Dr. Pip Brewer, a scientist in the Department of Earth Sciences at the Natural History Museum, London.
“It suggests that adaptations to dig for food may have existed in the earliest members of the wombat family and likely led to their eventual survival to this day.”
“Although previously suggested, it had not been possible to prove this, as the oldest fossil wombats discovered are only known from teeth and some skull fragments.”
The team observed how body size has evolved in vombatiforms, which is the group that includes Mukupirna nambensis, wombats, koalas and their fossil relatives, and showed that body weights of 100 kg or more evolved at least six times in the past 25 million years.
The largest known vombatifom was Diprotodon, which weighed over 2 tons and survived until approximately 50,000 years ago.
“Mukupirna nambensis it is one of the best-preserved marsupials we know of at this time in Australia, ”said Dr. Beck.
“It tells us a lot about the evolution of wombats, koalas and their families. Remarkable for its large size, this was clearly an impressive and powerful beast. “
“The description of this new family adds a great new piece to the puzzle about the diversity of ancient and often very strange marsupials that preceded those who rule the continent today,” said Dr. Julien Louys, a researcher at the Center. Research Institute for Human Evolution at Griffith University.
The study was published in the journal. Scientific reports.
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RMD Beck et al. 2020. A new family of diprotodontian marsupials from the late Oligocene of Australia and the evolution of wombats, koalas and their relatives (Vombatiformes). Science representative 10, 9741; doi: 10.1038 / s41598-020-66425-8
