• Crop from an illustration comparing size of Australian marsupials. Credit: Karen Black/UNSW (Supplied)Source: Supplied
It’s the first species yielded by ‘New Riversleigh’ - an exciting fossil site in remote north-western Queensland.
Signe Dean

26 Jul 2016 - 2:04 PM  UPDATED 26 Jul 2016 - 2:04 PM

Five million years ago, this toothy marsupial would have been terrorising the local residents of increasingly dry Australian forests. Nearly double the size of its distant cousin the Tasmanian devil, Whollydooleya tomnpatrichorum was a hypercarnivore, meaning its diet consisted of at least 70 per cent meat.

“[It] had very powerful teeth capable of killing and slicing up the largest animals of its day,” says UNSW Professor Mike Archer, lead author of a study describing this discovery in Memoirs of Museum Victoria.

The formal description of this new flesh-eating marsupial species is based on a fossil molar tooth found in ‘New Riversleigh’, an exciting new Australian fossil site. 

Deemed one of the four most important fossil deposits in the world, Riversleigh became a World Heritage area in 1994. Now, there’s even more reason to treasure this part of Australia. 

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“In 2012, we discovered a whole new fossil field that lies beyond the internationally famous Riversleigh World Heritage Area fossil deposits in north-western Queensland,” says Archer.

“This exciting new area – New Riversleigh – was detected by remote sensing using satellite data.”

“While we’ve been making discoveries and interpreting the messages in the rocks of the Riversleigh World Heritage Area for 40 years, we’ve only just started to explore the treasures of New Riversleigh,” says Archer.

Researchers have already established some key differences between the two areas. Firstly, the new fossil site shows insights from Late Miocene between 12 and 5 million years ago, a time span not well represented in the ‘Old Riversleigh’ fossils.

“This was a critical time when at least northern Australian environments were transforming from rainforests to cool open forests and woodlands,” explains Archer.

The adaptations Aussie animals rapidly evolved have led to the critters we see today in the arid and semiarid parts of our continent.

The tooth of W. tomnpatrichorum was one of the first items discovered in a particularly rich fossil site in the area, which team member Phil Creaser named Whollydooley Hill to honour his partner Genevieve Dooley.

Researchers are certain that many discoveries will ensue from the fossils gathered there.

“The small to medium-size mammals from the New Riversleigh deposits will reveal a great deal about how Australia’s inland environments and animals changed .. [at] a critical time when increasing dryness ultimately led to the Ice Ages of the Pleistocene,” says team member Dr Karen Black, UNSW palaeontology researcher.

The team has been systematically exploring New Riversleigh since 2013, with help from ARC funding and a National Geographic Society grant.

“As to what we expect to find, who knows - that’s the delight of palaeontology, the serendipity factor,” says Archer. “Until we look inside those rocks, we often have no idea what to expect, which makes every expedition as exciting as every previous one!” 

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