Australasian Science: Australia's authority on science since 1938

Devil’s Bigger Extinct Cousin Discovered

A new species of extinct carnivorous marsupial has been identified from a fossil discovered in north-western Queensland.

Weighing in it 20–25 kg, Whollydooleya tomnpatrichorum is a distant cousin of Australia’s largest living carnivorous marsupial, the Tasmanian Devil – and about twice as large.

A description of the new marsupial, based on its fossil molar tooth, has been published in the Memoirs of Museum Victoria. “W. tomnpatrichorum had very powerful teeth capable of killing and slicing up the largest animals of its day,” says the study’s lead author Prof Mike Archer of the University of NSW.

During the late Miocene period 5–12 million years ago, Australia began to dry out and the megafauna began to evolve. However, the arid conditions were largely unsuitable for fossil preservation, making this period one of the most mysterious and least well-understood.

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

The New Riversleigh deposit provides clues about how the environment was changing 5–12 million years ago, when increasing dryness ultimately led to the ice ages of the Pleistocene. For example, it contains the first signs of wind-blown sand grains, which are absent from the older Riversleigh World Heritage deposits.

Furthermore, the teeth of other animals in this deposit are unusual for Riversleigh because they are more worn down. This suggests that the animals in the late Miocene were eating tougher, more drought-resistant plants, and there was more abrasive dust in the environment.

“New Riversleigh is producing the remains of a bevy of strange new small- to medium-sized creatures,” Archer says. “These new discoveries are starting to fill in a large hole in our understanding about how Australia’s land animals transformed from being small denizens of its ancient wet forests to huge survivors on the second most arid continent on Earth.”

Archer says that Whollydooleya “represented a distinctive subgroup of hypercarnivores that did not survive into the modern world. Climate change can be a merciless eliminator of the mightiest of mammals.”