Mammals' Tusked Ancestor Roamed Tasmania

Scientists say rare fossils found in Tasmania's south-east prove that an ancient species of prehistoric animal did exist throughout Australia.

The dicynodont was an early ancestor of modern-day mammals and lived about 250 million years ago. Roughly the size of a cow, the plant-eating animal had two tusks and a horny beak.

Queensland Museum palaeontologist Andrew Rozefelds said they lived on every continent, including Antarctica. But until now, the only Australian specimen was found in Queensland almost 30 years ago. He said it is surprising more remains have not been found, given the animal's size.

"There must be more material out there to be found," he said. "Obviously we'd love to find more, because at the moment, [of] this entire group of animals called dicynodonts, there's only about four bones known from Australia. We've got better fossil records from Antarctica for these animals than we have for Australia."

He describes the dicynodont as a bizarre-looking creature.

"They're a strange-looking beast," he said. "They had tusks at the front of their skull, which makes you think maybe they were a carnivore but in fact they were a plant eater. They had slightly splayed legs, so their posture was quite different to say some of the modern mammals you see and they're very, very distantly related to modern mammals."

Bob and Penny Tyson discovered the bone fragments a few years ago when they were walking along the beach on the Tasman Peninsula. Mr Tyson had gone for a walk along the rocky foreshore when he found some rare amphibian skulls. He took a few photos of the fossils and then went back to the place where they were staying to get his wife.

She started looking closer to the waterline and found a fossilized tusk, right on the low tide mark, sitting in seaweed.

"It was sitting on top of the rock surface, so all the surrounding rock had been worn away," said Mrs Tyson. "It was just sitting there waiting to be knocked off."

University of Tasmania sedimentologist Dr Stuart Ball, who dated the fossils, said the remains are from the early Triassic period. They predate the dinosaurs by at least 30 million years. He said it is likely floods washed the animals' remains into billabongs, which is why only fragments have turned up.

Rozefelds said the latest find proves that not only did dicynodonts exist in Australia, but they may have survived here longer than anywhere else in the world. He said scientists from places like China have been contacting him about the Tasmanian find.

Read more at Discovery News