A Tasmanian couple on a quiet walk down to the beach a few years ago discovered a fossil that scientists say is 250 million years old.
Bob and Penny Tyson found the fossilised remains of a dicynodont, a tusked plant-eating animal that's believed to be a distant ancestor of modern mammals.
Roughly the size of a cow, it had two tusks and a horny beak.
Queensland Museum palaeontologist Andrew Rozefelds says the dicynodont lived on every continent, including Antarctica.
The ABC reports that until now, the only specimen previously found in Australia was in Queensland almost 30 years ago.
He describes the dicynodont as a ''strange-looking beast''.
''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.''
Sitting in seaweed
Bob and Penny Tyson discovered fragments of bone while walking along the beach on the Tasman Peninsula.
Mr Tyson had been for a walk along the rocky foreshore when he found some rare amphibian skulls.
The ABC reports 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 fossilised 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,'' she told the ABC.
''It was just sitting there waiting to be knocked off.''
Early Triassic period
University of Tasmania sedimentologist Stuart Ball, who dated the fossils, says the remains are from the early Triassic period. They predate the dinosaurs by at least 30 million years.
Dr Rozefelds says scientists from places like China have been contacting him about the Tasmanian find.
''We're looking at animals that survived the Permian Triassic extinction," he said.
''Most of the animal life on the planet was destroyed, it was exterminated. Yet these animals for some reason survived that extinction event and we don't know why.''
The research team's findings have been published in the Journal of Vertebrate Palaeontology.
The ABC reports the specimens are being stored at the Tasmanian Museum and Art Gallery, but are not yet on display.