SYDNEY, April 21 (UPI) -- Australian paleontologists say they've discovered fossils of two previously unknown species of extinct marsupials with teeth unlike those of any other mammal.
Scientists at the University of New South Wales say they believe the strange hammer-like teeth were used to crack open the shells of prehistoric snails, the animals' main diet.
The specimen they first investigated "appeared so odd that initially none of the team could work out exactly what it was," researcher Rick Arena told LiveScience.com. "The teeth were unlike any we had ever seen before in a mammal, so we were scratching our heads."
The unusual teeth might have been used like ball-peen hammers to crack open hard objects, researchers say, and although no known modern mammals possess such teeth, remarkably similar teeth are found in some lizards in eastern Australian rain forests that use them to crush snail shells.
"We are not sure exactly why the hammer-toothed, snail-eating marsupials became extinct," Arena said. "However, they seem to have died out sometime after 10 million years ago, when the Australian continent began to respond to rapid climate change.
"During this time, once expansive regions of forest retracted toward the coast while more arid habitats expanded," he said. "It is possible these conditions began to favor lizards over mammals and the mammals lost out."
