Ancient Kangaroo Teeth Reveal Australia’s Tropical Past

Denise Chow, LiveScience Staff Writer

Date: 12 June 2013 Time: 05:01 PM ET

The fossilized teeth of ancient marsupials that roamed through northeastern Australia roughly 2.5 million years ago suggest these animals fed on leafy plants in a much more lush and tropical environment than was previously thought, according to a new study.

A chemical analysis of tooth enamel from extinct marsupials in Queensland, the second-largest state in Australia, revealed clues about the diet and habits of these ancient mammals. The findings indicate that this region of Australia, which today is made up mostly of arid grasslands, was once covered in tropical forests, said Shaena Montanari, a comparative biologist at the American Museum of Natural History in New York and lead author of the new study.

"It was probably a wetter and moister environment," Montanari told LiveScience. "Marsupials have been around in Australia for tens of millions of years, but these fossils help us understand how their diets changed with the environments."

Montanari and her colleagues studied fossilized teeth from a variety of early marsupials, including two that are in the same genus as present-day kangaroos and wallabies. The fossils dated back to the early- to mid-Pliocene epoch, which extends from 2.5 million to 5 million years ago, but most of the animals in the study went extinct approximately 50,000 years ago, Montanari said.

"Some of them would have looked similar to modern kangaroos, but were much larger," she explained. "They probably looked like giant kangaroos with longer noses. One of the animals we looked at, called Euryzygoma, would have looked quite different from typical Australian megafauna. People sometimes call it a giant wombat, but it was much larger and looked very different."

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