Kangaroo teeth redraft ancient Queensland
A STUDY OF ANCIENT kangaroo teeth from south-eastern Queensland suggests that 2.5–5 million years ago, the region was not arid as previously thought.
Experts analysed fossil teeth belonging to three kangaroos and a giant, wombat-like diprotodon, all of which lived during the Pliocene, when Queensland was thought to have become increasingly arid.
Chemicals in the teeth of the ancient marsupials, however, suggest the region was a mosaic of tropical forests, wetlands and grasslands.
“In this study, we sought to characterise an ancient environment in Australia like never before,” says lead researcher Dr Shaena Montanari, a biologist at the American Museum of Natural History in New York, USA.
Pliocene Queensland a tropical environment
Shaena’s team anlaysed chemicals in the tooth enamel of the extinct marsupials to glean clues about their diet. The findings suggested that they ate similar food to the tropics-dwelling kangaroos of today.
The results, published in the journal PLoS ONE, also reveal that animals living in this environment filled different roles in the ecosystem and ate different kinds of food. This suggests that the region was once varied enough to support a diverse ecosystem of large animals, rather than the fewer, smaller animals found in very arid environments.
Shining light on these ancient ecosystems is crucial to understand where today’s marsupials came from. “It was in the Pliocene that modern species such as the agile wallaby (Macropus agilis) made their first appearances in the fossil record,” Shaena says.
Roo provides clues on megafauna
With more information on the environments in which large Australian animals thrived during the Pliocene, researchers are closer to discovering what sent them some of them to extinction, she adds.
Dr Karen Black, a palaeontologist at the University of New South Wales in Sydney, agrees. “Studies such as this allow us to gain a greater understanding of the role of extinct fauna such as the ‘giant wombat’ in past ecosystems and why they became extinct,” she says.
Karen adds that a clear picture of the ecosystem at this time is “of particular importance in understanding the driving forces behind the evolution of Australia’s modern ecosystems, and how these ecosystems will continue to evolve under future climate change scenarios.”
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