Australasian Science: Australia's authority on science since 1938

Ancient Swingers

Nimbadon skulls representing developmental ages

AL90 has produced dozens of exceptionally well-preserved Nimbadon skulls representing developmental ages from pouch-young (left) to mature adults (right). Credit: K.Black/H. Godthelp

By Karen Black

Skeletons unearthed in a fossil cave in north-western Queensland reveal that 15 million years ago Australia’s ancient forest treetops were home to mobs of 70 kg wombat-like marsupials – the largest tree-dwelling marsupial herbivores to have ever lived.

Karen Black is an Australian Research Council Postdoctoral Fellow in the School of Biological, Earth and Environmental Sciences at the University of NSW.

The full text of this article can be purchased from Informit.

Entombed in a fossil cave in remote north-western Queensland lie the skeletons of hundreds of bizarre as well as familiar extinct creatures that occupied the ancient forests of Australia 15 million years ago. The World Heritage-listed Riversleigh cave known as AL90 is providing a unique window into our ancient past at a critical time in Australia’s history when our continent began its transformation from a land dominated by lush forests to the cooler, drier, climatically unpredictable habitats we know today. It was a time of significant faunal turnover that saw the extinction of a range of archaic mammal groups and the emergence of Australia’s iconic and globally distinctive marsupial fauna.

One of the greatest success stories of Australia’s climatic transformation was the spectacular radiation of kangaroos, with 70 living species that have evolved to occupy a wide variety of habitats ranging from deserts to wet tropical rainforests. Among their ranks are Australia’s largest living terrestrial (e.g. red kangaroo) and arboreal (e.g. Bennett’s tree kangaroo) mammals, with large males of both species clocking in at 85 kg and 14 kg, respectively.

Prior to about 30,000 years ago, the largest mammals in Australian ecosystems were not kangaroos but a group of wombat-like herbivores called diprotodontoids. These marsupials are common and widespread in fossil...

The full text of this article can be purchased from Informit.