University of New South Wales paleontologist Mike Archer has been visiting Riversleigh, a 600-square-mile fossil bed in northeastern Australia, for decades. Each year he brings back more evidence of countless bizarre animals that roamed the outback between 10 million and 20 million years ago. So far, Archer has found remains of carnivorous kangaroos, marsupial lions, giant snakes, tree-climbing crocodiles, miniature tyrannosaurs, prehistoric lungfish, and the largest-ever bird, a 10-foot-tall 1,000-pounder that he likes to call the "demon duck of doom."
Archer has come to realize that the proliferation of oddball animals offers a unique showcase of the long-term biological effects of climate change. Because of the continent's physical isolation, "the Australian story is probably the only one in the world that through history can be read as a pure record," he says. The record shows, for example, that in a world unmarred by humans, global warming actually increases biodiversity. "Because of Australia's isolation it becomes a tool to make predictions about what kinds of things are likely to happen during climate change," Archer says.
Now That's Odd
The Skull of Ekaltadeta ima, a 23-million-year-old carnivorous kangaroo (left), suggests that it had powerful jaw muscles. With its long incisors and buzz-saw-shaped premolars, it could have bitten through just about any small animal. Archer's "demon duck of doom" (right) would have stood 10 feet tall and weighed 1,000 pounds.
Images courtesy of Ross Arnett, University of New South Wales.