Fossilized remains of a ceratosaurian dinosaur discovered in Australia in 2006 is the first evidence that a major group of meat-eating dinosaurs roamed the eastern part of the supercontinent Gondwana some 125 million years ago.
An artist’s impression of the ceratosaur discovered in Australia (Brian Choo)
The ceratosaur discovery, published in the journal Naturwissenschaften, improves understanding of the distribution and evolution of dinosaurs in eastern Gondwana, the supercontinent of which Australia was once a part.
“Until now, this group of dinosaurs has been strangely absent from Australia, but now at last we know they were here – confirming their global distribution,” said Dr. Erich Fitzgerald, a paleontologist at the Museum Victoria and a lead author of the discovery paper.
Carnivorous creatures one to two meters in height, ceratosaurs have been found in both the northern and southern hemispheres.
“This discovery joins other widespread carnivorous dinosaurs now known to have lived in Australia – tyrannosaurs, spinosaurids and allosaurs,” Dr. Fitzgerald explained.
The discovery also lends weight to the idea that Australia was once a melting-pot of dinosaur diversity.
“It had been thought that isolation played a lead role in the formation of Australia’s dinosaur fauna,” Dr. Fitzgerald said. “But the ceratosaur and other new discoveries show that several dinosaur groups were here. These dinosaur lineages date back to the Jurassic, 170 million years ago, when dinosaurs could walk between any two continents.”
Fossilized ankle bone of the ceratosaur found at San Remo in Victoria (B. Healley)
“So perhaps Australia’s dinosaurs represent those groups that achieved global distributions early in their history, before the continents split up. It’s the old age of their lineages – not continental isolation – which explains these dinosaurs’ presence in Australia,” he added.
The ceratosaur fossil, an ankle bone about 6 cm wide was found near the seaside town of San Remo, 87 kilometres southeast of Melbourne.
“Apart from Antarctica, Australia has the world’s most poorly known dinosaur record – one of the last frontiers for dinosaur hunters,” Dr. Fitzgerald concluded. “Although discovery rates are accelerating, we’re still in the early days of exploring which dinosaurs actually lived here. Each discovery has the potential to change what we know.”
