Unusual carnivorous dinosaurs called noasaurids lived in Australia

Most noasaurids stretched no longer than seven feet and weighed less than 50 pounds. Photo by Tom Brougham

Jan. 30 (UPI) -- New fossil evidence suggests an unusual group of predatory dinosaurs called noasaurids lived in Australia during the middle to late Cretaceous Period.

Noasaurids were small-bodied carnivores that walked on two legs and were characterized by a variety of unique facial features. The largest of the diminutive meat eaters stretched no more than seven feet in length. Most weighed less than 50 pounds.

Noasaurid fossils had previously been recovered from all of the landmasses that made up the southern supercontinent of Gondwana, except Australia. Now scientists can be sure the rare group of theropod dinosaurs lived Down Under too.

After identifying a single neck bone, recovered from an opal mine in New South Wales, as belonging to a noasaurid dinosaur, paleontologists reexamined a fossil unearthed along the south coast of Victoria. It too belonged to a noasaurid.

Researchers described their analysis of the fossils this week in the journal Scientific Reports.

"It was assumed that noasaurids must have lived in Australia because their fossils have been found on other southern continents that, like Australia, were once part of the Gondwanan supercontinent," lead researcher, Tom Brougham of the Palaeoscience Research Center, said in a press release. "These recent fossil finds demonstrate for the first time that noasaurids once roamed across Australia. Discoveries of theropods are rare in Australia, so every little find we make reveals important details about our unique dinosaur fauna."

After acquiring the neck bone recovered from the mine, near the outback town of Lightning Ridge, scientists compared it to the neck bones of a range of carnivorous dinosaurs known to have inhabited Australia. It didn't look like any other of the others. Instead, researchers found it most closely matched the neck bones of noasaurids.

"This prompted us to re-examine an ankle bone of a dinosaur that was discovered in Victoria in 2012, about 20 million years older than the Lightning Ridge bone, and using the same methods we concluded that this also belonged to a noasaurid," Brougham said. "In addition, this ankle bone is approximately the same age, or perhaps even older, than the oldest known noasaurids, which come from South America."

Noasaurids were similar in size -- and likely in hunting style -- to dromaeosaurids, or raptors. But whereas paleontologists have unearthed raptors on nearly every major landmass on Earth, noasaurids had, until now, been found only in South America, Africa, Madagascar and India.

Now, scientists know the unusual predators lived in Australia, too, suggesting they had spread across the entirety of Gondwana before it began to break apart at the end of the Cretaceous.