Washington: Tyrannosaurus rex, once believed to have only roamed the Earth north of the Equator, may also have lived in the southern hemisphere, paleontologists said Thursday.
In a study, the researchers said they had found a hip bone belonging to a T. rex ancestor in Australia, shedding new light on the evolutionary history of this group of dinosaurs.
The discovery in Dinosaur Cove in Victoria, Australia, laid to rest the belief that tyrannosaurs never made it to the southern continents, said the team from Cambridge, London and Melbourne.
"This is an exciting discovery because tyrannosaur fossils had only ever been found in the northern hemisphere before and some scientists thought tyrannosaurs never made it down south," said Roger Benson, from the Department of Earth Sciences at the University of Cambridge, who identified the find.
"The bone is unambiguously identifiable as a tyrannosaur because these dinosaurs have very distinctive hip bones," he said, of the study released Thursday in the journal Science.
"Although we only have one bone, it shows that 110 million years ago small tyrannosaurs like ours might have been found worldwide. This find has major significance for our knowledge of how this group of dinosaurs evolved."
The 30 centimeter- (11.8-inch-) long pubis bone resembles a rod with two expanded ends, one of which is flattened and connects to the hip, while the other looks like a boot.
Scientist said the find will lead them to rewrite their view of the dinosaur's evolutionary path.
"This find shows that tyrannosauroids were able to reach these areas early in their evolutionary history and also hints at the possibility that others remain to be discovered in Africa, South America and India," said Paul Barrett, paleontologist at London's Natural History Museum.
Scientists said the T. rex ancestor would have had the same distinctive large head and small arms, but would have been far smaller, measuring only about three meters (nine feet) long and weighing around 80 kilograms (176 pounds). It lived during the Cretaceous period around 110 million years ago.
In contrast T. rex, which lived about 70 million years ago at the end of Cretaceous period, measured about 12 meters (39 feet) in length and weighed around four tonnes.
First Published: Friday, March 26, 2010, 10:48