Tiny tyrannosaur made it to Australia

Posted by Emma Woollacott

Australia... where men are men, the skies are huge, and T rex is a rather cute little thing.

Yes, British and Aussie scientists have found the first ever evidence that the tyrannosaur existed in the southern continents. But - whisper it quietly - it seems it was a bit of a titch.

The team identified a 30cm hip bone found at Dinosaur Cove in Victoria as belonging to an ancestor of Tyrannosaurus rex.

The discovery sheds new light on the evolutionary history of this group of dinosaurs. But it also raises the crucial question of why it was only in the north that tyrannosaurs really piled on the pounds.

According to Dr Roger Benson of the University of Cambridge, who identified the find, "The bone is unambiguously identifiable as a tyrannosaur because these dinosaurs have very distinctive hip bones."

The discovery lays to rest the belief held by some scientists that tyrannosaurs never made it to the southern continents.

"The absence of tyrannosauroids from the southern continents was becoming more and more anomalous as representatives of other 'northern' dinosaur groups started to show up in the south," says Dr Paul Barrett, palaeontologist at London's Natural History Museum.

"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."

The bone would have come from an animal about three metres long and weighing around 80kg - similar to a human. Known as NMV P186069, the creature was much smaller than T rex, which was 12 metres long and weighed around four tonnes. It lived 40 million years earlier than T Rex, about 70 million years ago.

"It is difficult to explain why different groups succeeded in the north and the south if they originally existed in both places," says Benson.

"What we need to know now is just how diverse the early radiation of tyrannosaurs was, why they went extinct, leaving only giant-sized, short-armed species like T rex, and how successful they might have been in the southern hemisphere. We can only answer these questions with new discoveries."

The paper appears in Science.