Dr Tom H. Rich with the Australian tyrannosauroid fossil. | Image: Jon Augier | Source: Museum VictoriaFossils discovered by Australian scientists have provided the first ever evidence of tyrannosaur dinosaurs in the southern continents. A hip bone found at Dinosaur Cove in Victoria has been identified as belonging to a relative of the infamous Tyrannosaurus rex.The discovery of the fossil sheds new light on the evolutionary history of this group of dinosaurs and raises the crucial question of why it was only in the northern hemisphere that tyrannosaurs evolved into giant predators like Tyrannosaurus rex. The specimen suggests there may well be more tyrannosaurs on the southern continents.
“The existence of this hip bone shows that about 100 million years ago, in the Early Cretaceous period, small tyrannosaurs were found in other parts of the world. This discovery changes our understanding of the evolution of this group of dinosaurs,” said Dr Rich, Senior Curator, Vertebrate Palaeontology, Museum Victoria.
The fossil was discovered on an expedition to Dinosaur Cove led by co-authors on the Science paper, Dr Tom Rich of Museum Victoria and Dr Pat Vickers-Rich of Monash University. The fossil was later identified by the paper’s lead author Dr Roger Benson of the University of Cambridge with research supported by co-author Dr Paul Barrett from the Natural History Museum, London.
According to Dr Roger Benson of 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.”
The discovery challenges the idea held by some scientists that tyrannosaurs never made it to the southern continents.
Measuring around 30cm in length, the pubis bone, which is very distinctive of the tyrannosauroid lineage, looks like a rod with two expanded ends. One end is flattened and connects to the hip while the other is shaped like a boot. Compared with Tyrannosaurus rex, which lived about 70 million years ago at the end of the Cretaceous period, the newly identified dinosaur was about one-third its size and lived earlier during the Cretaceous, around 110 million years ago.
