SYDNEY, Feb. 20 (Xinhua) -- Australian paleontologists have discovered the first fossil evidence of a predatory dinosaur species that roamed the continent over 100 million years ago.
In research published on Thursday, researchers from Monash University and Museums Victoria Research Institute (MVRI) described five fossils found along Australia's southeast coast in the state of Victoria.
The fossils of theropods, a group of dinosaurs characterized by three toes and claws on each limb, included the first evidence of carcharodontosaurs in Australia.
Carcharodontosaurs were a subgroup of theropods with large skulls and teeth and small arms. Species of carcharodontosaurs included some of the largest land predators that ever existed such as the gigantosaurus.
The research found that the Australian carcharodontosaurs were much smaller than the apex predators found in South America and Africa at about 2-4 meters in length.
"The discovery of carcharodontosaurs in Australia is groundbreaking," Jake Kotevski, lead author of the study from the MVRI and Monash University, said.
The carcharodontosaurs roamed Australia between 122 and 108 million years ago during the Cretaceous period, when the continent was much further south and Victoria was positioned in the Antarctic Circle.
The researchers also discovered evidence of the megaraptoids, which measured up to seven meters in length.
Kotevski said the findings suggested that the predatory hierarchy in Cretaceous Australia was "reversed" from South America where carcharodontosaurs reached up to 13 meters in length, "towering over" megaraptoids.
The team said that the findings expand the global understanding of the evolutionary history of theropods.
Thomas Rich, senior curator of vertebrate paleontology at the MVRI, said the discoveries "offer compelling evidence" of faunal interchange between Australia and South America via Antarctica during the early Cretaceous. ■
