A new fossil discovery may rewrite Australia’s Cretaceous Period evolutionary history. Paleontologists led by Museums Victoria Research Institute and Monash University uncovered what they believe is the oldest known megaraptorid and possibly the first known evidence of carcharodontosaurs from Australia’s Victoria Coast.
According to the study published in the Journal of Vertebrate Paleontology, these findings could change what science has known about predatory hierarchy in Cretaceous Australia.
“The discovery of carcharodontosaurs in Australia is groundbreaking,” said Jake Kotevski a Ph.D. student with Museums Victoria Research Institute and Monash University, in a press release.
Carcharodontosaurs vs. Megaraptorids
During the Cretaceous Period, Australia was part of the supercontinent Gondwanan, along with Antarctica, New Zealand, Africa, India, and South America, among others. During this time, Gondwanan began breaking up.
As the continent broke apart, dinosaur evolution changed and diverged with it. In South America, for example, theropods like carcharodontosaurs dominated the predator hierarchy above megaraptorids.
According to the study, in South America, carcharodontosaurs reached the size of the Tyrannosaurus rex, about 40 feet, while megaraptorids were just under 30 feet.
While carcharodontosaurs may have been a South American Cretaceous apex predator, this can not be said for carcharodontosaurs living in Australia at the time.
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A Groundbreaking Discovery
The new findings from Australia describe five new theropod fossils uncovered along Victoria, Australia’s coast, an area known as the upper Strzelecki Group — Bunurong/Boonwurrung Country, Bass Coast, and the Eumeralla Formation Eastern Marr Country, Otway Coast.
Among the uncovered fossils were megaraptorids and carcharodontosaurs. However, the megaraptorids were about 20 feet long, while the carcharodontosaurs were about 6 feet to 13 feet long.
This discovery indicates that in Cretaceous Australia, megaraptorids likely dominated the predatory hierarchy over carcharodontosaurs.
“It’s fascinating to see how Victoria’s predator hierarchy diverged from South America, where carcharodontosaurs reached Tyrannosaurus rex-like sizes up to 13 meters [about 42 feet], towering over megaraptorids. Here, the roles were reversed, highlighting the uniqueness of Australia’s Cretaceous ecosystem,” said Kotevski in the press release.
According to the study, two of the fossils are some of the oldest megaraptorids known around the world. These findings help give researchers a better understanding of megaraptorid’s evolutionary history and suggest that these theropods played a crucial role in the ecosystems of Gondwanan.
Help from Museums
According to the study authors, these findings highlight the critical role museums play in helping to unearth new discoveries and improve scientific knowledge.
“Museum collections are crucial to advancing our understanding of prehistoric life,” Tim Ziegler, vertebrate paleontology collection manager at Museums Victoria Research Institute, said in a press release. “Specimens preserved in the State Collection for decades – unidentifiable until now – are providing new insights into the evolution of dinosaur ecosystems.”
The authors also note that three of the fossils in this study were uncovered by Melissa Lowery, a volunteer at Museums Victoria. Lowery’s contributions highlight how community members can help advance scientific research.
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A graduate of UW-Whitewater, Monica Cull wrote for several organizations, including one that focused on bees and the natural world, before coming to Discover Magazine. Her current work also appears on her travel blog and Common State Magazine. Her love of science came from watching PBS shows as a kid with her mom and spending too much time binging Doctor Who.
