World’s Oldest Carcharodontosaur Fossils In Australia Rewrite Dinosaur Evolution

Conny Waters – MessageToEagle.com – Recent groundbreaking research has revealed a significant discovery: fossils of the world’s oldest known megaraptorid and the first evidence of carcharodontosaurs in Australia have been discovered by scientists. These findings are reshaping our understanding of theropod dinosaur evolution, highlighting a unique predator hierarchy during the Cretaceous period in Australia.

Cretaceous Australia Landscape. Credit: Jonathan Metzger, Museums Victoria

The study, conducted by Jake Kotevski from Monash University School of Biological Sciences and the Museums Victoria Research Institute, details five theropod fossils found along Victoria’s coastline. These fossils were excavated from two geological formations: the upper Strzelecki Group (Bunurong/Boonwurrung Country, Bass Coast) dating back 121.4-118 million years ago, and the Eumeralla Formation (Eastern Marr Country, Otway Coast) from 113-108 million years ago.

These discoveries provide valuable insights into Victoria’s ancient ecosystem. It was characterized by large megaraptorids measuring 6–7 meters long, coexisting with smaller carcharodontosaurs ranging from 2–4 meters long and nimble unenlagiines or ‘southern raptors’ about one meter in length.

“The discovery of carcharodontosaurs in Australia is groundbreaking,” says Kotevski.

“It’s fascinating to see how Victoria’s predator hierarchy diverged from South America, where carcharodontosaurs reached Tyrannosaurus rex-like sizes up to 13 metres, towering over megaraptorids. Here, the roles were reversed, highlighting the uniqueness of Australia’s Cretaceous ecosystem.”

Two of the fossils represent the oldest known megaraptorids globally, expanding our understanding of the group’s evolutionary history and suggesting Australia’s theropod fauna played a pivotal role in Gondwanan ecosystems.

Dr Thomas Rich, senior curator of vertebrate palaeontology at Museums Victoria Research Institute, explains, “The findings not only expand Australia’s theropod fossil record but offer compelling evidence of faunal interchange between Australia and South America through Antarctica during the Early Cretaceous. The findings also challenge previous assumptions about body-size hierarchies in Gondwanan predator ecosystems, highlighting Victoria’s unique Cretaceous fauna.”

Jake Kotevski, lead author and Tim Ziegler, collection manager, vertebrate paleontology, Museums Victoria Research Institute. Photographer: Nadir Kinani Source: Museums Victoria

The research demonstrates the vital role of museum collections in building on scientific knowledge and fostering significant scientific breakthroughs. “Museum collections are crucial to advancing our understanding of prehistoric life,” says Tim Ziegler, vertebrate paleontology collection manager at Museums Victoria Research Institute. “Specimens preserved in the State Collection for decades – unidentifiable until now – are providing new insights into the evolution of dinosaur ecosystems.”

Between 2022 and 2023, three fossils were discovered and initially identified by Melissa Lowery, a dedicated volunteer at Museums Victoria.

This finding highlights the crucial contribution of community members working alongside experienced researchers to enhance our understanding of Australia’s Cretaceous period. Kotevski and the team continue their exploration of significant fossil sites, including locations where large megaraptorid fossils have been found.

These efforts are paving new research avenues for the Dinosaur Dreaming project, which has already achieved notable results. Since its inception, the project has uncovered over 10,000 fossil bones and teeth from at least seven different dinosaurs as well as groups of mammals, birds, pterosaurs, plesiosaurs, turtles, and fishes.

The study was published in the Journal of Vertebrate Paleontology

Written by Conny Waters – MessageToEagle.com – AncientPages.com Staff Writer