Scientists discover a new dinosaur from Argentina with a crocodile bone in its mouth
Andrew Zinin
lead editor
Scientists have discovered a new dinosaur from Argentina with powerful claws, feasting on an ancient crocodile bone.
The new find was possibly 23 feet (7 meters) long and hailed from a mysterious group of dinosaurs called megaraptorans. They prowled across what's now South America, Australia and parts of Asia, splitting off into different species over millions of years.
Megaraptorans were known for their stretched-out skulls and "huge and very powerful claws," said Lucio Ibiricu with the Patagonian Institute of Geology and Paleontology, who was part of the discovery team.
But it's not yet clear how these creatures hunted and where they fall on the evolutionary timeline—mainly because the fossils recovered so far were incomplete.
In a new study, researchers said they uncovered part of a skull as well as arm, leg and tail bones from the Lago Colhué Huapi rock formation in Patagonia. They noticed unique features in the bones that made them realize this could be a new species.
This latest member of the megaraptoran clan named Joaquinraptor casali "fills a major gap by providing one of the most complete skeletons yet," Federico Agnolin with the Argentine Museum of Natural Science Bernardino Rivadavia said in an email. Agnolin was not involved with the research, which Tuesday in the journal Nature Communications.
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This undated image provided shows researcher Marcelo Luna holding a claw belonging to a type of dinosaur called a megaraptoran in Chubut, Argentina. Credit: Marcelo Luna via AP -
This rendering shows what a newly discovered dinosaur called Joaquinraptor casali may have looked like, with the bones that were uncovered in blue. Credit: T.K. Robinson, Andrew McAfee via AP
The creature likely lived between 66 and 70 million years ago—close to the time dinosaurs went extinct—and was at least 19 years old when it died, though scientists don't know what killed it.
The front leg bone pressed against its jaws—belonging to an ancient relative of crocodiles—could yield some clues to its diet and whether it was the top predator on the humid prehistoric flood plains.
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This undated photo provide by Marcelo Luna shows the bones of a newly-discovered dinosaur with powerful claws in Chubut, Argentina. Credit: Marcelo Luna via AP -
This undated photo provided by Marcelo Luna shows an aerial view of the site where bones belonging to a new kind of dinosaur with big claws were found in Chubut, Argentina. Credit: Marcelo Luna via AP
Ibiricu named the new dinosaur in memory of his son Joaquin. While Joaquin was very young and hadn't yet developed a fascination with dinosaurs, Ibiricu still thinks he would have appreciated being named after one.
"All children love dinosaurs so he would probably be a fan too," he said.
More information: Lucio Ibiricu, Latest Cretaceous megaraptorid theropod dinosaur sheds light on megaraptoran evolution and palaeobiology, Nature Communications (2025). .
Journal information: Nature Communications
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