New dinosaur discovered in Argentina with a crocodile leg in its jaws: “More than one way to be a top predator”

Scientists have discovered a new dinosaur from Argentina with powerful claws, feasting on an ancient crocodile bone.

The new find was possibly 23 feet 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.

“Megaraptorans are among the least understood dinosaurs of all,” Ibiricu told the Reuters news agency.

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 was published Tuesday in the journal Nature Communications.

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.

Study co-author Matt Lamanna told Reuters that unlike the T. rex, which had massive teeth and small arms, the Joaquinraptor likely used its long arms to capture prey.

“This suggests that these two predatory dinosaur lineages evolved different adaptations to accomplish basically the same thing – that is, to capture, subdue, kill and eat other animals such as other dinosaurs,” Lamanna told Reuters. “Precisely why these groups evolved along these different evolutionary pathways remains a mystery, but it shows that, during the Cretaceous, there was more than one way to be a top predator.”

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.

The discovery comes just a few months after  scientists identified the Khankhuuluu mongoliensis, a new T. rex ancestor that researchers called the “missing link” between apex predators.