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.