A group of paleontologists in Patagonia, Argentina, discovered a new dinosaur species resembling a T-rex that "causes fear."

Transcript

AILSA CHANG, HOST:

And now a story about a predator that was 16 feet long, had sharp teeth, tiny arms and roamed South America about 80 million years ago. No, we are not talking about T-rex. Paleontologists in Argentina announced last week that they had discovered a whole new dinosaur species, which helps advance our understanding of prehistoric times.

ARIEL MENDEZ: Llukalkan aliocranian.

ARI SHAPIRO, HOST:

Llukalkan means one who causes fear in a local Indigenous language. It is set apart by its unusual skull.

MENDEZ: (Through interpreter) They're dinosaurs that had rather short and high craniums, sharp teeth. They had extremely short arms but had very well-developed hind legs and feet, so it probably would have been a great runner.

CHANG: That is Ariel Mendez of the National Scientific and Technical Research Council in Argentina. His team used the skull they found to construct 3D models of the dinosaur's brain.

SHAPIRO: Their modeling suggests that Llukalkan had very keen hearing, which could have made him a fearsome hunter.

MENDEZ: (Through interpreter) A carnivorous dinosaur that has very sharp teeth, with very developed sense organs, specialized perhaps for hunting. Keeping in mind that it would be about 16 feet long, it surely caused fear in its potential prey.

CHANG: But that's not all. The scientists also found another skull they say belongs to a distinct but related species. That raises the possibility that two similar dinosaurs lived in the same environment around the same time.

RILEY BLACK: Then we're left with the question of, well, how did they divvy up the same habitat? It could also be they lived at the same time, and one species was relatively rare, and one species was very common.

SHAPIRO: That's science journalist Riley Black. She says discovering new dinosaur species is not too surprising.

BLACK: I think there's an assumption that we know the broad picture of dinosaur evolution or that we've answered most of the major questions. And that really can't be further from the truth. It's estimated that we haven't even really found a third of them yet.

CHANG: But Black says every new species discovered helps fill in another piece of an ancient timeline.

(SOUNDBITE OF T. REX SONG, "TEENAGE DREAM") Transcript provided by NPR, Copyright NPR.