New Megaraptor Dinosaur Species Discovered in Argentina

PATAGONIA, Argentina — Scientists in Argentina have discovered a dinosaur with a crocodile bone in its mouth.

The creature, known as Joaquinraptor casali, measured 23 feet (7 meters) long and weighed more than 2,200 pounds (1,000 kilograms). It likely lived between 66 million and 70 million years ago, near the time when all dinosaurs went extinct. The dinosaur was almost 19 years old when it died, though scientists are unsure of the cause of death.

Researchers uncovered part of a skull along with arm, leg and tail bones from the Lago Colhué Huapi rock formation in Patagonia. Unique features in the bones led them to identify the fossil as a new species.

Joaquinraptor belonged to a group of dinosaurs called megaraptors, known for their elongated skulls and powerful claws. Megaraptors lived in South America, Australia and parts of Asia. Unlike the well-known Tyrannosaurus rex, which lived in North America and had massive teeth but small arms, Joaquinraptor had long arms to capture prey.

Matthew Lamanna, a paleontologist with the Carnegie Museum of Natural History, said the discovery shows how predatory dinosaurs adapted in different ways.

“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 said. “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.”

Federico Agnolin and Bernardino Rivera of the Argentine Museum of Natural Sciences said the fossil “fills a major gap by providing one of the most complete skeletons yet.”

Lead scientist Lucio Ibiricu of the Patagonian Institute of Geology and Paleontology named Joaquinraptor in memory of his son, Joaquin, who died young.

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