Enormous Megaraptor That Lived Just Before Dinosaurs Went Extinct Discovered in Argentina

The remains of a dinosaur twice the size of a modern-day giraffe have been found by paleontologists digging in Estancia La Anita, a Cretaceous-era fossil deposit in Argentina.

At 33 feet (10 meters), the newly-discovered megaraptor is among the largest in the family, say paleontologists. It is also one of the youngest, with scientists describing it as "one of the last representatives of this group."

"This is the moment, 65 million years ago, when the extinction of the dinosaurs occurs, and this new megaraptor that we now have to study would be one of the last representatives of this group," Fernando Novas, a paleontologist at the Natural Sciences Museum in Buenos Aires who led the excavation, told Reuters.

Novas and the Natural Sciences Museum carried out the excavation in March with colleagues from National Museum of Tokyo, the University of La Plata and the University of Buenos Aires.

Megaraptors were a light-bodied group of carnivorous dinosaurs, who roamed what is now South America, Asia and Australia during the Cretaceous Period (145.5 million to 66 million years ago). According to Matt Lamanna, Assistant Curator and Head of Vertebrate Paleontology at Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, the family is known for its sharp teeth, low skulls and elongated limbs.

However, their defining features, according to a statement from the Natural Sciences Museum in Buenos Aires, were their long arms and powerful claws, which grew to around 14 inches (35 centimeters) in length. Paleontologists believe these strong arms were the dinosaur's main weapon, rather than their jaws as is the case in several other groups, including the Tyrannosaurus rex.

The new megaraptor was discovered during a month-long dig in Estancia La Anita in the Province of Santa Cruz, south Argentina. The site contains Cretaceous-era deposits from 70 million years ago, and the scientists involved hope their discovery can add to what we know about this particular group of dinosaurs.

"This new discovery represents what might be the largest-known member of this unusual and poorly understood group of meat-eating dinosaurs," Professor Paul Barrett, Merit Researcher at the Natural History Museum, London, who was not involved in the excavation, told Newsweek.

"It underlines the importance of Argentinean fossil sites for improving our understanding of the dinosaur communities that were alive just before the asteroid hit."

The megaraptor was first described in 1997 when they were initially thought to be a larger relative of the velociraptor, a small bird-like dinosaur paleontologists now believe were covered in feathers. The hypothesis has been disputed and scientists since have learned the claw was not from the foot, like a velociraptor, but from the thumb.

A recent addition to the Megaraptoridae family is the Murusraptor barrosaensis, a medium-sized dinosaur that would have inhabited Argentina 80 million years ago during the Late Cretaceous, described by scientists writing in Plos One in 2016.

The article has been updated to include comments from Professor Paul Barrett.

Megaraptor skeleton
Paleontologists in Argentina say they have found the remains of a new Megaraptor. Picture: The skeleton of a Megaraptor is displayed at an exhibition in Tokyo on March 13, 2009. AFP PHOTO/Kazuhiro NOGI/Getty