Gigantic Meat-eating Dinosaur Discovered

"Over the last decade, people have become increasingly aware of a group of gigantic meat-eating dinosaurs called carcharodontosaurids," explains Currie. "These animals include Giganotosaurus, which was larger than the largest known specimen of Tyrannosaurus rex. After four years of working in a dinosaur quarry in Argentina, we discovered that we had a new species of carcharodontosaurid that we called Mapusaurus roseae."

Hundreds of Mapusaurus bones were found in sandstone 100 million years old. The remains include what may be one of the biggest meat-eating dinosaurs known, slightly larger than its older cousin, Giganotosaurus. The discovery, made 15 miles south of the city of Plaza Huincul in 1995, took five years of excavation under the direction of Coria and Currie who removed 100 tons of sandstone from a desert hilltop.

For a century giant meat-eating dinosaurs such as Tyrannosaurus rex were assumed to be solitary animals. Family groupings of large meat-eating dinosaurs have only recently been identified, and could provide paleontologists with information on its behaviour, the probable ways that it ate, and what can be learned about changes during growth.

"The presence of so many animals in one quarry suggests that they were living together in a pack at the time leading up to their catastrophic death," comments Currie. "Similar sites found recently in Alberta, Mongolia and the United States suggests that this kind of social behavior may have been relatively common in Late Cretaceous (65 to 90 million years ago) times."

Currie speculates that by coordinating movements, the Mapusaurus pack or family might have been able to hunt the largest dinosaur that ever lived -- Argentinosaurus, the 40 meter (125 foot long) plant-eater which shared its habitat in central South America 100 million years ago.

The Mapusaurus individuals found ranged in size from slender juveniles 5.5 meters (18 feet) long to a robust adult that exceeded 12.5 meters (40 feet) in length. The fossils include the longest known fibula (shin) bone for any meat-eating dinosaur, slightly longer though less robust than that of its close cousin, Giganotosaurus. The skull of Mapusaurus is lower and lighter than that of its older sister genus, Giganotosaurus, with similar sharp, blade-shaped teeth.

"This is fresh information about the social lives of the largest carnivores on Earth. And its one of the most remarkable of a dozen new species discoveries, many of them gigantic, in the last decade from this region of western Patagonia," says dinosaur enthusiast and dig participant, "Dino" Don Lessem, one of several excavation sponsors, along with the Museo Carmen Funes and the Direccion de Patrimonio de Neuquen, and Amblin/Universal Pictures (via royalties from Mr. Lessem"s Jurassic Park exhibitions).

Mapusaurus is named for the word "Earth" in the language of the Mapuches, the Native American tribe of western Patagonia. Its species name roseae refers to the rose-coloured rocks that the specimens were found in and honors the first name of the principal donor of the Argentina-Canada Dinosaur Project.