Move over T. rex, there's a new king of the Cretaceous. A University of Alberta paleontologist was part of a team to unveil what may be one of the largest carnivorous dinosaurs known.
The U of A's Dr. Philip Currie and professor Rodolfo Coria of the Museo Carmen Funes in Argentina have identified and named the new species, Mapusaurus rosea. "Over the last decade, people have become increasingly aware of a group of gigantic meat-eating dinosaurs called carcharodontosaurids," said 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 100-million-year-old sandstone. The remains include what may be one of the biggest meat-eating dinosaurs known, slightly larger than its older cousin, Giganotosaurus. The discovery, made 24 kilometres south of the city of Plaza Huincul in 1995, took five years of excavation under the direction of Coria and Currie, who removed 90 tonnes 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 the creature 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," said Currie. "Similar sites found recently in Alberta, Mongolia and the United States suggest that this kind of social behaviour may have been relatively common in late cretaceous (65 - 90 million years ago) times."
Currie speculated that by co-ordinating movements, the Mapusaurus pack or family might have been able to hunt the largest dinosaur that ever lived - Argentinosaurus, the 40-metre plant-eater which shared its habitat in central South America 100 million years ago. Currie and Coria described this new species in the journal Geodiversitas.
The Mapusaurus individuals found ranged in size from slender juveniles 5.5 metres long to a robust adult that exceeded 12.5 metres in length. The fossils include the longest known fibula (shin) bone for any meat-eating dinosaur, slightly longer though than that of its close cousin, Giganotosaurus. The skull of Mapusaurus is lower and lighter than that of the Giganotosaurus, with similar sharp, blade-shaped teeth.
"This is fresh information about the social lives of the largest carnivores on Earth. And it's 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," said dinosaur enthusiast and dig participant, "Dino" Don Lessem, one of several excavation sponsors, along with the Museo Carmen Funes, the Direccion de Patrimonio de Neuquen and Amblin/Universal Pictures (via royalties from 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 honours the first name of the principal donor of the Argentina-Canada Dinosaur Project.
Source: University of Alberta
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