ARGENTINA: The fossilised remains of what may be the largest meat-eating dinosaur has been discovered in Argentina - a bus-sized monster that attacked its prey in roving packs, scientists announced on Monday.
The remains of at least seven beasts, named Mapusaurus roseae, were found clustered in 100-million-year-old rocks, south of the city of Plaza Huincul in western Patagonia. Based on a shin bone that was about a metre long, researchers estimate that the largest adult in the group stretched about 41 feet and weighed about 6,800kg (15,000lb).
The new dinosaur ran on its hind legs like Tyrannosaurus rex, but had teeth that suggested a different way of killing its prey. The thin blade-like teeth of the Mapusaurus probably sliced the flesh of other dinosaurs, in contrast to Tyrannosaurus rex's stronger, spike-shaped teeth that crunched through its prey.
Rodolfo Coria, a palaeontologist at the Museo Carmen Funes in Plaza Huincul and lead author of the study, said the cluster of Mapusaurus fossils suggested that the dinosaurs were part of a single group that possibly co-ordinated attacks on their natural prey, the nearly 8m (125-ft) long Argentinosaurus, the largest dinosaur ever discovered.
"The theory was that large meat-eating dinosaurs were lonely hunters," Mr Coria said. "With Mapusaurus, we would not say all of them are. Maybe some of them hunt in packs."
He said he wasn't sure why the Mapusaurus fossils were found together.
"We didn't find any evidence of disease, any accident or catastrophic death, so maybe they just drowned when they were going across a river or died of starvation."
The fossils were discovered in the same area where scientists had discovered Giganotosaurus, which previously held the size record for meat-eating dinosaurs.