Scientists have discovered the bones of what could be the largest meat-eating dinosaur ever to walk the Earth--a needle-nosed, razor-toothed beast that may have been more terrifying than even the Tyrannosaurus rex.
A team of researchers from Argentina and North America unearthed the fossilized bones of as many as six of the previously unknown species in Patagonia, a desert region on the eastern slopes of the Andes in South America. The dig began in 1997.
The discovery of the predators' graveyard challenges the theory that the largest meat-eaters were loners. It also raises the possibility that they lived and hunted in packs, which would make them even more terrifying to their prey.
"You always think of these things as being solitary; now we know they traveled in packs," Philip Currie, one of two scientists to make the discovery, said in an interview Friday. He works with the Royal Tyrrell Museum in Alberta, Canada.
Currie said the newly discovered species lived about 100 million years ago and was heavier and had slightly shorter legs than the T. rex, which roamed North America. It had a tail and short front legs that were basically useless.
The dinosaur also was characterized by a long, narrow skull and a jaw shaped like scissors. That suggests it could have dissected its prey with an almost surgical precision, "where the Tyrannosaur had a nutcracker skull," Currie said.
Researchers estimated the meat-eating giant was 45 feet long, bigger than the reigning king of the carnivores, the 41-foot Giganotosaurus. The better-known T. rex was about 40 feet long.
"I think it would look just as nasty, if not worse," Currie said. "This guy has a long snout, long skull, incredibly sharp teeth--I think it would have been terrifying."
Currie said the animal is apparently related to the Giganotosaurus, but it's a new species and genus, making the two creatures as closely related as a dog and a fox. The dinosaur is further removed from the T. rex, at least as different as a dog is from a cat.
The researchers have given their discovery a South American Indian name, but they are withholding it until their findings are published. They released some details of the discovery in conjunction with an exhibit of some of Currie's other findings at the Riverfront Arts Center in Wilmington, Del. The exhibit opened Friday.
"The bigness of it--well, obviously it gets headlines--but scientifically, it's not that important. But the fact that they traveled together, that's very interesting," said Jack Horner, a paleontologist from Montana State University in Bozeman.
Horner said he is awaiting the geological evidence that could determine whether the dinosaurs really did die together.
Dinosaur paleontologist Kenneth Carpenter of the Denver Museum of Natural History agreed that the size of the dinosaur is not what makes it scientifically interesting.
"It's that we've got a new species and that we've got more than one individual," Carpenter said. "It shows that the diversity of dinosaurs has increased."
In 1995, a farmer led Currie's colleague Rodolfo Coria of the Carmen Funes Municipal Museum to the site in the Andes foothills about 640 miles southwest of Buenos Aires. The region has yielded a number of discoveries, including the Giganotosaurus.
"There were lots of animals, and when they died, there was lots of mud and sand to get buried in. And if you can get buried, you can get fossilized," Currie said.
They now have remains from at least half a dozen dinosaurs, ranging from half-grown to full-grown animals.
Now a desert, the area where the bones were found was probably a forest when the dinosaurs prowled across it during the late Cretaceous period, Currie said.
The Royal Tyrrell Museum can be reached on the Internet at http://www.tyrrellmuseum.com