Most complete new giant dinosaur found in Patagonia

RIO DE JANEIRO (Reuters) - Brazilian and Argentine paleontologists have discovered the largely complete fossil of a new species of giant dinosaur that roamed what is now northern Patagonia about 80 million years ago.

The herbivorous Futalognkosaurus dukei measured an estimated 105 feet to 112 feet from head to tail and was as high as a four-storey building. It is one of the three biggest dinosaurs yet found in the world.

"It's a new species, it's a new group," Argentine paleontologist Juan Porfiri told a news conference in Rio de Janeiro on Monday.

The find pointed to a new lineage of titanosaurs, with particularly bulky necks, he said.

"Its neck was very big in diameter, strong and huge."

Fossilized remains of an ecosystem from the same Late Cretaceous age, including well-preserved leaves and fish, were also found. The description was published in the latest issue of the annals of the Brazilian Academy of Sciences.

Futalognkosaurus dukei's name is derived from the indigenous Mapuche language meaning "giant chief of the lizards", and the name of U.S. power company Duke Energy Corp, which financed a large part of the excavation in Argentina.

The fossil was 70 percent preserved, which compares to about 10 percent for other giant dinosaur finds in the world.

"It's among the biggest dinosaur finds and the most complete for a giant dinosaur. We have all vertebrae between the first of the neck to the first of the tail, which may allow us to reevaluate other dinosaurs," said Alexander Kellner, a researcher with the National Museum in Rio de Janeiro.

'LOST WORLD'

The dinosaur is part of a series of finds in the area, where the first fossils were discovered in 2000.

"The accumulation of fish and leaf fossils, as well as other dinosaurs around the find, is just something fantastic. Leaves and dinosaurs together is a great rarity," he told Reuters. "It's like a whole lost world for us."

He was referring to "The Lost World" by Arthur Conan Doyle, a classic tale set in a remote part of South America where a scientific expedition finds dinosaurs still roaming an isolated plateau.

Some of the leaves made part of the diet of the titanosaur and other specimens found there. The researchers said the fossilized ecosystem pointed to a warm and humid climate in Patagonia, which had forests during the Late Cretaceous period. The area is steppe-like now and almost bare of vegetation.

Researchers believe the carcass of the giant dinosaur, which died of unknown causes, its flesh devoured by predators, was washed into a nearby slow-flowing river, where it created a barrier, accumulating bones and leaves in its structure for many years until all became fossilized.

A fossil of a carnivorous theropod Megaraptor found at the site contained a complete and articulated arm with very large sickle-shaped claws. Previously, similar fragmented bones were interpreted as a foot, researchers said.

The joint Argentine-Brazilian project also works in the Brazilian state of Mato Grosso, where Kellner said an important find has been made but would be revealed at a later date.

Desert-like areas in Argentina are good for preserving fossils, while they are more difficult to find in the wetter soil in Brazil.