Scientists unveil rare dinosaur discovery

Scientists have unveiled a replica of a new species of dinosaur whose fossils were recently discovered in Brazil. The new dinosaur, an ancestor of the brontosaurus, has more in common with species found in Europe than other finds in South America.

A replica of Unaysaurus tolentinoi, a small plant-eater that lived some 230 million years ago, was unveiled last week at the National Museum in Rio.

"It differs from all other dinosaurs," Zootaxa, a scientific journal published in New Zealand, said. "Unaysaurus represents the first 'prosauropod' grade dinosaur from Brazil."

Prosauropods were primitive dinosaurs with long necks and tails, like the earthshaking giants in the film Jurassic Park. Although unaysaurus was just 2.5 metres long and weighed about 70 kilogrammes, he was the ancestor of the huge brontosaurus and diplodocus that appeared millions of years later.

"He's a unique dinosaur," said biologist Luciano Leal of the National museum, who helped unearth the fossil.

"We thought at first the dinosaur was related to dinosaurs from Argentina," Leal said. "But research proved that it was related to animals from Germany."

The continents then were joined in one huge land mass scientists call Pangea, which eventually broke up and drifted apart. But they don't know why Argentine dinosaurs seem to be more closely related to African dinosaurs than to those from Brazil.

"The geographical distribution of this group is much more complex than we imagined," Leal said. "Something separated the group in the sub-continent."

Unaysaurus is the oldest of the 11 dinosaurs found in Brazil. It lived in the Triassic period, long before the huge dinosaurs evolved.

Signs of prehistoric life have been found across Brazil, Latin America's largest country.

The rock formations of the far south are especially rich and have yielded the Staurakisaurus and the Saturnalia, very primitive sauropods.

When the unaysaurus died, its bones were calcified and remained buried until May 1998.