Scientists have discovered the bones of a new dinosaur in Patagonia, Argentina. They say it is one of the largest types of dinosaur, if not the biggest, that ever walked the Earth.

The dinosaur stood as tall as two building stories tall up to its shoulder. It weighed as much as seven Tyrannosaurus rex. From head to tail, it measured 85 feet, including its 37-foot-long neck and 30-foot-long tail.

Scientists have named it Dreadnoughtus schrani.

The dinosaur's name comes from the word "dreadnought," which means "fearing nothing." In the early 1900s, a dreadnought was a huge metal battleship.

Pieces Of A Huge Bone

Nothing could have attacked Dreadnoughtus and won, scientists say, because it was just too big.

The dinosaur found in Patagonia died sometime between 66 million and 84 million years ago. Scientists believe it weighed 65 tons - even more than a Boeing 737 airplane.

What's more, at the time of its death, the giant creature was still growing.

The giant was discovered by Kenneth Lacovara. He is a paleontologist - a scientist who studies ancient animal remains, or fossils. Lacovara first stumbled on the crumbled bones of the Dreadnoughtus during a fossil-hunting trip in February 2005.

"I found a little cluster of broken-up bones," said Lacovara.

Lacovara and his team soon realized that the bones were pieces of a giant thigh bone. Still, they weren't that excited at first.

Very Well Preserved

"That's not uncommon," he said. Then more bones started showing up. "At that point we were getting excited."

The bones themselves were enormous. The animal's shin bone was the length of a grown man.

The truly thrilling part was that there were so many bones.

In the case of most dinosaurs, scientists don't usually find more than 10 bones, Lacovara said. "We had 145."

After the fossils had been cleaned the scientists realized they had bones from two different animals.

Both animals are very well preserved, particularly the larger one. Almost half of that skeleton has been recovered, though its small skull is missing.

Having so many bones will help scientists understand just how the enormous animals moved around.

A Giant Appetite

Dreadnoughtus belonged to a group of dinosaurs known as titanosaurian sauropods. They lived in the Southern Hemisphere for 30 million years and died out some 66 million years ago.

To feed their huge bodies, Dreadnoughtus would have had to eat almost all the time. Lacovara imagines them as eating machines, using their long necks to graze on all sorts of plants, including trees.

The area where the fossils were found was once a forest. Several rivers ran through it. Lacovara thinks the two dinosaurs died when one of those rivers flooded and turned the solid ground nearby into quicksand. Then the huge animals probably sank to their deaths.

The way the dinosaurs died explains why their bones are in such good shape, Lacovara said. "We even see muscle scars on many of the bones," he added. "That is because they got buried so fast."]]>