Scientists have discovered a new type of dinosaur. It was one of the largest creatures ever to have walked the Earth. Its bones were found in Patagonia, Argentina, in South America.

It weighed as much as seven Tyrannosaurus rex. From head to tail, it measured 85 feet. Its neck was 37 feet long. Its tail was 30 feet long.

Scientists have named it Dreadnoughtus schrani, after giant battleships called dreadnoughts. "Dreadnought" means "fearing nothing." Nothing could have attacked Dreadnoughtus and won, scientists say. It was just too big.

The dinosaur found in Patagonia died between 66 million and 84 million years ago. Scientists believe it weighed 65 tons. In other words, Dreadnoughtus weighed more than a Boeing 737 airplane.

Enormous Bones Found

At the time of its death, the giant creature was even still growing.

The bones were discovered by Kenneth Lacovara. He is a paleontologist - a scientist who studies ancient bones, or fossils.

Lacovara made his discovery in 2005 on a fossil-hunting trip. "I found a little cluster of broken-up bones," he said.

Lacovara and his team soon realized that the bones were pieces of a giant thigh bone. Then more bones started showing up. "At that point we were getting excited," Lacovara said.

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

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

In most dinosaur digs, scientists don't usually find more than 10 bones, Lacovara said. "We had 145."

Sank To Their Deaths

Only after the fossils had been cleaned did the scientists realize they had bones from two different animals.

Both animals are very well preserved. Almost half of the larger one has been recovered, but its skull is missing.

Having almost a full skeleton will help scientists understand something puzzling: Just how did the enormous animals move around?

To feed their huge bodies, the animals had to eat all the time. Lacovara says they were like eating machines. They used their long necks to graze on all sorts of plants, including trees.

The area where the fossils were found was once a forest. Rivers ran through it. Lacovara thinks the two dinosaurs died when a river flooded. The water turned the ground 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. He said it "is because they got buried so fast."]]>