Scientists in Patagonia have announced the discovery of fossil remains of a dinosaur, which researchers say was the heaviest land animal - dinosaur or otherwise - on planet earth.

Dreadnoughtus schrani inhabited planet earth 77 million years ago in Argentina and weighed 59,300 kg, more than a herd of African elephants.

Its weight was calculated on the basis of the bones in its upper arm and thigh.

According to Dr Lacovara, another giant Argentine dinosaur, Argentinosaurus, might have been larger but its scant remains do not allow are liable weight estimate.

Another group of scientists in May had cited Argentinosaurus, with an estimated weight of 82,107kg, as the largest dinosaur.

"We decided on Dreadnoughtus - meaning 'fearer of nothing' -because when you're as big as this thing was, you're probably not afraid of too much," said one of the researchers, Matt Lamanna of the Carnegie Museum of Natural History in Pittsburgh.   

Dr Lacovara said the name was also a reference to the powerful battleships called dreadnoughts, dating from the turn of the last century, that were designed to be impervious to attack.

Dreadnoughtus was a vegetarian dinosaur and a member of a group called titanosaurs, who are thought to have been the largest dinosaurs that ever lived.

Argentinosaurus was also a titanosaur.

Most titanosaurs are known only from fragmentary remains, but the scientists found 45% of the skeleton of Dreadnoughtus, including most of the important bones.

The researchers found two specimens of Dreadnoughtus side by side - one larger than the other.

"It appears that both individuals died and were buried rapidly after a river flooded and broke through its natural levee, turning the ground into a soupy mixture of sand, mud and water," Dr Lacovara said.

To attack a healthy adult Dreadnoughtus, a solitary predator "would have to have been suicidal," Lamanna said.

The study appears in the Nature journal Scientific Reports.