An enormous species of dinosaur, which weighed more than a Boeing 737, has been discovered by scientists who claim the beast was so large it would have “feared nothing”.
Named Dreadnoughtus schrani, after the fortified dreadnought battleships of the early 20th century, the herbivore would have done little other than eat in order to support its vast frame.
Measurements of its fossilised bones suggest that the creature measured 85ft (26m) in length and weighed about 65 tonnes – equal to more than seven Tyrannosaurus Rex, four diplodocus or a dozen African elephants.
The remains unearthed in Argentina represent by far the most complete skeleton ever recovered of a supermassive herbivore from a group known as titanosaurs.
Although partial skeletons of potentially larger cousins have previously been found, the find makes Dreadnoughtus the largest land animal for which a body size can be accurately estimated.
“It is by far the best example we have of any of the most giant creatures to ever walk the planet,” said Dr Kenneth Lacorvara of Drexel University in Philadelphia, who made the discovery.
Examination of the 77-million-year-old specimen suggested it may not even have been fully grown at the time it died, he reported in the Scientific Reports journal.
The haul of bones unearthed in southern Patagonia between 2005 and 2009 included most of the vertebrae from the 30ft tail, a neck vertebra measuring more than a yard across, and a thigh bone which at 6ft in length is taller than the average man.
Also included were a shoulder blade, several ribs, toes, a claw, a small section of jaw along with most bones from both forelimbs and hindlimbs, adding up to 70 per cent of bone types and 45 per cent of the total skeleton, as well as a tooth.
A second, smaller skeleton from the same species was also uncovered at the same site, but its skeleton was less complete.
The discovery of the thigh and upper arm bones in particular were crucial in allowing experts to calculate Dreadnoughtus’s size, an unprecedented feat.
“Titanosaurs are a remarkable group of dinosaurs, with species ranging from the weight of a cow to the weight of a sperm whale or more,” said Dr Matthew Lamanna, another of the researchers.
“But the biggest titanosaurs have remained a mystery because, in almost all cases, their fossils are very incomplete.”
For example another giant titanosaur known as Argentinosaurus was of a similar size to Dreadnoughtus and could have been even larger, but its measurements remain a mystery with only half a dozen vertebrae, a shin bone and some other fragments ever having been recovered.
Dr Lacorvara said he had chosen the name “Dreadnoughtus” – meaning “fears nothing” – because the species reminded him of the “virtually impervious” battleships of the early 20th century.
“With a body the size of a house, the weight of a herd of elephants and a weaponized tail, Dreadnoughtus would have feared nothing,” he said.
In order to reach such a size the creatures must have had a “lifelong obsession with eating” and spent every day battling to take in enough calories to sustain their bodies.
“I imagine their day consists largely of standing in one place,” he said. “You have this 37ft-long neck balanced by a 30ft-long tail in the back. Without moving your legs, you have access to a giant feeding envelope of trees and fern leaves.
“You spend an hour or so clearing out this patch that has thousands of calories in it, and then you take three steps over to the right and spend the next hour clearing out that patch.”