Scottish experts yesterday hailed the discovery of bones belonging to what is believed to be the largest creature ever to walk the Earth as one of the most exciting finds in the dinosaur world.
The fossilised remains of an enormous herbivore known as titanosaur were uncovered after a farm worker stumbled across them in the desert of Patagonia in Argentina, it emerged yesterday.
It is believed to have roamed the forests of what is now South America between 95 million and 100 million years ago.
The bones were excavated by a team from the Museum of Palaeontology Egidio Feruglio in Argentina, led by Dr Jose Luis Carballido and Dr Diego Pol.
Paleontology expert Dr Steve Brusatte, from Edinburgh University's school of geosciences, said as well as the size, the number of bones which had been discovered made it a hugely significant find.
Around 150 bones from seven individuals have been unearthed so far. The fossils are enormous, with one titanosaur thigh bone bigger than a human being.
"There are some vertebrae, some limb bones, and they are just absolutely massive," Brusatte said.
"It would be either the biggest dinosaur or one of the biggest dinosaurs, there is no doubt about that. Exactly how big it would have been it is hard to say, as they don't have a complete skeleton,
"But what sets this find apart is the previous two or three dinosaurs which have vied for the title of 'world's biggest' are only known from a few bones each. When all these bones are excavated, it will be our first really good picture of what one of these enormous dinosaurs would have looked like.
"It is a major discovery - one of the most important dinosaur discoveries of the last 10 or 20 years."
Brusatte's own work on identifying a new type of long-snouted tyrannosaur - nicknamed "Pinocchio rex" - made headlines around the world earlier this month.
He cautioned that the peer-reviewed research on the Patagonia titanosaur had yet to be published, but said initial estimates suggested it would have been big enough to swat away a dinosaur such as Tyrannosaurus rex "like a fly".
"T-rex was at most 40ft long or so and would have weighed about seven tonnes at the very most," he said. "If these scientists are correct, you are talking about something that is maybe double the length of T-rex, something that maybe weighed 10 times as much as T-rex.
"Of course, he wouldn't have lived near a T-rex, as they lived in different parts of the world at different times, but there would have been other big predators that this guy would have lived alongside.
"Something of this size - at least the adults - would probably have been almost incapable of being taken down by even the biggest carnivorous dinosaurs."
He added: "These guys do seem to be at the limit of how big dinosaurs could get. They are really 'outliers'."
Dr Nick Fraser, keeper of natural sciences at National Museums Scotland, said the thickness of the thigh bone which had been uncovered suggested it had supported an extremely bulky weight. He said the logistics of collecting big dinosaur bones were complicated, as skeletons were often scattered over a wide area after, for example, being washed away by floods.
"It certainly looks comparable if not bigger than many of the other large dinosaurs," he said. "The problem is you never know with these incomplete remains - did it have a particularly long neck or did it have a particularly long tail? Or it could have been shorter, so therefore that might have changed the weight and obviously the length of it.
"There is a lot of variety, but just based on that leg bone, I think it is fair enough to say that it is certainly up with the biggest, if not the biggest dinosaur to date."
The previous contender for the title of the world's biggest dinosaur was a similar type of sauropod - those with small heads, long necks, long tails and sturdy legs - known as Argentinosaurus, which was also discovered in Patagonia.
It was originally thought to weigh 100 tonnes, but further work reduced this estimate to around 70 tonnes.