The skeleton of Dreadnoughtus schrani is seen during an excavation in Argentina. REUTERS/Kenneth Lacovara/Drexel University
The word big does not do justice to a massive, long-necked
dinosaur that shook the Earth in Argentina about 77 million
Try colossal, enormous, gargantuan and stupendous - and you
might come close to an accurate description of this behemoth,
known to scientists as Dreadnoughtus schrani.
Scientists this week announced the discovery in southern
Patagonia of remarkably complete and well-preserved fossil
remains of the dinosaur, which weighed 59,300kg and measured
26m long with a neck 11.3m long and a tail 8.7m long.
Paleontologist Kenneth Lacovara of Drexel University in
Philadelphia, who discovered the dinosaur and led the effort
for its excavation and analysis, said the scientists
calculated its weight on the basis of the bones in its upper
arm and thigh.
Dreadnoughtus weighed more than an adult sperm whale or a
herd of African elephants. Tipping the scales at seven times
as much as the dinosaur T. rex, it made the North American
menace that also lived during the Cretaceous Period look
Dreadnoughtus had "the largest reliably calculable weight" of
any known land animal - dinosaur or otherwise, Lacovara said.
Another giant Argentine dinosaur, Argentinosaurus, might have
been larger, he said, but its scant remains do not allow a
reliable weight estimate. Another group of scientists in May
had cited Argentinosaurus, with an estimated weight of
82,107kg, as the largest dinosaur.
While strictly a vegetarian, Dreadnoughtus was no pansy. With
its size and a tail that could have clobbered any predator
foolish enough to attack it, it probably had nothing to fear
from even the largest meat-eating dinosaurs.
Its name reflects that.
"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
"Not to mention we thought it was time a plant-eating
dinosaur got a badass name. Those are usually reserved for
the meat-eaters," said Lamanna, a paleontologist.
Lacovara said the name also was a nod to the powerful
battleships called dreadnoughts, dating from the turn of the
last century, that were designed to be impervious to attack.
Dreadnoughtus probably spent its days munching massive
quantities of plants to fuel its enormous body. It was a
member of a group of dinosaurs called titanosaurs that are
thought to have been the largest dinosaurs that ever lived.
Argentinosaurus also was a titanosaur.
Most titanosaurs are known only from fragmentary remains, but
the scientists found 45 percent of the skeleton of
Dreadnoughtus, including most of the important bones. Lamanna
called it "a treasure trove of information on one of the most
successful, but least understood, dinosaur groups of all."
The researchers found two specimens of Dreadnoughtus side by
side - one larger than the other, but the scary thought is
that they believe the larger one was not even fully grown.
"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," Lacovara said.
To attack a healthy adult Dreadnoughtus, a solitary predator
"would have to have been suicidal," Lamanna said. "It's
conceivable that a pack of these predators could take down a
sick or old Dreadnoughtus, but a single carnivore versus a
'Dread' would be a drubbing."
The study appears in the Nature journal Scientific Reports.