Dreadnoughtus is a newly discovered dinosaur that makes even the fearsome Tyrannosaurus rex appear small.

The dinosaur measured 85 feet long, including a tail 30 feet long and a 37-foot neck. The creatures weighed more than a modern sperm whale, an entire herd of elephants, or seven T. rex. This is the greatest weight ever reliably calculated for a dinosaur. Roughly 45 percent of the bones that made up Dreadnoughtus were discovered, allowing paleontologists to accurately estimate the weight. Another species, Argentinosaurus, may have been more massive, up to 90 tons, but not enough remains of the species have been collected for a reliable estimate.

Kenneth Lacovara, a paleontologist at Drexel University in Philadelphia, made the discovery of the previously unknown dinosaur. Fossils of a pair of the ancient animals were found lying alongside one another, and paleontologists believe the larger creature may not have still been growing when it perished. That conclusion was obtained through study of growth patterns in the remains.

Bones in the thighs and upper arm of the fossil were measured to determine the weight of the ancient creature.

Dreadnoughtus schrani lived around 77 million years ago, in the area now known as Patagonia, in Argentina.

Although Dreadnoughtus was a herbivore, its massive size likely made the dinosaur an unlikely target for predators. The creatures would have been formidable fighters, using their tails and swinging their heads.

"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. Not to mention we thought it was time a plant-eating dinosaur got a badass name. Those are usually reserved for the meat-eaters," Matt Lamanna, a paleontologist at the Carnegie Museum of Natural History in Pittsburgh, said.

Dreadnought battleships were first launched at the start of the 20th century, and the basic design was quickly copied. Some observers said they were impervious to attack. These massive, heavily armed marine vessels were commonly used in the First World War, and some continued in service through World War Two. The newly discovered massive dinosaur was given its name, in part, in honor of these classic naval vessels.

Dreadnoughtus schrani, like the giant Argentinosaurus, was a member of a group of gigantic dinosaurs known as titanosaurs.

Little is known about titanosaurs, due to a sparse fossil record of the giant creatures. These new discoveries are the most-complete titanosaur fossils ever recovered, potentially providing valuable insight into the group of dinosaurs.

Discovery of Dreadnoughtus schrani was profiled in the journal Scientific Reports, published by Nature.