Paleontologists in southern Patagonia, Argentina, have discovered fossils of a new long-necked, long-tailed dinosaur the size of 12 elephants. Bigger than a Boeing 737. At 65 tons, it’s now the largest terrestrial animal with a body mass that can be accurately determined from the fossil record.

Ken J. Lacovara, from the Department of Biodiversity, Earth and Environmental Science at Drexel University in Philadelphia, announced the discovery of the whopping dinosaur this morning in Nature: Scientific Reports.

Lacovara and his American-Argentinian team have named the new Upper Cretaceous titanosaur “Dreadnoughtus (‘fears nothing’) schrani” after the huge battleships of World War I. Lacovera found a gigantic femur bone first, and his team uncovered hundreds of other bones during the excavation.

And you thought brachiosaurus was pretty large. Have a look at the video here.

Of course, Dreadnoughtus was a vegetarian. It had a 30-foot-long muscular, weaponized tail, the most powerful ever seen. But if it fell over, like Angela Lansbury, it might not have been able to get up.

Unlike most of the giant titanosaurs, Dreadnoughtus left very comprehensive fossil remains—70% of the postcranial skeleton, plus craniodental features. Scientists will use 3-D laser scanning, curate the fossil digitally, and create biomechanical models from the skeleton.

What’s perhaps the most striking fact about Dreadn0ughtus: its bone histology reveals that at the time of its death, this particular dinosaur was still growing.

Here’s the key to the drawings above: