Alamosaurus Confirmed as North America's Biggest Dinosaur

A new fossil analysis puts a giant plant-eater right up there with Argentinosaurus as one of the biggest dinosaurs on the planet.

A team of paleontologists have claimed to have unearthed the fossilized remains of what has been confirmed to be the largest dinosaur ever found in North America. Digging in New Mexico between 2003 and 2006, the researchers found a femur and two massive vertebrae belonging to an Alamosaurus sanjuanensis, a long-necked vegetarian dinosaur similar to the Brontosaurus and other members of the sauropod family. The Alamosaurus itself isn't a new discovery, but recent analyses of the remains of the dinosaur have led to drastically larger estimates of just how big the dinosaur would be. These fossils suggest the dinosaur was almost 100 feet long and weighed some 70 tons – about as much as the Argentinosaurus, the world's largest dinosaur, and twice as big as earlier estimates put the Alamosaurus at. The Alamosaurus roamed what is now the southwestern United States some 65 million years ago until they, like every other type of dinosaur, were wiped off the face of the planet.