Haplocanthosaurus

dinosaur · sauropod · Late Jurassic · North America

Massive long-necked dinosaur. Haplocanthosaurus was a sauropod, which means it had a long neck, a small head, and walked on four legs. These dinosaurs were some of the biggest land animals that ever lived.

Incomplete fossil clues. Scientists only know Haplocanthosaurus from incomplete fossil skeletons, so paleontologists have to piece together what the whole animal looked like from the bones they found.

Colorado discovery. One species, Haplocanthosaurus delfsi, was discovered by a college student named Edwin Delfs in Colorado and wasn't officially described until 1988, long after the first species was named in 1903.

Morrison Formation home. Haplocanthosaurus lived in North America during the Late Jurassic and shared its environment with other famous dinosaurs like Allosaurus and Brontosaurus.

Ancient timing. This dinosaur lived between 155 and 152 million years ago, during the time when many of the largest dinosaurs roamed the Earth.