Apatosaurus

Apatosaurus/Brontosaurus was one of the largest land animals that ever existed. The dinosaur Brontosaurus is now called Apatosaurus. This enormous plant-eater measured about 70-90 feet (21-27 m) long and about 15 feet (4.6 m) tall at the hips. It weighed roughly 33-38 tons. Its head was less than 2 feet long; it had a long skull and a very tiny brain. This plant-eater had a long neck (with 15 vertebrae), a long whip-like tail (about 50 ft = 15 m long), a hollow backbone, peg-like teeth in the front of the jaws, and four massive, column-like legs. Its hind legs were larger than the front legs. Fossilized Apatosaurus footprints (called trackways) have been found (in Colorado, USA) that were about a yard wide.
Age: Late Jurassic