Apatosaurus: the heavy sauropod built for Jurassic plains

When and where

Apatosaurus lived about 152 to 151 million years ago, near the end of the Jurassic Period. Its fossils come from the Morrison Formation in the western United States, including Colorado, Oklahoma, New Mexico, Wyoming, and Utah. That landscape held broad floodplains, river channels, and stretches of seasonal woodland. Apatosaurus shared it with other giant sauropods, but its body plan was heavier and deeper through the neck and shoulders than the slimmer Diplodocus.

How we know

Othniel Charles Marsh named Apatosaurus ajax in 1877 from fossils found in Colorado. William H. Holland later named Apatosaurus louisae in 1916 after a skeleton from what is now Dinosaur National Monument in Utah. The best material includes skull fragments, vertebrae, limb bones, and near-complete mounted skeletons. For a long time, Apatosaurus was tangled with Brontosaurus in museum labels and popular books. The fossils now give Apatosaurus a clearer shape: a massive Morrison sauropod around 21 to 23 metres long. Source: Wikipedia.

What set it apart

Apatosaurus was not the longest sauropod in its neighbourhood, but it was one of the most powerfully built. Adults averaged roughly 16 to 22 tonnes, with some specimens reaching about 33 tonnes. Its neck bones were thick and strongly braced, so the animal carried a sturdy neck rather than the whip-thin look many people imagine for long-necked dinosaurs. The tail was long, tapering, and flexible. The legs stood like columns under the body, with the front limbs slightly shorter than the hind limbs. That gave Apatosaurus a high-hipped stance and a slow, weighty profile.

For collectors and classrooms

Apatosaurus works well in a classroom set because it lets children compare two kinds of sauropod: the heavier Apatosaurus and the leaner Diplodocus. Put the model beside a ruler and the scale lesson becomes simple. A 23 metre animal is longer than two London buses. For a desk, shelf, or lesson tray, start with a hand-painted figurine.