Diplodocus (Dip-lod-acus) “The long friendly Dinosaur”
One of the longest dinosaurs, Diplodocus had a unique body construction, with two rows of bones on the underside of its tail to provide extra support and greater mobility. Because of Diplodocus' unusual skeleton, palaeontologist Othniel C. Marsh coined its name in 1878, deriving it from the Greek words "diplos," meaning "double," and "dokos" meaning "beam." One of the best-known sauropods (long-necked herbivorous dinosaurs), this genus of dinosaur lived during the late Jurassic Period, about 155.7 million to 150.8 million years ago, an d primarily roamed western North America. Four species are recognized: D. longus, D. carnegii, D. hayi and D. hallorum (previously known as Seismosaurus). Diplodocus is the longest dinosaur known from a near-complete skeleton — that is, other dinosaurs, such as the sauropod Supersaurus, may be longer, but those length estimates are based on fairly incomplete skeletons.