Apatosaurus considered a junior synonym of "Apatosaurus"; its only species was reclassified as "A.excelsus" in 1903. A 2015 study concluded that "Brontosaurus" is a valid genus of sauropod distinct from "Apatosaurus", but not all paleontologists agree with this division. As it existed in North America during the late Jurassic, "Apatosaurus" would have lived alongside dinosaurs such as "Allosaurus", "Camarasaurus", "Diplodocus", and "Stegosaurus". "Apatosaurus" was a large, long-necked, quadrupedal animal with a long, whip-like tail. Its forelimbs were slightly shorter than its hindlimbs. Most size estimates are based on specimen CM3018, the type specimen of "A.louisae". In 1936 this was measured to
Shishugou Formation dinosaur traps sporting a crest running from its nose to the back of its head. Its discovery was hailed by paleontologists as the earliest known remains of the tyrannosauroid clan that culminated with "Tyrannosaurus rex". Shishugou Formation dinosaur traps The Shishugou Formation dinosaur traps also known as death pits or death traps are found in the Shishugou Formation, located in the Junggar Basin within Xinjiang Province of northwestern China. They are a rich source of Jurassic Period dinosaur fossils, many of which were new species to palaeontology. The Junggar Basin is a large continental basin made up of fluviatile and lacustrine sediments