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
The Lost World: Jurassic Park since the release of the first film, Spielberg noted that "the artistry of the creative computer people" had advanced: "There's better detail, much better lighting, better muscle tone and movement in the animals. When a dinosaur transfers weight from his left side to his right, the whole movement of fat and sinew is smoother, more physiologically correct." Winston said, "I wanted to show the world what they didn't see in 'Jurassic Park': more dinosaurs and more dinosaur action. 'More, bigger, better' was our motto." Some of the animatronics cost $1 million and weighed nine and a half tons. Michael Lantieri,