Apatosaurus "Apatosaurus" may have been more solitary than other Morrison Formation dinosaurs. Fossils of the genus have only been found in the upper levels of the formation. Those of "Apatosaurus ajax" are known exclusively from the upper Brushy Basin Member, about 152–151 mya. "A.louisae" fossils are rare, known only from one site in the upper Brushy Basin Member; they date to the late Kimmeridgian stage, about 151mya. Additional "Apatosaurus" remains are known from similarly aged or slightly younger rocks, but they have not been identified as any particular species, and thus may instead belong to "Brontosaurus". The Morrison Formation records a
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,