Allosaurus fishes, frogs, salamanders, turtles, sphenodonts, lizards, terrestrial and aquatic crocodylomorphans, several species of pterosaur, numerous dinosaur species, and early mammals such as docodonts, multituberculates, symmetrodonts, and triconodonts. Dinosaurs known from the Morrison include the theropods "Ceratosaurus", "Ornitholestes", "Tanycolagreus", and "Torvosaurus", the sauropods "Haplocanthosaurus", "Camarasaurus", "Cathetosaurus", "Brachiosaurus", "Suuwassea", "Apatosaurus", "Brontosaurus", "Barosaurus", "Diplodocus", "Supersaurus", and "Amphicoelias", and the ornithischians "Camptosaurus", "Dryosaurus", and "Stegosaurus". "Allosaurus" is commonly found at the same sites as "Apatosaurus", "Camarasaurus", "Diplodocus", and "Stegosaurus". The Late Jurassic formations of Portugal where "Allosaurus" is present are interpreted as having been similar to the Morrison but with a stronger marine influence.
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,