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.
Sarahsaurus animals were also present. Non-vertebrates in this ecosystem included microbial or "algal" limestone, freshwater bivalves, freshwater mussels and snails, and ostracods. The plant life known from this area included trees that became preserved as petrified wood. Sarahsaurus Sarahsaurus is a genus of basal sauropodomorph dinosaur which lived during the lower Jurassic period in what is now northeastern Arizona, United States. "Sarahsaurus" is known from a nearly complete articulated holotype skeleton referred to as TMM 43646-2, another partial skeleton known as TMM 43646-3, and a nearly complete but poorly preserved skull known as MCZ 8893. This last specimen was previously described