Coelophysidae is a family of primitive carnivorous theropod dinosaurs. Nodosaurs were large, herbivorous armored dinosaurs resembling armadillos. Birds themselves are thought to be descendants of theropod dinosaurs. During the Late Jurassic, birds evolved from small, predatory theropod dinosaurs. It is set in a primitive world inhabited by dinosaurs and other creatures. These were the Archosauriformes, a diverse assortment of animals including the famous dinosaurs and pterosaurs. It was set in a fictionalized stone age of cavemen and dinosaurs. Birds are now recognized as being the sole surviving lineage of theropod dinosaurs. Dromaeosauridae is a family of feathered theropod dinosaurs. The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs. Insects inhabited Earth since before the time of the dinosaurs. "Brontosaurus" is a member of the family Diplodocidae, a clade of gigantic sauropod dinosaurs. The forelimbs were proportionally shorter than in any other large carnivorous dinosaurs, including "Tyrannosaurus". All known theropod dinosaurs from the Yixian Formation are coelurosaurs. "Apatosaurus" is a member of the family Diplodocidae, a clade of gigantic sauropod dinosaurs.