Carnosaur is a large group of predatory dinosaurs that lived during the Jurassic and Cretaceous periods. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin. Starting from the 1990s, scientists have discovered some very large carnosaurs in the carcharodontosaurid family, such as Giganotosaurus and Tyrannotitan which are among the largest known predatory dinosaurs.
Distinctive characteristics of carnosaurs include large eyes, a long narrow skull and modifications of the legs and pelvis such as the thigh (femur) being longer than the shin (tibia).
Carnosaurs first appeared in the Middle Jurassic, around 176 mya. The last definite known carnosaurs, the carcharodontosaurs, became extinct in the Turonian epoch of the Cretaceous, roughly 90 mya; reportedly later remains of carcharodontosaurids, from the Campanian and Maastrichtian epochs, are likely misidentified remains of abelisaurids. The phylogenetically problematic megaraptorans, which may not be carnosaurs, became extinct around 84 mya.