Carnosauria is an extinct group of carnivorous theropod dinosaurs that lived during the Jurassic and Cretaceous periods.

While Carnosauria was historically considered largely synonymous with Allosauroidea, some recent studies have revived Carnosauria as clade including both Allosauroidea and Megalosauroidea (which is sometimes recovered as paraphyletic with respect to Allosauroidea), and thus including the majority of non-coelurosaurian members of theropod clade Tetanurae. Other researchers have found Allosauroidea and Megalosauroidea to be unrelated groups.

Distinctive characteristics of carnosaurs include large eye sockets, 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 174 million years ago, and the last definitive carnosaur family Carcharodontosauridae became extinct in the Turonian epoch of the Late Cretaceous around 90 million years ago. Some theropod remains, once suggested to be putative carcharodontosaurids from the Maastrichtian epoch (72–66 mya) in South America, were later reinterpreted as those of other theropod groups including the abelisaurids and maniraptorans.

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