Allosauroidea is a superfamily or clade of theropod dinosaurs which contains three families — the Sinraptoridae, Carcharodontosauridae and Allosauridae. The oldest-known allosauroid, Sinraptor dongi, appeared in the Middle Jurassic (Bathonian stage) of China, and the latest-known survivors of the family are the carcharodontosaurids of the Late Cretaceous, Cenomanian stage). Allosauroids had long, narrow skulls, large orbits, three-fingered hands, and usually had "horns" or ornamental crests on their heads. The most famous and best understood allosauroid is the North American genus Allosaurus.