Allosauroidea
Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Metriacanthosauridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae. The oldest-known allosauroid,
Shidaisaurus jinae, appeared in the early Middle Jurassic of China. The last known definitive surviving members of the group died out around 93 million years ago in Asia and South America, though the megaraptorans, including the late-surviving
Orkoraptor of the Late Cretaceous,, may belong to the group as well. Additional, but highly fragmentary, remains probably belonging to carcharodontosaurids have been found from the Campanian-Maastrichtian boundary in Brazil. 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.