allosauroids were a clade of theropod dinosaurs. the oldest-known allosauroid, "shidaisaurus", appeared in the early middle jurassic (probably bajocian stage) of china. the last known surviving members of the group died out around 93 million years ago in asia ("shaochilong") and south america ("mapusaurus"), though the megaraptorans, including the late-surviving "orkoraptor". allosauroids had long, narrow skulls, large orbits, three-fingered hands, and usually had "horns" on their heads. the most famous and best understood allosauroid is the "allosaurus".