 Ornithocheiroids were the most advanced group of pterosaurs, as the group includes the clade Azhdarchoidea, of which its members lived until the Maastrichtian stage of the Late Cretaceous, around 66 million years ago.Notable pterosaurs from this group include the pteranodontians "Pteranodon" and "Nyctosaurus", the ornithocheirids "Ornithocheirus" and "Tropeognathus", as well as the azhdarchids "Hatzegopteryx" and "Quetzalcoatlus".The name Ornithocheiroidea was originally defined as an apomorphy-based taxon by Christopher Bennett in 1994.