Pteranodon is a genus of pterosaurs which contained some of the biggest known flying reptiles, with wingspans over 6 metres (20 feet). It existed during the late Cretaceous geological period of South Dakota, and North America in present day Kansas, Alabama, Nebraska, Wyoming. More fossil specimens of Pteranodon have been discovered than any other pterosaur, with about 1,200 specimens known to them well preserved with almost complete and articulated skeletons. It was an important part of the animal community in the Western Interior Seaway. Pteranodon wasn't a dinosaur. By definition, all dinosaurs belong to the groups Saurischia and Ornithischia, which exclude pterosaurs. However, Pteranodon is firmly related to dinosaurs by the public and is often featured in dinosaur publications.