Pteranodon
Pteranodon (; from Greek πτερόν ( pteron, "wing") and ἀνόδων (anodon, "toothless") is a genus of pterosaur that included some of the largest known flying reptiles, with wingspans over 8 meters (26 feet). They lived during the late Cretaceous geological period of North America in present-day Kansas, Alabama, Nebraska, Wyoming, and South Dakota. More fossil specimens of "Pteranodon" have been found than any other pterosaur, with about 1,200 specimens known to science, many of them well preserved with nearly complete skulls and articulated skeletons. It was an important part of the animal community in the Western Interior Seaway.
Azhdarchidae
Azhdarchidae (from Persian word "azhdar" (), a dragon-like creature in Persian mythology) is a family of pterosaurs known primarily from the late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the early Cretaceous as well (late Berriasian age, about 140 million years ago). Azhdarchids included some of the largest-known flying animals of all time, but members no larger than a cat have also been found. Originally considered a sub-family of Pteranodontidae, Nesov (1984) named the azhdarchinae to include the pterosaurs "Azhdarcho", "Quetzalcoatlus", and "Titanopteryx" (now known as "Arambourgiania"). They were among the last known surviving members of the pterosaurs, and were a rather successful group with a worldwide distribution. By the time of the end-Cretaceous mass extinction, most pterosaur families except for the Azhdarchidae disappear from the fossil record, but recent studies indicate a wealth in pterosaurian faunas, including pteranodontids, nyctosaurids, tapejarids and several indeterminate forms. Some taxa like "Navajodactylus", "Bakonydraco" and "Montanazhdarcho" were moved from Azhdarchidae to other clades.