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.
Ankalagon saurognathus
The main feature that distinguishes "A. saurognathus" from the ancestral "Dissacus" species is its size: "Ankalagon" grew to be as large as a bear, as compared to the coyote or jackal-sized species of "Dissacus". In fact, the only North American mesonychids that surpassed "Ankalagon" in size were the larger species of the Early Eocene genus, "Pachyaena", such as "P. gigantea" and "P. ossifraga", which, too, grew to the size of bears.