Hesperornis regalis

A large, flightless ornithuran close to the origin of modern birds, Hesperornis lived in the Late Cretaceous inland seas of North America. Hesperornis had powerful hind limbs for foot-propelled swimming, vestigial wings, and jaws still lined with teeth. It presumably dove to chase fish, while coming ashore to rest, or when it was time to mate and lay eggs. On land they would have walked with their bodies upright, perhaps with a clumsy-looking gait not too different from penguins today.