Nyctosaurus is a genus of nyctosaurid pterosaur from the Late Cretaceous period of what is now the Niobrara Formation of the mid-western United States, which, during the time Nyctosaurus was alive, was covered in an extensive shallow sea. Some remains belonging to a possible Nyctosaurus species called N.lamegoi have been found in Brazil, making Nyctosaurus more diverse. The genus Nyctosaurus has had numerous species referred to it, though how many of these may actually be valid requires further study. At least one species possessed an extraordinarily large antler-like cranial crest.