Nyctosaurus is a genus of pterodactyloid pterosaur, the remains of which have been found in the Niobrara Formation of the mid-western United States, which, during the late Cretaceous Period, was covered in an extensive shallow sea. 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.