Ornithostoma is a genus of pterodactyloid pterosaurs. Pterodactyloids were the last surviving pterosaurs when the order became extinct at the end of the Cretaceous Period, together with the non-avian dinosaurs and most marine reptiles. Pterodactyls were any of a number of genera of flying reptiles of the extinct order Pterosauria, from the Jurassic and Cretaceous periods, having a highly reduced tail and teeth, birdlike beak and and a wingspan of 3.3 ft or less. Pterosaurs (winged lizard) were flying reptiles of the order Pterosauria. Pterosaurs are the earliest vertebrates known to have evolved powered flight. Illustration originally captioned: The Great Pterodactyl Ornithostoma, after Lucas. American Museum of Natural History. No date.