supply and strong muscles made pterosaurs powerful and capable flyers. Pterosaurs are often referred to by popular media or the general public as "flying dinosaurs", but dinosaurs are defined as the descendants of the last common ancestor of the Saurischia and Ornithischia, which excludes the pterosaurs. Pterosaurs are nonetheless more closely related to birds and other dinosaurs than to crocodiles or any other living reptile, though they are not bird ancestors. Pterosaurs are also colloquially referred to as pterodactyls, particularly in fiction and journalism. However, technically, pterodactyl may refer to members of the genus Pterodactylus, and more broadly to members of the suborder Pterodactyloidea of the pterosaurs. Pterosaurs had a variety of lifestyles. Traditionally seen as fish-eaters, the group is now understood to have also included hunters of land animals, insectivores, fruit eaters and even predators of other pterosaurs. They reproduced by eggs, some fossils of which have been discovered. Description The anatomy of pterosaurs was highly modified from their reptilian ancestors by the adaptation to flight. Pterosaur bones were hollow and air-filled, like those of birds. This provided a higher muscle attachment surface for a given skeletal weight. The bone walls were often paper-thin. They had a large and keeled breastbone for flight muscles and an enlarged brain able to coordinate complex flying behaviour. Pterosaur skeletons often show considerable fusion. In the skull, the sutures between elements disappeared. In some later pterosaurs, the backbone over the shoulders fused into a structure known as a notarium, which served to stiffen the torso during flight, and provide a stable support for the shoulder blade. Likewise, the sacral vertebrae could form a single synsacrum while the pelvic bones fused also. Basal pterosaurs include the clades Dimorphodontidae (Dimorphodon), Campylognathididae (Eudimorphodon, Campyognathoides), and Rhamphorhynchidae (Rhamphorhynchus, Scaphognathus). Pterodactyloids include the clades Ornithocheiroidea (Istiodactylus, Ornithocheirus, Pteranodon), Ctenochasmatoidea (Ctenochasma, Pterodactylus), Dsungaripteroidea (Germanodactylus, Dsungaripterus), and Azhdarchoidea (Tapejara, Tupuxuara, Quetzalcoatlus). The two groups overlapped in time, but the earliest pterosaurs in the fossil record are basal pterosaurs, and the latest pterosaurs are pterodactyloids. The position of the clade Anurognathidae (Anurognathus, Jeholopterus, Vesperopterylus) is debated. Anurognathids were highly specialized. Small flyers with shortened jaws and a wide gape, some had large eyes suggesting nocturnal or crepuscular habits, mouth bristles, and feet adapted for clinging. Parallel adaptations are seen in birds and bats that prey on insects in flight. Size Pterosaurs had a wide range of sizes, though they were generally