page_title: Pterosaur
section_title: Extinction
hierarchical_section_title: Pterosaur / Evolution and extinction / Extinction
caption_attribution_description: English: The skeleton of a Pterosaurs on display in the Arizona Museum of Natural History in Mesa Arizona.
context_page_description: Pterosaurs were flying reptiles of the extinct clade or order Pterosauria. They existed during most of the Mesozoic: from the late Triassic to the end of the Cretaceous. Pterosaurs are the earliest vertebrates known to have evolved powered flight. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the ankles to a dramatically lengthened fourth finger.
  There were two major types of pterosaurs. Basal pterosaurs were smaller animals with fully toothed jaws and, typically, long tails. Their wide wing membranes probably included and connected the hind legs. On the ground, they would have had an awkward sprawling posture, but their joint anatomy and strong claws would have made them effective climbers, and they may have lived in trees. Basal pterosaurs were insectivores or predators of small vertebrates. Later pterosaurs evolved many sizes, shapes, and lifestyles. Pterodactyloids had narrower wings with free hind limbs, highly reduced tails, and long necks with large heads.
context_section_description: It was once thought that competition with early bird species might have resulted in the extinction of many of the pterosaurs. Part of this is due to the fact it used to be thought that by the end of the Cretaceous, only large species of pterosaurs were present (no longer true; see below). The smaller species were thought to have become extinct, their niche filled by birds. However, pterosaur decline (if actually present) seems unrelated to bird diversity, as ecological overlap between the two groups appears to be minimal. In fact, at least some avian niches were reclaimed by pterosaurs prior to the KT event. At the end of the Cretaceous period, the Cretaceous–Paleogene extinction event, which wiped out all non-avian dinosaurs and most avian dinosaurs as well, and many other animals, seems also to have taken the pterosaurs.
  In the early 2010s, several new pterosaur taxa were discovered dating to the Campanian/Maastrichtian, such as the ornithocheirids Piksi and "Ornithocheirus", possible pteranodontids and nyctosaurids, several tapejarids and the indeterminate non-azhdarchid Navajodactylus. Small azhdarchoid pterosaurs were also present in the Campanian. This suggests that late Cretaceous pterosaur faunas were far more diverse than previously thought, possibly not even having declined significantly from the early Cretaceous.
  Small-sized pterosaur species apparently were present in the Csehbánya Formation, indicating a higher diversity of Late Cretaceous pterosaurs than previously accounted for. The recent findings of a small cat-sized adult azhdarchid further indicate that small pterosaurs from the Late Cretaceous might actually have simply been rarely preserved in the fossil record, helped by the fact that there is a strong bias against terrestrial small sized vertebrates such as juvenile dinosaurs, and that their diversity might actually have been much larger than previously thought.
  At least some non-pterodactyloid pterosaurs survived into the Late Cretaceous, postulating a Lazarus taxa situation for late Cretaceous pterosaur faunas.
caption: The skeleton of a pterosaur on display in the Arizona Museum of Natural History in Mesa Arizona.
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