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Pterosaur
Pterosaurs (; meaning "winged lizard") were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period (228 to 66 million years ago〔Barrett, P. M., Butler, R. J., Edwards, N. P., & Milner, A. R. (2008). "Pterosaur distribution in time and space: an atlas". ''Zitteliana'', 61-107. ()〕). 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. Early species had long, fully toothed jaws and long tails, while later forms had a highly reduced tail, and some lacked teeth. Many sported furry coats made up of hair-like filaments known as pycnofibers, which covered their bodies and parts of their wings. Pterosaurs spanned a wide range of adult sizes, from the very small ''Nemicolopterus'' to the largest known flying creatures of all time, including ''Quetzalcoatlus'' and ''Hatzegopteryx''.
Pterosaurs are often referred to in the popular media and by the general public as flying dinosaurs, but this is scientifically incorrect. The term "dinosaur" is restricted to just those reptiles descended from the last common ancestor of the groups Saurischia and Ornithischia (clade Dinosauria, which includes birds), and current scientific consensus is that this group excludes the pterosaurs, as well as the various groups of extinct marine reptiles, such as ichthyosaurs, plesiosaurs, and mosasaurs. Like the dinosaurs, and unlike these other reptiles, pterosaurs are more closely related to birds than to crocodiles or any other living reptile. Pterosaurs are also colloquially referred to as pterodactyls, particularly by journalists. Technically, "Pterodactyl" refers only to members of the genus ''Pterodactylus'',〔 and more broadly to members of the suborder Pterodactyloidea of the pterosaurs.
==Description==
The anatomy of pterosaurs was highly modified from their reptilian ancestors by the adaption to flight. Pterosaur bones were hollow and air-filled, like the bones of birds. They had a keeled breastbone that was developed for the attachment of flight muscles and an enlarged brain that shows specialised features associated with flight. 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 scapula (shoulder blade).
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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