Pterosauria
Noun | 1. | Pterosauria - extinct flying reptiles: pterosaurs |
单词 | pterosauria | |||
释义 | Pterosauria
PterosauriaPterosauria[‚ter·ə′sȯr·ē·ə]Pterosauria(flying reptiles), a superorder of extinct reptiles of the subclass Archosauria that lived in the Jurassic and Cretaceous periods. In the process of adaptation for flight, pterosaurs became greatly specialized. A membrane of skin—the wing—stretched between the sides of the body and the front extremities, which had an exceptionally long fourth finger. Judging from impressions in rocks, the body had a hairy covering. Possibly, the pterosaurs were warm-blooded. The bones lacked spongy tissue and were frequently hollow; the skull had no apparent sutures between the bones. The orbital cavities were very large. Early forms (rhamphorhynchids) had well-developed pointed teeth. Later species, such as the pterodactyls, had reduced teeth and the jaw evolved into a toothless bill covered with a horny layer. The tail was long in the rhamphorhynchids and very short in the pterodactyls. All species had long, mobile necks and a powerful sternum. In size, pterosaurs ranged from the size of a sparrow to sizes with a wingspread exceeding 7 m (in the pteranodons). Pterosaurs inhabited the shores of seas and other bodies of water, feeding primarily on fish; small species fed on insects. Numerous remains have been found in North America and Western Europe. In the USSR remains have been found in southern Kazakhstan and the Trans-Volga Region. Pterosaurs are an interesting example of the convergence of reptiles with birds and mammals (the bats). REFERENCEOsnovy paleontologii: Zemnovodnye, presmykaiushchiesia i ptitsy. Moscow, 1964.A. K. ROZHDESTVENSKII PterosauriaPterosauriapterodactyls; flying archosaurs of the Jurassic and Cretaceous.Pterosauria
Synonyms for Pterosauria
|
|||
随便看 |
|
英语词典包含2567994条英英释义在线翻译词条,基本涵盖了全部常用单词的英英翻译及用法,是英语学习的有利工具。