Pterosauria


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Pterosauria

[‚ter·ə′sȯr·ē·ə]
(paleontology)
An extinct order of flying reptiles of the Mesozoic era belonging to the subclass Archosauria; the wing resembled that of a bat, and a large heeled sternum supported strong wing muscles.

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).

REFERENCE

Osnovy paleontologii: Zemnovodnye, presmykaiushchiesia i ptitsy. Moscow, 1964.

A. K. ROZHDESTVENSKII