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(vertebrate zoology)
The superclass of the subphylum Vertebrata whose members typically possess four limbs; includes all forms above fishes.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a superclass of the subphylum Vertebrata. Tetrapods are predominantly terrestrial animals. However, they include amphibians, which did not lose their ties with water; the groups Ichthyosauria, Plesiosauria, Mosasauridae, Cetácea, and Pinnipedia, which returned to an aquatic way of life; and Pterosauria, birds, and bats, which adapted to life in the air.

In contrast to fish, which move by means of fins, tetrapods have two pairs of extremities that became adapted to locomotion on dry land. Another example of adaptation to life on land was the replacement of gill respiration by pulmonary respiration, which is preserved even in tetrapods that have returned to aquatic life. The body, naked in amphibians, the earliest tetrapods, became covered with horny scales, feathers, and fur in the higher vertebrates—reptiles, birds, and mammals. Other changes include the disconnection of the shoulder girdle from the skull, the separation of the cervical and sacral sections of the spinal column, and the development, in mammals, of the middle ear and later the outer ear to supplement the inner ear. The excretory and circulatory systems of tetrapods improved; in higher reptiles (mammal-like reptiles and Archosauria), birds, and mammals, arterial and venous blood circulated separately, and warm-bloodedness developed. The central nervous system also developed progressively.

Remains of the oldest tetrapods, of the genus Ichthyostega, have been discovered in Upper Devonian deposits.


Zhizn’ zhivotnykh, vols. 4–6. Moscow, 1969–71.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Studies of Brazilian snakes have indicated that the pentastomid Cephalobaena tetrapoda utilizes small vertebrates as intermediate hosts (Almeida et al., 2006a; 2007; 2008a).
Consideracoes sobre o genero Cephalobaena Heymons, 1922 (Linguatulida), Cephalobaena tetrapoda. Atas da Sociedade de Biologia do Rio de Janeiro, vol.
(2006a; 2008a; 2008b) indicates that two species of pentastomids, Cephalobaena tetrapoda Heymons, 1922 and Raillietiella furcocerca, should be generalists because of their recorded variety of hosts.
In Brazil, only four species of pentastomids have been reported until now, as snake parasites: Cephalobaena tetrapoda Heymons, 1922; Kiricephalus coarctatus (Diesing, 1850); Porocephalus crotali (Humboldt, 1808) and Raillietiella furcocerca (Diesing, 1863).
tetrapoda as a generalist parasite of the colubrids L.
nattereri were Cephalobaena tetrapoda and Raillietiella furcocerca.
tetrapoda the most frequent species, representing a prevalence of 30.8% (4/13) and the highest mean of intensity of infection (51.5 [+ or -] 32.7; range of 3-147).