Amphibia

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Amphibia (amphibians) Class that appeared first in the Devonian, having evolved from rhipidistian (lobe-finned) fish (see RHIPIDISTIA). They flourished in the Carboniferous and Permian. During the Triassic some forms, e.g. Mastodontosaurus, grew to 6 m long, and the first modern types were established. Today the amphibians are represented by just three groups, of which the Urodela (salamanders) and Anura (frogs and toads) are the best known (the third group, the caecilians (Apoda), are worm-like and burrowing). Most amphibians are found in damp environments and they occur on all continents except Antarctica.

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