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an order of Amphibia. The adult salientians living today have short, wide bodies; the tail disappears during metamorphosis, and the tail section of the vertebral column turns into a rodlike bone called the urostyle. Both pairs of extremities are well-developed; the hind are longer than the fore. Most of the salientians are adapted to jumping. There are more than 2,500 species distributed in all parts of the world. The order Salientia is divided into six suborders—one fossil and five living—primarily on the basis of differences in vertebrae structure.
The suborder Proanura includes one family of primitive salientians (Protobatrachidae) with a single example (Protobatrachus massinoti) from the Lower Triassic deposits in northern Madagascar. It is about 10 cm long.
The suborder Amphicoela includes the most primitive modern salientians. The vertebrae are biconcave (amphicoelous), with vestiges of cartilage. The single family Liopelmidae has two genera—the Liopelma in New Zealand and the Ascaphus in North America.
Frogs of the suborder Opisthocoela have vertebrae that are concave behind (opisthocoelous). The family Discoglossidae is widespread in Europe and Asia; in the USSR it is represented by the genus Bombina. The family Pipidae is exclusively aquatic; frogs of the genus Xenopus live in Africa and those of the Pipa, in South America.
Frogs of the suborder Anomocoela have procoelous vertebrae or vertebrae with free intervertebral discs. The only family is the Pelobatidae in North America, in Europe, in Southeast Asia, and on the Seychelles. There are two genera in the USSR—the Pelobates and the Pelodytes.
Frogs of the suborder Procoela have procoelous vertebrae. There are three families containing numerous genera and species, which vary completely in external appearance and biology. The broad and diverse family of Bufonidae is found in all parts of the world; in the USSR it is represented only by the genus Bufo. The African toad Nectophrynoides is the only salientian whose tadpoles develop internally (live birth). Among the South American family of toads Pseudidae, the large and brightly-colored Ceratophrys is particularly known. The genus Leptodactylus, which is widespread in South and Central America, resembles frogs more than toads. The family of South American Brachycephalidae contains a large number of small toads, mostly ground or tree species, often having bright and varied colors. Among them are the Rhinoderma and Dendrobates. The large family of Hylidae is distributed largely in America and Australia, with some species in Eurasia; the USSR has only the genus Hyla. Most frogs of the Hylidae live in trees and many lay their eggs out of water; for example, frogs of the genus Phyllomedusa deposit spawn on the leaves of bushes overhanging water. In the Hemiphractinae subfamily, the laid eggs develop between folds of skin on the mother’s back.
In the Diplasiocoela the first seven vertebrae are usually procoelous and the eighth is biconcave; sometimes all the vertebrae are procoelous. Frogs of the family Ranidae, which contains many species, are found in all parts of the world; they are absent in New Zealand and the southern parts of Australia and South America. The USSR has only the genus Rana, which has an extraordinarily wide distribution. The family Brevicipitidae is located in North and South America, in Africa, on Madagascar, in South and East Asia, and on nearby islands. The family Polypedatidae is distributed in Southeast Asia, Indonesia, Africa, and on Madagascar; the family contains mostly arboreal species.
REFERENCESTerent’ev, P. V. Gerpetologiia. Moscow, 1961.
Zhizn’ zhivotnykh, vol. 4, part 2. Moscow, 1969.
N. V. SHIBANOV