''Triadobatrachus'' is an extinct genus of salientian

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

-like amphibians, including only one known species, ''Triadobatrachus massinoti''. It is the oldest member of the frog lineage known, and an excellent example of a transitional fossil. It lived during the

Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between 251.9 Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which ...

about 250 million years ago, in what is now

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

. ''Triadobatrachus'' was long, and still retained many primitive characteristics, such as possessing at least 26

vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

e, where modern frogs have only four to nine. At least 10 of these vertebrae formed a short tail, which the animal may have retained as an adult. It probably swam by kicking its hind legs, although it could not jump, as most modern frogs can. Its

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

resembled that of modern frogs, consisting of a latticework of thin bones separated by large openings. This creature, or a relative, evolved eventually into modern frogs, the earliest example of which is '' Prosalirus'', millions of years later in the

Early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic� ...

. It was first discovered in the 1930s, when Adrien Massinot, near the village of Betsiaka in northern Madagascar, found an almost complete skeleton in the

Induan The Induan is the first age of the Early Triassic epoch in the geologic timescale, or the lowest stage of the Lower Triassic series in chronostratigraphy. It spans the time between 251.9 Ma and 249.9 Ma (million years ago). The Induan is so ...

Middle Sakamena Formation of the Sakamena Group. The animal must have fossilized soon after its death, because all bones lay in their natural anatomical position. Only the anterior part of the skull and the ends of the limbs were missing. This fossil was initially described under the name ''Protobatrachus massinoti'' by the French paleontologist Jean Piveteau in 1936. Much more detailed description were published more recently. Although it was found in marine deposits, the general structure of ''Triadobatrachus'' shows that it probably lived for part of the time on land and breathed air. Its proximity to the mainland is further borne out by the remains of terrestrial plants found with it, and because most extant amphibians do not tolerate saltwater, and that this saltwater intolerance was probably present in the earliest

lissamphibia The Lissamphibia (from Greek λισσός (lissós, "smooth") + ἀμφίβια (amphíbia), meaning "smooth amphibians") is a group of tetrapods that includes all modern amphibians. Lissamphibians consist of three living groups: the Salientia ( ...

ns. ''Triadobatrachus'' is similar in age to the salientian '' Czatkobatrachus'' which is known from the

(

Olenekian In the geologic timescale, the Olenekian is an age (geology), age in the Early Triassic epoch (geology), epoch; in chronostratigraphy, it is a stage (stratigraphy), stage in the Lower Triassic series (stratigraphy), series. It spans the time betw ...

) of Poland.

Gallery

File:Triadobatrachus CT scan.jpg, CT-scan File:Triadobatrachus skeletal diagram.jpg, Diagram File:Triadobatrachus massinoti.JPG, Cast File:Triadobatrachus BW.jpg, Life restoration by N. Tamura

References

{{Taxonbar, from=Q134290 Prehistoric amphibian genera Triassic amphibians Early Triassic amphibians of Africa Induan life Fossils of Madagascar Transitional fossils Fossil taxa described in 1936