''Triadobatrachus'' is an extinct genus of

salientia The Salientia (Latin ''salire'' (''salio''), "to jump") are a total group of amphibians that includes the order Anura, the frogs and toads, and various extinct proto-frogs that are more closely related to the frogs than they are to the Urodela ...

frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...

-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 Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is ...

about 250 million years ago, in what is now

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Afric ...

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

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...

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 is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...

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-J ...

. It was first discovered in the 1930s, when Adrien Massinot, near the village of

Betsiaka Betsihaka or Betsiaka is a town and commune ( mg, kaominina) in Madagascar. It is part of the district of Ambilobe, which is in the Diana Region. According to the 2001 commune census, the population of Betsihaka was 10,661. The genus ''Triadobat ...

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 251.902 Ma and Ma (million years ago). The Induan is someti ...

Middle Sakamena Formation Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (disambiguation) * Middle Brook (disambiguation) * Middle Creek ( ...

of the

Sakamena Group Sakamena is a village near Betroka in the region of Anosy in Madagascar. Sakamena is also the name of a Permian sedimentary geological formation that has yielded many vertebrate fossil, including Triadobatrachus (the first lissamphibian), Claudios ...

. 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 is a group of tetrapods that includes all modern amphibians. Lissamphibians consist of three living groups: the Salientia (frogs, toads, and their extinct relatives), the Caudata (salamanders, newts, and their extinct relativ ...

ns.

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

*Benes, Josef. Prehistoric Animals and Plants. Pg. 114. Prague: Artia, 1979. {{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