The Japanese fire-bellied newt or Japanese fire-bellied salamander (Cynops pyrrhogaster) is a species of newt endemic to Japan. The skin on its upper body is dark and its lower regions bright red, although coloration varies with age, genetics, and region. Adults are 8 to 15 cm (3.1 to 5.9 in) long. To deter predators, Japanese fire-bellied newts contain high levels of tetrodotoxin, a neurotoxin accumulated mainly from their diet.
The species is found on many Japanese islands, including Honshu, Shikoku, and Kyushu. Their habitats include both natural and artificial bodies of water, as well as forests and grasslands. They breed from spring to the beginning of summer, both sexes producing pheromones when ready to mate. Eggs are laid separately, hatching after about three weeks. They grow from larval to juvenile form in between five and six months. Juveniles eat soil-dwelling prey, and adults eat a wide variety of insects, tadpoles, and the eggs of their own species. They have several adaptations to avoid predators, although which they use depends on where they live. Several aspects of their biology have been studied, including their ability to regrow missing body parts.
The Japanese fire-bellied newt first diverged from its closest relative in the Middle Miocene, before splitting into four distinct varieties, each with a mostly separate range, although all four are formally recognized as composing a single species. Currently, their population is declining, and they face threats from disease and the pet trade. They can be successfully kept in captivity.
Etymology and taxonomy
The species was first scientifically described by German zoologist Heinrich Boie in 1826 as Molge pyrrhogaster,[note ] based on specimens brought from Japan to Europe. He compared it to the smooth newt, saying he would have mistaken the former for the latter, had he not known it was from Japan. None of the specimens he studied were fully mature. Pyrrhogaster is derived from Greek, purrhos (lit.β'fire') and gastΔr (lit.β'belly'). Salamandra subcristata was described by Coenraad Jacob Temminck and Hermann Schlegel in 1838 and transferred to Cynops later that year by Swiss naturalist Johann Jakob von Tschudi, and in 1850, Cynops subcristata and Molge pyrrhogaster were synomized as Cynops pyrrhogaster by the British zoologist John Edward Gray.A study of mitochondrial DNA in 2001 indicated that its supposed fellow members of Cynops, C. cyanurus and C. wolterstorffi, may belong to a different genus.
The Integrated Taxonomic Information System lists sixteen synonyms for Cynops pyrrhogaster.Common names of the species include Japanese fire-bellied newt, red-bellied newt, and Japanese fire-bellied salamander.Studies examining morphological and geographic variation had formerly recognized six races: Tohoku, Kanto, Atsumi, intermediate, Sasayama, and Hiroshima, one of which, the Sasayama, was described as a subspecies in 1969 by Robert Mertens as Triturus pyrrhogaster sasayamae, which is now considered a synonym of C. pyrrhogaster. Modern molecular analysis supports the division of C. pyrrhogaster into four clades instead.In particular, the validity of the Sasayama and intermediate races has never been proven, with one study finding no behavioral differences between the two supposed forms.
