The Otton frog (''Babina subaspera'') is a species of

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 ...

in the family Ranidae. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the islands of

Amami Ōshima , also known as Amami, is the largest island in the Amami Islands, Amami archipelago between Kyūshū and Okinawa Prefecture, Okinawa. It is one of the Satsunan Islands, all of which belong to Kagoshima Prefecture, Japan. The island, 712.35 ...

and Kakeromajima in the

Ryukyu Islands The , also known as the or the , are a chain of Japanese islands that stretch southwest from Kyushu to Geography of Taiwan, Taiwan: the Ryukyu Islands are divided into the Satsunan Islands (Ōsumi Islands, Ōsumi, Tokara Islands, Tokara and A ...

, Japan. Its natural

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

s are subtropical or tropical moist lowland

forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...

s, freshwater

marsh In ecology, a marsh is a wetland that is dominated by herbaceous plants rather than by woody plants.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p More in genera ...

es, and intermittent freshwater marshes. Once considered a delicacy as a source of food, it is now threatened by

habitat loss Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

through

deforestation Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...

, and predation by introduced

mongoose A mongoose is a small terrestrial carnivorous mammal belonging to the family Herpestidae. This family has two subfamilies, the Herpestinae and the Mungotinae. The Herpestinae comprises 23 living species that are native to southern Europe, A ...

s. Otton Frogs have a lifespan of approximately 7 years which is significantly different to common frog species’ life span of 10 -12 years. Due to the isolated island ecosystem, many factors play into the endangerment and the shorter lifespan of the species. It is one of only two species (the other being ''

Babina holsti Holst's frog (''Babina holsti'') is a species of frog in the family Ranidae. It is endemic to the Ryukyu Islands of Japan. It occurs on mountains of the Okinawa and Tokashiki islands. It lives in primary or recovered secondary broad-leaved eve ...

'') to possess a "pseudothumb" on the forelimbs.

Physiology and morphology

The Otton frog has been denoted the 'wolverine frog' due to hidden retractable claws, which are sharp and shoot out from under their thumbs. Both male and female Otton frogs have these claws, with male claws being typically longer than those of the females. Like the '' Hypsiboas rosenbergi'' frogs of Latin America, the Otton frog possess a thumb-like structure called the pseudothumb on its forelimbs, giving the impression of a total of five fingers. The pseudothumb helps the Otton frog defend themselves from predators.
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Behaviour

This rare frog uses its switch-blade claws to fight and in mating. Although both sexes have claws, apparently only the males use them, probably to anchor the female to the male during mating. During fighting, two male Otton frogs wrestle each other until in an embrace. They then impale their opponent on their retractable spikes.

References

Endemic amphibians of Japan Babina (frog) Amphibians described in 1908 Endemic fauna of the Ryukyu Islands Taxonomy articles created by Polbot {{Ranidae-stub