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

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 ...

in the family Ranidae. It is

endemic Endemism is the state of a species being found 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 found elsew ...

to the islands of

Amami Ōshima , also known as Amami, is the largest island in the Amami archipelago between Kyūshū and Okinawa. It is one of the Satsunan Islands. The island, 712.35 km2 in area, has a population of approximately 73,000 people. Administratively it is d ...

and

Kakeromajima or Kakeroma-tō is one of the Satsunan Islands, classed with the Amami archipelago between Kyūshū and Okinawa. The island, in area, has a population of approximately 1,600 persons. Administratively it is part of the town of Setouchi in ...

in the

Ryukyu Islands The , also known as the or the , are a chain of Japanese islands that stretch southwest from Kyushu to Taiwan: the Ōsumi, Tokara, Amami, Okinawa, and Sakishima Islands (further divided into the Miyako and Yaeyama Islands), with Yonaguni ...

, Japan. Its natural

habitat In ecology, the term habitat summarises the array of resources, physical and 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 ...

s are subtropical or tropical moist lowland

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

s, freshwater

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...

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 and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

through

deforestation Deforestation or forest clearance is the removal 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. The most concentrated d ...

, and predation by introduced

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

s. 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 five-fingered '' Hypsiboas rosenbergi'' frogs of Latin America, the Otton frog has five fingers.

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

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