Otton Frog - Otton Frog

A frog of the family Ranidae in the order Anura in the class Amphibians. It inhabits Amami Oshima, where it is simply called Otton by locals. Its back is brown with small black spots scattered over it, small bumps on its skin are prominent on the sides, and there are large irregular dark spots on its ventral surface. It has a stocky body, reaching a length of 12 cm. It inhabits shallow puddles in forests or on the forest edges, and lays eggs in the summer. Along with its closely-related Holst's frog R. holsti, which inhabits the main island of Okinawa, it is exceptional for a frog in having five fingers on its forelimbs, with the bone of the first finger being sharp and causing bleeding when scratched.

[Mitsuru Kuramoto]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

両生綱無尾目アカガエル科のカエル。奄美(あまみ)大島に生息し、現地では単にオットンとよばれる。背面は茶褐色で小黒斑(こくはん)が散在し、皮膚にある小さな隆起は体側部に顕著で、腹面には不規則な大形暗色斑がある。ずんぐりした体形で、体長は12センチメートルに達する。森林内や林縁部の浅い水たまりにすみ、夏季に産卵する。沖縄本島にすむ近縁のホルストガエルR. holstiとともにカエルとしては例外的に前肢に5本の指があり、第1指の骨は鋭くとがって、ひっかかれると出血する。

［倉本　満］

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