Chiromantes haematocheir

Chiromantes haematocheir is a mudflat crab of the family Sesarmidae (subfamily Sesarminae), which is endemic to East Asia. It is known under the common names red-clawed crab or akategani (Japanese) and the Latin names Grapsus haematocheir and Sesarma haematocheir. It is quite distinct from the other species placed in the genus Chiromantes, and the genus may be restricted to this one species. C. haematocheir has a square carapace with a smooth surface and irregular stripes along the sides. Males have large, smooth chelae with curved claws. The color of these crabs varies throughout their development; juvenile crabs typically have a white or yellow carapace, while adults are usually crimson red. Known as 'yama-gani' in Japan, this variety of C. haematocheir can be found in Nagano prefecture where elevations often exceed 600 metres (2,000 ft) above sea level, and distances to the ocean can be over 80 kilometres (50 mi). This indicates that they are freshwater crabs, probably living in forest streams (if they live in water at all).