Species information
Scientific name: Geograpsus crinipes
Japanese name: オオカクレイワガニ
Chinese name: 毛足陸方蟹
English name: Pale shore crab
Origin: Japan (Izu Oshima, Ogasawara Islands, Satsuma Peninsula, Ryukyu Islands south of Amami Oshima), Taiwan, Red Sea, east coast of Africa, Indian Ocean, Pacific Ocean
Ecology and description
The pale shore crab is a land crab that lives on coasts near the high-tide line. It lives in burrows behind the beach and is often found under objects in the splash zone. Large individuals have a carapace width of more than 40mm.
This species is similar to the congeneric purple-backed shore crab (Geograpsus grayi), but its carapace is flattened and broadly square with nearly straight sides, whereas the carapace of the purple-backed shore crab narrows toward the rear. This species is mostly brown with slightly paler large claws, while the purple-backed shore crab is mostly purple.
References:
Crabs of Japan (Geograpsus crinipes)
Australian Faunal Directory (Geograpsus crinipes)
Cook Islands Biodiversity & Natural Heritage (Geograpsus crinipes)
Nature of Kagoshima vol. 52 (record of Geograpsus crinipes from the Satsuma Peninsula, Kagoshima Prefecture)
Nature of Kagoshima vol. 50 (first record of Geograpsus grayi in Kyushu, from the Satsuma Peninsula)
Field photographs taken during our tours, with observation dates
Most of the crabs I have seen in northern Okinawajima are purple-backed shore crabs (Geograpsus grayi), and I do not think I have seen this species. It may be easier to find at night, closer to the shoreline.
