砂浜性スナガニ類の関東以南太平洋岸における分布

抄録

The distribution of the ghost crabs (genus Ocypode) was investigated in 9 regions (the Boso Peninsula, the Izu Peninsula, south Shikoku, Amakusa, Kagoshima mainland, Tanegashima Island, Amami-Oshima Island, Okinawajima Island and Iriomotejima Island) along the Pacific coast of Japan. The temperate species of Ocypode stimpsoni was rec­orded from Izu, south Shikoku, Amakusa, Kagoshima mainland and Tanegashima, with their abundance being lower than the tropical/subtropical species of Ocypode ceratophthalma and Ocypode sinensis in all the regions. Juvenile O. stimpsoni, which occurred in Amakusa, Kagoshima mainland and Tanegashima, was not collected in Izu or south Shikoku. Ocypode ceratophthalma and O. sinensis occurred in all regions. Another tropical/subtropical species of Ocypode cordimanus was rec­orded by a few specimens from south Shikoku, Amami-Oshima Island and Okinawajima Island. In all the three tropical/subtropical species, the body size of the collected specimens was smaller in the mainland of Japan than in the Nanseishoto Islands. From the body sizes of the largest specimens collected in each region, the maturation was estimated to occur in regions southern from south Shikoku in O. ceratophthalma and in regions southern from Izu in O. sinensis.