Rediscovery of two carcinoplax crabs in the kumanonada sea east of the kii peninsula central japan with notes on distribution of the related species

Takeda, M.; Yanagisawa, F.

Two species of crabs of the family Goneplacidae, Carcinoplax indica Doflein, 1904 known from off Great Nicobar Island and the Suez Canal, and C. microphthalma Guinot et Richer de Forges, 1981 reported from off New Caledonia, were rediscovered in the Kumanonada Sea, Central Japan. C. indica is distinguished from C. longimana (de Haan) by having the narrower and rounded carapace with the front developed forward as a plated, and the short and heavy cheliped without a tubercle at the subdistal part of inner surface of palm. C. microphthalma is rather aberrant in the genus Carcinoplax as having the dorsally and laterally convex carapace with a quite circular contour, and the short eyestalks with the degenerated corneae. The known Carcinoplax species are listed in Table 1, with brief notes on some species; most of the species are the West Pacific inhabitants known only by some records, only four species are extended their distribution to the indian Ocean, and only one species is known from West Africa. Such a pattern of occurrence and distribution as a whole indicates that the recent Carcinoplax species are possible relics of the Miocene ancestor.