Deep sea swimming crabs of the Charybdis miles species group in the western Indian Ocean (Crustacea : Decapoda : Portunidae)

The deep-sea species of the Charybdis miles group occurring in the western Indian Ocean are revised on the basis of recent collections obtained by Ger man and Russian expeditions. Two new species are described, Charybdis meteo r sp. n. from the Straits of Bab el Mandeb and Charybdis crosnieri sp. n. f rom the insular margins and seamounts of the western Indian Ocean, which ha s been previously identified as Charybdis sagamiensis Parisi, 1916. The C. miles group represents a lineage with a probably relatively recent tendency for submergence which culminated in the formation of C. acutidens Turkay, 1986, a characteristic species of the deep Red Sea water mass.