A new species of bythograeid crab, Austinograea rodriguezensis (Decapoda, brachyura), associated with active hydrothermal vents from the Indian Ocean

Austinograea rodriguezensis sp. nov. is the first bythograeid crab to be described from the Indian Ocean. Specimens were collected from 22 kin north of the Rodriguez Triple Junction, at 2,420 to 2,450 in depth, during the KR00-05 Indian Ocean Cruise (JAMSTEC) in August 2000. This is the fourth species of the genus Austinograea described and the tenth in the family Bythograeidae. This crab inhabits black smoker complexes (temperature 360degreesC, pH 3.4) with other vent-associated animals, including Rimicaris shrimps, Bathymodiolus mussels, Alviniconcha snails, unidentified actiniarians, and zoarcid fish. Austinograea rodriguezensis differs remarkably from the other three species of Austinograea in the male gonopod and chela morphology. However, other characters of the species are very similar to Austinograea williamsi. A key to the species of the genus Austinograea is provided.