Description of the supergiant isopod Bathynomus raksasa sp. nov. (Crustacea, Isopoda, Cirolanidae) from southern Java, the first record of the genus from Indonesia

The giant isopod genus Bathynomus A. Milne-Edwards, 1879, is recorded for the first time in Indonesian waters, from deep waters off southern Java in the Indian Ocean. Bathynomus raksasasp. nov. is described and notes on juvenile specimens of an unidentified species found in the same locality are also provided. Bathynomus raksasasp. nov. is characterized by the large size (averaging at 330 mm), narrowly rounded clypeus apex, prominent longitudinal carina on the clypeus, convex lateral margins of the uropodal exopod and endopod, produced distolateral corners of the uropodal exopod and endopod which have acute ends, an uropodal exopod with a setal fringe of medium length (69%), a pleotelson 1.6 times wider than long with the posterior margin medially concave, and the large number (11–13) of spines on the pleotelson.