The identity of Pilumnoplax acanthomerus Rathbun, 1911 (Crustacea: Decapoda: Brachyura: Xanthidae), with new records from the central and western Pacific

The identity of the rare xanthid crab, Pilumnoplax acanthomerus Rathbun, 1911, originally described from the Amirante Islands in the western Indian Ocean, is elucidated. Stevcic (2005) transferred the species from Pilumnoplax Stimpson, 1858, to a new genus, Linnaeoxantho. This monotypic genus is re-diagnosed and new morphological characters are highlighted. New records from Ryukyu and Line Islands, in the western and central Pacific, respectively, are reported. Linnaeoxantho is compared with the morphologically similar Melybia Stimpson, 1871, from the western Atlantic, and their affinities are discussed. Linnaeoxanthinae Stevcic, 2005, is here recognised as a valid xanthid subfamily for Linnaeoxantho and Melybia, and is considered to have priority over Melybiidae Stevcic, 2005.