The systematics of the land crabs of the Discoplax hirtipes (Dana, 1851) species-group (Crustacea: Decapoda: Brachyura: Gecarcinidae), with description of a new species from the eastern Indian Ocean

The Indo-West Pacific gecarcinid Discoplax hirtipes (Dana, 1851) is one of the best known land crabs in the Indo-West Pacific, with a range spanning from the eastern Indian Ocean to Hawaii. Recently, the famous blue population of "D. hirtipes" from Christmas Island was described as a new species, D. celeste Ng & Davie, 2012. A revision of the D. hirtipes species-group using morphological and genetic data from mitochondrial 16S rRNA and COI (cytochrome oxidase subunit I) shows that the species can be divided into three distinct species; with the Indian Ocean population belonging to an undescribed taxon. The redescription of the taxa in the species-group as well as characterisation of the new species from the eastern Indian Ocean forms the basis of the present paper.