What is (H. Milne Edwards, 1837) (Crustacea: Brachyura: Sesarmidae)?

The identity of the widely distributed mangrove and riverine sesarmid crab (H. Milne Edwards, 1837) is clarified. The species has been reported from Madagascar to the South Pacific, but its taxonomy was previously confused. On the basis of morphological characters and available molecular evidence (using 16S rDNA and cytochrome oxidase subunit I), is restricted to the western Indian Ocean and A. Milne-Edwards, 1869 is confirmed to be its junior synonym. (Hess, 1865), long synonymised under , is here recognised as a separate species and a neotype from Samoa is designated. The identity of the poorly known (Hess, 1865), which has often been confused with , is also clarified, and a neotype is selected from Fiji. Specimens from the eastern Indian Ocean and western Pacific are here identified as two new species, sp. nov. and sp. nov.