 The closest relatives of "Seychellum" are the two species of "Deckenia" from the African mainland.The two-lobed shape of the last segment of the mandibular palp, which had been used to argue for a close relationship between "Seychellum" and Indian crabs of the family Gecarcinucidae, does not appear to be a reliable phylogenetic character.The presence of a strictly freshwater species on the Seychelles is hard to explain, biogeographically.