Portal:Crustaceans/Selected article/17

Seychellum alluaudi is a species of freshwater crab endemic to the Seychelles, and the only true freshwater crab in that country. It lives in rainforest streams on the archipelago's granitic high islands. Although it may be abundant, little is known about its biology, and it is currently listed as Least Concern on the IUCN Red List. Adults are dark yellow to brown in colour, and have a quadrangular carapace with a width of around 50 mm (2 in). The claws are unequal in size.

S. alluaudi was described as a species of Deckenia in 1893 and 1894, and later split off into the monotypic segregate genus Seychellum. Its closest relatives are the two species currently in Deckenia, both of which are found in East Africa. Several hypotheses have been published to explain how Seychellum reached its isolated location; some means of transport across the open ocean is considered the most likely explanation. Seychellum differs from Deckenia in a number of characters, including the lengths of the legs and antennae, and the fact that Deckenia species have flattened legs, compared to those of Seychellum.