Seychellum

Seychellum alluaudi
Drawing of dorsal view of Seychellum alluaudi
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Infraorder: Brachyura
Family: Deckeniidae
Genus: Seychellum
Ng, Števčić & Pretzmann, 1995
Species:
S. alluaudi
Binomial name
Seychellum alluaudi
Synonyms [2]
  • Deckenia alluaudi A. Milne-Edwards & Bouvier, 1893
  • Deckenia cristata Rathbun, 1894

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. If its habitat were to decline in quality, S. alluaudi might become endangered, but it is currently listed as Vulnerable on the IUCN Red List.

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, including submerged "land bridges" and ancient vicariance, although some means of transport across the open ocean is considered the most likely explanation.

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. 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.

  1. ^ Cumberlidge, N. (2016). "Seychellum alluaudi". IUCN Red List of Threatened Species. 2016: e.T58511956A58513166. doi:10.2305/IUCN.UK.2016-3.RLTS.T58511956A58513166.en. Retrieved 12 November 2021.
  2. ^ Cite error: The named reference Systema was invoked but never defined (see the help page).