Taxonomic composition, distribution and zoogeographic relationships of theGrapsid and Ocypodid crab fauna of intertidal soft bottoms in the Arabian Gulf

Brachyuran decapods of the families Grapsidae and Ocypodidae are a dominant faunal element of intertidal fiats and mangroves in the Arabian Gulf and t he Gulf of Oman. Recent collections along the coasts of the U.A.E. and Saud i Arabia and examination of material from other parts of the Gulf revealed in total six species of grapsid and 21 taxa (species and subspecies) of ocy podid crabs occurring in these habitats within the Arabian Gulf. Great diff erences in species diversity and composition exist between the different pa rts of the Arabian Gulf. Maximum diversity was observed for the easternmost part of the U.A.E. (Ras al Khaimah, Umm al Quwain) and for Kuwait. Highly reduced species numbers were found along the shorelines of Abu Dhabi and Sa udi Arabia. The most likely factor causing this pattern is salinity. Zoogeo graphically it appears, that most of the Arabian Gulf species are of an 'ea stern' (Indian) origin. 'Western' (East African and Red Sea) elements are r estricted to the south-eastern part of the Gulf (coast of the U.A.E.) and t o the Gulf of Oman. (C) 1999 Academic Press.