Updated checklist and identification of areas of endemism of benthic amphipods (Caprellidea and Gammaridea) from offshore habitats in the SW Gulf of Mexico

Abstract

An updated checklist of the benthic amphipods associated with soft bottoms in the SW Gulf of Mexico has been made and the areas of endemism have been identified. Amphipods were collected in a depth interval of 25 to 3700 in during six cruises freom 1994 to 1999. A total number of 56 species were identified, 11 belonging to the suborder Caprellidea and 45 to the suborder Gammaridea. Thirteen species extended their geographical distribution within the Gulf of Mexico and four species were considered new records in the Gulf of Mexico. A biogeographic analysis based on the shared species and the parsimony criterion helped identify three areas of endemism in the SW Gulf of Mexico. They were rallied: area A, a small area oil the continental shelf of the Bay of Campeche

area B, the continental slope of the Bay of Campeche and area C, the lower continental slope of the Mexican ridges extending into the western Sigsbee abyssal plain. These areas are defined ill terms of their complex topography that may help isolate habitats that promote endemicity.