Submarine canyons as habitats of prolific plankton populations: three new deep-sea Hydroidomedusae in the western Mediterranean

Three previously undescribed species of Hydroidomedusae are described from plankton collected in sediment traps placed in the Foix submarine canyon of f the Catalan coast near Barcelona. This rich collection of medusae leads u s to postulate the presence of an unusually prolific plankton community in this canyon which is probably supported by a continuous flux of organic mat ter from the continental shelf. particularly during spring. Foersteria arai ae sp. nov, and Teclaia recincolae gen. el sp. nov. were common at 1200m; a single specimen of Barcino foixensis fam., gen. et sp. nov, was also colle cted at this depth this depth. The collection of 14 well preserved specimen s of Ptychogastria asteroides has allowed the redescription and reillustrat ion of this uncommon species. These four species, together with five specim ens of other medusae were found over the course of 1 year of sampling. (C) 1999 The Linnean Society of London.