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 off the Catalan coast near Barcelona. This rich collection of medusae leads us to postulate the presence of an unusually prolific plankton community in this canyon which is probably supported by a continuous flux of organic matter from the continental shelf, particularly during spring. Foersteria araiae sp. nov. and Teclaia recincolae gen. et sp. nov. were common at 1200 m; a single specimen of Barcino foixensis fam., gen. et sp. nov. was also collected at this depth this depth. The collection of 14 well preserved specimens of Ptychogastria asteroides has allowed the redescription and reillustration of this uncommon species. These four species, together with five specimens of other medusae were found over the course of 1 year of sampling.