Harpacticoida (Crustacea: Copepoda) associated with cold-water coral substrates in the Porcupine Seabight (NE Atlantic): species composition, diversity and reflections on the origin of the fauna

摘要

The harpacticoid copepod fauna associated with the coral degradation zone of Lophelia pertusa (Linnaeus, 1758) reefs was investigated for the first time in the Porcupine Seabight (NE Atlantic). The species list of the coral degradation zone includes 157 species, 62 genera and 19 families, and the most species-rich families were Ectinosomatidae (36 species), Ameiridae (29 species) and Argestidae (17 species). At least 80% of the species were considered new to science. Most of the 23 known species have been reported from ne Atlantic coastlines and from higher latitudes in northern Subpolar and Polar seas. At the family level, the harpacticoid fauna in the Porcupine Seabight did not seem to differ markedly from other deep-sea areas, with essentially the same abundant families. However, the presence of typically epifaunal taxa indicates that the hard substrates of the coral degradation zone provide an exceptional habitat. Further, harpacticoid composition and diversity of sediment and coral fragments were compared with similar substrates in a tropical reef lagoon (Zanzibar, Tanzania). Both regions harboured different fauna and the difference between coral and sediment was more obvious in the tropical lagoon. Species richness and evenness of the two microhabitats in the tropical lagoon were lower than in the deep sea.