Phyllochaetopterus polus, a new species of the polychaete family Chaetopteridae is described. Specimens were collected at the Ashadze-1 vent field (Mid-Atlantic Ridge), from 4100-4200 m depth. P polus is the first chaetopterid reported from the Atlantic hydrothermal vents. Three chaetopterid species have been recorded from deep-sea hydrothermal vents belonging to two genera, Spiochaetopterus and Phyllochaetopterus. P polus sp. nov. is a medium-sized chaetopterid, characterized by 9 chaetigers in region A and 2 in region B; region C is usually incomplete in the specimens examined, but has at least 40-70 chaetigers. This polychaete has one pair of modified chaetae in chaetiger 4 with a pear-shaped obliquely truncated head, triangular uncini and a branched... |