Several collections of magelonids from Easter Island, Guam in the Mariana Islands and Hawaii were examined. Five magelonids are fully described and illustrated: Magelona anuheone sp. nov. (Easter Island), M. cf. symmetrica Mortimer Mackie, 2006 (Guam), M. alexandrae sp. nov. (Hawaii), M. cinthyae sp. nov. (Hawaii) and M. paulolanai sp. nov. (Hawaii and Guam). Magelona anuheone sp. nov. has a distinctly longer than wide prostomium with inflated and well-developed prostomial horns, similar to M. montera from the Indian Ocean. Magelona alexandrae sp. nov. belongs to Magelona species with crenulated upper margin of thoracic postchaetal lamellae and also well-developed prostomial horns. Magelona cinthyae sp. nov. is unique among its congeners in that several collected adult individuals presented two or more eyespots in the prostomium, a feature only previously recorded to pelagic larval stages. Magelona paulolanai sp. nov. belongs to a group of species with rudimentary prostomial horns, simple capillaries on chaetiger 9 and tridentate abdominal hooks. All species are illustrated and compared to their morphologically similar congeners.
Keywords: Taxonomy, new species, new records, Magelonidae, Pacific Islands, Annelida.