Abstract
Pherusa Oken, 1807 was the first genus of flabelligerids to be described and was regarded as having over 40 species. Following revision of all available material two morphological patterns are recognized: Pherusa is restricted to those species with eight branchial filaments of similar width, and anchylosed falcate neurohooks, shorter than body width. Species with the same number of branchial filaments but with neurochaetae mostly straight, distally foliose and often as long as body width are transferred to a new genus: Lamispina n. gen. Pherusa contains 14 species, including six newly described: P. plumosa (Müller, 1776), type-species, restricted, from Greenland, P. affinis (Leidy, 1855) from the NW Atlantic, P. andersonorum n. sp. from the NE Pacific (California), P. aspera (Stimpson, 1854) from the NW Atlantic, P. hobsonae n. sp. from the NE Pacific (Washington), P. incrustata Quatrefages, 1866, reinstated from the Mediterranean Sea, P. mikacae n. sp. from the Adriatic Sea, P. moorei n. sp. from the NW Pacific (Japan), P. neopapillata Hartman, 1961 from the NE Pacific (California), P. nipponica n. sp. from the NW Pacific (Japan), P. obscura Quatrefages, 1866 reinstated from the NE Atlantic (France), P. papillata (Johnson, 1901) from the NE Pacific (Washington), P. rullieri n. sp. from the Eastern tropical Atlantic (Benin), and Pherusa sibogae (Caullery, 1944) n. comb. from Western Timor, Indonesia. Lamispina n. gen. has 10 species with five newly described: L. schmidtii (Annenkova-Chlopina, 1924) n. comb., type-species from the Japan Sea (incl. P. negligens (Berkeley & Berkeley, 1950)), L. amoureuxi n. sp. from the NE Atlantic (off SW Ireland), L. carrerai n. sp. from the NE Pacific (Mexico), L. chilensis n. sp. from the SE Pacific (Chile), L. falcata (Støp-Bowitz, 1948) n. comb. from the Norwegian Sea, L. gymnopapillata (Hartmann-Schröder, 1965) n. comb. from the SE Pacific (Chile), L. horsti (Haswell, 1892) n. comb. from Southern Australia, L. keeli n. sp. from the Gulf of Mexico (Florida), L. kerguelarum (Grube, 1877) n. comb. from the Southern Indian Ocean (Kerguelen Islands), and L. milligani n. sp. from the NW Atlantic (Florida). Keys to identify these two genera and all species in each genus are also included.