Two new species of Owenia (Annelida: Polychaeta) in the northern part of the North Atlantic Ocean and remarks on previously erected species from the same area

Two new species of Owenia are erected from the northern part of the North Atlantic. Owenia borealis sp. nov. was found in regions influenced by Atlantic waters at depths from 41 to 1350 m, with a bottom temperature of −0.97 to +9.3 °C. It builds tubes from flattened elongated particles. Owenia polaris sp. nov. was found at depths from 12 to 930 m, with a bottom temperature of −1.8 to +2.3 °C. It inhabits cold waters on the Arctic shelf: the Barents Sea and the lower part of the slope of the Norwegian Sea outside the Atlantic waters and builds tubes with long particles fixated by their smaller section, giving a characteristic ray-like pattern. Owenia borealis and O. polaris have in common a short branchial panache, an oblique collar with an angle at the level of the lateral notch. They are differentiated by the following characters: the angle between the hooks on the first abdominal segment and body axis, the presence or absence of shoulders on the hooks, tooth ends recurved or not and the tube structure. In addition, new observations of specimens of O. assimilis (Sars, 1851) show that these specimens differ both from the two new species just described and from O. fusiformis delle Chiaje 1841, which leads us to reinstate this denomination.