Host identification for the deep-sea snail genus with description of a new species (Caenogastropoda, Eulimidae).

A new parasitic species of eulimid gastropod, , is described from bathyal (728-978 m) waters off the Pacific coasts of Japan. It shows the closest resemblance to the type species from the North Atlantic and Barents Sea in having a tall shell with an almost straight outer lip, but differs in having a junction of the parietal wall and columellar lip at 38% of the aperture height from the suture (33% in ), a slightly wider aperture and a more curved and extended columellar lip. The holotype of was found attached to an irregular sea urchin, Brissopsis sp. cf. luzonica (Spatangoida: Brissidae). This represents the first direct observation of parasitic ecology and echinoderm host for the genus . A new replacement name, , is proposed here for A. Adams, 1861, which is preoccupied by Jeffreys, 1858 (type of ).