Norway and British Isles to Canarias, Azores to Mediterranean. Ectoparasit on benthic mollusca (but there is, for now, only one reported example of association: with a Littorinid). Usual habitat of the hosts: rocky shores under stones, or in empty shells such as Bolma rugosa, Buccinum undatum… Depth range: from intertidal-subtidal grounds down to at least the lower circalittoral. Original taxon: Odostomia carrozzai.