Lobochona prorates is a ciliate ectosymbiont, described from Newport Bay and Los Angeles Harbor, from the non-native gribbles (wood-boring isopods) Limnoria tripunctata and L. quadripunctata, It was found once on the boring amphipod Chelura terebrans. Like its hosts, its origin is unknown, but it has been widely introduced. Mohr et al. (1963) gave its range as 'In temperate seas of northern and southern hemispheres.', with mentions of the Douro estuary, Portugal, Thasos, Greece, and Manila Harbor, Philippines, Limnoria tripunctata and L. quadripunctata and their ciliates were introduced to California waters ar ound 1870, in the hulls of ships.