A Field Guide to the Snails of Lord Howe Island

58 Family Bothriembryontidae (Tapered Snails) Placostylus bivaricosus (Gaskoin, 1855) (cont’d) Remarks. One species of Placostylus is currently recognised on Lord Howe Island. In the past four subspecies were recognised, three of which were considered extinct due to rat predation: P. bivaricosus etheridgei (southern mountains), P. bivaricosus cuniculinsulae (Blackburn Island) and P. bivaricosus solidus (eastern side of the settlement area). These subspecies were recognised solely on shell morphology due to the lack of spirit-preserved material, and are now considered to be synonyms of P. bivaricosus (Smith, 1992). Placostylus bivaricosus 10 mm