A Field Guide to the Snails of Lord Howe Island

56 Family Bothriembryontidae (Tapered Snails) The Bothriembryontidae are medium-sized to very large snails with an ovate to cylindrical shell, occurring in Australia, southern Africa and the Pacific Islands. Most Australian bothriembryontids are found in Western, South and Central Australia, apart from a single species on Lord Howe Island. Bothriembryontids are characterised by their large size, ovately conical to elongate shape with rounded whorls and moderately impressed, sometimes crenulated (scalloped or notched) sutures. Shell sculpture is minimal, with teleoconch sculpture consisting of axial growth lines, with additional decussate sculture in some species. The aperture is ovate and the interior of the shell is glossy and often coloured, sometimes thickened to form an internal tooth or ridge. Adults are found living in leaf litter, in vegetation or on trees, or on rock faces. Genus Placostylus Beck, 1837 Remarks. As well as Lord Howe Island, the genus Placostylus is found in New Zealand, New Caledonia, Fiji, the Solomon Islands andVanuatu. Many Placostylus species are of conservation concern and have experienced declines, with predation by rats a significant threat. Placostylus bivaricosus