A Field Guide to the Snails of Lord Howe Island

57 Placostylus bivaricosus (Gaskoin, 1855) Lord Howe Flax Snail Shell. Size: H = 55.3-62.5 mm, D = 26.3-28.9 mm. Colour: Dark orange- brown with orange apical whorls; shell interior glossy dark orange-red. Shape: Conical, elongate. Whorls rounded. Sutures weakly impressed. Shell thick. Sculpture: Protoconch with oblique wrinkles; teleoconch with strong growth lines. Aperture: Ovate; lip thickened in adults with an elongate apertural tooth. Umbilicus: Closed. Animal. Body grey. Key distinguishing features. Large, heavy, elongate shell. Habitat and occurrence. This species was once widespread across Lord Howe Island and was also found on Blackburn Island, but is now known only from the northern and settlement areas. Juveniles are arboreal while adults are ground-dwelling. Animals are active by night, and very difficult to find during the day, despite their large size. Placostylus bivaricosus is listed as Endangered under the NSW Biodiversity Conservation Act (2016). Malabar Kim’s Lookout Transit Hill Intermediate Hill Mt Lidgbird Mt Gower ▲ ▲ ▲ ▲ ▲ ▲ P. bivaricosus ● 1999-2019 ● pre 1999