A Field Guide to the Snails of Lord Howe Island

139 Semilaoma laevis Shea & Griffiths, 2010 Smooth Pinhead Snail Shell. Size: H = 0.7-0.8 mm, D = 1.2-1.3 mm. Colour: Pale yellow to white. Shape: Depressedly turbinate with a low spire; sutures impressed; whorls rounded. Sculpture: Protoconch with spiral lirae; teleoconch with very fine, irregular, closely spaced radial ribs and microsculpture of fine spiral lirae. Aperture: Roundly lunate. Umbilicus: Narrowly open. Animal. Not known. Key distinguishing features. Minute size, rounded whorl profile, fine and less distinct radial sculpture, narrowly open umbilicus. Habitat and occurrence. Widespread across the whole island, in habitats including rainforest, lowland forest and scrub. Common but under- collected due to its small size. Remarks. Differs from congeners in its rounded whorl profile and finer, less distinct shell sculpture. Semilaoma lidgbirdensis (Iredale, 1944) Mt Lidgbird Pinhead Snail Shell. Size: H = 0.8-0.9 mm, D = 1.5-1.6 mm. Colour: Pale golden. Shape: Depressedly turbinate with a low spire; sutures weakly impressed; whorls rounded above and below an angulate periphery. Sculpture: Protoconch with spiral lirae; teleoconch with moderately closely spaced, sinuate radial ribs and microsculpture of radials and very weak spirals. Aperture: Ovately lunate (width greater than height). Umbilicus: Very narrow, sometimes closed. Animal. Not known. Key distinguishing features. Minute size; angulate whorls; very narrow, almost closed umbilicus. Habitat and occurrence. Common and widespread across the island, in habitats including rainforest, lowland forest and scrub. Remarks. Another species not included here, Semilaoma abjecta , is probably a synonym of P. lidgbirdensis .