A Field Guide to the Snails of Lord Howe Island

70 Family Charopidae (Pinwheel Snails) Genus Gyropena Iredale, 1944 Shell. Size: H = 0.9-1.5 mm, D = 1.9-2.9 mm. Colour: Golden brown to pale fawn, sometimes with irregular flammulations. Shape: Discoidal with a low to sunken spire; whorls shouldered; sutures impressed. Sculpture: Protoconch smooth or with coarse spiral lirae; teleoconch with prominent, closely to moderately widely spaced radial ribs. Aperture: Roundly lunate. Umbilicus: Widely open. Habitat and occurrence. On the southern end of the island, on the slopes and summits of Mt Gower and Mt Lidgbird, living in leaf litter. Remarks. Differs from all other charopid genera in its small to minute size. Gyropena minuta Shea & Griffiths, 2010 Mt Gower Pinwheel Snail Shell. Size: H = 0.9 mm, D = 1.9 mm. Colour: Golden brown. Shape: Discoidal with a low spire; last whorl descending; whorls shouldered; sutures impressed; adult shell of around 4 whorls. Sculpture: Protoconch with coarse spiral lirae; teleoconch with prominent, moderately widely spaced radial ribs. Aperture: Roundly lunate. Umbilicus: Widely open. Animal. Not known. Key distinguishing features. Tiny size, discoidal shell with low spire and shouldered whorls (appearing rather like a punctid in shape); unicoloured, golden brown shell; prominent, moderately widely spaced ribs; wide umbilicus; low whorl count. Habitat and occurrence. On the southern end of the island, on the slopes and summits of Mt Gower and Mt Lidgbird, living in leaf litter. Rare. Remarks. Sympatric with congener G. verans throughout its range. Gyropena minuta 1 mm