Trivia oryza (Lamarck, 1810)
Description: Shell globular, ends slightly drawn out, spire concealed. Whole surface strongly ribbed, with about 27 ribs on the outer lip. Deep groove on the dorsum, crossed by weakened or obsolete ribs. Fossula deep, crossed by ribs, extending as a groove along the length of the aperture. Colour white.
Size: Up to 11 mm in length.
Distribution: Widely distributed throughout the tropical Indo-West Pacific region. In Australia, reported from south-western WA around northern Australia to Twofold Bay, NSW.
Habitat: Common in the tropics on intertidal coral reefs, under stones and dead coral. Rarely found alive in NSW, and uncommonly as an empty beach shell.
Comparison: The pure white colour of T. oryza readily distinguishes it from T. merces, which is always spotted dorsally with brown.
Remarks: This species was misidentified in Iredale and McMichael's NSW checklist as Trivirostra scabriuscula (Gray, 1827) and possibly also as Dolichupis insecta (Mighels, 1845).
Figs. 1,2: Balmoral, Middle Harbour, NSW (C.360596)
Copyright Des Beechey 2000