Cavoliniidae: Diacria trispinosa (Blainville, 1821) (‘three-spined sea-butterfly’)

Synonym(s): trispinosa Blainville, 1821.

Typical shell-length 13 mm. Lives in offshore waters in midwater. Native. Occurs all around Australia (QLD, NSW, TAS, VIC, SA, WA and NT); also widespread in warmer oceanic waters worldwide.