Ranella australasia is a species of large predatory sea snail, a marine gastropod mollusk in the family Ranellidae, the triton snails, triton shells or tritons. This species is native to Australia and New Zealand where it is widespread, as well as Norfolk Island, Lord Howe Island, and the Kermadec Islands.
A closely related species, Ranella gemmifera, formerly known as Ranella australasia gemmifera, is native to South Africa.
References
Wilson, B. 1993. Australian Marine Shells. Prosobranch Gastropods. Kallaroo, Western Australia : Odyssey Publishing Vol. 1 408 pp.