Low tide, On outer reef, Shoal Point, Queensland, Australia, 38mm.
The « Blue-Mouthed Star » is a remarkable turbinid with a striking sky blue columellar and operculum. It is one of the most celebrated blue shells, as true blue is rare in the shells of marine gastropods. Although usually a vivid blue, the operculum may sometimes carry a purplish hue. A locally comrn.on algae-grazing gastropod, it inhabits low tide zone of intertidal waters down to very shallow depths of around -5m. Geographically it is best known from Australia where is ranges from Queensland to Western Australia but is supposed to have a wider distribution in the Indo-West Pacific. Individuals vary greatly in development of varices, some specimens have very strong spine-like varices while others have modest nodule-like development. Often a very rough shell, it is not easy to find a quality specimen. Typical shell length around 35mm., very large specimens may exceed 50mm.