Retusa truncatula

Retusa truncatula is a species of very small head-shield sea snail or barrel-bubble snail, a marine gastropod mollusc in the family Retusidae

The subspecies Retusa truncatula var. mammilata: is a synonym of Retusa mammillata (Philippi, 1836)

Description
The shell is minute with a flattened spire and longitudinal striations. The colour of the living animal is white. The adult length is usually less than 4 mm.

Distribution
This species occurs in South Africa, from False Bay to Durban in shallow estuaries. It is also known from northern Europe, the Mediterranean Sea and the Canary Islands.

Natural history
This small sea snail lives from the intertidal zone to just below the low water mark. It burrows in the mud or sand of tidal marshes, and feeds on foraminiferans.