Critter of the Week: Gibberula ficula - rice snails

Gibberula ficula (Murdoch & Suter, 1906) are micro snails in the family Cystiscidae.

These cute little snails are about the size of a grain of rice when adults and their species name, ficula, comes from their fig-like shell shape. 

Tiny fig shaped snails, Gibberula ficula (Murdoch & Sutler, 1906), crawling around on this tree-like bryozoan, Cellaria tenuirostris (Busk, 1852) during a night dive at the Middle Arch in the Poor Knights Islands, New Zealand. [Crispin Middleton, NIWA]

Cystiscids, the rice snails, are frequently found on arborescent bryozoans like the one pictured (Cellaria tenuirostris (Busk, 1852)). However, they are micro-carnivores so they eat prey like small amphipods or benthic copepods. The Cysticidae family are also commonly known as “False Marginellas” because of their close resemblance to some of the Marginellidae, or margin shells, which are glossy and colourful and prized by shell collectors.

The Cysticidae family is very diverse, and worldwide there are 192 species of Gibberula alone.  We have five species in the family in New Zealand waters and Gibberula ficula can be found from off the Three Kings Island in the north all the way south to Foveaux Strait from 10–180 m.

Further information 

 World Register of Marine Species database entry on the genus Gibberula 

A map of some previous records of Gibberula ficula around New Zealand