Ammonicera rota

(Forbes & Hanley, 1850)

Description (shell):
Shell minute, three or four rapidly expanding, tumid whorls of almost circular cross-section. Sculpture of transverse costae but no spiral element; sometimes with three tubercles: above, at, and below the periphery which may give a keeled appearance when well-developed. Aperture oval; slightly flattened where it abuts the penultimate whorl, angulate in keeled shells.

Up to 0.5 x 1.0 mm.

Reddish brown or horn coloured, with iridescent throat (A. rota-photo).

On weeds and in rock pools at LWST; recorded to 25 m on sandy bottoms.

Distributed from Mediterranean to Norway. Absent from continental shores of North Sea (Distr. A. rota).