Alvania punctura

(Montagu, 1803)

Description (shell):
Shell semi-transparent, oval-conical, with six tumid whorls, apex pointed; spire slightly cyrtoconoid. Apical, larval whorls lightly tuberculate, contrasting sharply with decussate pattern of teleoconch (A. punctura-protoconch); the costate element of decussation lost below the periphery of the last whorl. Aperture oval or egg-shaped, peristome with an anal sinus; inner lip reflected over umbilical groove leading to a narrow, elongate umbilicus; outer lip with a slight varix, not thickened or ridged internally (A. punctura-drawing).

Up to 3 x 1.8 mm.

Shell white, cream, or tinged reddish brown, often darkened by a conspicuous periostracum; red-brown blotches in three series on last whorl, umbilical region similarly stained.

Body similar to Manzonia crassa ; metapodial tentacle single.

Locally common among Laminaria at LWST and sublittorally on sandy bottoms to 100 m.

Distributed from Mediterranean to northern Norway (Distr. A. punctura); absent from Baltic and eastern basin of English Channel.