Description: A medium to large, slightly depressed globular shell with 5½-6 slightly convex whorls and shallow sutures. Aperture elliptical with an internal rib. Surface white, yellow-brown to pink, with a complex and varied pattern of dark spiral bands which may be faint or broken up. Sand dunes on south and east coasts. Spreading. 16-22 mm.

World Distribution: A native of the Mediterranean but introduced to the coasts of north-west Europe as far north as the low countries and the British Isles.

Irish Distribution: Known since the nineteenth century from a small number of sites on the coasts of Louth, Meath and Dublin between Clogher Head and Rush (Kerney 1976a). More recently three colonies have been found in West Cork, at Garrettstown/White Strand, Ownahinchy Strand and Inchydoney Island (Cawley & Colville, 2001). It has also spread from its north Dublin sites to the North Bull sands in the city of Dublin (Anderson, 2008).

Ecology:

• Confined to coastal dunes in relatively frost-free localities
• Has a predilection for climbing dead vegetation or walls during dry periods and remaining cemented in position for long periods by a copious chalky secretion used to block the shell opening and reduce water loss

Key Identification Features:

• A medium large whitish, globular shell of 5½-6 whorls
• Spire very low, whorls slightly convex and sutures shallow
• Colour white to yellow-brown or pink with a complex pattern of brown spiral bands which may be interrupted or faint
• Aperture elliptical with an internal rib
• Umbilicus narrow, partly closed by the reflected columella
• Surface with coarse growth ridges crossed by fine spiral striae

Red list status:

• Not applicable.

Distribution Map from NBN: Theba pisana at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Theba pisana at iNaturalist World Species Observations database.

GBIF data for Theba pisana | Classification: Gastropoda, Stylommatophora, Helicidae, Theba

Thumbnails for genus Theba