Description: The ribs on this beautiful little shell are so fine and close that it appears to have a bloom due to interference effects. It is pyramidal rather than conical (about as high as wide) with 6 whorls which increase gradually in size. The shell is light yellow-brown colour with a silky lustre. Local and uncommon except in parts of the north and west. Declining, probably as a result of climate warming and drying out of its habitats. 2-2.2 mm.

World Distribution: A relic of the wet Atlantic period with a narrow range from coastal southern Scandinavia to the British Isles, and one or two outlying populations on the north German plain. It has recently become extinct in Holland. Distribution type: Oceanic Temperate (71).

Irish Distribution: Common only in broadleaf woods in northern and western counties but not the central limestone plain (Anderson, 1977). In southern Britain it is extinct except for a small number of isolated and vulnerable sites (Kerney, 1999) and is evidently in decline over most of Ireland.

Ecology:

• A classic 'Atlantic' species restricted to the wet fringes of north-west Europe
• Preferred habitats are older broadleaf woodlands where it inhabits deep, stable leaf litter, and is particularly common in planted beech woods
• In the past it has been able to survive considerable disturbance including the clear-felling of woods or isolation in tiny broadleaf strips within large conifer plantations, but recent drier, warmer decades have seen a steep decline in many areas
• On the Atlantic seaboard it also occurs widely in moss on rocky headlands or heaths

Key Identification Features:

• A very small pyramidal brown shell with close-set ribs
• Ribs are very fine and close creating interference effects (bloom)
• Colour a light yellow-brown with a silky appearance
• Mouth oval, thin-lipped

Red list status:

• Endangered (EN).

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

iNaturalist: Spermodea lamellata at iNaturalist World Species Observations database.

GBIF data for Spermodea lamellata | Classification: Gastropoda, Stylommatophora, Valloniidae, Spermodea

Thumbnails for genus Spermodea