MolluscIreland - land and freshwater
  • Spermodea lamellata (Jeffreys 1830) Plaited snail
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Spermodea lamellata
© Dr Roy Anderson
Spermodea lamellata
© Dr Roy Anderson
Spermodea lamellata
© Dr Roy Anderson

Map hosted by the National Biodiversity Data Centre, Waterford
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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.

Key characteristics

  • 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

Size

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

Red List status

  • Endangered (EN).

Wikipedia link

Wikipedia page for Spermodea lamellata

 Anderson, R., (2016). Spermodea lamellata (Jeffreys 1830). [In] MolluscIreland.
http://www.habitas.org.uk/molluscireland/species.asp?ID=154 Accessed on 2017-12-14.