MolluscIreland - land and freshwater
  • Vertigo (Vertigo) geyeri Lindholm 1925 Whorl Snail
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Vertigo (Vertigo) geyeri
© Dr Roy Anderson
Vertigo (Vertigo) geyeri
© Dr Roy Anderson
Vertigo (Vertigo) geyeri
© Dr Roy Anderson

Map hosted by the National Biodiversity Data Centre, Waterford
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Shell dextral. Slightly barrel-shaped with strongly tumid whorls. Aperture rounded, with 4 denticles: 1 parietal; 1 columellar; 2 palatal. Shell glossy, nearly smooth (fine growth lines) and pale red-brown but appearing dark because of the very dark animal. Lip with no thickening and lacking a pale callus around the denticles.

Key characteristics

  • A tiny dextral, barrel-shaped, red-brown shell
  • Aperture rounded, without indent
  • Four teeth present: 1 parietal; 1 columellar; 2 palatal
  • Lip with no thickening and lacking a pale callus around the denticles
  • Shell glossy, appearing smooth, but dark because of the dark animal inside

Size

1.8-2 mm.

World Distribution

Found the Alps, in scattered relict localities across the north European lowlands, and into north and central Scandinavia. Distribution type: Suboceanic Boreal-montane (42).

Irish Distribution

This species is known historically from scattered sites across central and west Ireland (Cos. Offaly, Mayo and Sligo) (Phillips, 1935; Norris & Pickrell, 1972; Cawley, 1996a). In more recent times its range has been extended by field work to Cos Donegal, Leitrim, Fermanagh and Londonderry which suggests a wide distribution in base-rich flushes in the north and west.

Ecology

  • The principal habitat appears to be base-rich flushes in ombrogenous bog, with communities isolated from each other by the spontaneous growth of bog following the end of the Boreal period of the Irish Postglacial
  • It requires short, mossy vegetation and an alkaline pH to thrive
  • Sward height may be critically important

Red List status

  • Vulnerable (VU).

Wikipedia link

Wikipedia page for Vertigo geyeri

 Anderson, R., (2016). Vertigo (Vertigo) geyeri Lindholm 1925. [In] MolluscIreland.
http://www.habitas.org.uk/molluscireland/species.asp?ID=183 Accessed on 2017-10-21.