MolluscIreland - land and freshwater
  • Anisus (Anisus) spirorbis (Linnaeus 1758) Button ramshorn

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A flat-coiled shell of 4½ whorls. Similar to A. leucostoma but whorls broader and maximum width of the last whorl >25% of shell width. Status in Ireland uncertain.

Key characteristics

  • Shell a flat coil of 4½ whorls
  • Has broader and fewer whorls than A. leucostoma so that the last whorl is greater than 25% of the maximum shell width
  • Aperture round but lacking an internal rib
  • Internally, the number of diverticulae of the prostate gland are significantly fewer (10-15) than in leucostoma (20-25) (Glöer & Meierbrook, 2008)

Size

6-8 mm.

World Distribution

Widespread in Europe, with a Eurasian Wide-temperate range (65).

Irish Distribution

Very uncommon in Ireland and possibly confined to the south and south-east. Not recorded recently and status uncertain.

Ecology

  • Characteristic of temporary water-bodies, like A. leucostoma, but probably with a more southerly range

Red List status

  • Data deficient.

Wikipedia link

Wikipedia page for Anisus spirorbis

 Anderson, R., (2016). Anisus (Anisus) spirorbis (Linnaeus 1758). [In] MolluscIreland.
http://www.habitas.org.uk/molluscireland/species.asp?ID=10 Accessed on 2017-10-24.