MolluscIreland - land and freshwater
  • Pisidium pseudosphaerium J. Favre 1927 False orb pea mussel

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Shell a flattened, regular, slightly angulated oval with low central umbos. Surface silky with very fine concentric striations. Colour straw coloured with scattered red-brown deposits. Rare and very local.

Key characteristics

  • Shell a flattened nearly regular oval
  • Umbos low and central
  • Surface silky with very fine concentric striations
  • Shell straw coloured with scattered red-brown deposits

Size

2.5-3.2mm.

World Distribution

Confined to Europe. Distribution type: European Temperate (73).

Irish Distribution

Added to the Irish list by Kerney (1969) from three sites along the Royal Canal in Kildare and Westmeath, and from the Lagan Canal near Moira, Antrim. It has not been seen recently in the Lagan canal but is still found in the Royal Canal.

Ecology

  • On the Continent it is said to be restricted to stagnant water of swamps and ditches, but in any event, mainly in unstable environments
  • In Britain it occupies grazing marshes in eastern and southern England
  • It has been found only in canals in Ireland but may have been introduced

Red List status

  • Endangered (EN).

Wikipedia link

Wikipedia page for Pisidium pseudosphaerium

 Anderson, R., (2016). Pisidium pseudosphaerium J. Favre 1927. [In] MolluscIreland.
http://www.habitas.org.uk/molluscireland/species.asp?ID=136 Accessed on 2017-10-19.