MolluscIreland - land and freshwater
  • Pisidium personatum Malm 1855 Red-crusted pea mussel
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Pisidium personatum
© Dr Roy Anderson

Map hosted by the National Biodiversity Data Centre, Waterford
To view the species profile on Biodiversity Maps and access the live map, please click on the map.


Shell a rounded, regular oval, shape with low, rounded umbos placed centrally. Surface dull or silky with very fine irregular concentric striations. Colour yellowish to grayish but invariably coated in a red-brown to dark brown deposit. Widespread and often abundant.

Key characteristics

  • The rounded oval shape is characteristic
  • Shell moderately tumid with centrally placed umbos
  • Surface usually dull, or silky if clean, with very fine irregular striations
  • Colour yellowish to grayish, sometimes slightly rosy from the animal within but also may be coated with a red-brown deposit



World Distribution

Restricted to Europe, and rare or absent in northern regions. Distribution type: European Southern Temperate (83).

GBIF distribution map [open in new tab]

Irish Distribution

One of our commonest species, particularly in wet woodland, marshes and ditches.


  • A notably amphibious species which thrives in temporary habitats
  • Frequent in temporary pools and floodplain marshes, also flood-prone margins of lakes and rivers
  • Especially common in alder carr and other wet woodland types

Red List status

  • Least concern (lc).

Wikipedia link

Wikipedia page for Pisidium personatum

 Anderson, R., (2016). Pisidium personatum Malm 1855. [In] MolluscIreland. Accessed on 2024-03-02.