MolluscIreland - land and freshwater
  • Pisidium henslowanum (Sheppard 1823) Henslow's pea mussel

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.

An obliquely oval shell with prominent, narrow umbos well behind the middle and with oblique raised crests. Surface silky with fairly even, fine concentric striae. Colour grayish, especially at the umbos. Widespread but local and uncommon.

Key characteristics

  • A tumid, obliquely oval to slightly elongate shell
  • Umbos prominent, lying behind the mid point and with raised crests
  • Surface sliky with even, concentric striae
  • Colour grayish, especially at the umbos



World Distribution

Another species which is widely distributed in the northern hemisphere. Distribution type: Circumpolar Southern-temperate (86).

GBIF distribution map [open in new tab]

Irish Distribution

Widely but thinly spread across the central plain into Connemara and north into Loughs Erne and Neagh.


  • A species of large, calcareous, river, canal and lake habitats, mainly in central Ireland
  • Prefers waters with at least a slight flow

Red List status

  • Least concern (lc).

Wikipedia link

Wikipedia page for Pisidium henslowanum

 Anderson, R., (2016). Pisidium henslowanum (Sheppard 1823). [In] MolluscIreland. Accessed on 2024-03-02.