MolluscIreland - land and freshwater
  • Sphaerium corneum (Linnaeus 1758) Horny orb mussel
Click on the image to enlarge it in a new window
Sphaerium corneum
© 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.


A small, broadly oval, tumid bivalve coloured yellowish, grey or shades of brown. Umbos rounded, more or less central. Shell pores are few and irregularly dispersed. Widespread and often abundant.

Key characteristics

  • A small, broadly oval, tumid bivalve
  • Surface silky with very fine, irregular concentric growth ridges
  • Coloured yellowish, grey or shades of brown
  • Umbos rounded, more or less central
  • Pores present on the shell but these are few in number and irregularly dispersed


9-11 mm.

World Distribution

Very widespread in Europe and across Asia to North America. Distribution type: Circumpolar Wide-temperate (66).

GBIF distribution map [open in new tab]

Irish Distribution

Widespread and usually abundant throughout but more thinly distributed to the west and north.


  • Abundant in a variety of freshwaters but especially lakes and rivers of moderate hardness
  • Commonest in bottom sediments but it will readily climb macrophytes
  • Rarely found in swiftly flowing water although abundant in hill streams in one or two of the Antrim Glens

Red List status

  • Least concern (lc).

Wikipedia link

Wikipedia page for Sphaerium corneum

 Anderson, R., (2016). Sphaerium corneum (Linnaeus 1758). [In] MolluscIreland. Accessed on 2024-03-02.