information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

Wart Barnacle (Verruca stroemia)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.



Verruca stroemia is a small grey box-like barnacle growing up to 1 cm in diameter. This species is distinguished from other barnacles present in Britain and Ireland by its assymmetrical 4 plated shell wall, with strong interlocking sutures. Instead of the paired moveable opercular valves of typical barnacles, half of the operculum is fixed to the substrate, while the other half forms a hinged 'lid'.

Recorded distribution in Britain and Ireland

Widespread in British and Irish seas.

Global distribution

Verruca stroemia has been recorded along the Atlantic coast of Europe from southern Portugal to the White Sea, including Svalbard.


Verruca stroemia is found between extreme low water and 500 m depth. It can be found on rocky shores attached to the undersides of rocks and in crevices.

Depth range


Identifying features

  • Shell flattened, wall comprised of 4 plates (rostrum, carina, tergum, scutum).
  • Shell plates with longitudinal ridges and serrated sutures.
  • Operculum lid-like.
  • Membranous base.

Additional information

The related species Verruca spengleri found from the Azores to the Black Sea has often been confused with Verruca stroemia, which led to erroneous records of Verruca stroemia present in the Mediterranean (see Young et al., 2003). Verruca spengleri has pores permeating the external shell wall and the shell plates (parietes) lack longitudinal ridges, distinguishing it from Verruca stroemia.

Listed by

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Further information sources

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    This review can be cited as:

    Hosie, A.M. 2008. Verruca stroemia Wart Barnacle. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 24-09-2018]. Available from:

    Last Updated: 09/10/2008