Biodiversity & Conservation

An acorn barnacle - Balanus perforatus

Balanus perforatus

Image Peter Barfield - Balanus perforatus on rock with Mytilus edulis.
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Distribution map

Balanus perforatus recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

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Balanus perforatus is not listed under any importance categories.

Taxonomy icon Taxonomy Taxon English term
Phylum Arthropoda Arthropods, joint-legged animals, e.g. insects, crustaceans & spiders
Class Maxillopoda Barnacles, copepods and fish lice
Authority Brugiére, 1789
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Balanus perforatus is a southern species extending to south-west England and south Wales but not recorded from Ireland.
Habitat information icon Habitat information Balanus perforatus is found from the mid-shore to the sublittoral on rocks and artificial structures and is sometimes common in wave exposed situations. Also present on ships' hulls.
Text page icon Description Up to 30 mm in diameter and 30 mm tall, Balanus perforatus is recognised by its tapered, volcano-like shape. The shell wall consists of 6 purplish plates that are often vertically ridged, and sometimes separated at the apex leaving a jagged lip. Inside the operculum aperture, the tissue is marked with bright colours of pink, purple and blue. The tergoscutal flaps are brown to purple in colour, with blue and white spots.
Identifying features
  • Volcano-like shape.
  • Small oval aperture.
  • Operculum deeply immersed within the aperture.
  • Terga with short, pointed beaks.
  • Base calcareous.
Additional information icon Additional information Aperture usually very small but quite large in sublittoral specimens.

This review can be cited as follows:

Marie Skewes 2008. Balanus perforatus. An acorn barnacle. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 04/02/2012]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=2719>