Biodiversity & Conservation

Montagu's stellate barnacle - Chthamalus montagui

Chthamalus montagui

Image Alan J. Southward - Close up of Chthamalus montagui from High Water of Spring Tide level seen dry. Image width ca 20 mm.
Image copyright information

  • #
  • #
  • #
  • #
Distribution map

Chthamalus montagui recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

Sightings Have you seen Chthamalus montagui?
If so please submit your record.

Chthamalus montagui 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 Southward, 1976
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland A warm-water species recorded on the south and west coasts of Britain as far north as Orkney and along the Scottish east coast south to Aberdeen. The Isle of Wight is its eastern limit in the English Channel. It is relatively abundant on Irish coasts.
Habitat information icon Habitat information Recorded in the high to mid eulittoral zone on exposed to moderately exposed rocky shores. Its vertical distribution overlaps with that of Chthamalus stellatus and Semibalanus balanoides.
Text page icon Description An intertidal barnacle with six coarsely ridged wall plates, a kite-shaped opercular opening, and a membranous base. The rostral plate is relatively narrow and plates are of roughly equal size. The rostral plate is not fused with rostrolaterals. The tissue inside the opercular aperture is blue (paler than in Chthamalus stellatus) with brown and black markings. Usually conical in shape, however when crowded may become tubular. It reaches a maximum diameter of approximately 14 mm, depending on habitat, food availability and level on shore.
Identifying features
  • Shell wall of six solid plates.
  • Kite-shaped operculum opening.
  • The joint between the terga and scuta crosses the centre line less than one third of the way down towards the rostrum.
  • Tissue inside opercular aperture is usually blue/pale blue with brown and black markings.
  • Junction between terga and scuta is concave towards rostral plate.
  • Shell base is membranous.
Additional information icon Additional information Before 1976 Chthamalus montagui was considered a variety of Chthamalus stellatus, but in 1976 was identified as a distinct species due to differences in its vertical zonation on the shore and morphology, particularly in the shape of the opercular plates, setation of the smaller cirri, the more sheltered locations in which it was found and its different pattern of zonation (Southward, 1976).

Want to know more? more

This review can be cited as follows:

Karen Riley 2002. Chthamalus montagui. Montagu's stellate barnacle. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 09/02/2010]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=2981>