Description: A 6-plated barnacle reaching up to 10 mm in diameter. On the outer shell the rostral plate is narrower than the opercular opening and the lateral plates overlap it. The opercular opening is distinctly kite-shaped. This species often brown to light grey in colour but can often become discoloured and worn, often obscuring sutures. The tergo-scutal flap is white to very pale blue with brown or orange coloured markings.

Habitat: Found intertidally on the mid to upper shore.

Distribution: Found on most shores around Britain and Ireland, more rarely recorded on east coast of Britain.

Similar Species: Could be confused with Chthamalus stellatus but it has a more rounded opercular opening and the tergo-scutal flap differs in colour if visible.

Key Identification Features:

• 6-plated barnacle often brown to light grey in colour but can be discoloured or worn.
• Rostral plate narrower than opening, with lateral plates overlapping.
• Relatively large, distinctly kite-shaped opercular opening.
• White to pale blue tergo-scutal flap with brown to orange coloured markings.

Distribution Map from NBN: Chthamalus montagui at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Chthamalus montagui at iNaturalist World Species Observations database.

GBIF data for Chthamalus montagui

WoRMS: Chthamalus montagui at World Register of Marine Species. Accepted name: Chthamalus montagui Southward, 1976. AphiaID: 106230.

Classification: Biota; Animalia; Arthropoda; Crustacea; Multicrustacea; Thecostraca; Cirripedia; Thoracica; Thoracicalcarea; Balanomorpha; Chthamaloidea; Chthamalidae; Chthamalus