Description: A 6-plated barnacle reaching up to 15 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 relatively large and more rounded at one (carinal) end. It is kite-shaped in juveniles but becomes more oval or rounded with age. This species is light grey in colour but can often become discoloured and worn, often obscuring sutures. The tergo-scutal flap is bright blue and features a central orange spot.

Habitat: Found intertidally on the mid to lower 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 montagui but it has a very distinctly kite-shaped opercular opening with a distinct obtuse angle at one end.

Key Identification Features:

• 6-plated barnacle often light grey in colour but can be discoloured or worn.
• Rostral plate narrower than opening, with lateral plates overlapping.
• Relatively large opercular opening, rounded at one end.
• Bright blue tergo-scutal flapt with a central orange spot.

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

iNaturalist: Chthamalus stellatus at iNaturalist World Species Observations database.

GBIF data for Chthamalus stellatus

WoRMS: Chthamalus stellatus at World Register of Marine Species. Accepted name: Chthamalus stellatus (Poli, 1791). AphiaID: 106231.

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