Description: This mussel can reach just over 6 cm in length, and has a deep reddish colour, usually with a yellow tint. The periostracum is very conspicuous in this species and may cover most or all of the outer surface of the shell. It is yellow to brown in colour and covered the outer surface of the shell in a series of concentric fringes that get thicker towards the shell margins. These fringes are drawn out to form serrated spines, which trap sand and shell fragments. Inside of the shell is a glossy pale blue and occasionally may have a pink tint.

Habitat: Found from the lower shore down to depths of over 100 m. Found under rocks or in kelp holdfasts,

Distribution: Scattered records from around Britain and Ireland, mostly found on south, southwestern and western coasts.

Similar Species: Adult specimens unlikely to be confused but juveniles may be confused with a number of species (e.g. Modiolus adriaticus, Modiolula phaseolina, Musculus subpictus and Musculus discors or Mytilus edulis).

Key Identification Features:

• Periostracum forms concentric fringes on outer surface of shell.
• Distinctive serrated spines on periostracum.
• Inside of shell glossy pale blue sometimes with hints of pink.

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

iNaturalist: Modiolus barbatus at iNaturalist World Species Observations database.

GBIF data for Modiolus barbatus

WoRMS: Modiolus barbatus at World Register of Marine Species. Accepted name: Modiolus barbatus (Linnaeus, 1758). AphiaID: 140464.

Classification: Biota; Animalia; Mollusca; Bivalvia; Autobranchia; Pteriomorphia; Mytilida; Mytiloidea; Modiolidae; Modiolinae; Modiolus