Species description: This mussel has a thin but solid shell and is the usual Mytilus wedge shape, with beaked or pointed umbones. Reported to reach up to 15 cm, but more commonly 5-8 cm in length. The shell is dark blue to purple or purple-brown. Periostracum often covers a lot of the shell and ranges from a light brown to dark brown or blue-black in colour. The mantle edge is usually purple to violet.

Habitat: Attached to hard substrata from rocky shores to artificial structures in harbours and marinas. Found from upper intertidal to shallow sublittoral.

Distribution: True distribution currently unknown due to confusion and hybridisation with Mytilus edulis. There are known populations in SW Ireland, SW England and south Wales, but it is likely to be more widespread.

Similar Species: Could be confused with other species of Mytilus, including Mytilus edulis, and there has been some hybridisation documented.

Key Identification Features:

• Thin but solid shell.
• Distinctive mussel wedge shape.
• Beaked or pointed umbones.
• Violet or purple mantle edge.

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

iNaturalist: Mytilus galloprovincialis at iNaturalist World Species Observations database.

WoRMS: Mytilus galloprovincialis at World Register of Marine Species. Accepted name: Mytilus galloprovincialis Lamarck, 1819. AphiaID: 140481.

Classification: Biota; Animalia; Mollusca; Bivalvia; Autobranchia; Pteriomorphia; Mytilida; Mytiloidea; Mytilidae; Mytilinae; Mytilus