Description: This chiton reaches a maximum length of 3 cm, and is usually around twice as long as it is wide. The valves are very smooth and usually an orange or red, occasionally greenish, and have white or off-white marbling. Marbling can also occasionally be green, yellow or orange. The girdle is relatively broad (around 1/3 the width of the animal) and covered in dense, overlapping fine spines or spicules. The girdle is also fringed with fine spines/spicules. It is coloured yellow to orange and usually has red markings, sometimes these are so prevalent there is little yellow to orange visible.

Habitat: Found on the lower shore and sublittoral. Usually under boulders or cobbles.

Distribution: Found all around Britain and Ireland.

Similar Species: Could be confused with Tonicella marmorea.

Key Identification Features:

• Large chiton, up to 3 cm.
• Very smooth valves.
• Usually orange to red in colour.
• Relatively broad girdle (1/3 width of animal).
• Girdle covered in small spines, and has a fringe of small spines.

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

iNaturalist: Callochiton septemvalvis at iNaturalist World Species Observations database.

WoRMS: Callochiton septemvalvis at World Register of Marine Species.