Description: A small chiton (up to 22 mm) with a relatively broad. leathery girdle that is densely covered in thick, coarse spines. The spines are arranged in 18 conspicuous tufts of bristles that can be up to 1 mm long. There are also small brown spicules visible on the girdle. The overall shape is an elongate oval. Colouration is highly variable usually not uniform. It can be dark brown to red, with beige, dark brown or even blue blotching. They have arched valves with a slight beak.

Habitat: Found from the lower shore to the sublittoral.

Distribution: There has historically been some confusion over the taxonomy and therefore distribution of the Acanthochitona spp. in Britain and Ireland. DNA barcoding has suggested Acanthochitona discrepans is a northern species and that Acanthochitona crinita has a much broader range. Acanthochitona fasicularis appears to be more southern.

Similar Species: Could be confused with Acanthochitona fasicularis or Acanthochitona crinita.

Key Identification Features:

• Small chiton up to 22 mm.
• Girdle has 18 dense tufts of coarse spines.
• Valves arched with only a slight beak.

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

iNaturalist: Acanthochitona discrepans at iNaturalist World Species Observations database.

GBIF data for Acanthochitona discrepans

WoRMS: Acanthochitona discrepans at World Register of Marine Species. Accepted name: Acanthochitona discrepans (T. Brown, 1827). AphiaID: 138676.

Classification: Biota; Animalia; Mollusca; Polyplacophora; Neoloricata; Chitonida; Acanthochitonina; Cryptoplacoidea; Acanthochitonidae; Acanthochitoninae; Acanthochitona