Velvety mail shell (Acanthochitona fascicularis)
|Researched by||Sonia Rowley||Refereed by||This information is not refereed|
|Other common names||Velvety mail chiton||Synonyms||-|
Acanthochitona fascicularis is an oval-shaped chiton with a flattened elongated body 6 cm in length. Its width is half that of its length. The body is protected by a shell composed of eight interlocked transverse, coarsely keeled plates or valves. The valves on the shell are strongly arched and, when viewed under a hand-lens, appear coarsely granular due to densely packed and evenly arranged dorsal papillae. The colour varies; marbled with off-white, grey, yellowish or brown. This species has a broad and spiny girdle with 18 dense tufts of long bristles (up to 1.5 mm long), four of which are in an arc around the head valve. The surface is covered with recumbent spines, making it feel velvety to the touch. The girdle is fringed with spines, up to 1 mm in length.
Recorded distribution in Britain and IrelandThis species is probably under-recorded. Recorded from Kent, south-east coast of England; Lyme Bay south Devon coast; south Wales north to Angelsey; South Uist, Outer Hebrides; and Galway Bay and Lough Hyne, Co. Cork.
Global distributionRecorded from northern Norway, the west coasts of the British Isles, the English Channel and north-west France, south into the Mediterranean and the Black Sea.
HabitatThis chiton is found on the lower shore to 50 m depth, on rocks, boulders or in crevices.
Depth rangeLower shore - 50 m
- Flat, extended oval shape, with eight transverse shell valves on the dorsal surface.
- Girdle has 18 dense tufts of long bristles/spines, up to 1.5 mm long.
- Up to 6 cm in length and width is half its length.
- Variable colouration; marbled with off-white, grey, yellowish or brown.
- Feels velvety to touch due to recumbent spines on its shell surface.
'Coat-of-mail' shells (chitons) get their name from the armoured appearance of the valves like links in chain mail. This species is larger than Acanthochitona crinita but the two are very similar and therefore easily confused. Acanthochitona fascicularis has finer shell valves with more regular granulation. This species is a grazer, feeding on encrusting or filamentous algae and possibly bryozoans.
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OBIS (Ocean Biodiversity Information System), 2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2023-12-09
South East Wales Biodiversity Records Centre, 2018. SEWBReC Molluscs (South East Wales). Occurrence dataset: https://doi.org/10.15468/jos5ga accessed via GBIF.org on 2018-10-02.
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Last Updated: 03/06/2008