Onchidella celtica
Taxon version key
[NBNSYS0000176823]
Sort order
490
Taxonomic group
Land snail
Otina ovata
Taxon version key
[NHMSYS0020528241]
Acanthochitona fascicularis
Distribution and status
A southern species occurring from the south of the British Isles to the Mediterranean Sea, the Black Sea, the Azores and the Canary Islands. It is a relatively uncommon species in Britain whose distribution is still poorly understood.
Acanthochitona fascicularis
The map provided here shows the distribution of the species based on Conchological Society data held by the National Biodiversity Network (NBN). See terms and conditions.
The following datasets are included:
- Conchological Society of Great Britain & Ireland: marine mollusc records
Open an NBN Atlas interactive map of this data in a new window.
Ecology and behaviour
Lives on the underside of rocks and boulders usually lightly embedded in sand or gravel. When displaced from substrate, can roll into a ball [4]. It feeds by grazing material from the rock surface using its radula. Most common in the low shore or shallow subtidal areas but can occur to a depth of 70m.
Similar species
- Acanthochitona crinita has a narrower girdle and more variable oval or tear drop shaped granulation on the valve surface.
Key identification features
References and links
- Baxter, J.M. and Jones, A.M. 1987. Molluscs: Caudofoveata Solenogastres Polyplacophora and Scaphopoda. London.
Taxon details available from MolluscaBase (AphiaID 138677):
Acanthochitona fascicularis (Linnaeus, 1767)
The UK NBN Atlas entry for the species can be accessed via this link.
Taxon version key
[NBNSYS0000173555]
Sort order
470
Taxonomic group
Chiton
Size: Up to about 60mm long - Britain's largest chiton. Shape: Very broad girdle with the shell making up 30-40% of the width.
Acanthochitona crinita
Distribution and status
Occurs from Norway to the Mediterranean and Adriatic seas [GBIF map]. It is found all around the coasts of Britain and Ireland and is not uncommon. While it sometimes occurs in very high densities it more generally found in relatively low numbers.
Acanthochitona crinita
The map provided here shows the distribution of the species based on Conchological Society data held by the National Biodiversity Network (NBN). See terms and conditions.
The following datasets are included:
- Conchological Society of Great Britain & Ireland: marine mollusc records
Open an NBN Atlas interactive map of this data in a new window.
Ecology and behaviour
Lives on the underside of rocks and boulders usually lightly embedded in sand or gravel. It feeds by grazing material from the rock surface using its radula. Most common in the low shore or shallow subtidal areas but can occur to a depth of 50m.
Similar species
- Acanthochitona fascicularis has densely packed round granulations on the valve surface and a wider girdle.
Key identification features
- Relatively wide girdle with eighteen conspicuous tufts of colourless bristles.
- Coarse granules on the valves which are tear-drop shaped or oval.
References and links
- Baxter, J.M. and Jones, A.M. 1987. Molluscs: Caudofoveata Solenogastres Polyplacophora and Scaphopoda. London.
Taxon details available from MolluscaBase (AphiaID 138675):
Acanthochitona crinita (Pennant, 1777)
The UK NBN Atlas entry for the species can be accessed via this link.
Taxon version key
[NBNSYS0000173552]
Sort order
460
Taxonomic group
Chiton
Size: Up to about 34mm long. Shape: Very broad girdle with the shell making up 40-50% of the width. Valves are relatively flat, with a very slight keel.
Boreochiton ruber (Linnaeus, 1767)
Distribution and status
It occurs from the Barents and White Seas in the north, around the coasts of Norway, Sweden, Greenland and as far south as the Azores. It is found on all shores around Britain and Ireland.
The map provided here shows the distribution of the species based on Conchological Society data.
Ecology and behaviour
Occurs from low water to depths of 300m but never in high densities. It feeds by grazing material from the rock surface using its radula. Rocky bottoms but also pebbles on sand.
Key identification features
- Valve surface appears smooth under hand lens
- Girdle is covered with tightly packed oval granules
References and links
- Ávila, S , Sigwart, J 2013. New records for the shallow-water chiton fauna (Mollusca, Polyplacophora) of the Azores (NE Atlantic). Zookeys. 2013; (312): 23–38.
- Baxter, J.M. and Jones, A.M. 1987. Molluscs: Caudofoveata Solenogastres Polyplacophora and Scaphopoda. London.
Taxon version key
[NBNSYS0000178410]
Sort order
450
Taxonomic group
Chiton
Size: Up to about 21mm long. Shape: Relatively narrow girdle with the shell making up 75% of the width. Valves are rounded with a moderate keel.
Tonicella marmorea
Distribution and status
It is a northern species extending as far south as north Wales in the west and Yorkshire in the east. Elsewhere it occurs across the Arctic Ocean around Norway, Sweden, Greenland and the Atlantic coast of North America.
Ecology and behaviour
Most common on expanses of bedrock though also occurs on stones and pebbles. It feeds by grazing material from the rock surface using its radula. It can occur in fairly high densities (40-50 per square metre) making it an important grazer within the ecosystem. It occurs very low on the shore down to depths of 200m.
Key identification features
- Smooth, "leathery" appearance of girdle
- Valve surface appears smooth
References and links
- Baxter, J.M. and Jones, A.M. 1987. Molluscs: Caudofoveata Solenogastres Polyplacophora and Scaphopoda. London.
Taxon version key
[NBNSYS0000178409]
Sort order
440
Taxonomic group
Chiton
Size: Up to about 45mm long. Shape: Relatively narrow girdle with the shell making up 70% of the width. Valves are moderately tall with a definite keel.
Ischnochiton exaratus
Taxon version key
[NBNSYS0000183066]
Sort order
410
Taxonomic group
Chiton
Hanleya nagelfar
Taxon version key
[NBNSYS0000182551]
Sort order
390
Taxonomic group
Chiton
Hanleya hanleyi
Distribution and status
Relatively rare species. It occurs from the Arctic Ocean and Barents Seas in the north, around the coasts of Norway, Sweden, Greenland and as far south as the Mediterranean. Present all around the British Isles.
Ecology and behaviour
Occurs mainly on sandy bottoms attached to small shells and pebbles from 15m to 300m depth (though most common below 100m). It feeds by grazing material from the rock surface using its radula.
Key identification features
- Very coarse sculpturing of valve surface
- Girdle is covered with short spicules and long smooth spines
References and links
- Baxter, J.M. and Jones, A.M. 1987. Molluscs: Caudofoveata Solenogastres Polyplacophora and Scaphopoda. London.
Taxon version key
[NBNSYS0000175666]
Sort order
380
Taxonomic group
Chiton
Size: Up to about 22mm long. Shape: Relatively elongate species. It has a narrow girdle with the shell making up 80% of the width.
Lepidopleurus cajetanus
Taxon version key
[NBNSYS0000183382]
Sort order
370
Taxonomic group
Chiton