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Marine Habitat Classification

Description of biotope or habitat type

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   Amphiura filiformis, Mysella bidentata and Abra nitida in circalittoral sandy mud

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Exposed, Moderately exposed
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Sandy mud
Zone Circalittoral
Depth Band 10-20 m, 20-30 m
Other Features

Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.

Distribution of habitat SS.SMu.CSaMu.AfilMysAnit <I>Amphiura filiformis</I>, <I>Mysella bidentata</I> and <I>Abra nitida</I> in circalittoral sandy mud

  • Records used to define the biotope (core records)
  • Other records assigned to this biotope, marked as 'certain'
  • Other records assigned to this biotope, marked as 'uncertain'
  • Predicted extent of the level 3 (for sublittoral rock & deep sea) or 4 (for sublittoral sediment) habitat

Point data based on records in the UK Marine Recorder Snapshot. Predicted habitat extent is from UKSeaMap.


Cohesive sandy mud off wave exposed coasts with weak tidal streams can be characterised by super-abundant Amphiura filiformis with Mysella bidentata and Abra nitida. This community occurs in muddy sands in moderately deep water (Hiscock 1984; Picton et al. 1994) and may be related to the 'off-shore muddy sand association' described by other workers (Jones 1951; Thorson 1957; Mackie 1990) and is part of the infralittoral etage described by Glemarec. This community is also characterised by the sipunculid Thysanocardia procera and the polychaetes Nephtys incisa, Phoronis sp. and Pholoe sp., with cirratulids also common in some areas. Other taxa such as Nephtys hombergii, Echinocardium cordatum, Nucula nitidosa, Callianassa subterranea and Eudorella truncatula may also occur in offshore examples of this biotope (e.g. Knitzer et al. 1992).


No situation data available.

Temporal variation

No temporal data available.

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Tubularia indivisa 2 Rare 21-40 %
Sagartiogeton undatus 2 Rare 21-40 %
Nemertea 1 41-60 %
Thysanocardia procera 4 61-80 %
Phascolion strombus strombus 2 Rare 21-40 %
Polychaeta 14 Abundant 41-60 %
Aphrodita aculeata 2 Rare 21-40 %
Pholoe inornata 3 Frequent 61-80 %
Nephtys hombergii 1 Frequent 21-40 %
Nephtys incisa 5 61-80 %
Levinsenia gracilis 2 41-60 %
Cirratulidae 4 Super abundant 41-60 %
Chaetozone setosa 1 Frequent 21-40 %
Tharyx 2 Common 41-60 %
Tharyx 1 Frequent 21-40 %
Diplocirrus glaucus 2 41-60 %
Pectinariidae 6 Occasional 41-60 %
Lagis koreni 1 41-60 %
Melinna palmata 3 41-60 %
Lanice conchilega 5 Rare 41-60 %
Pariambus typicus 2 Common 41-60 %
Pagurus bernhardus 11 Occasional 61-80 %
Turritella communis 5 Rare 41-60 %
Mysella bidentata 22 Abundant 81-100 %
Abra nitida 11 Super abundant 61-80 %
Corbula gibba 1 21-40 %
Phoronis 2 Abundant 61-80 %
Ophiuroidea 7 Abundant 41-60 %
Amphiura chiajei 12 Common 41-60 %
Amphiura filiformis 19 Super abundant 81-100 %
Amphiura filiformis 12 Abundant 41-60 %
Ophiura ophiura 6 Rare 61-80 %

Similar biotopes or habitat types

In sandier sediments AfilMysAnit may grade into AalbNuc

In shallower sandy sediments AfilMysAnit may grade into FfabMag

AfilNten may be distinguished from AfilMysAnit by the abundance of the characterising species Nuculoma tenuis in AfilNten and by the importance of other characterising species such as Thysanocardia procera and Nephtys incise in AfilMysAnit. AfilNten is also generally found in deeper water.

ThyNten may be distinguished from AfilMysAnit by the abundance of the characterising species Thyasira flexuosa and by the decreased abundance of Amphiura filiformis in ThyNten. ThyNten is generally found in deeper waters.

Classification history of this biotope or habitat type

Classification version Code
96.7 CGS.AfilEcor

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