Description of biotope or habitat type
To understand more about what this page is describing, see How to use the classification. See also How to cite.
Kurtiella bidentata and Thyasira spp. in circalittoral muddy mixed sediment
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Moderately exposed, Sheltered |
| Tidal streams | Moderately strong (1-3 kn), Weak (>1 kn) |
| Substratum | Muddy sand and gravel |
| Zone | Circalittoral |
| Depth Band | 10-20 m, 20-30 m, 30-50 m, 50-100 m |
| Other Features |
Biotope origin
| Derived using data from | Various |
| Faunal group | Infauna |
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.
- 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.
Description
In moderately exposed or sheltered, circalittoral muddy sands and gravels a community characterised by the bivalves Thyasira spp. (often Thyasira flexuosa), Kurtiella bidentata and Prionospio fallax may develop. Infaunal polychaetes such as Hilbigneris gracilis, Chaetozone setosa and Scoloplos armiger are also common in this community whilst amphipods such as Ampelisca spp. and the cumacean Eudorella truncatula may also be found in some areas. The brittlestar Amphiura filiformis may also be abundant at some sites. Conspicuous epifauna on larger pebbles or shell gravel may include hydroids, encrusting bryozoans Escharella spp. particularly Escharella immersa, Disporella hispida, and, in shallower waters, maerl (Phymatolithon calcareum), although at very low abundances and not forming maerl beds. In some sheltered areas, organic enrichment of this biotope increases the occurrence of species such as Ophryotrochasp., Scoloplos sp., Mediomastus fragilis, Lumbrineris sp., Capitellids and Tubificoides pseudogaster.
Situation
No situation data available.
Temporal variation
No temporal data available.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | % of core records where taxon was recorded | Relative frequency % |
|---|---|---|---|
| Nemertea | 6 | 1-20% | 10.6 |
| Thyasira flexuosa | 5 | 1-20% | 3.2 |
| Kurtiella bidentata | 4 | 1-20% | 2.5 |
| Hilbigneris gracilis | 3 | 1-20% | 1.8 |
| Scalibregma inflatum | 3 | 1-20% | 1.1 |
| Pholoe inornata | 3 | 1-20% | 1.3 |
| Mediomastus fragilis | 3 | 1-20% | 1.8 |
| Prionospio fallax | 2 | 1-20% | 5.7 |
| Terebellides stroemiii | 2 | 1-20% | 0.5 |
| Chaetozone setosa | 2 | 1-20% | 1.3 |
| Goniada maculata | 2 | 1-20% | 0.4 |
| Owenia fusiformis | 2 | 1-20% | 0.6 |
| Galathowenia oculata | 2 | 1-20% | 1.5 |
| Abra alba | 2 | 1-20% | 3.6 |
| Ampelisca tenuicornis | 2 | 1-20% | 1.1 |
| Nephtys hombergii | 1 | 1-20% | 0.4 |
| Paradoneis lyra | 1 | 1-20% | 0.7 |
| Amphiura filiformis | 1 | 1-20% | 1.2 |
| Spiophanes bombyx | 1 | 1-20% | 1 |
| Phoronis | 1 | 1-20% | 1.8 |
| Glycera alba | 1 | 1-20% | 0.3 |
| Polycirrus | 1 | 1-20% | 0.3 |
| Diplocirrus glaucus | 1 | 1-20% | 0.3 |
| Scoloplos | 1 | 1-20% | 1 |
| Ophelina acuminata | 1 | 1-20% | 0.3 |
| Nephtys | 1 | 1-20% | 0.5 |
| Eudorella truncatula | 1 | 1-20% | 0.5 |
| Spiophanes kroyeri | 1 | 1-20% | 0.3 |
| Eteone longa | 1 | 1-20% | 0.2 |
| Phaxas pellucidus | 1 | 1-20% | 0.3 |
| Chamelea gallina | 1 | 1-20% | 0.4 |
| Levinsenia gracilis | 1 | 1-20% | 1 |
| Leptochiton asellus | 1 | 1-20% | 0.4 |
| Lagis koreni | 1 | 1-20% | 0.5 |
| Notomastus latericeus | 1 | 1-20% | 0.8 |
| Spirobranchus triqueter | 1 | 1-20% | 0.6 |
| Scoloplos armiger | 1 | 1-20% | 0.5 |
| Exogone | 1 | 1-20% | 0.3 |
| Hydroides norvegica | 1 | 1-20% | 0.7 |
| Abra nitida | 1 | 1-20% | 0.2 |
| Parexogone hebes | 1 | 1-20% | 0.6 |
| Eumida sanguinea | 1 | 1-20% | 0.1 |
| Nematoda | 1 | 1-20% | 3.2 |
Similar biotopes or habitat types
SS.SMu.CSaMu.AfilKurAnit
The current biotope is closely related to the muddier, less heterogeneous SS.SMu.CSaMu.AfilKurAnit.
SS.SMu.OMu.ForThy
SS.SMx.CMx.KurThyMx may be a shallower, less heterogeneous variant of the offshore SS.SMu.OMu.ForThy biotope.
SS.SMu.OMu.PjefThyAfil
SS.SMx.CMx.KurThyMx may be a shallower, less heterogeneous variant of the offshore SS.SMu.OMu.PjefThyAfil biotope.Classification history of this biotope or habitat type
| Classification version | Code | Habitat name |
|---|---|---|
| 2015 (15.03) | SS.SMx.CMx.MysThyMx | Mysella bidentata and Thyasira spp. in circalittoral muddy mixed sediment |
| 2004 (04.05) | SS.SMx.CMx.MysThyMx | Mysella bidentata and Thyasira spp. in circalittoral muddy mixed sediment |