EUNIS habitat classification 2012 amended 2019 > A - Marine habitats > A5 - Sublittoral sediment > A5.1 - Sublittoral coarse sediment > A5.14 - Circalittoral coarse sediment > A5.142 - Mediomastus fragilis, Lumbrineris spp. and venerid bivalves in circalittoral coarse sand or gravel

Mediomastus fragilis, Lumbrineris spp. and venerid bivalves in circalittoral coarse sand or gravel

English name: Mediomastus fragilis, Lumbrineris spp. and venerid bivalves in circalittoral coarse sand or gravel

Quick facts

EUNIS habitat type code A5.142
Bern Convention Included in a Resolution 4 habitat type at a higher level (A5)

Description (English)

Circalittoral gravels, coarse to medium sands, and shell gravels, sometimes with a small amount of silt and generally in relatively deep water (generally over 15-20m), may be characterised by polychaetes such as Mediomastus fragilis, Lumbrineris spp., Glycera lapidum with the pea urchin Echinocyamus pusillus. Other taxa may include Nemertea spp., Protodorvillea kefersteini, Owenia fusiformis, Spiophanes bombyx and Amphipholis squamata along with amphipods such as Ampelisca spinipes. This biotope may also be characterised by the presence of conspicuous venerid bivalves, particularly Timoclea ovata. Other robust bivalve species such as Moerella spp., Glycymeris glycymeris and Astarte sulcata may also be found in this biotope. Spatangus purpureus may be present especially where the interstices of the gravel are filled by finer particles, in which case, Gari tellinella may also be prevalent (Glemarec 1973). Venerid bivalves are often under-sampled in benthic grab surveys and as such may not be conspicuous in many infaunal datasets. Such communities in gravelly sediments may be relatively species-rich and they may also contain epifauna such as Hydroides norvegicus and Pomatoceros lamarcki. In sand wave areas this biotope may also contain elements of the A5.242 biotope, particularly Magelona species. This biotope has previously been described as the 'Deep Venus Community' and the 'Boreal Off-Shore Gravel Association' by other workers (Ford 1923; Jones 1950) and may also be part of the Venus community described by Thorson (1957) and in the infralittoral etage described by Glemarec (1973). A5.142 may be quite variable over time and in fact may be closer to a biotope complex in which a number of biotopes or sub-biotopes may yet be defined. For example, Ford (1923) describes a 'Series A' and a 'Series B' characterised by Echinocardium cordatum-Chamelea gallina and Spatangus purpurea-Clausinella fasciata. Furthermore, mosaics of cobble and lag gravel often contain ridges of coarse gravelly sand and these localised patches are also characterised by robust veneriid and similar bivalves including Arcopagia crassa, Laevicardium crassum and others including Glycymeris glycymeris (E.I.S. Rees pers. comm. 2002). This high porosity fine gravel or coarse sand may be a separate biotope.
Situation: This biotope and variants of it make up a significant proportion of the offshore Irish Sea benthos (Mackie, Oliver & Rees 1995).
Temporal variation: A5.142 may be quite variable over time.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Ampelisca spinipes
Invertebrates Amphipholis squamata
Invertebrates Astarte sulcata
Invertebrates Echinocyamus pusillus
Invertebrates Gari tellinella
Invertebrates Glycera lapidum
Invertebrates Glycymeris glycymeris
Invertebrates Hydroides norvegicus
Invertebrates Mediomastus fragilis
Invertebrates Owenia fusiformis
Invertebrates Protodorvillea kefersteini
Invertebrates Spatangus purpureus
Invertebrates Spiophanes bombyx
Invertebrates Timoclea ovata
Species scientific name English common name Species group
Ampelisca spinipes Invertebrates
Amphipholis squamata Invertebrates
Astarte sulcata Invertebrates
Echinocyamus pusillus Invertebrates
Gari tellinella Invertebrates
Glycera lapidum Invertebrates
Glycymeris glycymeris Invertebrates
Hydroides norvegicus Invertebrates
Mediomastus fragilis Invertebrates
Owenia fusiformis Invertebrates
Protodorvillea kefersteini Invertebrates
Spatangus purpureus Invertebrates
Spiophanes bombyx Invertebrates
Timoclea ovata Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 SS.SCS.CCS.MedLumVen <I>Mediomastus fragilis</I>, <I>Lumbrineris</I> spp. and venerid bivalves in circalittoral coarse sand or gravel source
CORINE Land Cover 5.2.3. Sea and ocean n/a
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200410 A5.132 Mediomastus fragilis, Lumbrineris spp. and venerid bivalves in circalittoral coarse sand or gravel same
EUNIS Habitat Classification 200308 A4.131 Venerid bivalves in circalittoral coarse sand or gravel wider
EUNIS Habitat Classification 200202 A4.131 Venerid bivalves in circalittoral coarse sand or gravel overlap
EUNIS Habitat Classification 199910 A4.141 Venerid bivalves in circalittoral coarse sand or gravel overlap
MNCR BioMar 97.06 (Britain & Ireland) CGS.Ven Venerid bivalves in circalittoral coarse sand or gravel overlap
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