BIOTIC Species Information for Musculus discors
Researched byLizzie Tyler Data supplied byUniversity of Sheffield
Refereed byThis information is not refereed.
General Biology
Growth formBivalved
Feeding methodPassive suspension feeder
Active suspension feeder
Mobility/Movement Environmental positionEpilithic
Typical food typesPhytoplankton, bacteria, organic particulates and dissolved organic matter (DOM). HabitAttached
BioturbatorNot relevant FlexibilityNone (< 10 degrees)
FragilityIntermediate SizeSmall(1-2cm)
HeightInsufficient information Growth RateSee additional information
Adult dispersal potential<10m DependencyIndependent
General Biology Additional Information

Musculus discors usually occurs as distinct clumps but occasionally forms dense, extensive beds (Könnecker & Keegan, 1983; Cartlidge & Hiscock, 1980; Hiscock, 1984b; Baldock et al., 1998).

Adults attach to their substratum using byssus threads. They then weave a 'nest' of several thousand of fine byssus threads around their shell, so that the shell is suspended in a network of byssus threads, similar to a 'ball of twine' . The byssus threads are not attached to the shell but only emanate from the byssal aperture. The nest completely encloses the adult so that the crenella is only visible when its valves are open and it is feeding with siphons extended (MacGinitie, 1955; Merrill & Turner, 1963). An adult may produce between 200 -500 threads/ week (Merrill & Turner, 1963). Nest construction is detailed by Merrill & Turner (1963).

The nest may incorporate a variety of pieces of seaweeds or detritus or may be fouled by epifauna, the exact composition depending on the location and habitat, which provide camouflage. For example, the nest may incorporate; the stolons of hydroids, bryozoans, small bivalves and annelids (MacGinitie, 1955; Merrill & Turner, 1963); fragments of Flustra foliacea (Forbes & Hanley, 1853), or fragments or blades of fucoids and laminarians (Thorson, 1935).

MacGinitie (1955) noted that specimens from East Greenland >20mm were nearly always covered by a byssal nest. However, in British Columbia Merrill & Turner (1963) noted that the smallest specimens with nests were 8.1mm in length and most specimens over 15mm had nests, although some specimens up to 18mm in length were without a nest.

Thorson (1935) reported that Musculus discors was 5-7mm in length by the first growth ring (presumably Ist year), 10 -11mm by the second and 13 -16mm by the third (presumably 3rd year) in east Greenland, however, growth rates will probably depend on environmental conditions.

Little other information on the biology of Musculus discors was found.
Biology References Fish & Fish, 1996, Baldock et al., 1998, Könnecker & Keegan, 1983, Ockelmann, 1958, Thorson, 1946, Merrill & Turner, 1963, Forbes & Hanley, 1853, Jeffreys, 1863, MacGinitie, 1955, Cartlidge & Hiscock, 1980, Lauckner, 1983,
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