Jim Greenfield, Großbritannien
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Ophiocomina nigra (Abildgaard in O.F. Müller, 1789)
Ophiocomina nigra occurs in the northeastern Atlantic, the North Sea and the Mediterranean. The black brittle star can be found from the sublittoral to a depth of around 400 m on coarse sand, rocks, boulders and gravel. The brittle star is also said to tolerate low salt levels.
Ophiocomina nigra is a large brittle star with five narrow arms up to 125 mm long and a distinct central disk up to 25 mm wide. The general color is black or various shades of brown, although pale colored specimens occasionally occur. The top of the disc is covered with fine grains, and comb-like spines are arranged on either side of the arms, giving them a bristly appearance. There are tube feet on the bottom, but they do not have suction cups.
In Scotland, for example, propagation takes place in June. A large female is often found with a smaller male clinging above or below her. However, fertilization occurs in the water column and is a chance meeting of two gametes. The larvae live planktonically. Only after several months do young brittle stars settle on the ground. The species appears to be slow growing and long lived. She doesn't fully grow until she's three or four years old.
Ophiocomina nigra often lives in association with another brittle star, Ophiothrix fragilis. Numerous individuals of these two species sometimes form dense communities with hundreds of brittle stars per square meter. These layers can extend for hundreds of square meters across sandy and gravelly sediments on the seafloor and contain millions of brittle stars. These can be either Ophiocomina nigra or Ophiocomina fragilis or a mixed community of both species.
Black brittle stars are eaten by predatory sea stars Asterias rubens, Luidia ciliaris and Crossaster papposus as well as the sea urchins Echinus esculentus and Psammechinus miliaris. The crayfish Cancer pagurus, Necora puber and Liocarcinus spp. as well as the hermit crab Pagurus bernhardus are probably present.
The soft coral Alcyonium digitatum, Nemertesia antennina (Hydrozoa) and the sea anemone Metridium senile are often found on rocky outcrops amidst the seething mass of brittle stars. Another sea anemone, Urticina felina, may be half-buried in sediment and surrounded by an area free of brittle stars.
The brittle star is host to the following ectoparasites:
Cancerilla tubulata Dalyell, 1851
Collocheres elegans Scott A., 1896
Synonymised names
Asterias nigra Abildgaard in O.F. Müller, 1789 · unaccepted (synonym)
Ophiacantha (Ophiotreta) danae Mortensen, 1933 · unaccepted (synonym)
Ophiacantha danae Mortensen, 1933 · unaccepted (synonym)
Ophiacantha valenciennesi sensu Lieberkind, 1929, non Lyman · uncertain > nomen dubium (synonym, misapplication)
Ophiocoma granulata Forbes, 1839 · unaccepted (synonym)
Ophiocoma nigra (Abildgaard in O.F. Müller, 1789) · unaccepted (synonym acc. to Mortensen (1927))
Ophiocoma nigru (Abildgaard in O.F. Müller, 1789) · unaccepted (most likely a spelling error of...)
Ophiocoma nilssoni Müller & Troschel, 1842 · unaccepted (synonym)
Ophiocoma raschi G.O. Sars, 1872 · unaccepted (synonym)
Ophiothrix granulata (Johnston, 1935) · unaccepted (synonym)
Ophiura granulata Johnston, 1935 · unaccepted (synonym)
Ophiocomina nigra occurs in the northeastern Atlantic, the North Sea and the Mediterranean. The black brittle star can be found from the sublittoral to a depth of around 400 m on coarse sand, rocks, boulders and gravel. The brittle star is also said to tolerate low salt levels.
Ophiocomina nigra is a large brittle star with five narrow arms up to 125 mm long and a distinct central disk up to 25 mm wide. The general color is black or various shades of brown, although pale colored specimens occasionally occur. The top of the disc is covered with fine grains, and comb-like spines are arranged on either side of the arms, giving them a bristly appearance. There are tube feet on the bottom, but they do not have suction cups.
In Scotland, for example, propagation takes place in June. A large female is often found with a smaller male clinging above or below her. However, fertilization occurs in the water column and is a chance meeting of two gametes. The larvae live planktonically. Only after several months do young brittle stars settle on the ground. The species appears to be slow growing and long lived. She doesn't fully grow until she's three or four years old.
Ophiocomina nigra often lives in association with another brittle star, Ophiothrix fragilis. Numerous individuals of these two species sometimes form dense communities with hundreds of brittle stars per square meter. These layers can extend for hundreds of square meters across sandy and gravelly sediments on the seafloor and contain millions of brittle stars. These can be either Ophiocomina nigra or Ophiocomina fragilis or a mixed community of both species.
Black brittle stars are eaten by predatory sea stars Asterias rubens, Luidia ciliaris and Crossaster papposus as well as the sea urchins Echinus esculentus and Psammechinus miliaris. The crayfish Cancer pagurus, Necora puber and Liocarcinus spp. as well as the hermit crab Pagurus bernhardus are probably present.
The soft coral Alcyonium digitatum, Nemertesia antennina (Hydrozoa) and the sea anemone Metridium senile are often found on rocky outcrops amidst the seething mass of brittle stars. Another sea anemone, Urticina felina, may be half-buried in sediment and surrounded by an area free of brittle stars.
The brittle star is host to the following ectoparasites:
Cancerilla tubulata Dalyell, 1851
Collocheres elegans Scott A., 1896
Synonymised names
Asterias nigra Abildgaard in O.F. Müller, 1789 · unaccepted (synonym)
Ophiacantha (Ophiotreta) danae Mortensen, 1933 · unaccepted (synonym)
Ophiacantha danae Mortensen, 1933 · unaccepted (synonym)
Ophiacantha valenciennesi sensu Lieberkind, 1929, non Lyman · uncertain > nomen dubium (synonym, misapplication)
Ophiocoma granulata Forbes, 1839 · unaccepted (synonym)
Ophiocoma nigra (Abildgaard in O.F. Müller, 1789) · unaccepted (synonym acc. to Mortensen (1927))
Ophiocoma nigru (Abildgaard in O.F. Müller, 1789) · unaccepted (most likely a spelling error of...)
Ophiocoma nilssoni Müller & Troschel, 1842 · unaccepted (synonym)
Ophiocoma raschi G.O. Sars, 1872 · unaccepted (synonym)
Ophiothrix granulata (Johnston, 1935) · unaccepted (synonym)
Ophiura granulata Johnston, 1935 · unaccepted (synonym)
