Ophiuroidea


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Ophiuroidea

[äf·ə·yə′rȯid·ē·ə]
(invertebrate zoology)
The brittle stars, a subclass of the Asterozoa in which the arms are usually clearly demarcated from the central disk and perform whiplike locomotor movements.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Ophiuroidea

 

(brittle stars), a class of benthic marine animals of the phylum Echinodermata. The body consists of a flat disk, which usually measures about 2 cm across (sometimes up to 10 cm). Five or, less frequently, ten flexible arms extend from the disk. The length of each arm is several times (sometimes 20 to 30 times) greater than that of the disk. In contrast to the arms of starfishes, the arms of brittle stars are sharply marked off from the disk and are jointed, consisting of numerous vertebrae. Most brittle stars have simple, unbranched arms. The disk and the arms are covered with thin calcareous plates.

In most species the sexes are separate. Development is usually by metamorphosis; the free-swimming larva is called an ophiopluteus. Some species are viviparous; others are capable of reproducing by division.

Brittle stars crawl by flexing their arms, or they bury themselves in the bottom. They feed on small animals or detritus. Many tropical species that inhabit shallows are brightly colored. Some species are capable of luminescence. The regeneration of arms is well developed.

Brittle stars are found throughout the world on ocean and sea bottoms (to depths of 8 km). They often form large colonies and serve as food for fishes. Some species live commensally with algae, sponges, corals, and sea urchins. Of the approximately 2,000 species, about 120 are encountered in the seas of the USSR. Fossils of extinct species have been traced to the Ordovician.

G. M. BELIAEV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Lecithotrophic development and metamorphosis in the Indo-West Pacific brittle star Ophiomastix venosa (Echinodermata: Ophiuroidea).
Host species of the non-indigenous brittle star Ophiothela mirabilis (Echinodermata: Ophiuroidea): an invasive generalist in Brazil?
Liao, Fauna Sinica Invertebrata Echinodermata Ophiuroidea, vol.
Depositivoros Superficiales {SDF}, Consumidores Superficiales (IF), Omnivoros/Depredadores (0P), Depositivoros Su bsuperficiales {SSDF} a) Densidad No Grupo Familia Especie % GT 1 Polychaeta Spionidae Polydora socialis 23,39 SDF 2 Polychaeta Spionidae Paraprionospio 12,50 IF pinnata 3 Polychaeta Capitellidae Capitellidae 8,60 SDF 4 Polychaeta Spionidae Prionospio peruana 5,82 IF 5 Echinodermata Ophiuroidea 4,18 OP 6 Polychaeta Paraonidae Aricidea simplex 3,73 SDF 7 Crustacea Oedicerotidae 2,21 IF 8 Sipunculida Sipunculidae 2,10 OP 9 Polychaeta Nereidae Nereis sp.
All organisms were counted after identification to species level, with the exception of Ophiuroidea, Turbellaria, Nemertea and Polychaeta which were identified to higher taxonomic levels.
9.09 0.69 1.28 Caprella californica Isopoda 37.27 3.89 3.45 2.75 Dinamitella dilatata Paracerceis cordata 3.64 0.14 0.35 0.02 Cirolana hurfordi 36.36 3.75 3.10 2.50 Assellota UI Echinodermata Ophiuroidea Amphiodia sp.
Another group for which species are reported to occur on both sides of the ACC and APF is the Ophiuroidea, a dominant component of Southern Ocean benthic fauna (Stohr et al., 2012).
Se identificaron 229 especies correspondientes a 11 Filos: Annelida (Polychaeta), Arthropoda (Pycnogonida, Malacostraca, Ostracoda), Bryozoa, Chordata (Ascidiacea), Cnidaria (Anthozoa, Hydrozoa), Echinodermata (Echinoidea, Ophiuroidea, Holothuroidea, Asteroidea), Mollusca (Gastropoda, Bivalvia, Polyplacophora, Cephalopoda, Scaphopoda), Nemertea (Anopla, Enopla), Platyhelminthes, Porifera y Sipuncula, todos son grupos representativos de comunidades bentonicas costeras (Tabla 1, Apendice I).
This trend has been confirmed in a wide variety of phylogenetically distant clades, including, sea stars (Echinodermata: Asteroidea; Menge 1975 and references therein), basket stars (Echinodermata: Ophiuroidea; Hendler 1979 and references therein), slipper limpets (Mollusca: Gastropoda; Gallardo 1977), and octopuses (Mollusca: Cephalopoda; Green 1973).