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Ophiurida
The Ophiurida are an order of echinoderms within the class Ophiuroidea. It includes the vast majority of living brittle stars. Characteristics Ophiurida have bursae for respiration and excretion, and dorsal and ventral arm shields are present and usually well developed. Arms are unbranched and incapable of coiling vertically. Most are five-armed, some with 4 or 6 arms as an abnormality, but others properly bear six or seven arms. The madreporite is on the oral surface. The digestive glands are entirely within the central disc. They move their arms side to side by means of ball-and-socket joints. Tropical species tend to contrast color from the environment, but most others prefer to blend in. These biochromes do not include echinochromes. Systematics and phylogeny There is currently no consensus as to the subdivision of the Ophiurida. The order has been divided into the following suborders and infraorders * Ophiomyxina * Ophiurina ** Hemieuryalina ** Chilophiurina ** Gna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brittle Stars
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomotion. The ophiuroids generally have five long, slender, whip-like arms which may reach up to in length on the largest specimens. The Ophiuroidea contain two large clades, Ophiurida (brittle stars) and Euryalida (basket stars). Over 2,000 species of brittle stars live today. More than 1,200 of these species are found in deep waters, greater than 200 m deep. Range The ophiuroids diverged in the Early Ordovician. Ophiuroids can be found today in all of the major marine provinces, from the poles to the tropics. Basket stars are usually confined to the deeper parts of this range; Ophiuroids are known even from abyssal (>6,000 m) depths. However, brittle stars are also common members of reef communities, where they hide under rocks and even w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiurida
The Ophiurida are an order of echinoderms within the class Ophiuroidea. It includes the vast majority of living brittle stars. Characteristics Ophiurida have bursae for respiration and excretion, and dorsal and ventral arm shields are present and usually well developed. Arms are unbranched and incapable of coiling vertically. Most are five-armed, some with 4 or 6 arms as an abnormality, but others properly bear six or seven arms. The madreporite is on the oral surface. The digestive glands are entirely within the central disc. They move their arms side to side by means of ball-and-socket joints. Tropical species tend to contrast color from the environment, but most others prefer to blend in. These biochromes do not include echinochromes. Systematics and phylogeny There is currently no consensus as to the subdivision of the Ophiurida. The order has been divided into the following suborders and infraorders * Ophiomyxina * Ophiurina ** Hemieuryalina ** Chilophiurina ** Gna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiura Ophiura
''Ophiura ophiura'' or the serpent star is a species of brittle star in the order Ophiurida. It is typically found on coastal seabeds around northwestern Europe. Description ''Ophiura ophiura'' has a circular central disc up to 35 mm (1.5 in) wide and five radially arranged, narrow arms each up to long. The general colour is mottled reddish-brown with a paler underside. Both the top and the underside of the disc are covered with calcareous plates. The arms are joined to the top rather than the edge of the disc and further small, articulating plates allow the arms to bend from side to side. Small spines on the arms lie flat against the surface. Four larger plates occur across the root of each arm with the outer pair having a comb-like edge, with 20 to 30 fine papillae in each.''Ophiura ophiura'' (Linn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiurina
Ophiurina are a suborder of brittle stars containing the majority of living brittle star species. Characteristics Ophiurina contain a large number of ophiuroids with characteristics ranging from skin just covering the disk, the presence or absence of arm combs, and an infradental papilla occurring with a distinct diastema between it and its flanking oral papillae Systematics There is currently no consensus as to the subdivision of the Ophiurina (traditionally, the infraorders have been treated as suborders). It contains the genera Amphiura, Amphipholis, and Ophiacantha. The suborder has been divided into the following recent infraorders and families :Smith, A.B.; Paterson, G.L.J., Ophiuroid phylogeny and higher taxonomy: morphological, molecular and palaeontological perspectives. Zool. J. Linn. Soc. 114 (1995) *Ophiacanthidae Hemieuryalina *Hemieuryalidae Chilophiurina *Ophiuridae Gnathophiurina *Amphilepididae *Amphiuridae *Ophiothricidae *Ophiactidae *Ophionereididae *Ophio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnathophiurina
The Gnathophiurina are a group of Ophiuroidea mostly treated as suborder (but at first as an order Gnathophiurida, and sometimes as infraorder of OphiurinaSmith, A.B.; Paterson, G.L.J. . Ophiuroid phylogeny and higher taxonomy: morphological, molecular and palaeontological perspectives. Zool. J. Linn. Soc. 114 (1995) or not used at all). Families * Amphilepididae Matsumoto, 1915 * Amphiuridae Ljungman, 1867 * Ophiactidae Matsumoto, 1915 * Ophiocomidae Ljungman, 1867 * Ophionereididae Ophionereididae are a family of brittle star Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the ... Ljungman, 1867 * Ophiothricidae Ljungman, 1867 References Ophiurida {{ophiuroidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Detritus
In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Remineralisation, remineralise) it. Such microorganisms may be decomposers, detritivores, or coprophages. In terrestrial ecosystems detritus is present as plant litter and other organic matter that is intermixed with soil, known as soil organic matter. The detritus of aquatic ecosystems is organic substances suspended in the water and accumulated in depositions on the floor of the body of water; when this floor is a seabed, such a deposition is called marine snow. Theory The remains of decaying plants or animals, or their tissue parts, and feces gradually lose their form due to physical processes and the action of decomposers, including grazers, bacteria, and fungi. Decomposition, the process by which organic matter is decomposed, occurs in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herbivore
A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat non-vascular autotrophs such as mosses, algae and lichens, but do not include those feeding on decomposed plant matters (i.e. detritivores) or macrofungi (i.e. fungivores). As a result of their plant-based diet, herbivorous animals typically have mouth structures ( jaws or mouthparts) well adapted to mechanically break down plant materials, and their digestive systems have special enzymes (e.g. amylase and cellulase) to digest polysaccharides. Grazing herbivores such as horses and cattles have wide flat- crowned teeth that are better adapted for grinding grass, tree bark and other tougher lignin-containing materials, and many of them evolved rumination or cecotropic behaviors to better extract nutrients from plants. A larg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiothricidae
Ophiotrichidae are a family of brittle stars within the suborder Gnathophiurina. All of its species have arms with delicate, translucent, thorny spines. Their arms are flexible in all directions. Their jaws contain clusters of well-developed tooth papillae on the apex but not on the sides. There are no mouth papillae. Inside the mouth edge there is a second pair of tube feet. They show large radial shields. The dorsal surface of the disc is covered with spines and thorny towers. Systematics Ophiotrichidae contains the following genera: *''Asteria'' (''nomen dubium'') *'' Gymnolophus'' Brock, 1888 *'' Lissophiothrix'' H.L. Clark, 1938 *'' Macrophiothrix'' H.L. Clark, 1938 *'' Ophioaethiops'' Brock, 1888 *'' Ophiocampsis'' Duncan, 1887 *'' Ophiocnemis'' Müller & Troschel, 1842 *'' Ophiogymna'' Ljungman, 1866 *'' Ophiolophus'' Marktanner-Turneretscher, 1887 *'' Ophiomaza'' Lyman, 1871 *'' Ophiophthirius'' Döderlein, 1898 *'' Ophiopsammium'' Lyman, 1874 *'' Ophiopteron'' Ludwig, 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
