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Asteroidea
Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish are also known as asteroids due to being in the class Asteroidea. About 1,900 species of starfish live on the seabed in all the world's oceans, from warm, tropical zones to frigid, polar regions. They are found from the intertidal zone down to abyssal depths, at below the surface. Starfish are marine invertebrates. They typically have a central disc and usually five arms, though some species have a larger number of arms. The aboral or upper surface may be smooth, granular or spiny, and is covered with overlapping plates. Many species are brightly coloured in various shades of red or orange, while others are blue, grey or brown. Starfish have tube feet operated by a hydraulic system and a mouth at the centre of the oral or lower surface. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brisingida
The Brisingids are deep-sea-dwelling starfish in the order Brisingida. Description These starfish have between 6 to 18 long, attenuated arms which they use for suspension feeding. Other characteristics include a single series of marginals, a fused ring of disc plates, the lack of actinal plates, a spool-like ambulacral column, reduced abactinal plates, and crossed pedicellariae. They are 40 times the size of disk radius and have 7-20 flexible spiny arms. Distribution Brisingida occur in a number of deep-sea locations, particularly in the Caribbean and New Zealand. This type of species are found of varying size especially in the eastern Pacific Ocean at a depth of 1,820–2,418 m. Taxonomy The Brisingida contain two families, with 18 genera: *Family Brisingidae, G.O. Sars, 1875 **Genus ''Astrolirus'', Fisher, 1917 — (two species) **Genus '' Astrostephane'', Fisher, 1917 — (two species) **Genus ''Brisinga'' Asbjørnsen, 1856 (synonym: ''Craterobrisinga'', Fisher, 1916) — ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valvatida
The Valvatida are an order of starfish in the class Asteroidea, which contains 695 species in 172 genera in 17 families. Description The order encompasses both tiny species, which are only a few millimetres in diameter, like those in the genus '' Asterina'', and species which can reach up to 75 cm, such as species in the genus '' Thromidia''. Almost all species in this order have five arms with tube feet. This order is primarily identified by the presence of conspicuous marginal ossicles, which characterize most of the species. Most members of this order have five arms and two rows of tube feet with suckers. Some species have paxillae and in some, the main pedicellariae are clamp-like and recessed into the skeletal plates. This group includes the cushion star, and the leather star. Families According to the World Register of Marine Species, the following families are included in Valvatida: * family Acanthasteridae Gervais, 1841 * family Archasteridae Viguier, 1878 * f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forcipulatida
The Forcipulatida are an order of sea stars, containing three families and 49 genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat .... Description Forcipulatids share with the brisingid sea stars distinctive pedicellariae, consisting of a short stalk with three skeletal Ossicle (echinoderm), ossicles. Unlike that group, however, the forcipulatids tend to have more robust bodies. The order includes some well-known species, such as the common starfish, ''Asterias rubens''. This order can be commonly found from Nor Carolina in the United States all the way to Santos in Brazil. Phylogeny The order is divided into three families: * Family Asteriidae — 39 genera * Family Heliasteridae — two genera * Family Zoroasteridae — eight genera World Register of Marine Species gives ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinoderm
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest entirely marine phylum. The first definitive echinoderms appeared near the start of the Cambrian. The echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the biotic desert of the deep sea, as well as shallower oceans. Most echinoderms are able to reproduce asexually and regenerate tissue, organs, and limbs; in some cases, they can undergo complete regeneration from a single limb. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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, about 500 million years ago. 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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forcipulatacea
The Forcipulatacea are a superorder of sea stars. Subdivision * order Forcipulatida * order Brisingida The Brisingids are deep-sea-dwelling starfish in the order Brisingida. Description These starfish have between 6 to 18 long, attenuated arms which they use for suspension feeding. Other characteristics include a single series of marginals, a fu ... * incertae sedis: ** family Paulasteriidae References Asteroidea {{Asteroidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Velatida
The Velatida are an order of sea stars containing about 200 species in five families. These sea stars normally have thick bodies with large discs. Description and characteristics This order contains mostly deep or cold seas sea stars, often with a wide distribution (sometimes global). They have a pentagonal or star shape, with between 5 and 15 arms. Their skeleton is weakly developed, which confers them a good flexibility, and numerous papillae on the aboral surface allow them to breathe in poorly oxygenated waters. Their pedicellariae are often provided with spines. The smallest are Caymanostellidae (between 0,5 and 3 cm) and the biggest Pterasteridae (up to 30 cm). Taxonomy New molecular evidence now suggests a relationship between some velatid and valvatid families. List of families according to World Register of Marine Species: * Caymanostellidae Belyaev, 1974 * Korethrasteridae Danielssen & Koren, 1884 * Myxasteridae Perrier, 1885 * Pterasteridae Perrier, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentricycloidea
Sea daisies (infraclass Concentricycloidea; order Peripodida) make up an unusual group of deep-sea taxa belonging to the phylum Echinodermata, with three species described in the genus ''Xyloplax''. Intestine and anus are absent. Distribution Sea daisies have been discovered in three localities, including deep-sea habitats off New Zealand, the Bahamas and most recently from the northern central Pacific. They have been collected primarily from sunken, deep-sea (1000+ meters) wood. Although known from only a handful of specimens initially, many specimens have now been collected from the Bahamas. Classification Since they were discovered in 1986, their position within the echinoderms has been debated. At first they were placed in a new class, Concentricycloidea, since it was unclear whether they might have affinities with asteroids or ophiuroids. The former view gained acceptance, and since 2006, they are currently considered a sister group to the Infraclass Neoasteroidea, which re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xyloplax
Sea daisies (infraclass Concentricycloidea; order Peripodida) make up an unusual group of deep-sea taxa belonging to the phylum Echinodermata, with three species described in the genus ''Xyloplax''. Intestine and anus are absent. Distribution Sea daisies have been discovered in three localities, including deep-sea habitats off New Zealand, the Bahamas and most recently from the northern central Pacific. They have been collected primarily from sunken, deep-sea (1000+ meters) wood. Although known from only a handful of specimens initially, many specimens have now been collected from the Bahamas. Classification Since they were discovered in 1986, their position within the echinoderms has been debated. At first they were placed in a new class, Concentricycloidea, since it was unclear whether they might have affinities with asteroids or ophiuroids. The former view gained acceptance, and since 2006, they are currently considered a sister group to the Infraclass Neoasteroidea, which re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinulosida
The Spinulosida are an order of sea stars containing at least 120 species in seven genera and one family. Spinulosids completely lack pedicellariae and have a delicate skeletal arrangement. Their name comes from the presence of numerous low spines on the aboral (upper) surface. No fossil spinulosids have yet been found. Taxonomy The following family is recognised by the World Register of Marine Species: * Echinasteridae The Echinasteridae are a family of starfish in the monotypic order Spinulosida. The family includes eight genera and about 133 species found on the seabed in various habitats around the world. Taxonomy Echinasteridae contains eight genera and ... Verrill, 1870 References Echinoderm orders {{Asteroidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notomyotida
Benthopectinidae is a family of sea stars containing at least 75 species in eight genera. It is the only family in the monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ... order Notomyotida. These asteroids are deep-sea dwelling and have flexible arms. The inner dorso-lateral surface of the arms contain characteristic longitudinal muscle bands. Eight genera of deep-water species make up the majority of the family benthopectinidae, and many of its members are expected to have a greater range than is currently recognized. Shin. (2015). A New Record of Sea Star Genus Nearchaster (Asteroidea: Notomyotida: Benthopectinidae) from East Sea, Korea. Animal Systematics, Evolution and Diversity, 31(2), 135–138. https://doi.org/10.5635/ASED.2015.31.2.135 Taxonomy Nine genera are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paxillosida
The Paxillosida are a large order (biology), order of sea stars. Characteristics Paxillosida adults lack an anus and have no suckers on their tube feet. They do not develop the brachiolaria stage in their early development.Matsubara, M., Komatsu, M., Araki, T., Asakawa, S., Yokobori, S.-I., Watanabe, K. & Wada, H. (2005) The phylogenetic status of Paxillosida (Asteroidea) based on complete mitochondrial DNA sequences. Molecular Genetics and Evolution, 36, 598–605 They possess marginal plates, and have sessile pedicellariae. They mostly inhabit soft-bottomed environments of sand or mud. Systematics Recent analyses suggest Paxillosida may be a sister taxon of Asterina (starfish), Asterina. The order is divided into these families: * family Astropectinidae Gray, 1840 * family Ctenodiscidae Sladen, 1889 * family Goniopectinidae Verrill, 1889 * family Luidiidae Sladen, 1889 * family Porcellanasteridae Sladen, 1883 * family Pseudarchasteridae * family Radiasteridae Fisher, 1916 Fil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
