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Abatus Cordatus
''Abatus cordatus'' is a species of sea urchin in the family Schizasteridae. It is native to shallow seas surrounding certain island groups in the southern Indian Ocean. The body is protected by a hard test or shell which is covered with spines. The female broods its young in deep pockets on the upper surface, retaining the young in place with specialised spines. American zoologist Addison Emery Verrill first scientifically described ''A. cordatus'' in 1876.Kroh, A. (2010)''Abatus cordatus''(Verrill, 1876). In: Kroh, A. & Mooi, R. (2010) World Echinoidea Database. at the World Register of Marine Species Description The test of this species is oval and bilaterally symmetrical, up to long. The oral (under) surface is relatively flat but the aboral (upper) surface is domed, the colour being some shade of yellowish or greenish-brown. The test is thin and fragile, and is entirely covered with spines of various lengths in different parts. The anterior ambulacrum forms a shallow depr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Addison Emery Verrill
Addison Emery Verrill (February 9, 1839 – December 10, 1926) was an American invertebrate zoologist, museum curator and university professor. Life Verrill was born on February 9, 1839 in Greenwood, Maine, the son of George Washington Verrill and Lucy (Hillborn) Verrill. As a boy he showed an early interest in natural history, building collections of rocks and minerals, plants, shells, insects and other animals. When he moved with his family to Norway, Maine at age fourteen he attended secondary school at the Norway Liberal Institute. Verrill started college in 1859 at Harvard University and studied under Louis Agassiz. He graduated in 1862 with a B.A. He went on scientific collecting trips with Alpheus Hyatt and Nathaniel Shaler in the summer of 1860 to Trenton Point, Maine and Mount Desert Island and in the summer of 1861 to Anticosti Island and Labrador. In 1864 Verrill made reports on mining, or prospective mining, properties in New Hampshire, New York, and Pennsylvania. Tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Urchin
Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of sea urchins are round and spiny, ranging in diameter from . Sea urchins move slowly, crawling with tube feet, and also propel themselves with their spines. Although algae are the primary diet, sea urchins also eat slow-moving (sessile) animals. Predators that eat sea urchins include a wide variety of fish, starfish, crabs, marine mammals. Sea urchins are also used as food especially in Japan. Adult sea urchins have fivefold symmetry, but their pluteus larvae feature bilateral (mirror) symmetry, indicating that the sea urchin belongs to the Bilateria group of animal phyla, which also comprises the chordates and the arthropods, the annelids and the molluscs, and are found in every ocean and in every climate, from the tropics to the pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schizasteridae
Schizasteridae is a family of echinoderms belonging to the order Spatangoida. Genera: * ''Abatus'' Troschel, 1851 * '' Aceste'' Thomson, 1877 * ''Agassizia'' Agassiz & Desor, 1847 * '' Aguayoaster'' Sanchez Roig, 1952 * '' Aliaster'' Valdinucci, 1975 * '' Amphipneustes'' Koehler, 1900 * '' Brachybrissus'' Pomel, 1883 * '' Brachysternaster'' Larrain, 1985 * '' Brisaster'' Gray, 1855 * '' Calzadaster'' * '' Caribbaster'' Kier, 1984 * '' Cestobrissus'' Lambert, 1912 * '' Diploporaster'' Mortensen, 1950 * '' Dipneustes'' Arnaud, 1891 * '' Gregoryaster'' Lambert, 1907 * '' Hemifaorina'' Jeannet & Martin, 1937 * '' Hypselaster'' H.L.Clark, 1917 * '' Kina Henderson'' , 1975 * '' Lambertona'' Sanchez-Roig, 1953 * '' Linthia'' Desor, 1853 * '' Lutetiaster'' * '' Moira'' A.Agassiz, 1872 * '' Moiropsis'' A.Agassiz, 1881 * '' Neoproraster'' * '' Opissaster'' Pomel, 1883 * ''Ova , abbreviated as OVA and sometimes as OAV (original animation video), are Japanese animated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Test (biology)
In biology, a test is the hard shell of some spherical marine animals and protists, notably sea urchins and microorganisms such as testate foraminiferans, radiolarians, and testate amoebae. The term is also applied to the covering of scale insects. The related Latin term testa is used for the hard seed coat of plant seeds. Etymology The anatomical term "test" derives from the Latin ''testa'' (which means a rounded bowl, amphora or bottle). Structure The test is a skeletal structure, made of hard material such as calcium carbonate, silica, chitin or composite materials. As such, it allows the protection of the internal organs and the attachment of soft flesh. In sea urchins The test of sea urchins is made of calcium carbonate, strengthened by a framework of calcite monocrystals, in a characteristic "stereomic" structure. These two ingredients provide sea urchins with a great solidity and a moderate weight, as well as the capacity to regenerate the mesh from the cuticle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species Description
A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have been described previously or are related. In order for species to be validly described, they need to follow guidelines established over time. Zoological naming requires adherence to the ICZN code, plants, the ICN, viruses ICTV, and so on. The species description often contains photographs or other illustrations of type material along with a note on where they are deposited. The publication in which the species is described gives the new species a formal scientific name. Some 1.9 million species have been identified and described, out of some 8.7 million that may actually exist. Millions more have become extinct throughout the existence of life on Earth. Naming process A name of a new species becomes valid (available in zo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Register Of Marine Species
The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialists on each group of organism. These taxonomists control the quality of the information, which is gathered from the primary scientific literature as well as from some external regional and taxon-specific databases. WoRMS maintains valid names of all marine organisms, but also provides information on synonyms and invalid names. It is an ongoing task to maintain the registry, since new species are constantly being discovered and described by scientists; in addition, the nomenclature and taxonomy of existing species is often corrected or changed as new research is constantly being published. Subsets of WoRMS content are made available, and can have separate badging and their own home/launch pages, as "subregisters", such as the ''World List of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambulacrum (anatomy)
In zoology, an ambulacrum is an elongated area of the shell of an echinoderm in which a row of tube feet are arranged. It is pluralized as ''ambulacra''. The area on the shell between ambulacra is known as an interambulacrum Ambulacral is a term typically used in the context of anatomical parts of the phylum Echinodermata or class Asteroidea and Edrioasteroidea. Echinoderms can have ambulacral parts that include ossicles, plates, spines, and suckers. For example, se .... References Echinoderm anatomy {{echinoderm-anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemism
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can be also be referred to as an ''endemism'' or in scientific literature as an ''endemite''. For example '' Cytisus aeolicus'' is an endemite of the Italian flora. '' Adzharia renschi'' was once believed to be an endemite of the Caucasus, but it was later discovered to be a non-indigenous species from South America belonging to a different genus. The extreme opposite of an endemic species is one with a cosmopolitan distribution, having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kerguelen Islands
The Kerguelen Islands ( or ; in French commonly ' but officially ', ), also known as the Desolation Islands (' in French), are a group of islands in the sub-Antarctic constituting one of the two exposed parts of the Kerguelen Plateau, a large igneous province mostly submerged in the southern Indian Ocean. They are among the most isolated places on Earth, located more than from Madagascar. The islands, along with Adélie Land, the Crozet Islands, Amsterdam and Saint Paul islands, and France's Scattered Islands in the Indian Ocean, are part of the French Southern and Antarctic Lands and are administered as a separate district. The main island, Grande Terre, is in area, about three quarters of the size of Corsica, and is surrounded by a further 300 smaller islands and islets, forming an archipelago of . The climate is harsh and chilly with frequent high winds throughout the year. The surrounding seas are generally rough and they remain ice-free year-round. There are no indig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heard Island And McDonald Islands
The Territory of Heard Island and McDonald Islands (HIMI) is an Australian external territory comprising a volcanic group of mostly barren Antarctic islands, about two-thirds of the way from Madagascar to Antarctica. The group's overall size is in area and it has of coastline. Discovered in the mid-19th century, the islands lie on the Kerguelen Plateau in the Indian Ocean and have been an Australian territory since 1947. They contain Australia's only two active volcanoes. The summit of one, Mawson Peak, is higher than any mountain in all other Australian states or territories, except Dome Argus, Mount McClintock and Mount Menzies in the Australian Antarctic Territory. The islands are among the most remote places on Earth: They are located about southwest of Perth, southwest of Cape Leeuwin, Australia, southeast of South Africa, southeast of Madagascar, north of Antarctica, and southeast of the Kerguelen Islands (part of French Southern and Antarctic Lands). The is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonochorism
In biology, gonochorism is a sexual system where there are only two Sex, sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric. Gonochorism contrasts with Hermaphrodite, simultaneous hermaphroditism but it may be hard to tell if a species is gonochoric or sequentially hermaphroditic. (e.g. Parrotfish, ''Patella ferruginea''). However, in gonochoric species individuals remain either male or female throughout their lives. Species that reproduce by Thelytokous, thelytokous parthenogenesis and do not have males can still be classified as gonochoric. Terminology The term is derived from Greek language, Greek (''gone'', generation) + (''chorizein,'' to separate). The term gonochorism originally came from German gonochorismus. Gonochorism is also referred to as unisexualism or gonochory. Evolution Gonochorism has Convergent evolution, evolved independently multiple time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonopore
A gonopore, sometimes called a gonadopore, is a genital pore in many invertebrates. Hexapods, including insects have a single common gonopore, except mayflies, which have a pair of gonopores. More specifically, in the unmodified female it is the opening of the common oviduct, and in the male, it is the opening of the ejaculatory duct. The position of the gonopore varies considerably between groups, but is generally constant within groups, allowing its position to be used as a "segmental marker". In Malacostraca, it is on the sixth thoracic segment; in Symphyla it is on the fourth trunk segment; in arachnids, it is on the second segment of the opisthosoma. In insects and centipedes, the gonopores are close to the animal's tail, while in millipedes they are on the third body segment behind the head, near the second pair of legs. See also * Gonopod * Gonopodium Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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