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Cephalodiscus Densus
''Cephalodiscus densus'' is a sessile hemichordate belonging to the order Cephalodiscida. The species is endemic to the Antarctic, being found in the Ross Sea and much of the Antarctic coastline, as well as near the Kerguelen Islands. Specimens appear bush-like, with fleshy tubules approximately 1 mm in diameter wrapped in a rock shell built of cemented sediment and other foreign material. Individuals live in the upper portion of the shell, and eggs and young are stored in the lower portion, or the colony to which the base attaches. The body is roughly 6 mm long, of which the stalk composes about 4 mm. The preserved flesh appears on average orange in color, with individuals ranging from pale to dark brown. The largest-known colony of peanut worms The Sipuncula or Sipunculida (common names sipunculid worms or peanut worms) is a class containing about 162 species of marine annelid worms, that have secondarily lost their segmentation. Sipuncula was o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animalia
Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, have myocytes and are motility, able to move, can reproduce sexually, and grow from a hollow sphere of Cell (biology), cells, the blastula, during embryonic development. Animals form a clade, meaning that they arose from a single common ancestor. Over 1.5 million extant taxon, living animal species have been species description, described, of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are as many as 7.77 million animal species on Earth. Animal body lengths range from to . They have complex ecologies and biological interaction, interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemichordata
Hemichordata ( ) is a phylum which consists of triploblastic, eucoelomate, and bilaterally symmetrical marine deuterostome animals, generally considered the sister group of the echinoderms. They appear in the Lower or Middle Cambrian and include two main classes: Enteropneusta (acorn worms), and Pterobranchia. A third class, Planctosphaeroidea, is known only from the larva of a single species, '' Planctosphaera pelagica''. The class Graptolithina, formerly considered extinct, is now placed within the pterobranchs, represented by a single living genus '' Rhabdopleura''. Acorn worms are solitary worm-shaped organisms. They generally live in burrows (the earliest secreted tubes) and are deposit feeders, but some species are pharyngeal filter feeders, while the family are free living detritivores. Many are well known for their production and accumulation of various halogenated phenols and pyrroles. Pterobranchs are filter-feeders, mostly colonial, living in a collagenous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pterobranchia
Pterobranchia, members of which are often called pterobranchs, is a class of small worm-shaped animals. They belong to the Hemichordata, and live in secreted tubes on the ocean floor. Pterobranchia feed by filtering plankton out of the water with the help of cilia attached to tentacles. There are about 25 known living pterobranch species in three genera, which are '' Rhabdopleura'', '' Cephalodiscus'', and '' Atubaria''. On the other hand, there are several hundred extinct genera, some of which date from the Cambrian Period. The class Pterobranchia was established by Ray Lankester in 1877. It contained, at that time, the single genus '' Rhabdopleura''. ''Rhabdopleura'' was at first regarded as an aberrant polyzoon, but when the ''Challenger'' report on '' Cephalodiscus'' was published in 1887, it became clear that ''Cephalodiscus'', the second genus now included in the order, had affinities with the Enteropneusta. Electron microscope studies have suggested that pterobranch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalodiscida
Cephalodiscida is one of two orders in the class Pterobranchia, which are small, worm-shaped animals. Members belong to the hemichordata, hemichordates. Species in this order are Sessility (zoology), sessile, living in clear water and secretion, secrete tubes on the ocean floor. Taxonomy The order is a small one, with only two known families, each containing a single extant genus. The validity of the family Atubaridae, who has only a sole member, is regarded as questionable. * Order Cephalodiscida Fowler 1892 ** Family Cephalodiscidae Harmer 1905 *** Genus †''Aellograptus'' Obut 1964 *** Genus †''Eocephalodiscus'' Kozlowski 1938 ex Kozlowski 1949 *** Genus †''Melanostrophus'' Öpik 1930 ex Öpik 1933 *** Genus †''Pterobranchites'' Kozlowski 1967 *** Genus ''Atubaria'' Sato 1936 *** Genus ''Cephalodiscus'' M'Intosh 1882 ** Family †Rotaciurcidae Briggs and Koch 2023 *** Genus †''Rotaciurca'' Briggs and Koch 2023 References Harmer. S. F. 1905. The Pterobranchia ol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalodiscidae
''Cephalodiscus'' is a genus of hemichordates in the monotypic family Cephalodiscidae of the order Cephalodiscida. Description All known species live in a secreted coenecium attached to a rock substrate. Unlike ''Rhabdopleura'', ''Cephalodiscus'' species do not form large colonies and are only pseudocolonial, but they do share a common area with individual buds for each zooid. ''Cephalodiscus'' zooids are also more mobile than their ''Rhabdopleura'' counterparts, and are able to move around within tubaria. ''Cephalodiscus'' zooids can be produced via asexual budding. There are a few pairs of tentacled arms, whereas ''Rhabdopleura'' has only one pair of arms. Species 19 living species of ''Cephalodiscus'' have been described: * '' Cephalodiscus agglutinans'' Harmer & Ridewood, 1914 * '' Cephalodiscus atlanticus'' Bayer, 1962 * '' Cephalodiscus australiensis'' Johnston & Muirhead, 1951 * '' Cephalodiscus calciformis'' Emig, 1977 * '' Cephalodiscus densus'' Andersson 1907 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalodiscus
''Cephalodiscus'' is a genus of hemichordates in the monotypic family Cephalodiscidae of the order Cephalodiscida. Description All known species live in a secreted coenecium attached to a rock substrate. Unlike ''Rhabdopleura'', ''Cephalodiscus'' species do not form large colonies and are only pseudocolonial, but they do share a common area with individual buds for each zooid. ''Cephalodiscus'' zooids are also more mobile than their ''Rhabdopleura'' counterparts, and are able to move around within tubaria. ''Cephalodiscus'' zooids can be produced via asexual budding. There are a few pairs of tentacled arms, whereas ''Rhabdopleura'' has only one pair of arms. Species 19 living species of ''Cephalodiscus'' have been described: * '' Cephalodiscus agglutinans'' Harmer & Ridewood, 1914 * '' Cephalodiscus atlanticus'' Bayer, 1962 * '' Cephalodiscus australiensis'' Johnston & Muirhead, 1951 * '' Cephalodiscus calciformis'' Emig, 1977 * '' Cephalodiscus densus'' Andersson 1907 ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sessility (zoology)
Sessility is the biological property of an animal describing its lack of a means of self-locomotion. Sessile animals for which natural ''motility'' is absent are normally immobile. This is distinct from the botanical concept of sessility, which refers to an organism or biological structure attached directly by its base without a stalk. Sessile animals can move via external forces (such as water currents), but are usually permanently attached to something. Organisms such as corals lay down their own substrate from which they grow. Other organisms grow from a solid object, such as a rock, a dead tree trunk, or a human-made object such as a buoy or ship's hull. Mobility Sessile animals typically have a motile phase in their development. Sponges have a motile larval stage and become sessile at maturity. Conversely, many jellyfish develop as sessile polyps early in their life cycle. In the case of the cochineal, it is in the nymph stage (also called the crawler stage) that the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemichordate
Hemichordata ( ) is a phylum which consists of triploblastic, eucoelomate, and bilaterally symmetrical marine deuterostome animals, generally considered the sister group of the echinoderms. They appear in the Lower or Middle Cambrian and include two main classes: Enteropneusta (acorn worms), and Pterobranchia. A third class, Planctosphaeroidea, is known only from the larva of a single species, '' Planctosphaera pelagica''. The class Graptolithina, formerly considered extinct, is now placed within the pterobranchs, represented by a single living genus '' Rhabdopleura''. Acorn worms are solitary worm-shaped organisms. They generally live in burrows (the earliest secreted tubes) and are deposit feeders, but some species are pharyngeal filter feeders, while the family are free living detritivores. Many are well known for their production and accumulation of various halogenated phenols and pyrroles. Pterobranchs are filter-feeders, mostly colonial, living in a collagenous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic
The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau, and other list of Antarctic and Subantarctic islands, island territories located on the Antarctic Plate or south of the Antarctic Convergence. The Antarctic region includes the ice shelf, ice shelves, waters, and all the island territories in the Southern Ocean situated south of the Antarctic Convergence, a zone approximately wide and varying in latitude seasonally. The region covers some 20 percent of the Southern Hemisphere, of which 5.5 percent (14 million km2) is the surface area of the Antarctica continent itself. All of the land and ice shelf, ice shelves south of 60th parallel south, 60°S latitude are administered under the Antarctic Treaty System. Biogeograph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ross Sea
The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its name from the British explorer James Clark Ross who visited this area in 1841. To the west of the sea lies Ross Island and Victoria Land, to the east Roosevelt Island and Edward VII Peninsula in Marie Byrd Land, while the southernmost part is covered by the Ross Ice Shelf, and is about from the South Pole. Its boundaries and area have been defined by the New Zealand National Institute of Water and Atmospheric Research as having an area of . The circulation of the Ross Sea is dominated by a wind-driven ocean gyre and the flow is strongly influenced by three submarine ridges that run from southwest to northeast. The circumpolar deep water current is a relatively warm, salty and nutrient-rich water mass that flows onto the continental shelf at certain locations. The Ross Sea is covered ... [...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 subantarctic, sub-Antarctic region. They are among the Extremes on Earth#Remoteness, most isolated places on Earth, with the closest territory being the Heard Island and McDonald Islands territory of Australia located at roughly , and the nearest inhabited territory being Madagascar at more than in distance. The islands, along with Adélie Land, the Crozet Islands, Île Amsterdam, Amsterdam and Île Saint-Paul, 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 islands constitute one of the two exposed parts of the Kerguelen Plateau (the other being Heard Island and the McDonald islands), a large igneous province mostly submerged in the southern Indian Ocean. The main island, Grande Terre, is in area, about ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biodiversity Heritage Library
The Biodiversity Heritage Library (BHL) is the world’s largest open-access digital library for biodiversity literature and archives. BHL operates as a worldwide consortium of natural history, botanical, research, and national libraries working together to address this challenge by digitizing the natural history literature held in their collections and making it freely available for open access as part of a global "biodiversity community". The BHL consortium works with the international taxonomic community, publishers, bioinformaticians, and information technology professionals to develop tools and services to facilitate greater access, interoperability, and reuse of content and data. BHL provides a range of services, data exports, and APIs to allow users to download content, harvest source data files, and reuse materials for research purposes. Through taxonomic intelligence tools developed by Global Names Architecture, BHL indexes the taxonomic names throughout the collection, al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
