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Promachocrinus Mawsoni
''Promachocrinus'' is a genus of free-swimming, stemless Crinoid, crinoids. It was a Monotypic taxon, monotypic genus, with the only species in the genus being ''Promachocrinus kerguelensis,'' until the discovery of four new species, establishment of two others previously described and the transfer of another species to the genus in 2023. Known for being coldwater crinoids, members of ''Promachocrinus'' are typically found in the seas around Antarctica and surrounding island groups, including under the sea ice. Previously known for having 20 arms, two of the species now included in the genus have 10 arms. Many of the species are circum-Antarctic and can be difficult to tell apart without DNA sequencing. Species There are eight accepted species of ''Promachocrinus'' as of August 2023: * ''Promachocrinus fragarius'' McLaughlin, Wilson and Rouse 2023 * ''Promachocrinus joubini'' Vaney, 1910 * ''Promachocrinus kerguelensis'' Carpenter, 1879; Type species * ''Promachocrinus mawson ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. Phylogeneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crinoid
Crinoids are marine invertebrates that make up the class Crinoidea. Crinoids that remain attached to the sea floor by a stalk in their adult form are commonly called sea lilies, while the unstalked forms, called feather stars or comatulids, are members of the largest crinoid order, Comatulida. Crinoids are echinoderms in the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers. They live in both shallow water and in depths of over . Adult crinoids are characterised by having the mouth located on the upper surface. This is surrounded by feeding arms, and is linked to a U-shaped gut, with the anus being located on the oral disc near the mouth. Although the basic echinoderm pattern of fivefold symmetry can be recognised, in most crinoids the five arms are subdivided into ten or more. These have feathery pinnules and are spread wide to gather planktonic particles from the water. At some stage in their lives, most crinoids have a sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monotypic Taxon
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 Genus, genera, the term "unispecific" or "monospecific" is sometimes preferred. In botanical nomenclature, a monotypic genus is a genus in the special case where a genus and a single species are simultaneously described. Theoretical implications Monotypic taxa present several important theoretical challenges in biological classification. One key issue is known as "Gregg's Paradox": if a single species is the only member of multiple hierarchical levels (for example, being the only species in its genus, which is the only genus in its family), then each level needs a distinct definition to maintain logical structure. Otherwise, the different taxonomic ranks become effectively identical, which creates problems for organizing biological diversity in a hierarchical o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Promachocrinus Kerguelensis
''Promachocrinus kerguelensis'' is a species of free-swimming, stemless crinoids. It was the only member of its genus until several species were discovered in 2023. ''P. keruguelensis'' a coldwater crinoid which is found in the seas around Antarctica and surrounding island groups, including under the sea ice. Description This crinoid is one of two living genera that has ten radial ossicles, each giving rise to a pair of arms; there is a single canal in each radial ossicle and no basal rays. At the base are a number of clawed structures known as cirri. Distribution and habitat ''P. kerguelensis'' is endemic to the waters of Antarctica. Its range includes the Graham Land peninsula, the South Shetland Islands, South Georgia and the South Sandwich Islands, Bouvet Island, Heard Islands and the Kerguelen Islands. The type locality is at the Kerguelen Islands, and it is from here that it gets its specific name. It occurs at depths between about . This is a common and abundant species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual Climate of Antarctica#Precipitation, precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the Lowest temperature recorded on Earth, lowest measured temperature on Earth, . The coastal regions can reach temperatures over in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Ice
Sea ice arises as seawater freezes. Because ice is less density, dense than water, it floats on the ocean's surface (as does fresh water ice). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world's sea ice is enclosed within the polar ice packs in the Earth's polar regions: the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean. Polar packs undergo a significant yearly cycling in surface extent, a natural process upon which depends the Arctic ecology, including the Arctic sea ice ecology and history, ocean's ecosystems. Due to the action of winds, currents and temperature fluctuations, sea ice is very dynamic, leading to a wide variety of ice types and features. Sea ice may be contrasted with icebergs, which are chunks of ice shelf, ice shelves or glaciers that Ice calving, calve into the ocean. Depending on location, sea ice expanses may also incorporate icebergs. General features and dynamics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Promachocrinus Fragarius
''Promachocrinus fragarius'', commonly known as the Antarctic strawberry feather star, is a species of stemless, free-swimming crinoid. It was one of several new species of ''Promachocrinus'' to be described in 2023. The discovery of the species gained significant media attention. Description The team which discovered the species said it was dubbed the 'Antarctic strawberry feather star' due to "the resemblance of its body to a strawberry". Its colour can range from "purple" to "dark-reddish", and it was described as having "ten rays" and "twenty arms". Distribution and habitat ''P. fragarius'' is found in the waters of Antarctica at depths between and . The type locality is at the South Sandwich Islands The South Sandwich Islands () are a chain of uninhabited volcanic islands in the South Atlantic Ocean. They are administered as part of the British Overseas Territory of South Georgia and the South Sandwich Islands. The chain lies in the sub-A .... The dispersal of ''Pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Promachocrinus Joubini
''Promachocrinus'' is a genus of free-swimming, stemless crinoids. It was a monotypic genus, with the only species in the genus being '' Promachocrinus kerguelensis,'' until the discovery of four new species, establishment of two others previously described and the transfer of another species to the genus in 2023. Known for being coldwater crinoids, members of ''Promachocrinus'' are typically found in the seas around Antarctica and surrounding island groups, including under the sea ice. Previously known for having 20 arms, two of the species now included in the genus have 10 arms. Many of the species are circum-Antarctic and can be difficult to tell apart without DNA sequencing. Species There are eight accepted species of ''Promachocrinus'' as of August 2023: * '' Promachocrinus fragarius'' McLaughlin, Wilson and Rouse 2023 * '' Promachocrinus joubini'' Vaney, 1910 * '' Promachocrinus kerguelensis'' Carpenter, 1879; Type species * ''Promachocrinus mawsoni ''Promachocrinus' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Promachocrinus Mawsoni
''Promachocrinus'' is a genus of free-swimming, stemless Crinoid, crinoids. It was a Monotypic taxon, monotypic genus, with the only species in the genus being ''Promachocrinus kerguelensis,'' until the discovery of four new species, establishment of two others previously described and the transfer of another species to the genus in 2023. Known for being coldwater crinoids, members of ''Promachocrinus'' are typically found in the seas around Antarctica and surrounding island groups, including under the sea ice. Previously known for having 20 arms, two of the species now included in the genus have 10 arms. Many of the species are circum-Antarctic and can be difficult to tell apart without DNA sequencing. Species There are eight accepted species of ''Promachocrinus'' as of August 2023: * ''Promachocrinus fragarius'' McLaughlin, Wilson and Rouse 2023 * ''Promachocrinus joubini'' Vaney, 1910 * ''Promachocrinus kerguelensis'' Carpenter, 1879; Type species * ''Promachocrinus mawson ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Promachocrinus Unruhi
''Promachocrinus'' is a genus of free-swimming, stemless crinoids. It was a monotypic genus, with the only species in the genus being '' Promachocrinus kerguelensis,'' until the discovery of four new species, establishment of two others previously described and the transfer of another species to the genus in 2023. Known for being coldwater crinoids, members of ''Promachocrinus'' are typically found in the seas around Antarctica and surrounding island groups, including under the sea ice. Previously known for having 20 arms, two of the species now included in the genus have 10 arms. Many of the species are circum-Antarctic and can be difficult to tell apart without DNA sequencing. Species There are eight accepted species of ''Promachocrinus'' as of August 2023: * '' Promachocrinus fragarius'' McLaughlin, Wilson and Rouse 2023 * ''Promachocrinus joubini'' Vaney, 1910 * '' Promachocrinus kerguelensis'' Carpenter, 1879; Type species * ''Promachocrinus mawsoni ''Promachocrinus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
