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Racovitzia Harrissoni
''Racovitzia'' is a genus of marine ray-finned fish belonging to the family Bathydraconidae, the Antarctic dragonfishes. They are found in the Southern Ocean around Antarctica. Taxonomy ''Racovitzia'' was formally described as a genus in 1900 by the Belgian palaeontologist Louis Dollo when he was describing the only species in what was then considered to be a monotypic genus, ''Racovitzia glacialis'' the type of which had been collected by the Belgian Antarctic Expedition off the Antarctic at 71°23'S, 87°32'W or 71°19'S, 87°37'W. In 1916 Edgar Ravenswood Waite described ''Aconichthys harrisoni'' which has since been determined to be the second species in the genus, however some authorities consider that ''R harrisoni'' is a junior synonym of ''R. glacialis''. The genus name honours the Romanian biologist Emil Racoviță who was the naturalist aboard the ''Belgica'' the ship which carried and supported the Belgian Antarctic Expedition. Species There are currently two recogn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis Dollo
Louis Antoine Marie Joseph Dollo (Lille, 7 December 1857 – Brussels, 19 April 1931) was a Belgian palaeontologist, known for his work on dinosaurs. He also posited that evolution is not reversible, known as Dollo's law. Together with the Austrian Othenio Abel, Dollo established the principles of paleobiology. Early life Louis Dollo was born in Lille, Nord-Pas-de-Calais, a scion of an old Breton family. He studied at the École centrale de Lille, with geologist Jules Gosselet and zoologist Alfred Giard, both of whom influenced the young Dollo. In 1877, he graduated with a degree in engineering. After his graduation, he worked in the mining industry for five years, but simultaneously developed a passion for paleontology. In 1879, he moved to Brussels. ''Iguanodon'' spp. For three years, starting in 1878, he supervised the excavation of the famous, multiple ''Iguanodon'' find at Bernissart, Belgium. He devoted himself to their study as a scientific passion, initially concurrently ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RV Belgica (1884)
''Belgica'' was a barque-rigged steamship that was built in 1884 by Christian Brinch Jørgensen at Svelvik, Norway as the whaler ''Patria''. In 1896, she was purchased by Adrien de Gerlache for conversion to a research ship, taking part in the Belgian Antarctic Expedition of 1897–1901, becoming the first ship to overwinter in the Antarctic. In 1902, she was sold to Philippe, Duke of Orléans and used on expeditions to the Arctic in 1905 and from 1907 to 1909. In 1916, she was sold and converted to a passenger and cargo ship, serving Spitsbergen from the Norwegian mainland under the name ''Isfjord''. In 1918, she was sold and renamed ''Belgica'', being converted to a factory ship. Requisitioned by the British in April 1940, she was used as a depôt ship, being scuttled when the Franco-British Expeditionary Force evacuated Harstad in northern Norway. In 2007, plans to build a modern replica of ''Belgica'' were announced. Description The ship was long, with a beam of and a d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bathydemersal
Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They occupy the sea floors and lake beds, which usually consist of mud, sand, gravel or rocks. In coastal waters they are found on or near the continental shelf, and in deep waters they are found on or near the continental slope or along the continental rise. They are not generally found in the deepest waters, such as abyssal depths or on the abyssal plain, but they can be found around seamounts and islands. The word ''demersal'' comes from the Latin ''demergere'', which means ''to sink''. Demersal fish are bottom feeders. They can be contrasted with pelagic fish which live and feed away from the bottom in the open water column. Demersal fish fillets contain little fish oil (one to four percent), whereas pelagic fish can contain up to 30 percent. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demersal
The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of the larger profundal zone. Being just above the ocean floor, the demersal zone is variable in depth and can be part of the photic zone where light can penetrate, and photosynthetic organisms grow, or the aphotic zone, which begins between depths of roughly and extends to the ocean depths, where no light penetrates. Fish The distinction between demersal species of fish and pelagic species is not always clear cut. The Atlantic cod (''Gadus morhua'') is a typical demersal fish, but can also be found in the open water column, and the Atlantic herring (''Clupea harengus'') is predominantly a pelagic species but forms large aggregations near the seabed when it spawns on banks of gravel. Two types of fish inhabit the demersal zone: those ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Shetland Islands
The South Shetland Islands are a group of Antarctic islands with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the nearest point of the South Orkney Islands. By the Antarctic Treaty of 1959, the islands' sovereignty is neither recognized nor disputed by the signatories and they are free for use by any signatory for non-military purposes. The islands have been claimed by the United Kingdom since 1908 and as part of the British Antarctic Territory since 1962. They are also claimed by the governments of Chile (since 1940, as part of the Antártica Chilena province) and Argentina (since 1943, as part of Argentine Antarctica, Tierra del Fuego Province). Several countries maintain research stations on the islands. Most of them are situated on King George Island, benefitting from the airfield of the Chilean base Eduardo Frei. There are sixteen research stations in different parts of the islands, with Chilean stations being ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elephant Island
Elephant Island is an ice-covered, mountainous island off the coast of Antarctica in the outer reaches of the South Shetland Islands, in the Southern Ocean. The island is situated north-northeast of the tip of the Antarctic Peninsula, west-southwest of South Georgia, south of the Falkland Islands, and southeast of Cape Horn. It is within the Antarctic claims of Argentina, Chile and the United Kingdom. The Brazilian Antarctic Program maintains a shelter on the island, Goeldi, supporting the work of up to six researchers each during the summer, and formerly had another ( Wiltgen), which was dismantled in the summers of 1997 and 1998. Toponym Elephant Island's name is attributed to both its elephant head-like appearance and the sighting of elephant seals by Captain George Powell in 1821, one of the earliest sightings. However, in Russia it is still known under the name given by its discoverers in 1821 – Mordvinova Island. Geography The island is oriented approximately ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Orkney Islands
The South Orkney Islands are a group of islands in the Southern Ocean, about north-east of the tip of the Antarctic Peninsula''Antarctica: Secrets of the Southern Continent'' p. 122 David McGonigal, 2009 and south-west of . They have a total area of about . The islands are claimed both by Britain (as part of the since 1962, previously as a [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Sandwich Islands
) , anthem = "God Save the King" , song_type = , song = , image_map = South Georgia and the South Sandwich Islands in United Kingdom.svg , map_caption = Location of South Georgia and the South Sandwich Islands in the southern Atlantic Ocean , mapsize = 255px , subdivision_type = Sovereign state , subdivision_name = , established_title2 = Separation from Falkland Islands , established_date2 = 3 October 1985 , official_languages = English , demonym = , capital = King Edward Point , coordinates = , largest_settlement = capital , largest_settlement_type = largest settlement , ethnic_groups = , ethnic_groups_year = , government_type = Directly administered dependency under a constitutional monarchy , leader_title1 = Monarch , leader_name1 = Charles III , leader_title2 = Commissioner , leader_name2 = Alison Blake , national_representation = Government of the United Kingdom , national_representation_type1 = Minister , national_representation1 = Zac Go ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continental Shelf
A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island is known as an ''insular shelf''. The continental margin, between the continental shelf and the abyssal plain, comprises a steep continental slope, surrounded by the flatter continental rise, in which sediment from the continent above cascades down the slope and accumulates as a pile of sediment at the base of the slope. Extending as far as 500 km (310 mi) from the slope, it consists of thick sediments deposited by turbidity currents from the shelf and slope. The continental rise's gradient is intermediate between the gradients of the slope and the shelf. Under the United Nations Convention on the Law of the Sea, the name continental shelf was given a legal definition as the stretch of the seabed adjacent to the shores of a par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Length
Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish measured from the tip of the snout to the posterior end of the last vertebra or to the posterior end of the midlateral portion of the hypural plate. Simply put, this measurement excludes the length of the caudal (tail) fin. * Total length (TL) is the length of a fish measured from the tip of the snout to the tip of the longer lobe of the caudal fin, usually measured with the lobes compressed along the midline. It is a straight-line measure, not measured over the curve of the body. Standard length measurements are used with Teleostei (most bony fish), while total length measurements are used with Myxini (hagfish), Petromyzontiformes (lampreys), and (usually) Elasmobranchii (sharks and rays), as well as some other fishes. Total length me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operculum (fish)
The operculum is a series of bones found in bony fish and chimaeras that serves as a facial support structure and a protective covering for the gills; it is also used for respiration and feeding. Anatomy The opercular series contains four bone segments known as the preoperculum, suboperculum, interoperculum and operculum. The preoperculum is a crescent-shaped structure that has a series of ridges directed posterodorsally to the organisms canal pores. The preoperculum can be located through an exposed condyle that is present immediately under its ventral margin; it also borders the operculum, suboperculum, and interoperculum posteriorly. The suboperculum is rectangular in shape in most bony fishy and is located ventral to the preoperculum and operculum components. It is the thinnest bone segment out of the opercular series and is located directly above the gills. The interoperculum is triangular shaped and borders the suboperculum posterodorsally and the preoperculum anterodorsa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Line
The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial cells, known as hair cells, which respond to displacement caused by motion and transduce these signals into electrical impulses via excitatory synapses. Lateral lines serve an important role in schooling behavior, predation, and orientation. Fish can use their lateral line system to follow the vortices produced by fleeing prey. Lateral lines are usually visible as faint lines of pores running lengthwise down each side, from the vicinity of the gill covers to the base of the tail. In some species, the receptive organs of the lateral line have been modified to function as electroreceptors, which are organs used to detect electrical impulses, and as such, these systems remain closely linked. Most amphibian larvae and some fully aquatic adult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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