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Acodontaster Conspicuus
''Acodontaster conspicuus'' is a species of starfish in the family Odontasteridae. It is found in the Southern Ocean, in the waters off Antarctica and the island groups nearby. Description ''Acodontaster conspicuus'' grows to about 30 cm (12 in) in diameter. It has 5 arms and the body has a cushion-like appearance, being thick except around the margins where there is a thin flat area. The upper surface has radially arranged granulations. The colour varies but is usually orange or brown.Acodontaster conspicuus (Koehler, 1920) Antarctic Field Guide. Retrieved 2011-11-27. Distribution ''Acodontaster conspicuus'' is found in the cold seas around Antarctica, including the |
Species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can reproduction, produce Fertility, fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starfish
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 su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family ( la, familia, plural ') is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". What belongs to a family—or if a described family should be recognized at all—are proposed and determined by practicing taxonomists. There are no hard rules for describing or recognizing a family, but in plants, they can be characterized on the basis of both vegetative and reproductive features of plant species. Taxonomists often take different positions about descriptions, and there may be no broad consensus across the scientific community for some time. The publishing of new data and opi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odontasteridae
Odontasteridae is a family of sea stars. Members of the family are known as cushion stars and have relatively broad discs and five short tapering arms. Genera The following genera are listed in the World Register of Marine Species: *'' Acodontaster'' Verrill, 1899 *'' Diabocilla'' McKnight, 2006 *'' Diplodontias'' Fisher, 1908 *'' Eurygonias'' Farquhar, 1913 *'' Hoplaster'' Perrier, in Milne-Edwards, 1882 *''Odontaster ''Odontaster'' is a genus of sea stars. The type species is ''Odontaster hispidus''. Species The following species are listed in the World Register of Marine Species: *'' Odontaster aucklandensis'' McKnight, 1973 *'' Odontaster australis'' H.L. ...'' Verrill, 1880 References Echinoderm families {{Asteroidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Ocean
The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-smallest of the five principal oceanic divisions: smaller than the Pacific, Atlantic, and Indian oceans but larger than the Arctic Ocean. Over the past 30 years, the Southern Ocean has been subject to rapid climate change, which has led to changes in the marine ecosystem. By way of his voyages in the 1770s, James Cook proved that waters encompassed the southern latitudes of the globe. Since then, geographers have disagreed on the Southern Ocean's northern boundary or even existence, considering the waters as various parts of the Pacific, Atlantic, and Indian oceans, instead. However, according to Commodore John Leech of the International Hydrographic Organization (IHO), recent oceanographic research has discovered the importance of Southe ... [...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, 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 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 measured temperature on Earth, . The coastal regions can reach temperatures over in summer. Native species of animals include mites, nematodes, penguins, seals and tardigrades. Where ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Peninsula
The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctica. The Antarctic Peninsula is part of the larger peninsula of West Antarctica, protruding from a line between Cape Adams (Weddell Sea) and a point on the mainland south of the Eklund Islands. Beneath the ice sheet that covers it, the Antarctic Peninsula consists of a string of bedrock islands; these are separated by deep channels whose bottoms lie at depths considerably below current sea level. They are joined by a grounded ice sheet. Tierra del Fuego, the southernmost tip of South America, is about away across the Drake Passage. The Antarctic Peninsula is in area and 80% ice-covered. The marine ecosystem around the western continental shelf of the Antarctic Peninsula (WAP) has been subjected to rapid climate change. Over the past ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Georgia Island
South Georgia ( es, Isla San Pedro) is an island in the South Atlantic Ocean that is part of the British Overseas Territory of South Georgia and the South Sandwich Islands. It lies around east of the Falkland Islands. Stretching in the east–west direction, South Georgia is around long and has a maximum width of . The terrain is mountainous, with the central ridge rising to at Mount Paget. The northern coast is indented with numerous bays and fjords, serving as good harbours. Discovered by Europeans in 1675, South Georgia had no indigenous population due to its harsh climate and remoteness. Captain James Cook in made the first landing, survey and mapping of the island, and on 17 January 1775 he claimed it a British possession, naming it "Isle of Georgia" after King George III. Through its history, it served as a whaling and seal hunting base, with intermittent population scattered in several whaling bases, the most important historically being Grytviken. The main s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycale Acerata
Mycale (). also Mykale and Mykali ( grc, Μυκάλη, ''Mykálē''), called Samsun Dağı and Dilek Dağı (Dilek Peninsula) in modern Turkey, is a mountain on the west coast of central Anatolia in Turkey, north of the mouth of the Maeander and divided from the Greek island of Samos by the 1.6 km wide Mycale Strait. The mountain forms a ridge, terminating in what was known anciently as the Trogilium promontory ( Ancient Greek Τρωγίλιον or Τρωγύλιον). There are several beaches on the north shore ranging from sand to pebbles. The south flank is mainly escarpment. In classical Greece nearly the entire ridge was a promontory enclosed by the Aegean Sea. Geopolitically it was part of Ionia with Priene placed on the coast on the south flank of the mountain and Miletus on the coast opposite to the south across the deep embayment into which the Maeander River drained. Somewhat further north was Ephesus. The ruins of the first two Ionian cities mentioned wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the system through photosynthesis and is incorporated into plant tissue. By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and microbes. Ecosystems are controlled by external and internal factors. External factors such as climate, parent material which forms the soil and topography, control the overall structure of an ecosystem but are not themselves influenced by the ecosyst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nemertea
Nemertea is a phylum of animals also known as ribbon worms or proboscis worms, consisting of 1300 known species. Most ribbon worms are very slim, usually only a few millimeters wide, although a few have relatively short but wide bodies. Many have patterns of yellow, orange, red and green coloration. The foregut, stomach and intestine run a little below the midline of the body, the anus is at the tip of the tail, and the mouth is under the front. A little above the gut is the rhynchocoel, a cavity which mostly runs above the midline and ends a little short of the rear of the body. All species have a proboscis which lies in the rhynchocoel when inactive but everts to emerge just above the mouth to capture the animal's prey with venom. A highly extensible muscle in the back of the rhynchocoel pulls the proboscis in when an attack ends. A few species with stubby bodies filter feed and have suckers at the front and back ends, with which they attach to a host. The brain is a rin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parborlasia Corrugata
''Parborlasia corrugatus'' is a proboscis worm in the family Cerebratulidae. This species of proboscis or ribbon worm can grow to in length, and lives in marine environments down to . This scavenger and predator is widely distributed in cold southern oceans. Description ''Parborlasia corrugatus'' is smooth and flat. Adults measure , with a diameter of approximately . Specimens can weigh up to . Their colouration is variable, ranging from cream through various tones of black.Peter Brueggeman''Nemertina, proboscis worms – Underwater Field Guide to Ross Island & McMurdo Sound, Antarctica''/ref> This worm has a wedge-shaped head containing a cavity filled with fluid. It uses this to fire an adhesive, barbed proboscis as a means of defense, and to capture prey. This organ has adhesive secretion to aid in securing its meal. Although this creature does not have a dedicated respiratory system, ''Parborlasia corrugata'' is able to obtain oxygen by absorbing it through its skin. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
