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Goblin shark
The goblin shark (''Mitsukurina owstoni'') is a rare species of deep-sea shark. Sometimes called a "living fossil", it is the only extant representative of the family Mitsukurinidae, a lineage some 125 million years old. This pink-skinned animal has a distinctive profile with an elongated, flattened snout, and highly protrusible jaws containing prominent nail-like teeth. It is usually between long when mature, though it can grow considerably larger. Goblin sharks inhabit upper continental slopes, submarine canyons, and seamounts throughout the world at depths greater than , with adults found deeper than juveniles.
Various anatomical features of the goblin shark, such as its flabby body and small fins, suggest that it is sluggish in nature. This species hunts for teleost fishes, cephalopods, and crustaceans both near the sea floor and in the middle of the water column. Its long snout is covered with ampullae of Lorenzini that enable it to sense minute electric fields produced by nearby prey, which it can snatch up by rapidly extending its jaws. Small numbers of goblin sharks are unintentionally caught by deepwater fisheries. The International Union for Conservation of Nature (IUCN) has assessed it as Least Concern, citing its wide distribution and low incidence of capture.
==Taxonomy==
American ichthyologist David Starr Jordan described the goblin shark in an 1898 issue of ''Proceedings of the California Academy of Sciences'', recognizing the peculiar fish not only as a new species, but also a new genus and family. He based his account on an immature male long caught in Sagami Bay near Yokohama, Japan. The specimen had been acquired by shipmaster and naturalist Alan Owston, who had given it to Professor Kakichi Mitsukuri at the University of Tokyo, who in turn had brought it to Jordan. Thus, Jordan named the shark ''Mitsukurina owstoni'' in honor of these two men.〔 The common name "goblin shark" is a translation of its old Japanese name ''tenguzame'', a ''tengu'' being a Japanese mythical creature often depicted with a long nose and red face.〔 Another name for this species is elfin shark.〔
Shortly after Jordan's description was published, several scientists noted the similarity between ''Mitsukurina'' and the extinct Mesozoic shark ''Scapanorhynchus''.〔 For a time, the prevailing view was to treat ''Mitsukurina'' as a junior synonym of ''Scapanorhynchus''. Eventually, more complete fossils revealed many anatomical differences between ''Scapanorhynchus'' and ''Mitsukurina'', leading modern authors to again regard them as distinct genera.〔 Several goblin shark specimens were described as separate species from 1904 to 1937, none of which are now considered valid. This taxonomic confusion arose because the specimens' jaws were fixed at varying degrees of protrusion during preservation, giving the appearance of proportional differences in the head.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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