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Glass knifefishes are fishes in the family Sternopygidae in the order Gymnotiformes. Species are also known as rattail knifefishes. These fishes inhabit freshwater streams and rivers in Panama and South America.〔 Many sternopygid species are specialized for life in the deep (>20 m) swiftly moving waters of large river channels, like that of the Amazon and its major tributaries〔Crampton, W.G.R., Hulen, K., & Albert, J.S. (2004). "''Sternopygus branco'', a new species of Neotropical electric fish (Gymnotiformes: Sternopygidae) from the lowland Amazon basin, with descriptions of ecology and electric organ discharges." ''Copeia'' 2004(2): 244-258.〕 where they have been observed swimming vertically. ''Sternopygus'' species inhabit both streams and rivers. Many species are highly compressed laterally and translucent in life.〔 These fish have villiform (brush-like) teeth on the upper and lower jaws. The snout is relatively short. The eyes are relatively large, with a diameter equal to or greater than the distance between nares. The anal fin originates at the isthmus (the strip of flesh on the ventral surface between the gill covers). The maximum length is 140 cm in ''Sternopygus macrurus''. ''Eigenmannia vicentespelaea'' is the only cave-dwelling gymnotiform. ''Humboldtichthys kirschbaumi'' (formerly genus ''Ellisella'') from Upper Miocene of Bolivia is the only fossil gymnotiform.〔 These fish have a tone-like electric organ discharge (EOD) that occurs monophasically. Some of these species are aquarium fishes. ==Genera== There are 30 living species of glass knifefish, grouped into six genera: * ''Archolaemus'' * ''Distocyclus'' * ''Eigenmannia'' * †''Humboldtichthys'' * ''Japigny'' * ''Rhabdolichops'' * ''Sternopygus'' 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「glass knifefish」の詳細全文を読む スポンサード リンク
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