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The freshwater pearl mussel, scientific name ''Margaritifera margaritifera'', is an endangered species of freshwater mussel, an aquatic bivalve mollusc in the family Margaritiferidae. Although the name "freshwater pearl mussel" is often used for this species, other freshwater mussel species can also create pearls and some can also be used as a source of mother of pearl. In fact, most cultured pearls today come from ''Hyriopsis'' species in Asia, or ''Amblema'' species in North America, both members of the related family Unionidae; pearls are also found within species in the genus ''Unio''. The interior of the shell of ''Margaritifera margaritifera'' has thick nacre (the inner mother of pearl layer of the shell). This species is capable of making fine-quality pearls, and was historically exploited in the search for pearls from wild sources. In recent times, the Russian malacologist Valeriy Zyuganov received worldwide reputation after he discovered that the pearl mussel exhibited negligible senescence and he determined that it had a maximum lifespan of 210–250 years. The data of V.V. Zyuganov have been confirmed by the Finnish malacologists and gained general acceptance. ==Subspecies== Subspecies within the species ''Margaritifera magaritifera'' include: * ''Margaritifera margaritifera margaritifera'' (Linnaeus, 1758) * ''Margaritifera margaritifera parvula'' (Haas, 1908) * ''Margaritifera margaritifera durrovensis'' Phillips, 1928 - critically endangered subspecies in Ireland.〔(2007 IUCN Red List – Search )〕 Synonym: ''Margaritifera durrovensis''. This subspecies is mentioned in annexes II and V of Habitats Directive as ''Margaritifera durrovensis''. 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「Freshwater pearl mussel」の詳細全文を読む スポンサード リンク
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