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(詳細はgenus of ocean-dwelling ray-finned bony fish from the Scombridae (Mackerel) family. More specifically, ''Thunnus'' is one of five genera which comprise the Thunnini tribe – a tribe that is collectively known as the tunas. Also called the true tunas or real tunas, ''Thunnus'' consists of eight species of tuna (more than half of the overall tribe), divided into two subgenera. The word ''ラテン語:Thunnus'' is the Middle Latin form of the – which is in turn derived from , "to rush; to dart".〔.〕 The first written use of the word was by Homer. Their coloring, metallic blue on top and shimmering silver-white on the bottom, helps camouflage them from above and below. Atlantic bluefin tuna, the largest member of this genus, can grow to long and weigh up to . All tunas are extremely strong swimmers, and the Yellowfin tuna is known to reach speeds of up to when pursuing prey. As with all tunas, members of this genus are warm-blooded, which is a rare trait among fish; this enables them to tolerate cold waters. Bluefin tunas, for example, are found in Newfoundland and Iceland, and also in the tropical waters of the Gulf of Mexico and the Mediterranean Sea, where some individuals go each year to spawn. Due to overfishing, the range of this genus has declined significantly, having been effectively removed from the Black Sea, for example.〔Hogan, C. Michael, (''Overfishing''. Encyclopedia of Earth. eds. Sidney Draggan and Cutler Cleveland ). National council for Science and the Environment, Washington DC〕 ==Taxonomy== This genus has eight species in two subgenera: * Subgenus ''Thunnus (Thunnus)'': * * Albacore, ''T. alalunga'' (Bonnaterre, 1788). * * Southern bluefin tuna, ''T. maccoyii'' (Castelnau, 1872). * * Bigeye tuna, ''T. obesus'' (Lowe, 1839). * * Pacific bluefin tuna, ''T. orientalis'' (Temminck & Schlegel, 1844). * * Atlantic bluefin tuna, ''T. thynnus'' (Linnaeus, 1758). * Subgenus ''Thunnus (Neothunnus)'': * * Yellowfin tuna, ''T. albacares'' (Bonnaterre, 1788). * * Blackfin tuna, ''T. atlanticus'' (Lesson, 1831). * * Longtail tuna, ''T. tonggol'' (Bleeker, 1851). }} |label2= subfamily |2= |2= }} |2= }} }} }} }} }} }} }} }} }} }} }} }} }} }} 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「thunnus」の詳細全文を読む スポンサード リンク
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