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The blue iguana (''Cyclura lewisi''), also known as the Grand Cayman iguana, Grand Cayman blue iguana or Cayman Island blue iguana, is an endangered species of lizard endemic to the island of Grand Cayman. Previously listed as a subspecies of the Cuban iguana (''Cyclura nubila''), it was reclassified as a separate species in 2004 because of genetic differences discovered four years earlier. The blue iguana is one of the longest-living species of lizard (possibly up to 69 years). The record is 67 years. The preferred habitat for the blue iguana is rocky, sunlit, open areas in dry forests or near the shore, as the females must dig holes in the sand to lay eggs in June and July. A possible second clutch is laid in September. The blue iguana's herbivorous diet includes plants, fruits, and flowers. Its coloration is tan to gray with a bluish cast that is more pronounced during the breeding season and more so in males. It is large and heavy-bodied with a dorsal crest of short spines running from the base of the neck to the end of the tail. The fossil record indicates that the blue iguana was abundant before European colonization; but fewer than 15 animals remained in the wild by 2003, and this wild population was predicted to become extinct within the first decade of the 21st century. The species' decline is mainly being driven by predation by feral pets (cats and dogs) and indirectly by the destruction of their natural habitat as fruit farms are converted to pasture for cattle grazing. Since 2004, hundreds of captive-bred animals have been released into a preserve on Grand Cayman run by a partnership headed by the Durrell Wildlife Conservation Trust, in an attempt to save the species. At least five non-profit organizations are working with the government of the Cayman Islands to ensure the survival of the blue iguana. According to the November 9, 2013 episode of ''Ocean Mysteries with Jeff Corwin'', the conservancy program has released over 700 captive bred Grand Cayman blue iguanas since the 2004 nadir of only 12 remaining animals. ==Taxonomy== The blue iguana (''Cyclura lewisi'') is endemic to the island of Grand Cayman.〔 The Lesser Caymans iguana has been introduced to Grand Cayman, where it has interbred with that island's native blue iguana. Its generic name (''Cyclura'') is derived from the Ancient Greek words ''cyclos'' (κύκλος) meaning "circular" and ''ourá'' (οὐρά) meaning "tail", after the thick-ringed tail characteristic of all ''Cyclura''. Its specific name is a Latinized form of the name of the scientist who first described this species, Bernard C. Lewis.〔 Its closest relatives are the Cuban iguana (''Cyclura nubila'') and the Northern Bahamian rock iguana (''Cyclura cychlura''), the three species having diverged from a common ancestor some three million years ago.〔〔 The species has a low genetic diversity but does not seem to suffer the same lack of vitality that afflicts other such species of rock iguana.〔〔 One theory is that the species evolved from a single female Cuban iguana (''C. nubila nubila'') with eggs inside her who drifted across the sea, perhaps during a storm. It is distinct from the subspecies found on Little Cayman and Cayman Brac known as ''C. nubila caymanensis'', although it can breed with this subspecies and produce fertile offspring.〔 In 1938, Bernard C. Lewis of the Institute of Jamaica joined an Oxford University biological expedition to the Cayman Islands.〔〔Beolens B, Watkins M, Grayson M. 2011. ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (''Cyclura lewisi'', p. 157).〕 Lewis was able to obtain two blue iguanas, a male and a female, which were later lodged with the British Museum of Natural History.〔 Chapman Grant, in a monograph published in 1940, formally described the blue iguana for the first time as ''Cyclura macleayi lewisi''.〔〔〔〔 〕 Schwartz and Carey established the trinomial (''Cyclura nubila lewisi'') in 1977.〔〔 They held that the blue iguana was a strongly distinct subspecies of the Cuban iguana (''C. nubila''), the species which it evolved from and can breed with. They emphasized its overall bright blue coloration, and noted that further study could reveal it to be a distinct species.〔〔 Frederick Burton reclassified the blue iguana as a distinct species in 2004,〔 after years of research comparing scale counts on the heads of Caribbean iguanas, including those found on Little Cayman, Cayman Brac, Cuba, and the Bahamas, as well as mitochondrial DNA analysis performed by Dr. Catherine Malone, to re-examine the phylogeography of the different species.〔 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「Blue iguana」の詳細全文を読む スポンサード リンク
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