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''Iguana'' (,〔(Cambridge Dictionary )〕〔(Oxford Dictionaries )〕 ) is a genus of herbivorous lizards native to tropical areas of Mexico, Central America, and the Caribbean. The genus was first described in 1768 by Austrian naturalist Josephus Nicolaus Laurenti in his book ''Specimen Medicum, Exhibens Synopsin Reptilium Emendatam cum Experimentis circa Venena''. Two species are included in the genus ''Iguana'': the green iguana, which is widespread throughout its range and a popular pet, and the Lesser Antillean iguana, which is native to the Lesser Antilles and endangered due to habitat destruction. The word "iguana" is derived from the original Taino name for the species, ''iwana''. In addition to the two species in the genus ''Iguana'', several other related genera in the same family have common names of the species including the word "iguana". ==Anatomy and physiology== Iguanas can range from including their tail. The two species of lizard within the genus ''Iguana'' possess a dewlap, a row of spines running down their backs to their tails, and a tiny "third eye" on their heads. This light-sensing organ is known as the parietal eye, visible as a pale scale on the top of the head, and cannot make out details, just brightness. Behind their necks are small scales which resemble spokes, known as tuberculate scales. These scales may be a variety of colors and are not always visible from close distances. They have a large round scale on their cheeks known as a subtympanic shield. Iguanas have great vision and can see shapes, shadows, colors, and movement at long distances. Iguanas use their eyes to navigate through crowded forests, as well as for finding food. They use visual signals to communicate with other members of the same species.〔 The tympanum, the iguana's ear drum, is located above the subtympanic shield and behind the eye. Iguanas are often hard to spot, as they tend to blend into their surroundings. Their scale colors are a mode of hiding from larger predators.〔 Male iguanas, as well as other male members of the order Squamata, have two hemipenes. 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「iguana」の詳細全文を読む スポンサード リンク
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