Turtle (Kame) - Turtle

Japanese: カメ(亀) - カメ

A general term for the order Testudins, class of reptiles. They are found on all continents and in the oceans except Antarctica. They are characterized by the combination of modified bony plates of skin and internal skeletons to form the carapace and plastron. Their limbs are well developed, and in sea turtles, they are paddle-shaped. Their ribs are fused to the carapace, and they breathe by compressing their internal organs against the lungs with muscular contractions. The oldest turtle fossils date back to the end of the Triassic period, and are not very different from modern species. There are currently about 230 species, all of which are oviparous, with the largest being the leatherback turtle with a carapace length of 2m and the smallest being the terrapin with a carapace length of less than 10cm. They are broadly divided into two groups based on how they retract their head and neck. The ankylosing necks are found in the southern hemisphere and bend their long necks sideways to fit between the carapace and plastron. There are few species, although species such as the matamata are well known. Cryptocephalans bend their neck vertically in an S-shape and retract it into their shell, but in the family Chelonidae, they cannot retract it completely. The leatherback turtle and the soft-shelled turtle are both species with a secondarily specialized shell.
→Related topicsReptiles

Source : Heibonsha Encyclopedia About MyPedia Information

Japanese:

爬虫(はちゅう)綱カメ目の総称。南極を除く各大陸および海洋に分布。皮膚の変化した骨質板と内骨格とが結合して背甲と腹甲を形成するのが特徴。四肢は発達し，ウミガメでは櫂(かい)状となる。肋骨は背甲骨板と癒合しており，呼吸は筋肉の収縮によって内臓を肺に押しつけて行う。最古のカメの化石は三畳紀末期のもので，現生種とあまり変りがない。現存は約230種，すべて卵生で，最大はオサガメの甲長2m，最小はテラピンの10cm以下。頭頸部の引っこめ方によって２群に大別される。曲頸類は南半球に分布し，長い頸部を横に曲げて，背甲と腹甲の間に入れる。マタマタなどが知られるが，種類は少ない。潜頸類は頸部を垂直方向にS字形に曲げ甲内に引っ込めるが，ウミガメ科では完全に引き込むことはできない。二次的に甲が特殊化したものにオサガメ，スッポン両科がある。
→関連項目爬虫類

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