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Turkana Boy, now called, Nariokotome Boy, is the common name of fossil KNM-WT 15000,〔KNM-WT 15000: Kenya National Museum; West Turkana; item 15000〕 a nearly complete skeleton of a hominin youth who lived during the early Pleistocene. This specimen is the most complete early human skeleton ever found. It is believed to be between 1.5 and 1.6 million years old. Estimates of his age at death range from seven to 18 years old; the most recent scientific review suggests eight years. It was initially suggested that he would have grown into a tall adult but the most recent analysis argues for the much shorter stature of . The reason for this shift has been research showing that his growth maturation differed from that of modern humans in that he would have had a shorter and smaller adolescent growth spurt.〔 The skeleton was discovered in 1984 by Kamoya Kimeu, a member of a team led by Richard Leakey, at Nariokotome near Lake Turkana in Kenya. ==Adolescence and maturity== The shape of the pelvis identifies the specimen as male. Estimates of age at death depends upon which of the maturity stages of teeth or skeleton is used, and whether that maturity is compared to that of modern humans or to chimpanzees. A key factor is that while modern humans have a marked adolescent growth spurt, chimpanzees do not. While initial research assumed a modern human type of growth, more recent evidence from other fossils suggests this was less present in early ''Homo''. This affects the estimation of both his age and his likely stature as a fully grown adult.〔 * Anthropologists Alan Walker and Richard Leakey in 1993 estimated the boy to have been about 11–12 years old based on known rates of bone maturity.〔Walker explains: "in KNM-WT 15000, his skeletal development can only be used to place an upper limit of about 14 years on his age at death. However, a less often recognized skeletal maturational event does generally occur prior to 14 years in modern males-- the union of the trochlea and capitulum (and also the lateral epicondyle) of the humerus, prior to their joint union with the humeral shaft.... That these elements were fused in KNM-WT 15000 (at least the capitulum and trochlea) suggests a skeletal age for him of somewhat more than 11 years.... In either event, 11 to 12 years would seem to be the best compromise figure to use for his chronological age at death."(Walker & Leakey, 1993, p. 235)〕 * Christopher Dean (M. C. Dean) of University College London, in a ''Nova'' special, stated that Turkana Boy was 8 years old at death.〔http://www.pbs.org/wgbh/nova/beta/evolution/becoming-human-part-2.html, at 38:00 minutes on countdown〕〔Lewin, p. 164〕 But Alan Walker and Richard Leakey said that dental dating often gives a younger age than a person's actual age.〔"Just as in the case of human dental age (above), estimates based on tooth formation give slightly younger ages than those based on emergence." (Walker & Leakey, 1993, p. 207)〕 * Ronda Graves and colleagues in the most recent review of the problems involved concluded that he would "have grown an additional five to 14 cm before reaching adulthood" and that "if, at death, he was eight to ten years of age, (would have been ) tall, and growing faster than a modern human but slower than a chimpanzee. According to this scenario, KNM-WT 15000 would have attained an adult stature ranging between and ." Moreover, that "according to our preferred models of growth and development, () growth in stature (have been ) completed by 12 years of age (4 years after death), so that the majority of growth has already occurred.〔 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「Turkana Boy」の詳細全文を読む スポンサード リンク
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