|Catalog number||KNM-WT 15000|
|Common name||Turkana Boy|
|Species||Tentatively assigned Homo ergaster|
|Place discovered||Lake Turkana, Kenya|
|Discovered by||Kamoya Kimeu/Richard Leakey|
Turkana boy, or Nariokotome boy, is the fossil KNM-WT 15000. It is a nearly complete skeleton of a hominid who died in the early Pleistocene 1.5 million years ago (mya). This specimen is the most complete early human skeleton ever found. It was first classified as Homo erectus; after much heated debate, it was re-classified as Homo ergaster.
His age at death has been estimated from 7 years six months to as old as 15 years. The most recent scientific review suggests 8 years of age. It was first thought that he would have grown to 1.85 m tall, but recently a height of 1.63 m was proposed. Research showed that his growth differed from that of modern humans: he would have had a shorter and smaller adolescent growth spurt.
Adolescence and maturity
The shape of the pelvis identifies that the specimen was a male. His estimated age at death depends upon whether the maturity stage of his teeth or skeletal is used, and whether that maturity is compared to that of modern humans or chimpanzees.
A key factor here 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.
The pelvis is narrower than in Homo sapiens, which might indicate more efficient running, whether to run down small game or to avoid predators. The Boy was relatively tall, which would have increased his surface area and helped him to lose heat.
Body hair may also have been thinner to hasten cooling. Body hair was lost in the shift towards savanna living. In equatorial Africa, modern humans evolved this trait an estimated one million years ago.
The skeleton still had features (such as a low sloping forehead, strong brow ridges, and the absence of a chin) not seen in H. sapiens. The arms were slightly longer. Turkana Boy had a projecting nose rather than the open flat nose seen in apes.
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