Turkana boy

Turkana Boy

Catalog no.	KNM-WT 15000
Common name	Turkana Boy
Species	Tentatively assigned Homo ergaster
Age	1.6 mya
Place discovered	Lake Turkana, Kenya
Date discovered	1984
Discovered by	Kamoya Kimeu/Richard Leakey

Turkana boy – steps of forensic facial reconstruction/approximation

Turkana boy, or Nariokotome boy, is the fossil KNM-WT 15000.^[1] It is a nearly complete skeleton of a hominid who died in the early Pleistocene 1.5 million years ago (mya), near present-day Lake Turkana in northwest Kenya. 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.^[2][3]

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.^[4] It was first thought that he would have grown to 1.85 m tall, but recently a height of 1.63 m was proposed.^[4] Research showed that his growth differed from that of modern humans: he would have had a shorter and smaller adolescent growth spurt.^[4]

The skeleton was discovered in 1984 by Kamoya Kimeu, a member of a team led by Richard Leakey, at Nariokotome near Lake Turkana in northwest Kenya.^[5]

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.^[4]

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.^[4]

Morphology

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.^[6]

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.^[7]

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.^[6]

References

1. KNM-WT 15000: Kenya National Museum; West Turkana; item 15000
2. Walter, Chip (2013). Last ape standing. Walker. p. 32. ISBN 978-0802717566.
3. "Homo ergaster: KNM-WT 15000". www.efossils.org. Archived from the original on 4 November 2013. Retrieved 7 June 2013.
4. Graves R.R. et al 2010. Just how strapping was KNM-WT 15000? J Hum Evol. doi:10.1016/j.jhevol.2010.06.007 PMID 20846707
5. Brown F; Harris J; Leakey R. & Walker A. 1985. Early Homo erectus skeleton from west Lake Turkana, Kenya. Nature. 316 (6031):788-92. PMID 3929141
6. "Homo erectus at Archaeology Info.com". Archived from the original on 2011-05-16. Retrieved 2013-06-11.
7. Wheeler P.E. 1984. The evolution of bipedality and loss of functional body hair in hominids. Human evolution 13, 91–98.

Sources

• Leakey, Richard (1992). Origins reconsidered. Doubleday. ISBN 0-385-41264-9.
• Walker, Alan; Shipman, Pat (2 September 1997). Wisdom of the bones. Knopf Doubleday Publishing. ISBN 0-679-74783-4. – Good popular level presentation
• Alan Walker and Richard Leakey, ed. (1993). Nariokotome Homo erectus skeleton. Harvard University Press. ISBN 0-674-60075-4. – Technical papers
• Lewin, Roger (2004). Human evolution: an illustrated introduction, 5th ed. Wiley. ISBN 978-1-4051-0378-7.