A momentous discovery
In August 1984, paleoanthropologist Kamoya Kimeu, part of a team led by Richard Leakey, spotted a single fragment of a hominin skull on the western side of Kenya's Lake Turkana. The site was a dry riverbed known as Nariokotome. This initial find triggered an extensive excavation that unearthed 108 bones, comprising the most complete early human skeleton ever found. Cataloged as KNM-WT 15000, the specimen is more famously known as the Nariokotome Boy or Turkana Boy. The skeleton dates to approximately 1.5 to 1.6 million years ago, placing it in the Early Pleistocene epoch. The individual belongs to the species Homo erectus or, as some scientists classify the African variant, Homo ergaster.
A very human body
The skeleton of the Nariokotome Boy provides a detailed picture of his species. Analysis of his teeth and bones indicates he was a juvenile, with age estimates ranging from 8 to 12 years old at death. He stood about 1.6 meters (5 feet 3 inches) tall and weighed an estimated 48 kilograms (106 pounds). Early projections suggested he would have reached 1.85 meters (6 feet 1 inch) in adulthood, but later analysis, suggesting a more rapid, ape-like growth rate, revised this estimate to a slightly shorter adult stature.
His body plan was surprisingly modern. The fossil shows long legs and narrow hips, anatomical features well-suited for efficient, fully terrestrial bipedalism. He differed from earlier hominins, like Australopithecus, who retained some adaptations for climbing. The boy's cranial capacity was about 880 cubic centimeters, smaller than modern humans and a significant increase over earlier species. His skull retained ancestral features like a low, sloping forehead and prominent brow ridges, and he lacked a chin.