A chronicle of evolution
The Turkana Basin in northern Kenya holds an unparalleled record of human origins. Sediments around the lake have preserved fossils of multiple hominin species that lived between 4.2 million and 1.3 million years ago. The geological layers, part of the Koobi Fora Formation, contain a nearly continuous sequence of deposition, allowing scientists to date finds with considerable accuracy. Discoveries here include more than 200 individual hominins, more than any other site on Earth.
The story begins with Australopithecus anamensis, one of the earliest undisputed bipedal hominins. As the layers of sediment progress, they reveal a branching family tree. Fossils of Kenyanthropus platyops, the "flat-faced man of Kenya," date to 3.5 million years ago and suggest that multiple hominin lineages coexisted. The basin also contains remains of Paranthropus boisei, a robust australopithecine, and several species of our own genus, Homo, including Homo habilis and Homo rudolfensis. The sheer density and variety of fossils establish the Turkana Basin as a primary location for understanding the complex history of human evolution.
Turkana Boy and the first tools
The most celebrated fossil from the basin is KNM-WT 15000, known as "Turkana Boy." Discovered in 1984 by Kamoya Kimeu, this 1.5 to 1.6-million-year-old skeleton of a Homo erectus (or Homo ergaster) youth is the most complete early human skeleton ever found. Comprising 108 bones, the specimen provided important information about the species. At the time of his death, the boy was estimated to be between 8 and 9 years old, stood about 1.6 meters (5 ft 3 in) tall, and had a brain capacity of 880 cubic centimeters. His body structure, with long legs and a narrow pelvis, shows an adaptation for upright walking.
The basin also provides the world's oldest evidence of stone tool manufacturing. At the Lomekwi 3 site, archaeologists found 3.3-million-year-old stone artifacts. These "Lomekwian" tools predate the next-oldest tools by 700,000 years and even predate the earliest known fossils of the genus Homo. The tools include anvils, cores, and flakes, with the largest weighing 15 kg. Their creation is attributed to either Australopithecus or Kenyanthropus platyops, showing that tool-making was not exclusive to our own genus.