The Omo-Turkana Basin in Africa—spanning parts of Kenya and Ethiopia—has long been recognized as one of the world’s most crucial regions for understanding human evolution. Decades of intensive research have yielded a wealth of hominin fossils, yet the fragmented nature of these discoveries has hindered a complete picture of early hominin life. Now, a new study consolidates data from 117 publications spanning 1967–2022, providing the most comprehensive catalog yet of hominin fossils from this region.
A Third of Africa’s Hominin Record
The Omo-Turkana Basin holds approximately one-third of all hominin fossils discovered in Africa dating from 7 to 0.78 million years ago. Researchers have recovered a total of 1,231 hominin specimens representing 658 individuals across the basin’s western, eastern, and northern sections. The study highlights that previous inventories were limited in scope, focusing on specific sites or anatomical regions. The current work seeks to integrate all available data to reveal broader patterns in hominin evolution and coexistence.
Uneven Distribution and Fragmentary Remains
The analysis reveals an uneven distribution of fossils: 47% were found in the east, 30% in the west, and 23% in the north. Most individuals (80%) are represented by single specimens, with few complete skeletons. The most common finds are teeth—687 isolated teeth or fragments—followed by cranial (175) and mandibular (116) fragments, and postcranial elements (253).
Preservation also varies by region, with lakeshore environments in the east yielding more complete remains than the fluviatile deposits of the north. This is attributed to differences in preservation conditions over time.
Hominin Coexistence and Species Dynamics
Over the 4.2 to 1.5 million-year period studied, the basin hosted a succession of early hominins. Australopithecus anamensis was present in earlier sediments (around 4 million years ago), followed by Kenyanthropus platyops, and later, Homo species became more abundant.
A key finding is the well-represented presence of early Homo —including Homo rudolfensis, Homo ergaster, Homo habilis, and early Homo erectus —between 2.7 and 2 million years ago, with at least 45 individuals identified. The genus Paranthropus coexisted with Homo for 1.5 million years, generally outnumbering Homo two to one—except in certain regions where Homo was dominant.
Incomplete Records and Future Discoveries
The study notes that only 70% of fossils have been assigned to a species level, with many specimens still poorly described. Ongoing fieldwork by numerous international teams continues to unearth new fossils and refine existing classifications using advanced methods such as imaging, dental morphology analysis, and geometric morphometry.
The Omo-Turkana Basin fossil record provides a nearly continuous 2.7-million-year span of hominin evolution, with only two gaps totaling 500,000 years. This record offers a unique opportunity to understand the dynamics of early hominin life, species coexistence, and the evolutionary trajectory leading to modern humans.
Future research promises further refinements to the fossil record, as ongoing discoveries and advanced analytical techniques continue to reveal new insights into the rich hominin history of this vital region
