The Omo-Turkana Basin located in East Africa, primarily Ethiopia and Kenya. This region has been incredibly important to researchers studying early hominins. This beautiful region has the distinction of providing nearly a third of Africa’s known hominin fossil record. It displays an incredible temporal range from 7 million years ago to 0.78 million years ago. The Omo-Turkana Basin is well known for its exceptional paleontological finds. It is one of the top three places on Earth to study human evolution in Africa.
The Omo-Turkana Basin’s rich fossil record sheds light on this outstandingly interesting and atypically long 2.7-million-year period. This time period goes from 4.2 million to 1.5 million years ago. The basin has been home to numerous other early hominins from then on. Most remarkably, Australopithecus anamensis appeared as little as 4 million years ago. While early members of our genus flourished, the genus Paranthropus went extinct. This truly remarkable coexistence lasted for more than 1.5 million years in the basin.
The Omo-Turkana Basin has the record of fossil hominins for 81% of the temporal range of 2.7 million years. This extraordinary discovery emphasizes its almost uninterrupted fossil record despite two large gaps totaling over 500,000 years. Paleoanthropologists have examined a total of 1,231 similar hominin specimens from these 658 individual fossils. These results are limited to three main areas of the basin.
Teeth are the most common specimens found in the Omo-Turkana Basin, with 687 isolated teeth or tooth fragments recognized. Other significant finds comprise 175 crania or cranial pieces, 116 mandibles or mandible pieces, and 253 postcranial remains. One last thing to stress is that 80% of the species represented in this fossil record are known only from single fossil specimens. Just a few of those skeletons are mostly intact.
Fossils are unevenly distributed throughout the basin. The eastern section, at 47%, the western section at 30%, and the northern section at 23% all add to the congestion clogs. Fossil evidence from the Pleistocene record (2.7 to 2 million years ago) suggests a diverse and abundant occurrence of early Homo species. This would include Homo rudolfensis, Homo ergaster, Homo habilis, and early Homo erectus, with at least 45 individuals described.
Even with these monumental discoveries, only 70% of fossils in the Omo-Turkana Basin have been classified to species! Specimens from multiple new species still await erection and full description.
“By compiling all the published hominin fossil data, our analysis treats the basin as an integrated system,” said François Marchal et al. “This reveals basin-wide patterns in the history of discovery and relative fossil abundance geographically and historically.”
Marchal brought greater attention to the obstacles that researchers have encountered because of the location of the basin. He noted that the project crosses an international border. Important research efforts from many international teams have resulted in a population of data that is siloed across its major components.
“Today, numerous international teams are continuing to carry out fieldwork in the three parts of the basin. New fossils will be unearthed, and previously discovered fossils will finally be described or better assigned taxonomically,” Marchal added.