Dikika Research Project

Discovering new fossils is key to exploring the evolutionary history of our species, and the Afar Region in Ethiopia has played an unparalleled role in this regard. The DRP research area is located in North Eastern Ethiopia, ca. 500 km from Addis Ababa, the capital, and at ca. 30 km from the nearest village of Adaytu. Extensive, continuous and thick sedimentary exposures at Dikika range in age from fewer than 500,000 to greater than 4 million years old, allowing recovery of paleontological and archaeological data from temporal intervals representing different biological and cultural evolutionary stages.

Along with a diverse and rich fossil faunal assemblage that includes many hominin remains, sediments at Dikika have already yielded some spectacular specimens including a ca. 60% complete skeleton of the earliest child ever discovered (nick-named Selam) which belongs to the species Australopithecus afarensis. The project continues to undertake a systematic collection of fossils using state of the art methods to address key questions about human origins, such as how many hominin species were present in the time interval between 0.5 and 4 Million years ago, and what are the evolutionary relationships of these species to other such species? What were their modes of evolution and diversification? How did they live and how did they interact with the animals and plants in their surroundings? Using data from Dikika to answer these major questions will contribute uniquely to the understanding of the link that exists between human evolution and environmental changes over time. To this end the geology of the area is also being reconnoitered in order to reconstruct the geotectonic background for human evolution. Data from this research will be made available to the paleoanthropological community, which will allow regional and international collaborative research and understanding of the history of our family.

It is suggested that the interval between 4.0 to 3.0 Ma was characterized by an increased diversity of hominin species. Ongoing analyses of existing fossils are contributing to a better understanding of the various species present at the time, and the relationships among them, but the best approach to exploring the degree of variation within early hominins and their proposed diversity is finding more fossil evidence from the right time intervals. Dikika contains many fossiliferous areas from the critical time period between 3 and 3.8 Ma. New hominin fossils from this time interval will either corroborate the hypothesized diversity of early hominins or will suggest the lack thereof.

There is currently a consensus that the australopithecines from Hadar and Laetoli belong to the same species, Australopithecus​ afarensis. However, there remain many questions regarding patterns of temporal and geographic variation with the species. Additional hominins from Dikika will not only contribute to testing hypotheses concerning temporal trends, but also allow us to understand whether the suggested patterns hold true for the pre-3.4 Ma time period in the Afar basin.

Documenting the paleoenvironments and paleoecology of hominin sites is a key element in exploring the biological forces and mechanisms responsible for the evolution of our ancestors. A well-documented and unbiased fossil assemblage with a faunal composition reflecting that of the actual fossil record is a prerequisite for any of these approaches to be successful. At Dikika a continuous series of fossiliferous sediments from the time interval between 4 and 3 Ma is extensively exposed. New data from older Dikika sites will fill in the gap between Hadar and earlier sites and will help address the paleoecological context of Australopithecus​ afarensis.

Fossil fauna from Dikika will contribute to increasing data on the pre-Hadar time period, understanding patterns of faunal change during the middle Pliocene and detecting any episodes of major faunal turnover similar to the ones that occurred after 3.0 Ma.

The DRP is also undertaking similar field work at the Middle Pleistocene site of Asbole, which contains highly fossiliferous sediments in which over 31 mammalian species were encountered, including five primate species. This area is on the left bank of the Awash River, opposite to the Dikika part of the DRP area, and covers a time period which is very poorly known elsewhere in East Africa. The faunal collection is now large enough for some significant environmental conclusions to be drawn.

The bulk of the bovid fauna consists of reduncines, grazers adapted to wetlands, but while several other taxa are also grazers, alcelaphines, the dominant grazers of Pleistocene and present-day African savannas, are rare. Two species of tragelaphines suggest the presence of bushes, and the rhino Diceros, who was also mostly a browser, suggests a rather closed environment. This preliminary investigation shows that the fauna from Asbole consists of a mixture of living and extinct species and sub-species. A widely spread tuff (the Bironita Tuff) is dated at ca. 600 K.

The site is also very rich in archaeological remains. It appears that the area was occupied from the Oldowan onwards, although the majority of the evidence suggests that hominin presence in the area was most intense in the Acheulean and MSA. The general range of behavior seems to represent movements on the landscape that were conditioned by variable access to diverse resources. The recovered artifacts span the range of time between the Oldowan and the MSA, and it is hoped that future fieldwork in the area will help researchers paint a more coherent picture of our collective human past.