The evolution of man and in particular the development of the first representatives of our genus Homo raise many questions. New insights now provide 2.6 to 2.8 million year old teeth that a research team discovered in Ledi-Geraru in the Ethiopian Afar region. Some of these 13 tooth fossils show characteristics of the Australopithecus, but cannot be assigned to any previously known type of these pre -human. Further teeth seem to come from a still unknown, early representative of the genus Homo. The discovery of relics of both types in one place and from the same time suggests that in the Afar region coexisted in the Afar region and the first early people. This once again confirms that in the course of human history, various species and development levels of the hominins occurred and met.
The human tree of humans is more like a bush than an orderly scheme. Because over the past three million years in Eastern and South Africa, many different forms of pre- and early people, some of which have occurred side by side, have occurred in a habitat in a row. Which of these hominins belonged to our direct ancestors, which lines died out without successors and how the various species were related is only partially clarified. However, it seems clear that the pre -human genre of Australopithecus dominated more than three million years ago. Among other things, it includes the famous fossil “Lucy” from the Afar region in Ethiopia. From the time around 2.5 million years ago, the first representatives of the genus Homo appeared. But when and how the transition from pre -people like Australopithecus to these first early people took place is so far unclear – also because there are only very incomplete fossil finds from the period three to two million years ago.
The foundation Ledi-Geraru plays a special role in our knowledge of early human development in the Afar region. Around ten years ago, researchers discovered the oldest known fossil of the genus Homo. They assigned the 2.8 million year old lower jawbone including their teeth due to its more archaic features to a predecessor of Homo Habilis and Homo Rudolfensis. It fits that in 2019 the oldest known stone tools of Oldowan technology were found near Ledi-Geraru-it was considered a license plate of the genus Homo.
13 teeth – but not the same type
Now there are new finds from Ledi-Geraru. An international research team led by Brian Vilmoare from the University of Nevada discovered several teeth from hominins in excavations at three different places in this site. The volcanic ash layers deposited in this area allowed researchers to date the finds relatively precisely. The oldest newly discovered tooth fossils are around 2.78 million years old, the youngest 2.59 million years. But who do they come from? More detailed analyzes of the tooth morphology showed: The oldest tooth find shows characteristics of the genus Homo and resembles the teeth of the lower jaw discovered at this site. The team of the genus Homo also assigns the two youngest tooth fossils, two molars. “The new finds confirm the old age of our genus,” says Vilmoare. However, the type of these early people cannot be determined solely on the basis of these teeth.
Another ten teeth were surprising, which comes from the approximately 2.63 million year old layer of found Lee Adoyta from Ledi-Geraru. Because contrary to expectations, they do not come from an early man, but from a pre -human. “Since these finds lack clear own characteristics of homo representatives, we temporarily assign them to the Australopithecus,” the team writes. This could result in these finds from one of the last surviving populations of these pre -people in East Africa. But what kind of Australopithecus these teeth belong is unclear how Vilmoare and his colleagues explain. The teeth features deviate from those of the Australopithecus Afarensis as well as the Australopithecus Garhi or the Paranthropus. The researchers therefore come to the conclusion: “The teeth from Lee Adoyta represent a previously unknown species of the Australopithecus from the early Pleistocene,” they write.
Coexistence of Australopithecus and Homo
Conservation of these finds draw an exciting picture. “The finds suggest that Australopithecus and the early Homo coexisted more than 2.5 million in the AFAR region in the period ago,” Vilmoare and his colleagues state. Both Hominine species did not stay in this area one after the other, but alternately or even at the same time. “In total in East Africa there could have been 3 to 2.5 million up to four people at the same time: the early homo, paranthropus, Australopithecus Garhi and the newly discovered Australopithecus art from Ledi-Geraru,” write the researchers. “This demonstrates how evolution experimented with various hominine forms at that time.
Next, Vilmoare and his team now want to analyze the fossil teeth to the tooth enamel. Among other things, this could show what these pre-people ate and early people ate- and so more about their coexistence: differed from the menu of the Australopithecus from that of the early homo representative or did you compete for the same resources? Who was their ancestors and could they have met? So far, these questions have been open. “Whenever you make an exciting new discovery, as a paleontologist you already know that you will need more information,” says senior author Kaye Reed from Arizona State University.
Source: Brian Villmoare (University of Nevada, Las Vegas) et al., Nature, DOI: 10.1038/S41586-025-09390-4
