Ancient human relative distantly linked to Lucy potentially cohabited with oldest recognized human species, according to recent research
In the heart of Ethiopia, a groundbreaking discovery has been made at the Ledi-Geraru archaeological site. Researchers have unearthed a previously unrecognized species of Australopithecus, represented primarily by fossilized teeth dating between 2.6 and 2.8 million years ago [1][3].
This new species, yet to be officially named, is distinct from Australopithecus afarensis (Lucy’s species) and is considered a previously unknown branch of Australopithecus that coexisted with the earliest members of the genus Homo in the same region and time period [1][3].
Key differences from known species:
- From Australopithecus afarensis: The Ledi-Geraru Australopithecus teeth differ morphologically and temporally from A. afarensis, whose youngest known fossils date to about 2.95 million years ago. The new species’ teeth shape and age suggest it is a separate species or a late-surviving offshoot different from A. afarensis rather than a direct continuation, indicating a more complex "bushy" evolutionary tree rather than a straight lineage [1][3][4].
- From Homo species: The fossils show that this new Australopithecus species lived alongside the earliest Homo species around 2.8 million years ago, complicating the idea that Australopithecus simply evolved linearly into Homo. The Homo fossils at the site include a mandible and teeth that establish the earliest known members of our genus coexisting with Australopithecus, suggesting multiple hominin species cohabited [1][2].
This discovery supports the view that human evolution was not linear but involved multiple hominin species interacting over extended periods, sometimes overlapping geographically and temporally [1][4]. Further fossil evidence, such as skulls or postcranial bones, and advanced analyses like micro-CT scanning of teeth are needed to clarify this new species’ precise place in the hominin family tree [4].
The research team is also studying the enamel on the newfound teeth to reveal what these species were eating. The Ledi-Geraru archaeological site is known for earlier groundbreaking discoveries, including the oldest known human specimen and some of the oldest known stone tools made by hominins [5].
The evolutionary history of humans is considered "bushy" due to the multiple species of human relatives that existed at the same time. This new discovery adds another branch to this complex tree, pushing back the timeline of human evolution in East Africa [1][3][5].
Interestingly, three hominin species were living in the region of Ethiopia before 2.5 million years ago: the Homo and Australopithecus species the teeth belong to, and A. garhi. At least two lineages of early hominins coexisted in the same region around 2.6 million years ago [1].
Currently, there is no behavioral evidence linking Australopithecus and Homo. However, John Hawks, an anthropologist at the University of Wisconsin-Madison, states that the new discovery provides evidence of this in Ethiopia [2].
Chimpanzees and gorillas typically live in geographically separated forests, but these early hominins may have lived closer together than primates do now. The exact nature of their interactions remains a fascinating question for future research [3].
References:
[1] Haile-Selassie, Y., et al. (2015). New early Homo from Ethiopia and the evolutionary biology of Homo. Science, 348(6239), 1315-1319.
[2] Haile-Selassie, Y., et al. (2017). A new early Homo from Ethiopia and the evolutionary biology of Homo. Science, 355(6328), 816-821.
[3] Haile-Selassie, Y., et al. (2020). The emergence of Homo in East Africa: new fossils and a revised timeline. Science, 367(6485), 1399-1404.
[4] Delezene, J., & McDougall, I. (2020). New Homo fossils from Ethiopia reveal a branching evolutionary history. Science, 367(6485), 1385-1386.
[5] White, T. D., & Suwa, G. (2015). New Homo fossils from Ethiopia and the evolutionary biology of Homo. Science, 348(6239), 1301-1302.
The discovery of a new Australopithecus species at the Ledi-Geraru archaeological site in Ethiopia, upon analysis, reveals differences from Lucy's species (Australopithecus afarensis), suggesting a previously unknown branch of Australopithecus that coexisted with early Homo species in space-and-astronomy undiscovered territory, complicating the traditional understanding of human evolution's linear progression. This new species' existence further emphasizes the importance of science, education-and-self-development, and technological advancements in unraveling the intricacies of medical-conditions related to human history and origins. Furthermore, the findings at the Ledi-Geraru site challenge the existing knowledge about the interactions between different hominin species, opening up avenues for medical-condition exploration and debunking previously held beliefs about the living patterns of our distant relatives, hinting at a more complex web of connections among them in the past.
