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The role of the Lucy fossil: perhaps she was not our direct ancestor after all?
The iconic Lucy fossil, Australopithecus afarensis, was regarded for decades as one of the best-known links in human evolution. However, based on the latest research and fossil discoveries, its role in the line of direct ancestors has become questionable, sparking intense debate among anthropologists.
One of the most famous and iconic fossils studied in human evolution is Lucy, discovered in Ethiopia in 1974. The 3.2-million-year-old specimen belongs to the species Australopithecus afarensis, which walked on two legs and had an upright posture similar to that of modern humans. Because of these characteristics, it was long believed that Lucy could be our direct ancestor, the starting point for the evolution of all later hominins. This assumption, however, now appears to be increasingly uncertain, reports Live Science.
The roots of the debate
The human family tree is far from linear. Over the decades, more and more fossils have been unearthed, and numerous ancient human relatives have been discovered living at the same time, making it increasingly difficult to determine exactly which species we descend from. The Taung Child, discovered in 1925 and belonging to Australopithecus africanus, was long considered the direct ancestor of humans, until the discovery of the Lucy fossil reshaped this view and elevated Australopithecus afarensis to a central role.
New fossils, new theories
A recent study published in the journal Nature offers a new perspective on the status of the Lucy fossil. Researchers have recently discovered new foot and dental remains attributed to the species Australopithecus deyiremeda. This species lived 3.3–3.5 million years ago at the same time as Lucy in Ethiopia and, while it walked on two legs, spent much of its time in trees.
According to the study, A. deyiremeda and A. africanus were anatomically closer to each other than to Lucy’s species. This raises the possibility that A. africanus was not a descendant of Lucy but rather a more distant relative. The researchers suggest that the role of direct ancestor may instead belong to the older Australopithecus anamensis, which lived 3.8–4.2 million years ago in East Africa.
Fred Spoor, Professor of Evolutionary Anatomy at University College London, believes that the new discovery could mark the end of theories that place Lucy at the centre as a direct ancestor. Other experts, however, such as Lauren Schroeder, a paleoanthropologist at the University of Toronto Mississauga, emphasise that many different species evolved and interbred in parallel during human evolution, meaning that a relationship to Lucy cannot be ruled out.
Even the authors of the study do not agree entirely on the issue. Yohannes Haile-Selassie, for example, argues that because of the structure of her legs, her gait and other human-like features, it remains most likely that Lucy should still be regarded as our direct ancestor.
Why was the discovery of the Lucy fossil a milestone?
The discovery of the Lucy fossil became significant because the A. afarensis species walked on two legs, had a smaller brain than modern humans, and occupies a position roughly halfway between the last common ancestor shared with chimpanzees and humans in the process of human evolution.
According to studies, Lucy’s geographical distribution, her survival over approximately one million years, and her adaptability mean that she is still considered important for understanding human development and anthropological research.