The discovery of a fossilized skeleton known as “Lucy” 50 years ago revolutionized our understanding of human evolution. This 3.2-million-year-old Australopithecus afarensis hominin offered valuable insights into our upright walking ancestors. However, recent findings suggest that Lucy was not the only hominin of her time—in fact, she had several proto-human neighbors that may have interacted with her species.
Understanding Lucy: Insights into the history of early humans
Lucy’s discovery on November 24, 1974, in Hadar of Ethiopia by American paleoanthropologist Donald Johanson marked a pivotal moment in the field. The most compelling evidence was Lucy’s knee joint, which resembled that of modern humans rather than those of earlier hominins.
This suggested that A. afarensis was able to walk on two legs. This discovery contradicted previous beliefs that larger brains preceded bipedalism. Indeed, Lucy’s small brain case added complexity to theories related to evolution, indicating that the ability to walk upright emerged long before the development of other cognitive abilities.
Lucy’s existence helped establish A. afarensis as a successful species that occupied a diverse range of habitats across East Africa during the middle Pliocene era (approximately three to four million years ago). Her anatomical features exhibited a combination of both primitive and advanced traits, highlighting the transitional nature of her species in the history of human evolution.
However, while Lucy’s kind flourished, it has since become evident that they weren’t alone. Other hominin species coexisted during this period, adding an enriching layer to the complex tapestry of human ancestry.
Exploring Lucy’s coexistence with other early humans
In 1995, the discovery of a fragmentary jawbone in the Bahr el Ghazal region of Chad transformed our understanding of hominin diversity. This 3.5-million-year-old fossil led to the identification of Australopithecus bahrelghazali, indicating the existence of other hominin species coexisting with Lucy, as noted by Ethiopian paleoanthropologist Yohannes Haile-Selassie and his team in a 2016 study.
Meanwhile, the Woranso-Mille site in Ethiopia—30 miles north of Lucy’s discovery site—revealed fossils of A. afarensis alongside distinct contemporaneous fossils. Among these was Australopithecus deyiremeda, dating between 3.5 million and 3.3 million years ago; it exhibited different teeth from Lucy’s species, indicating varying diets. However, the classification A. deyiremeda remains debated among paleoanthropologists.
Additionally, Woranso-Mille yielded a partial foot, known as the “Burtele foot,” dated to 3.4-3.3 million years ago. Its opposable big toe suggests adaptation for climbing, thus distinguishing it from A. afarensis, although it hasn’t been assigned to a specific species.
In 2001, at the Lomekwi site in Kenya, British paleoanthropologist Meave Leakey and her team unearthed Kenyanthropus platyops, dated to 3.3-3.2 million years ago. Noted for its flat face, this species coexisted with Lucy but lived over 620 miles away. While its brain size resembles that of A. afarensis, variations in the upper teeth have prompted debate about its classification as a separate genus and species.
Learning from our ancestors: What’s next for paleoanthropology?
These discoveries reveal that human evolution is more complex than the traditional “March of Progress” model. Instead, it resembles a “bushy tree” or “braided river,” illustrating that various human species evolved concurrently.
Altogether, this has significant implications for paleoanthropology. The coexistence of multiple hominin species suggests that they shared environments and resources, impacting survival and adaptation theories.
As researchers explore these dynamics, they are building a deeper understanding of the evolutionary pressures and ecological niches faced by early humans.
For now, the existence of Lucy’s contemporaries enriches our knowledge of our evolutionary past. Each newfound ancestor enhances our grasp of ancient interactions and adaptations. Indeed, it’s a historic journey that shines light on the unique paths that shaped humanity.