In one of the most groundbreaking discoveries in human evolution, researchers working in Ethiopia have uncovered the oldest human fossil ever discovered.
This jawbone, dating back to approximately 2.8 million years, could potentially shift the entire timeline of human ancestry, pushing the emergence of the Homo genus back by as much as half a million years.
This discovery has sent shockwaves through the scientific community, especially given that it was made so close to the remains of Australopithecus afarensis, one of the closest known ancestors to early humans.
But the mystery doesn’t stop there.
The fossil raises more questions about our evolutionary path than it answers.
A Glimpse Into Our Ancient Past
The jawbone, labeled LD 350-1, was first found in 2013 in the Afar region of Ethiopia.
It was only recently analyzed and dated to about 2.8 million years ago, making it at least 400,000 years older than the previous oldest Homo fossil, a key piece of evidence that has shaped our understanding of human evolution for decades.
Brian Villmoare, a co-author of the study and a researcher at the University of Nevada, Las Vegas, explained the significance of the find: “There is a big gap in the fossil record between about 2.5 million and 3 million years ago – there’s virtually nothing relating to the ancestors of Homo from that time period, despite a lot of people looking.” Villmoare added, “Now we have a fossil of Homo from this time, the earliest evidence of Homo yet.”
This discovery is especially important because it fills in one of the biggest gaps in our understanding of human evolution, which had left a vast chasm between the last known Australopithecus and the first appearance of Homo.
What Does This Fossil Mean for Our Origins?
The fossil is not just a random collection of ancient bone—
it is a key piece of evidence that allows researchers to better understand how Homo species, like us, emerged from the hominids that came before.
Interestingly, the jawbone was found in close proximity to the last known remnants of Australopithecus afarensis, the species famously represented by the skeleton of “Lucy.”
This proximity is crucial because many scientists believe Australopithecus afarensis might be a direct ancestor of the Homo genus.
The gap between the remains of Lucy, who lived about 3.2 million years ago, and the newly discovered Homo jawbone is only around 200,000 years.
While that might not sound like a significant amount of time in the grand sweep of human history, those two centuries likely represent a period of profound evolutionary change.
This fossil helps us piece together a more complete picture of that evolutionary leap.
Paleoanthropologist Donald Johanson, the scientist who discovered Lucy, called the find “exciting” and emphasized how it offers new insights into the very roots of our evolutionary tree.
A New Species or a Transitional Form?
One of the fascinating aspects of the discovery is the uncertainty surrounding whether the fossil belongs to an entirely new species or is related to already-known extinct Homo species, such as Homo habilis.
According to Villmoare, the morphology of the jawbone suggests that it could represent a species that existed at a key transitional point between Australopithecus and Homo, exhibiting characteristics of both.
The teeth cusp patterns and jaw proportions align closely with Homo species, while the sloping chin is more reminiscent of Australopithecus.
As Bill Kimbel, director of the Institute of Human Origins at Arizona State University, explained, this jawbone narrows the search for the origins of the human lineage to a much more specific time frame.
He said, “It’s very much a transitional form, as would be expected at that age. The chin looks backwards in time. But the shape of the teeth looks forward.”
This discovery doesn’t just fill a void in the fossil record—it offers a glimpse into a crucial moment in the evolutionary chain where early human ancestors began evolving into the Homo genus.
A Timeline Rewritten?
To understand the true significance of this discovery, we need to look at the broader timeline of human evolution. Up until now, Homo habilis, often considered the oldest Homo species, had been dated to around 2.3 million years ago.
The discovery of the LD 350-1 jawbone, dated to 2.8 million years, is pushing the timeline back and prompting scientists to rethink not just the age of Homo species, but also where and when our ancestors emerged.
The researchers used advanced techniques to date the fossil, analyzing radioactive isotopes in the volcanic ash layers above and below it.
This process allowed them to pinpoint the exact time the jawbone was deposited in the region, giving us a rare and valuable insight into the geographical and temporal evolution of Homo species.
As Villmoare explained, “This find helps place the evolution of Homo geographically and temporally – it tells us where and when Homo evolved.”
This is not just a question of “when”—it’s also about “where” our ancestors evolved, and this discovery could help reshape the map of early human migration.
The Unexpected Mix of Traits
While the discovery of LD 350-1 is undoubtedly exciting on its own, another recent paper published in Nature reveals some intriguing new details about Homo habilis, the species that had long been considered the oldest known Homo species.
The new research suggests that Homo habilis may have exhibited a surprising mix of both primitive and advanced traits.
This revelation opens up the possibility that the jawbone found in Ethiopia may actually represent a form of Homo habilis, which had a combination of characteristics that were previously thought to belong to separate branches of human evolution.
If the LD 350-1 fossil turns out to be a match for Homo habilis, this would dramatically shift our understanding of the species and its role in human evolution.
As Villmoare put it, “These findings raise more questions than they answer. Hopefully, these questions will be answered by further fieldwork.”
But that’s part of what makes this discovery so powerful—it’s not just providing answers, but sparking new lines of inquiry that will keep researchers busy for years to come.
What’s Next for Human Evolution Research?
While this discovery has already begun to challenge some long-standing assumptions about our evolutionary timeline, the road ahead is filled with more questions than answers.
The LD 350-1 fossil has opened up a host of new possibilities, but it has also highlighted just how much we still have to learn about the origins of our species.
As researchers continue their fieldwork, they will no doubt encounter more fossils that help fill in the gaps.
And with advancements in technology and dating techniques, we may uncover even older fossils, further complicating and refining our understanding of human evolution.
For now, however, LD 350-1 offers us a rare and invaluable glimpse into a pivotal moment in human history, shedding light on how we evolved from our ape-like ancestors into the beings we are today.
Sources: Live Science, National Geographic
