By Stephen Beech via SWNS
Footprints dating back 1.5 million years of two different species of human ancestors have been found at the same spot.
The “huge” discovery near the shore of Lake Turkana in Kenya proves the theory that some ancient hominins were neighbors, say scientists.
Detailed analysis of the fossils by an international research team led them to conclude they represent the first example of two sets of hominin footprints made about the same time on an ancient lake shore.
They say the discovery will provide more insight into human evolution and how species cooperated and competed with one another.
The team explained that “hominin” is a newer term that describes a subdivision of the larger category known as hominids.
Hominins include all organisms, extinct and alive, considered to be within the human lineage that emerged after the split from the ancestors of the great apes which is believed to have occurred between six and seven million years ago.
Scientists say that the discovery, published in the journal Science, offers “hard proof” that different hominin species lived simultaneously, overlapping as they evaded predators and weathered the challenges of safely securing food in the ancient African landscape.
They believe that hominins belonging to the species Homo erectus and Paranthropus boisei, the two most common living human species of the Pleistocene Epoch, made the tracks.
Study co-author Professor Craig Feibel said: “Their presence on the same surface, made closely together in time, places the two species at the lake margin, using the same habitat.
Feibel, of Rutgers University in New Jersey, has been conducting research in that area of northern Kenya since 1981. He dated the fossils as 1.5 million years old.
He also interpreted the depositional setting of the footprint surface, narrowing down the passage of the track makers to a few hours, and showing they were formed at the very spot of soft sediments where they were found.
Feibel says that If the hominins didn’t cross paths, they traversed the shore within hours of each other.
Study first author Professor Kevin Hatala, of Chatham University in Pittsburgh, said that while skeletal fossils have long provided the primary evidence for studying human evolution, new data from fossil footprints is revealing fascinating details about the evolution of human anatomy and locomotion.
He added: “Fossil footprints are exciting because they provide vivid snapshots that bring our fossil relatives to life.
“With these kinds of data, we can see how living individuals, millions of years ago, were moving around their environments and potentially interacting with each other, or even with other animals.
“That’s something that we can’t really get from bones or stone tools.”
The team distinguished one set of footprints from another using new methods they recently developed to enable them to conduct a 3D analysis.
Rebecca Ferrell, of the National Science Foundation which helped fund that part of the research, said: “In biological anthropology, we’re always interested in finding new ways to extract behavior from the fossil record, and this is a great example.
“The team used cutting-edge 3D imaging technologies to create an entirely new way to look at footprints, which helps us understand human evolution and the roles of cooperation and competition in shaping our evolutionary journey.”
The researchers uncovered the fossil footprints in 2021 when a team organized by Louise Leakey, a third-generation paleontologist who is the granddaughter of Louis Leakey and daughter of Richard Leakey, discovered fossil bones at the site.
The field team mainly consisted of a group of highly trained Kenyans who live locally and scour the landscape after heavy rains.
They noticed fossils on the surface and were excavating to try and find the source.
While cleaning the top layer of a bed, one of the excavators, Richard Loki, noticed some giant bird tracks, then spotted the first hominin footprint.
Leakey coordinated a team in response that excavated the footprint surface in July 2022.
Feibel said it has long been hypothesized that the fossil human species coexisted.
According to fossil records, Homo erectus, a direct ancestor of humans, persisted for one million years more.
But Paranthropus boisei went extinct within the next few hundred thousand years.
However, researchers don’t know why.
The team said both species possessed upright postures, and bipedalism and were “highly” agile.
Feibel says the footprints are “significant” because they fall into the category of “trace fossils” – which can include footprints, nests and burrows.
He said trace fossils are not part of an organism but offer evidence of behavior.
Body fossils – such as bones and teeth- are evidence of past life, but are easily moved by water or a predator.
But Feibel said trace fossils can’t be moved.
He added: “This proves beyond any question that not only one, but two different hominins were walking on the same surface, literally within hours of each other.
“The idea that they lived contemporaneously may not be a surprise. But this is the first time demonstrating it.
“I think that’s really huge.”
