Science Snippets: Different Hominids at Same Location 1.5 Million Years Ago
Draft script:
Paleontologists have long sought documentation about closely related humans crossing paths. We have long known about modern humans, Homo sapiens, crossing paths with Neanderthals, Homo neanderthalensis. However, paleontologists have been seeking other examples of interactions between our species and other human animals. At last, success was reported in the renowned peer-reviewed journal Science on 28 November 2024. More about the peer-reviewed paper shortly.
The headline at Phys.Org on 29 November 2024 reads A fossil first: Scientists find 1.5-million-year-old footprints of two different species of human ancestors at the same spot. Here’s the lede: “More than a million years ago, on a hot savanna teeming with wildlife near the shore of what would someday become Lake Turkana in Kenya, two completely different species of hominins may have passed each other as they scavenged for food.” As you know by now, you must insert might for may to correct this grammatically incorrect sentence.
The following paragraph tells the story: “Scientists know this because they have examined 1.5-million-year-old fossils they unearthed and have concluded they represent the first example of two sets of hominin footprints made about the same time on an ancient lake shore. The discovery will provide more insight into human evolution and how species cooperated and competed with one another, the scientists said.”
Use of the term hominin acknowledges a subdivision of the larger category, hominids. Hominid includes all organisms, extinct and alive, considered to be part of the human lineage that emerged after the split from other Great Apes. This division occurred six to seven million years ago.
A few paragraphs later, the article in Phys.Org indicates that the humans who interacted with each other 1.5 million years ago belonged to our immediate predecessor, Homo erectus, as well as Paranthropus boisei. These were the two most common extant human species during the Pleistocene Epoch. Lest you believe I am pronouncing Paranthropus boisei incorrectly, bear in mind that all words in Latin, a dead language, are pronounced the same: with authority. Not to confuse the issue, but some scientific names use Greek, including Paranthropus.
A Professor in the Department of Earth and Planetary Sciences and also in the Department of Anthropology in the Rutgers School of Arts and Sciences exudes enthusiasm as he is quoted in the Phys.Org article: “Their presence on the same surface, made closely together in time, places the two species at the lake margin, using the same habitat.”
The Professor at Rutgers indicated that if the two species of hominins didn’t cross paths, then they traversed the shore within hours of each other. According to his colleague, the first author of the peer-reviewed paper in Science: “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 one other, or even with other animals. That’s something that we can’t really get from bones or stone tools.”
This research results from that of the Leakey family, famous for their paleontological work in Africa. Specifically, a team of paleontologists organized by Louise Leakey discovered fossil bones on the site. Louise Leakey is the granddaughter of Louis Leakey and daughter of Richard Leakey. The fossil footprints were discovered in 2021 when highly educated, local Kenyans scoured the area after heavy rains. They noticed fossils on the surface and were excavating when one of the members of the team noticed giant bird tracks, after which he spotted the first hominin footprint. In response, Louise Leakey coordinated the team that excavated the footprint in July 2022. She is one of 19 scholars who authored the peer-reviewed paper.
As with Homo sapiens, Homo erectus and Paranthropus boisei had upright postures, bipedalism, and were highly agile. However, little is known about how these two coexisting species interacted, either culturally or reproductively. According to the article at Phys.Org, it has long been hypothesized that these two human species coexisted. Paranthropus boisei went extinct within the next few hundred thousand years after coexisting with modern humans in Kenya. Scientists do not know what caused the extinction of this species.
The footprints documented in this research are particularly significant. These footprints fall into the category of trace fossils, which can include footprints, nests, and burrows. Trace fossils are not part of an organism but they offer evidence of behavior. In contrasts, body fossils such as bones and teeth indicate past life, but they are easily moved by water or a predator. Trace fossils, on the other hand, cannot be moved.
The Professor at Rutgers again exudes enthusiasm when he provides the bottom line in the article at Phys.Org: “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.”
As I indicated, the peer-reviewed paper was published in Science on 28 November 2024. Written by 19 scholars, it is not open-access. However, the Editor’s summary and Abstract combine to provide sufficient information. The Editor’s summary includes this information: “It is now well accepted that hominin evolution is a story of many lineages existing contemporaneously. Evidence for this pattern has mostly come from fossils being dated to similar time periods. [This paper] describe[s] hominid footprints from 1.5 million years ago in the Turkana Basin in Kenya that were made by two different species within hours or days of each other. (see the Perspective by Harcourt-Smith). Analyses showed that the footprints were made by individuals with different gaits and stances, and the authors hypothesize these to be Homo erectus and Paranthropus [boisei] boilei. Although fossils of both species occur in the area, these footprints show that they coexisted and likely interacted.
The Abstract contains this information: “For much of the Pliocene and Pleistocene, multiple hominin species coexisted in the same regions of eastern and southern Africa. Due to the limitations of the skeletal fossil record, questions regarding their interspecific interactions remain unanswered. We report the discovery of footprints (~1.5 million years old) from Koobi Fora, Kenya, that provide the first evidence of two different patterns of Pleistocene hominin bipedalism appearing on the same footprint surface. New analyses show that this is observed repeatedly across multiple contemporaneous sites in the eastern Turkana Basin. These data indicate a sympatric relationship between Homo erectus and Paranthropus boisei, suggesting that lake margin habitats were important to both species and highlighting the possible influence of varying levels of coexistence, competition, and niche partitioning in human evolution.”
As I have been pointing out for many years, we are one. The research and resultant publications mentioned here provide yet another example.
In light of this evidence of two different Hominoids existing contemporaneously, I'm immediately wondering was Homo erectus the first species we drove to extinction?
Cynical I know, but my species behavior would lead me ponder that possibility considering we drive 200 species per day to extinction!
https://a-z-animals.com/blog/how-many-species-go-extinct-on-average-per-day-and-per-year/
Not much commentary on this which is too bad. This is a fascinating subject.
I thought this was a great find but basically it confirms what paleogenomics has been showing for years. We didn't "kill off" the other hominids. We subsumed them.
Random Thoughts — 01 : Oct 2021
https://smokingtyger.medium.com/random-thoughts-01-aac12a607250
Paleogenomics has revolutionized our understanding of human evolution. It tells us that we didn’t kill the Neanderthals, we absorbed them. They is us.
While "hard" fossil evidence is incredibly rare and difficult to find. The evidence in our genome exists in every single one of us and it tells a consistent story.
With the sequencing of the Neanderthal and Sapiens genomes we can see clearly now how the two species interacted over a several hundred-thousand-year time span. The fossil record may be murky, but the genes don’t lie.
The main reason that humans didn’t spread into Europe before 50,000BCE was most likely that the land North of the Middle East was already taken by Neanderthal communities. What we know from the genetic traces is that they intermingled, and they interbred. We know this because we can see Neanderthal genes flowing back into the African gene pool each time the ice retreated, and the Middle East became inhospitable again.
Some mixed-race humans returned to Africa and spread Neanderthal genes back into the African gene pool, where they can be detected today. We know that others moved back into Europe because their human heritage has been detected in Neanderthal remains in Eastern Europe that are over a hundred thousand years old.
That’s right, the flow of genes went both ways. We hybridized with the Neanderthals and other Homo species multiple times. We slept with our cousins. A lot.
The genetic evidence tells us this happened multiple times in prehistory. Each time the door out of Africa was open, some humans would move into the Middle East, interbreed with the people they found there, and then vanish as the climate changed and the region became desert once again.
Some would go back to Africa, carrying the new genes they had acquired back to the “root stock”. Others would go to Europe and their “humanism” would fade as they blended into the Neanderthal population. Spreading human genes through the Neanderthal gene pool.
This happened multiple times in a 200,000-year dance of hybridization, isolation, inbreeding, and re-hybridization. The two populations\species profoundly affected each other genetically.
They is us, and we are them.
What finally put an end to the dance was the disaster that nearly killed us about 74,000 years ago. Recent research suggests it was a massive eruption of a volcano in Indonesia. The Toba eruption likely released 100 times as much SO2 as the Pinatubo event, and was the greatest natural disaster of the last 2.5 million years.
Temperatures dropped between 3.5 and nine degrees Celsius worldwide, and global rainfall decreased by 25 percent. What’s worse, computer simulations of the Toba super-eruption, found this event could have wiped out up to half the ozone in the Earth’s atmosphere. Remember the concerns about “destroying the ozone”?
The effects on the human genome indicate that the human population shrank down to a remnant group of a no more than ten to twenty thousand, probably living in Southern Africa.
We know this because it caused a “genetic bottleneck” trace in the human genome.
Humanity survived but we are not a genetically diverse species. The most genetically diverse human populations are the African ones. Because they are the oldest and have evolved the most diversity.
The European and Asian populations have less diversity than the African because they are younger and because they went through a second genetic bottleneck when they migrated out of Africa. The Amerindian genome is the least diverse of all because it went through a third genetic bottleneck when it’s ancestral populations migrated out of Asia.
Human genetic diversity is actually really low for a species.
After the Toba disaster the human population seems to have rebounded. We expanded throughout Africa and absorbed all the other hominid species that we encountered. Cousins, that we have no fossil evidence for except for their traces in our genome.
There are somewhere between 5-7 other "cousin" hominid species that we subsumed as we expanded across Africa. Hominid species that we have almost no physical evidence for but, who live on as "ghosts" in our genes.