Re-Learning History
Discovery of 210,000 Year Old Human Skull in Greece Highlights Changing Timeline for Humankind’s Origins
Discovery of 210,000 Year Old Human Skull in Greece Highlights Changing Timeline for Humankind’s Origins
Did you know that what we now know about ancient human beings is very different than what most of us were taught in school? This isn’t because of ancient aliens or lost civilizations, or any other wildly speculative, theoretical imagining. It’s science — we’ve simply learned much more about our human origins in recent years.
Since most of us aren’t in school anymore, we don’t always get the chance to learn the new stuff. And history? It’s always changing. There’s always something new to learn, even when the questions don’t change, like –
How did we get here?
And –
Where do we come from?
Education is a never-ending journey.
Time to re-learn some history…
We used to think modern humans appeared in East Africa about 200,000 years ago, migrated out of Africa around 50,000 years ago, and migrated to the Americas about 12,000 years ago. But we’ve recently had to revise those dates — backwards. In some cases, new discoveries suggest dates for our origins going much further back than we once suspected.
Last week in Nature, the dating of a nearly anatomically modern human skull fragment was announced that may push back the estimated arrival of modern humans in Europe by tens of thousands of years. Two ancient skull fragments, found in Apidima Cave in southern Greece, have been around since the late 1970s, “but have remained enigmatic owing to their incomplete nature… and lack of archaeological context and chronology”.[i]
In the study, new virtual reconstructions, comparative descriptions and analyses, and up-to-date methods of dating the fragments by Katerina Harvati, a palaeoanthropologist at the Eberhard Karls University of Tuebingen, in Germany, and her colleagues offered up a revelation.
“Apidima 2 dates to more than 170 thousand years ago and has a Neanderthal-like morphological pattern. By contrast, Apidima 1 dates to more than 210 thousand years ago and presents a mixture of modern human and primitive features.”[ii]
“When the team analyzed the back of Apidima 1’s skull, they knew that they were dealing with something different,” the New York Times reported. “In Neanderthals and other extinct human relatives, the back of the skull bulges outward. ‘It looks like when you put your hair up in a bun,’ Dr. Harvati said. But in our own species, there is no bulge. Compared with our extinct cousins, the back of the modern human skull is distinctively round. To Dr. Harvati’s surprise, so was the back of Apidima 1’s skull. It also had other features found in Homo sapiens but not in other species”.[iii]
That means the fragment they call “Apidima 1” seems to be human, and pre-dates the Neanderthal-like “Apidima 2” fragment by 40,000 years — the human was there before the Neanderthal. “These results suggest that two late Middle Pleistocene human groups were present at this site — an early Homo sapiens population, followed by a Neanderthal population.”[iv]
“It shows that the early dispersal of Homo sapiens out of Africa not only occurred earlier — before 200,000 years ago — but also reached further geographically, all the way to Europe,” Harvati said.[v]
An early modern human in Europe 210,000 years ago? “Our findings support multiple dispersals of early modern humans out of Africa, and highlight the complex demographic processes that characterized Pleistocene human evolution and modern human presence in southeast Europe,” the report states.[vi]
This is a big revision in dating, if it holds up. As the New York Times reports, “Until now, the earliest remains of modern humans found on the Continent were less than 45,000 years old. …The finding is likely to reshape the story of how humans spread into Europe, and may revise theories about the history of our species.[vii]
But this isn’t the first indication of earlier migrations. Other finds had begun to push back the timeline for homo sapiens migration out of Africa. Last year, an ancient jawbone found on the Israeli coast was discovered to be “at least 175,000 years old, and it belonged to a member of our own species. Sophisticated stone tools were discovered nearby,” The Washington Post reported. “The find… is by far the oldest human fossil ever uncovered outside Africa, where Homo sapiens originated. It pushes back the timeline of when modern humans began venturing to other continents by about 60,000 years… …The jawbone, with eight teeth still embedded inside it, was excavated from Misliya Cave on the western slopes of Israel’s Mount Carmel.”[viii]
“…members of the Homo sapiens clade left Africa earlier than previously thought. This finding changes our view on modern human dispersal and is consistent with recent genetic studies, which have posited the possibility of an earlier dispersal of Homo sapiens around 220,000 years ago” they said in the paper in Science.[ix]
We keep moving further back.
The date and place of our beginnings in Africa have been revised. They had to be. Two years ago, the oldest Homo Sapiens fossils found thus far were discovered in Morocco, at Jebel Irhoud, just over 60 miles west of Marrakesh. These date back around 300,000 years, and their discovery challenged the previously held notion that Homo Sapiens had evolved in East Africa, near modern Ethiopia, 200,000 years ago.
“They knew the remains were old, but were stunned when dating tests revealed that a tooth and stone tools found with the bones were about 300,000 years old,” The Guardian reported. “The extreme age of the bones makes them the oldest known specimens of modern humans and poses a major challenge to the idea that the earliest members of our species evolved in a ‘Garden of Eden’ in East Africa one hundred thousand years later.”[x]
“This gives us a completely different picture of the evolution of our species. It goes much further back in time, but also the very process of evolution is different to what we thought,” Jean-Jacques Hublin, a senior scientist on the team at the Max Planck Institute for Evolutionary Anthropology in Leipzig told The Guardian at the time. “It looks like our species was already present probably all over Africa by 300,000 years ago.[xi]
We keep moving further back.
Advances in DNA and genetic testing and sequencing have also led to several breakthroughs, as researchers develop the ability to isolate ancient gene sequences in modern DNA, “as if they were genomes from the past embedded in amber,[xii]” as one put it.
Admitting, “Anatomically modern humans evolved in Africa, but pinpointing when has been difficult,” a report in Science in November of 2017 announced “Ancient DNA pushes human emergence back” as researchers sequenced three ancient African genomes from the Stone Age and discovered the earliest divergence between human populations may have occurred 350,000 to 260,000 years ago.[xiii]
That meant anatomically modern humans could have been appearing over 300,000 years ago. And so, from earlier estimates of around 180,000 years ago, we revised our origins further into history once more.
We keep moving further back.
Citing “growing evidence for multiple dispersals predating 60,000 years ago in regions such as southern and eastern Asia,” a December 2017 study in the journal Science suggested that “the traditional “out of Africa” model, which posits a dispersal of modern Homo sapiens across Eurasia as a single wave at ~60,000 years ago and the subsequent replacement of all indigenous populations, is in need of revision” as well. [xiv]
“Recent discoveries from archaeology, hominin paleontology, geochronology, genetics, and paleoenvironmental studies have contributed to a better understanding of the Late Pleistocene record in Asia. …Modern humans moving into Asia met Neandertals, Denisovans, mid-Pleistocene Homo, and possibly H. floresiensis, with some degree of interbreeding occurring. These early human dispersals, which left at least some genetic traces in modern populations, indicate that later replacements were not wholesale.”[xv]
That last bit is key. As these earlier and earlier signs of homo sapiens migration out of Africa are documented, some scientists who accept them refuse to grant the habitations found any permanency. They argue that if there were earlier incursions, they were short-lived, with no evidence humans remained in these places after the early incursions (though the authors of the December 2017 study could point to ancient genetic markers remaining in modern populations)[xvi].
That does seem to be the case with the most recent discovery, where the homo sapiens skull fragment predates the Neanderthal fragment. “We know from the genetic evidence that all humans that are alive today outside of Africa can trace their ancestry to the major dispersal out of Africa that happened between 70[,000] and 50,000 years before present,” Harvati insisted at the discovery’s announcement.
Acknowledging other early out-of-Africa discoveries, such as those in Israel, she continued. “We think that these early migrants did not actually contribute to modern humans living outside of Africa today, but rather died out and were probably locally replaced by Neanderthals,” Harvati said. “We hypothesize this is a similar situation with the Apidima 1 [the newly dated modern human skull] population.”[xvii]
There has been some genetic evidence of early interbreeding between humans and Neanderthals found in our modern DNA, and this early though seemingly temporary incursion could explain some of that new DNA evidence. And there was older DNA evidence that suggested the major migration of humans out of Africa occurred around 60,000 years ago. But those earlier conclusions are now being revised, as our genetic testing techniques advance.
With those advances, there is increasing evidence of an early human migration into Asia that stuck. “In the last few years, palaeontologists have discovered modern human fossils from Daoxian and Zhirendong in China dating to between 80,000 and 120,000 years ago. DNA studies have turned up signs of early interbreeding between African humans and Neanderthals. Evidence from German Neanderthals shows that mixing occurred between 219,000 and 460,000 years ago,” BBC News reported as part of the Apidima discovery.[xviii]
“We find a genetic signature in present-day Papuans that suggests that at least 2% of their genome originates from an early and largely extinct expansion of anatomically modern humans (AMHs) out of Africa,” Luca Pagani and their team reported in one of those DNA studies, in the journal Nature in September of 2016. “Our results contribute to the mounting evidence for the presence of AMHs out of Africa earlier than 75,000 years ago.[xix]
Given Harvati’s opposing stance, obviously the academic jury is still out.
But the evidence is mounting. In April of 2018 came the announcement of the discovery of what had been the earliest fossilized remains of an early modern human outside of Africa and the Levant, at the site of Al Wusta in the Nefud Desert in Saudi Arabia by the Max Planck Institute for the Science of Human History, a fossilized finger bone of an early member of our species, Homo sapiens, dating back 90,000 years. Unlike the researchers in the Apidima case, along with this announcement came the assertion of a more expansive and permanent migration.
“This discovery for the first time conclusively shows that early members of our species colonized an expansive region of southwest Asia and were not just restricted to the Levant,” Lead author Dr. Huw Groucutt, of the University of Oxford, said at the time. “The ability of these early people to widely colonize this region casts doubt on long held views that early dispersals out of Africa were localized and unsuccessful.”[xx]
So now, even in Saudi Arabia — we keep moving further back.
We’re moving further back in the Americas, too.
For the longest time, archaeologists believed modern humans came to the Americas from Asia relatively late, across a land bridge in the Bering Strait around 12,000 years ago (you might remember that one from school). But there is now evidence telling us that isn’t the case at all.
We may have been here over 15,000 years ago. In fact, there could be proof humans were here over 130,000 years ago!
But before we get to one of the most fascinating new discoveries on that front, there’s a point worth making. There’s an odd quality to Archaeology, it seems, among the sciences, where a prevailing assumption, if propounded with enough force by a forceful enough academic “personality”, becomes a prevailing “fact” — even to the detriment of doing actual science. It can be very difficult to change a prevailing idea.
One of these assumptions was what they called the “Clovis First” hypothesis.
“For nearly half a century, schoolchildren have been taught that the first human visitors to the New World belonged to the Clovis culture… (who) crossed the Bering Land Bridge from Asia about 12,000 years ago. To dispute Clovis-first by a few thousand years was controversial… But to propose a site more than 100,000 years older was professional suicide. It would undermine the research and reputations of most archaeologists now studying the New World,” noted the Los Angeles Times, in their December 2017 article, Archaeology As Blood Sport: How An Ancient Mastodon Ignited Debate Over Humans’ Arrival In North America.
And so, when The Cerutti Mastadon Site discoveries were announced in San Diego, California in 2017, offering a possible date around 130,000 years ago for the appearance of modern humans in the Americas — well over ten times earlier than had been the prevailing assumption — the peer-reviewed science, published in the most esteemed journal, Nature, was rejected and dismissed by many without proper consideration.
“‘If you claim something is that old, you get blasted,’ (Richard) Cerutti said, ‘which is why some archaeologists stopped working on sites like this. They didn’t want to get blasted’.”[xxi]
Blasted? The L.A. Times article explained: “George Jefferson, former associate curator of the Page Museum in Los Angeles and district paleontologist for the California State Parks, was blunt: The archaeological community was not ready for such an unsettling claim of antiquity. ‘Keep it under wraps,’ he said. ‘No one will believe you.’[xxii]
The San Diego Museum of Natural History’s curator of paleontology, Tom Deméré, was stunned by the backlash against their peer-reviewed findings after their publication in 2017. “I was taken by surprise that it would be that extreme,” he said in a video accompanying the article. “Certainly the extreme negative reactions. Almost emotional reactions, and saying ‘it’s impossible,’ ‘It can’t be! And it can’t be because I say it can’t be!’[xxiii]”
What they discovered — and documented with the assistance of a highly credentialed team — is pretty amazing: It’s what seem to be the remains left by human scavengers who picked apart a Mastadon carcass, and broke open its bones to get to the marrow. One of the mastodon’s tusks was stuck directly, vertically, into the ground, as if to mark the spot. Bones which defy breaking by natural elements were shattered, and piled around the site. Anomalous rocks and cobblestones were there, primitive hammers used in their scavenging.
“(They) assembled a team… of paleontologists, archaeologists, geoarchaeologists, mastodon specialists, Paleo-Indian specialists, sedimentologists, geomorphologists, geochronologists and lithic fabrication specialists,” the L.A. Times reported. “Each scientist took an element of the site and applied their proficiency. One concluded that there had been no raging torrents that might have crashed the stones and bones together in a seasonal fury. Another focused on the fragments scattered around the site. The few pieces of bone that they found fit into the smooth spiral fractures… another re-dated the site… …concluded that the bones were 130,700 years old… George Jefferson, who had advised Deméré to “keep it under wraps,” was invited for his experience… “Each new test,” he said, “supported the claim.”[xxiv]
“The earliest dispersal of humans into North America is a contentious subject, and proposed early sites are required to meet the following criteria for acceptance: (1) archaeological evidence is found in a clearly defined and undisturbed geologic context; (2) age is determined by reliable radiometric dating; (3) multiple lines of evidence from interdisciplinary studies provide consistent results; and (4) unquestionable artefacts are found in primary context,” [xxv] the group wrote in Nature in April of 2017.
After a year of peer review and testing, they revealed their findings: “Here we describe the Cerutti Mastodon (CM) site, an archaeological site from the early late Pleistocene epoch, where in situ hammerstones and stone anvils occur in spatio-temporal association with fragmentary remains of a single mastodon (Mammut americanum).”[xxvi]
The Mastodon bones, tusks and fragments found dated back to 130,700 (± 9,400) years. The way the fragments were spread around suggested that the breakage occurred at the site. The spiral-fracturing pattern of the bone and molar fragments indicated the breakage occurred while the corpse was fresh, and several fragments displayed evidence of having been pounded on by the rocks found nearby. Five of the rocks found on site (“large cobbles”) showed wear and impact marks indicating they were used as hammerstones and anvils. And given they were found in sand and silt, water didn’t wash them there.
“These findings confirm the presence of an unidentified species of Homo at the CM site during the last interglacial period (MIS 5e; early late Pleistocene), indicating that humans with manual dexterity and the experiential knowledge to use hammerstones and anvils processed mastodon limb bones for marrow extraction and/or raw material for tool production… The CM site is, to our knowledge, the oldest in situ, well-documented archaeological site in North America and, as such, substantially revises the timing of arrival of Homo into the Americas.”[xxvii]
They were savagely attacked by their fellow academics — the Times didn’t call Archaeology a “Blood Sport” for nothing.
Two of the more surprising sources of criticism, in a National Geographic article covering the Cerutti Mastodon announcement, were scientists who had suffered for their own Pre-Clovis discoveries.[xxviii] Now, they were, in effect, casting the same kind of aspersions at Deméré and his team.
Tom Dillehay fought for years for recognition that his discoveries at Monte Verde in Chile were authentic. And Jim Adovasio incurred the wrath of the “Clovis First”-ers when he kept digging at the Meadowcroft Rockshelter site in Pennsylvania and found signs of a demonstrably older human habitation.
“Adovasio… discovered evidence that humans had camped at Meadowcroft, under a protective rock overhang, sixteen thousand years ago — a few thousand years before the Siberian crossing. ‘Nobody believed it… ‘They said our dating had to be wrong’,” Adavasio said in a 2013 New Yorker story. “A couple of years later, however, archaeologists working at a site known as Monte Verde, in Chile, found evidence of a human presence at least fourteen thousand eight hundred years old.” [xxix]
Yet, even in 2013, Meadowcroft’s dating was still controversial: “You can find people who would sit here with you today and say, ‘None of these pre-Clovis sites are real. They’re all nonsense. There’s something wrong with every one of them,’ although that number keeps shrinking,” Adovasio said at the time. “It has become clear that there have been multiple incursions from Siberia by ethnically, linguistically, genetically, and technologically different populations. Some of these pulses may have begun before the last glacial maximum, before twenty-two thousand years ago. Not all of them would have succeeded.[xxx]
Now, all that said, Adavasio’s dismissal of the Cerutti Mastodon site seems surprising. Although, revising back a few thousand years is, perhaps, one thing — a hundred thousand certainly another. Then again, maybe Adovasio didn’t want Meadowcroft to have to give up the claim to possess “the earliest evidence of people in North America, dating back 16,000 years.”[xxxi] Or it could just be simple defensiveness — Meadowcroft’s dating continues to come under attack. A 2016 Pittsburgh Post-Gazette article on a reunion with old colleagues from the dig refers to “the still controversial idea that the Meadowcroft Rockshelter is pre-Clovis.”[xxxii]
As mentioned above, it was Dillehay in South America with his Monte Verde site in Chile that truly forced the Pre-Clovis issue after two decades of study — back in 1997. “A group of archeologists, including some of Monte Verde’s staunchest critics, inspected the artifacts and visited the site, coming away thoroughly convinced,” the New York Times reported at the time. “Finally vindicated, Dillehay said, ‘Most archeologists had always thought there was a pre-Clovis culture out there somewhere, and I knew that if they would only come to the site and look at the setting and see the artifacts, they would agree that Monte Verde was pre-Clovis’.”[xxxiii]
But. It is a tribute to the stubborn staying power of the Clovis hypothesis, and — perhaps moreso — to the ardent zeal and ignoble, vindictive academic power of its supporters, that over 20 years later most people still don’t know the Clovis claims have been disproven. Even some who agreed on the early dating of Monte Verde in ’97 have equivocated since.
Dillehay has continued to publish on Monte Verde. In 2015, he helped author a study on new evidence suggesting human habitation there between 18,500 and 14,500 years ago.[xxxiv] Intriguingly, towards the paper’s end they state that, “…the chronology and nature of the peopling of the New World are the focus of great deliberation between multiple schools of thought: some stress a short chronology and others a long chronology, some advocate one migration and others multiple migrations, some point to Asia as the only source of human entry and others point to Europe.” They go on to state, “For the moment, the majority of anatomical, archaeological and genetic evidence gives credence to the view that people were relatively recent arrivals to the Americas, probably sometime between 20,000 and 15,000 years ago. The current evidence presented here for the Monte Verde area best fits this scenario; however, this may change as more data are gathered and assessed. The early archaeological record of the Americas continues to be remarkably unpredictable and intriguingly complex”.[xxxv]
This was just over a year before Deméré et al published on the Cerutti Mastadon site, and yet this assessment seems more charitable than Dillehay was willing to be towards the Cerutti Mastodon Site findings.
Dillehay remains active. Earlier this year, he led publication on more evidence from Monte Verde for a date of habitation around 14,500 years ago.[xxxvi]
Like Adavasio, Dillehay was willing to go Pre-Clovis — but not by much. Yet the provenance of the Cerutti Mastodon site suggests the dating of human migration into North America may have to be reevaluated yet again, whether Dillehay, Adovasio and the others want to or not.
They forced a revision of the timeline for the migration into the Americas, which keeps creeping back still, based on new discoveries (recent findings in Texas place Pre-Clovis humans there 15,500 years ago).[xxxvii]
Adavasio, Dillehay, and their contemporaries overturned Clovis-First, allowing for slightly earlier settlements in the Americas. But taking a giant leap back more than 100,000 years seems to be too big of an ask for many of them right now.
All the same… We keep moving back.
The work continues — history is, indeed, always changing. Dillehay’s latest results were published in April, while at the same time another site near Monte Verde announced the discovery of — possibly — the oldest footprint found in the Americas, at 15,600 years old.[xxxviii] In May, in Tibet, we found the first fossil evidence of Denisovans outside of the cave where they were originally discovered, from about 160,000 years ago[xxxix].
And now? We have the Apidima skull announcement, placing an anatomically modern human in Greece 210,000 years ago — the discovery of humans in Europe tens of thousands of years earlier than we ever thought possible.
We do keep moving back.
We seem to discover something new about humankind’s early origins nearly every day.
And so? It seems we must always be relearning history.
Mike Luoma is a writer and researcher from Vermont — find out more at http://MikeLuoma.com.
End Notes
[i] “Apidima Cave fossils provide earliest evidence of Homo sapiens in Eurasia”, Nature, , July 10, 2019. https://www.nature.com/articles/s41586-019-1376-z.
[ii] Ibid.
[iii] “A Skull Bone Discovered in Greece May Alter the Story of Human Prehistory”, New York Times, July 10, 2019. https://www.nytimes.com/2019/07/10/science/skull-neanderthal-human-europe-greece.html.
[iv] Ibid.
[v] “New skull discovery shows mankind may have arrived in Europe 150,000 years earlier than previously thought”, The Telegraph, July 10, 2019. https://www.telegraph.co.uk/news/2019/07/10/new-skull-discovery-rewrites-history-humans-europe/.
[vi] Ibid.
[vii] Ibid.
[viii] “Scientists discover the oldest human fossils outside Africa”, The Washington Post, January 25, 2018. https://www.washingtonpost.com/news/speaking-of-science/wp/2018/01/25/scientists-discover-the-oldest-human-fossils-outside-africa/?utm_term=.4de9572b95e8.
[ix] “The earliest modern humans outside Africa”, Science, January 26, 2018. https://science.sciencemag.org/content/359/6374/456.
[x] “Oldest Homo sapiens bones ever found shake foundations of the human story”, The Guardian, June 7, 2017. https://www.theguardian.com/science/2017/jun/07/oldest-homo-sapiens-bones-ever-found-shake-foundations-of-the-human-story.
[xi] Ibid.
[xii] “Digging ancient signals out of modern human genomes”, ScienceDaily, April 5, 2019. https://www.sciencedaily.com/releases/2019/04/190405183901.htm.
[xiii] “Southern African ancient genomes estimate modern human divergence to 350,000 to 260,000 years ago”, Science, November 3, 2017. https://science.sciencemag.org/content/358/6363/652.
[xiv] “On the origin of modern humans: Asian perspectives”, Science, December 10, 2017. https://science.sciencemag.org/content/358/6368/eaai9067.
[xv] Ibid.
[xvi] Ibid.
[xvii] “Modern Humans Failed in Early Attempt to Migrate Out of Africa, Old Skull Shows”, by Laura Geggel, LiveScience.com, July 10, 2019. https://www.livescience.com/65906-oldest-modern-human-skull-eurasia.html.
[xviii] “Earliest modern human found outside Africa”, By Paul Rincon, Science editor, BBC News website, July 10, 2019. https://www.bbc.com/news/science-environment-48913307.
[xix] “Genomic analyses inform on migration events during the peopling of Eurasia”, Nature, September 21, 2016. https://www.nature.com/articles/nature19792.
[xx] Max Planck Institute for the Science of Human History. “First human migration out of Africa more geographically widespread than previously thought: The first Homo sapiens fossil discovery from Saudi Arabia dates to 90,000 years ago during a time when the region’s deserts were replaced by grasslands.” ScienceDaily, April 9, 2018. http://www.sciencedaily.com/releases/2018/04/180409112551.htm.
[xxi] “Archaeology as blood sport: How an ancient mastodon ignited debate over humans’ arrival in North America”, Los Angeles Times, December 22, 2017.
[xxii] Ibid.
[xxiii] Ibid (transcribed from video accompanying article).
[xxiv] Ibid.
[xxv] “A 130,000-year-old archaeological site in southern California, USA”, Nature, April 27, 2017. https://www.nature.com/articles/nature22065.
[xxvi] Ibid.
[xxvii] Ibid.
[xxviii] “Humans in California 130,000 Years Ago? Get the Facts”, National Geographic, April 26, 2017. https://news.nationalgeographic.com/2017/04/mastodons-americas-peopling-migrations-archaeology-science/.
[xxix] “Hunting Down the First Americans” by Michael Lemonick, The New Yorker, August 14, 2013. https://www.newyorker.com/tech/annals-of-technology/hunting-down-the-first-americans.
[xxx] Ibid.
[xxxi] History of Meadowcroft Rockshelter, by Dr. James Adovasio, October 9, 2012. Squirrel Hill Historical Society. https://squirrelhillhistory.org/history-of-meadowcroft-rockshelter-by-dr-james-adovasio/.
[xxxii] “Surprise reunion catches famed Meadowcroft archeologist off guard,” by David Templeton, Pittsburgh Post-Gazette, August 28, 2016.
[xxxiii] “Excavation in Chile Pushes Back Date of Human Habitation of Americas”, By John Noble Wilford, New York Times, February 11, 1997. https://archive.nytimes.com/www.nytimes.com/library/national/science/021197sci-archeology-chile.html.
[xxxiv] “New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile”, PSOS One, November 18, 2015. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0141923.
[xxxv] Ibid.
[xxxvi] “New excavations at the late Pleistocene site of Chinchihuapi I, Chile”, Cambridge University Press, April 5, 2019. https://www.cambridge.org/core/journals/quaternary-research/article/new-excavations-at-the-late-pleistocene-site-of-chinchihuapi-i-chile/FE7E68FA214DD393A164304F38BBD3BD.
[xxxvii] “The Oldest Weapon Discovered in North America is a 15,000-Year-Old Spearhead”, by David Grossman, Popular Mechanics, October, 2018. https://www.popularmechanics.com/science/archaeology/a24231310/oldest-weapon-north-america-spearhead/.
[xxxviii] “Is This The Oldest Human Footprint In the Americas?” by Gemma Tarlach, Discover, April 29, 2019. http://blogs.discovermagazine.com/deadthings/2019/04/29/oldest-human-footprint/#.XSs97utKi00
[xxxix] “First evidence of mysterious, ancient humans called Denisovans found outside of their cave”, by Ashley Strickland, CNN, May 1, 2019. https://www.cnn.com/2019/05/01/world/denisovan-fossil-discovery-scn/index.html.