3315. Neanderthal Genes Hint at Much Earlier Human Migration From Africa

By Carl Zimmer, The New York Times, January 31, 2020

A Neanderthal fossil on view at the Natural History Museum in London. A new genetic analysis revealed traces of Neanderthal DNA in all living humans, including Africans, who were thought to have none.Credit...The Natural History Museum/Alamy

In recent years, millions of people have been astonished, even thrilled, to learn from those popular genetic tests that their DNA is laced with Neanderthal genes.

Those genes were first discovered in 2010, in a study of Neanderthal fossils. From DNA recovered from the bones, researchers deduced that modern humans interbred with Neanderthals some 60,000 years ago, after leaving Africa.

As a result, the genes of non-Africans today are 1 percent to 2 percent Neanderthal. People of African ancestry, it was thought, have little to no Neanderthal DNA.

Using a new method to analyze DNA, however, a team of scientists has found evidence that significantly reshapes that narrative.

Their study, published on Thursday in the journal Cell, concludes that a wave of modern humans departed Africa far earlier than had been known: some 200,000 years ago.

These people interbred with Neanderthals, the new study suggests. As a result, Neanderthals were already carrying genes from modern humans when the next big migration from Africa occurred, about 140,000 years later.

The scientists also found evidence that people living somewhere in western Eurasia moved back to Africa and interbred with people whose ancestors never left. The new study suggests that all Africans have a substantially greater amount of Neanderthal DNA than earlier estimates.

“The legacy of gene flow with Neanderthals likely exists in all modern humans, highlighting our shared history,” the authors concluded.

“Overall, I find this a fantastic study,” said Omer Gokcumen, a geneticist at the University at Buffalo, who was not involved in the research. The research offers a view of human history “almost as a spider web of interactions, rather than a tree with distinct branches.”

But while evidence has been building that modern humans left Africa in waves, and that those migrations began much earlier than once thought, some scientists disputed the evidence that people of African descent may be carrying Neanderthal genes.

David Reich, a geneticist at Harvard Medical School, praised much of the study but said he had doubts about how extensive the flow of DNA back to Africa could have been. “It looks like this is a really weak signal,” he said of the data.

The ancestors of humans and Neanderthals lived about 600,000 years ago in Africa. The Neanderthal lineage left the continent; the fossils of what we describe as Neanderthals range from 200,000 years to 40,000 years in age, and are found in Europe, the Near East and Siberia.

Despite their reputation as brutes, Neanderthals showed signs of remarkable mental sophistication. They were adept hunters, and appear to have made ornaments as a form of self-expression.

Ten years ago, Dr. Reich and his colleagues gathered enough bits of DNA from fossils to create the first rough draft of the Neanderthal genome.

When the researchers compared it to the genomes of eight living people, they found that the Neanderthal was a little more similar to the people of Asian and European descent than to those of African heritage.

Roughly 60,000 years ago, the researchers argued, modern humans must have expanded from Africa and interbred with Neanderthals. The hybrid descendants passed their genes to later generations, who spread around the globe.

That hypothesis has held up well over the past decade, as paleoanthropologists have extracted more complete Neanderthal genomes from other fossils.

But Joshua Akey, a geneticist at Princeton University who carried out some of these studies, grew dissatisfied with the methods used to look for Neanderthal DNA in living people. The standard method was built on the assumption that most Africans had no Neanderthal DNA at all.

Dr. Akey and his colleagues figured out a new method, which they call IBDMix, that takes advantage of the fact that relatives share stretches of matching DNA.

Siblings, for example, share many long, identical stretches of DNA. But their children will have fewer identical segments, which will also be shorter. Distantly related cousins will have tinier matching segments that require sophisticated methods to uncover.

Dr. Akey and his colleagues figured out how to search the DNA of living humans and remains of Neanderthals for these minuscule matching segments. Then they pinpointed the segments that came from a relatively recent ancestor — and therefore were a sign of interbreeding.

The scientists searched 2,504 genomes of living humans for segments that matched those in a Neanderthal genome. When the scientists tallied up the results, the results took Dr. Akey by surprise.

The human genome is detailed in units called base pairs, about 3 billion such pairs in total. The scientists found that Europeans on average had 51 million base pairs that matched Neanderthal DNA, and East Asians had 55 million.

Dr. Akey’s previous research had indicated that East Asians carried far more Neanderthal ancestry than did Europeans.

Africans on average had 17 million base pairs that matched Neanderthal DNA — far higher than predicted by the original models describing how humans and Neanderthals interbred.

“That was just so completely opposite to my expectations,” said Dr. Akey. “It took a while to convince ourselves that what we are finding with this new approach was actually true.”

Looking at the size of these shared segments and how common they were around the world, Dr. Akey and his colleagues realized that some were the result of interbreeding very early in human history.

They concluded that a group of modern humans expanded out of Africa perhaps 200,000 years ago and interbred with Neanderthals. Those modern humans then disappeared. But Neanderthals who lived after that disappearance inherited some modern human DNA.

Other experts said the new study offered compelling support for earlier hints for this ancient expansion. Last year, for example, a team of scientists reported finding a modern human skull in Greece dating back over 210,000 years.

Other researchers discovered small fragments of DNA in Neanderthal fossils that showed a striking similarity to modern human genes.

Despite his hesitation over the analysis of African DNA, Dr. Reich said the new findings do make a strong case that modern humans departed Africa much earlier than thought.

“I was on the fence about that, but this paper makes me think it’s right,” he said.

It’s possible that humans and Neanderthals interbred at other times, and not just 200,000 years ago and again 60,000 years ago. But Dr. Akey said that these two migrations accounted for the vast majority of mixed DNA in the genomes of living humans and Neanderthal fossils.

In recent years, Dr. Reich and other researchers have found evidence that ancient people from the Near East moved back into Africa in the past few thousand years and spread their DNA to many African populations.

Dr. Akey and his colleagues confirmed this migration, although their study suggests that it may have taken place over a much longer period of time and introduced much more DNA into populations across the continent.

Janet Kelso of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who was not involved in the study, found this conclusion “quite convincing.”

The findings may allow researchers to begin pinpointing segments of Neanderthal DNA in living Africans.

Sarah Tishkoff, a geneticist at the University of Pennsylvania, is doing just that, using the new methods to look for Neanderthal DNA in more Africans to test Dr. Akey’s hypothesis.

Still, she wonders how Neanderthal DNA could have spread between populations scattered across the entire continent.

“I’m still trying to wrap my head around that,” she said.

3295. Mythical Beings May Be Earliest Imaginative Cave Art by Humans

By Becky Ferrira, The New York Times, December 11, 2019

A humanoid with a bird-like head was among the eight therianthrope figures depicted in a cave painting on the island of Sulawesi.Credit...Ratno Sardi

In December 2017, Hamrullah, an archaeologist on an Indonesian government survey, was exploring a cave system in Sulawesi, a large island in central Indonesia. He noticed a tantalizing opening in the ceiling above him. A skilled spelunker, Hamrullah (who only uses one name, like many Indonesians) climbed through the gap into an uncharted chamber. There, he laid eyes on a painting that is upending our understanding of prehistoric humans.

The dramatic panel of art, dating back at least 43,900 years, is “the oldest pictorial record of storytelling and the earliest figurative artwork in the world,” a group of scientists said in a paper published Wednesday in Nature, although additional research will be needed to confirm the age of every character in the painting.

In the story told in the scene, eight figures approach wild pigs and anoas (dwarf buffaloes native to Sulawesi). For whoever painted these figures, they represented much more than ordinary human hunters. One appears to have a large beak while another has an appendage resembling a tail. In the language of archaeology, these are therianthropes, or characters that embody a mix of human and animal characteristics.

Given that these extraordinary characters are wielding thin objects that might represent ropes or spears, the painting may be an artistic demonstration of a game drive, a hunting strategy that involves guiding animals toward an ambush.

The otherworldly nature of the therianthropes also raises the possibility that they are mythical beings, or manifestations of “animal spirit helpers” that are common in shamanic beliefs, according to the study.

“This scene may not be a depiction of an actual hunting scene but could be about animistic beliefs and the relationship between people and animals, or even a shamanic ritual,” said Sue O’Connor, an archaeologist at Australian National University who was not involved in the study.

These interpretations are speculative, however, and the original inspiration for the painting, as well as its significance to the humans who created it, is likely to remain a mystery.

The rock art predates the next oldest representation of a character with a mix of human and animal figures, found in a cave in Germany, by about 4,000 years. It is also more than 20,000 years older than a hunting scene on the walls of France’s Lascaux Cave.

Adam Brumm, an archaeologist at Griffith University in Australia and one of the study’s authors, said his team was “completely blown away” by the painting.

“We had never seen anything even remotely like this before in the hundreds of cave art sites we’d documented” on this Indonesian island, Dr. Brumm said.

“I immediately knew it was special and that it would be a very important site to understand the cognitive evolution of our species,” said Maxime Aubert, a co-author also at Griffith.

The scene is inside the Maros-Pangkep limestone cave system on the island’s southwestern end, which has been a hot spot for archaeologists since the 1950s. Local people in the region were likely aware of the paintings long before that time, however. A modern custom of marking wooden posts with a handprint may even have “some connection with local observations of prehistoric hand stencils in nearby caves,” Dr. Brumm said.

The scientists determined the painting’s age by performing uranium-series dating on “cave popcorn,” or mineral deposits that hang over three of the animal motifs in the scene. That gave it an age of at least 43,900 years old, and possibly older.

“This finding is very significant because it was previously thought that figurative painting dated to a time shortly after modern humans arrived in Europe, perhaps circa 40,000 years ago, but this result shows it has an origin outside Europe,” said Alistair Pike, an archaeologist at the University of Southampton in England, who was not involved in the study.

However, Dr. Pike considered it “very premature” to claim that the scene represents the earliest example of such storytelling, because only the animals in the scene have been definitively dated. It’s possible that the therianthropes, a vital part of the narrative, were added later.

Dr. Aubert said his team thinks the therianthropes were likely painted at the same time as the animal motifs because “they are of the same tone of red and are in a similar state of preservation.”

Very little is known about the people who originally decorated the walls of Maros-Pangkep in red pigment, in part because none of their skeletal remains have been found in the caves. They may have been related to a group of modern humans that migrated to Australia more than 50,000 years ago.

Despite these unresolved mysteries, it is now abundantly clear that these humans were storytellers whose abstract paintings shed light into the origins of human cognition and spirituality.

“Images of therianthropes often have complex meanings in modern religions and folklore,” said Dr. Brumm, who gave the examples of werewolves and the animal-headed deities of ancient Egypt.

“While we can’t know if this was the case in Sulawesi at least 44,000 years ago, we can point to these enigmatic images of therianthropes as the world’s earliest known evidence for our ability to conceive of the existence of supernatural beings,” he said, which is “a cornerstone of religious belief and experience.”

Shigeru Miyagawa, a linguist at the Massachusetts Institute of Technology who was not involved in the study, suggested that the painting could have implications for understanding humanity’s “unique capacity to communicate using intricate language.”

“It also hints at high order cognitive processes such as language and elaborate artwork emerging fairly recently in evolution,” Dr. Miyagawa said.

The painting has galvanized archaeologists to continue mapping the vast, unexplored reaches of the Maros-Pangkep caves, where the art is fading, “at an alarming rate” for unknown reasons, Dr. Aubert said.

These imaginative landscapes adorned Sulawesi’s caves for 44 millenniums, but they could vanish soon after they were rediscovered. At this point, they are the only link to this early culture that dreamed up fantastic beings and visualized the thrill of the chase — two activities that still preoccupy humans today.

“We also need to understand why it is deteriorating so rapidly and maybe we will find ways to save it,” Dr. Aubert said.

3120. Posture Maketh the Man

By Stephen Jay Gould, Monthly Review, December 1, 2018

Reconstructed skull of Lucy

No event did more to establish the fame and prestige of the Museum of Natural History than the Gobi Desert expeditions of the 1920s. The discoveries, including the first dinosaur egg, were exciting and abundant, and fit the sheer romance of Hollywood’s most heroic mold. It is still hard to find a better adventure story than Roy Chapman Andrew’s book (with its chauvinistic title:) The New Conquest of Central Asia. Nonetheless, the expeditions utterly failed to achieve their stated purpose: to find in Central Asia the ancestors of man. And they failed for the most elementary of reasons—we evolved in Africa, as Charles Darwin surmised fifty years earlier.

Our African ancestors (or at least our nearest cousins) were discovered in cave deposits during the 1920s. But these australopithecines failed to fit preconceived notions of what a “missing link” should look like, and many scientists refused to accept them as bonafide members of our lineage. Most anthropologists had imagined a fairly harmonious transformation from ape to human, propelled by increasing intelligence. A missing link should be intermediate in both body and brain—Alley Oop or the old (and false) representations of stoop-shouldered Neanderthals. But the australopithecines refused to conform. To be sure, their brains were bigger than those of any ape with comparable body size, but not much bigger. Most of our evolutionary increase in brain size occurred after we reached the australopithecine level. Yet these small-brained australopithecines walked as erect as you or I. How could this be? If our evolution was propelled by an enlarging brain, how could upright posture—another “hallmark of hominization,” not just an incidental feature—originate first? In a 1963 essay, George Gaylord Simpson used this dilemma to illustrate

the sometimes spectacular failure to predict discoveries even when there is a sound basis for such prediction. An evolutionary example is the failure to predict discovery of a “missing link,” now known [Australopithecus], that was upright and tool-making but had the physiognomy and cranial capacity of an ape.

We must ascribe this “spectacular failure” primarily to a subtle prejudice that led to the following invalid extrapolation: We dominate other animals by brainpower (and little else); therefore, an increasing brain must have propelled our own evolution at all stages. The tradition for subordinating the upright posture to an enlarging brain can be traced throughout the history of anthropology. Karl Ernst von Baer, the greatest embryologist of the nineteenth century (and second only to Darwin in my personal pantheon of scientific heroes) wrote in 1828: “Upright posture is only the consequence of the higher development of the brain…all differences between men and other animals depend upon construction of the brain.” One hundred years later, the English anthropologist G. E. Smith wrote: “It was not the adoption of the erect attitude or the invention of articulate language that made man from ape, but the gradual perfecting of the brain and the slow building of the mental structure, of which erectness of carriage and speech are some of the incidental manifestations.”

Against this chorus of emphasis on the brain, a very few scientists upheld the primacy of upright posture. Sigmund Freud based much of his highly idiosyncratic theory of the origin of civilization upon it. Beginning in his letters to Wilhelm Fliess in the 1890s and culminating in his 1930 essay on Civilization and Its Discontents, Freud argued that our assumption of upright posture has reoriented our primary sensation from smell to vision. This devaluation of the olfaction shifted the object of sexual stimulation in males from the cyclic odors of estrus to the continual visibility of female genitalia. Continual desire in males leads to continual receptivity in females. Most mammals copulate only around periods of ovulation; humans are sexually active at all times (a favorite theme of writers on sexuality). Continual sexuality has centered the human family and made civilization possible; animals with strongly cyclic copulation have no impetus for stable family structure. “The fateful process of civilization,” Freud concludes, “would have set in with man’s adoption of an erect posture.”

Although Freud’s ideas gained no following among anthropologists, another minor tradition did arise to stress the primacy of upright posture. (It is, by the way, the argument we tend to accept today in explaining the morphology of australopithecines and the path of human evolution.) The brain cannot begin to increase in a vacuum. A primary impetus must be provided by an altered mode of life that would place a strong, selective premium upon intelligence. Upright posture frees the hands from locomotion and for manipulation (literally, from manus = “hands”). For the first time, tools and weapons can be fashioned and used with ease. Increased intelligence is largely a response to the enormous potential in free hands for manufacture—again, literally. (Needless to say, no anthropologist has ever been so naive to argue that the brain and posture are completely independent in evolution, that one reached its full human status before the other began to change at all. We are dealing with interaction and mutual reinforcement. Nevertheless, our early evolution did involve a more rapid change in posture than in brain size; complete freeing of our hands for using tools preceded most of the evolutionary enlargement of our brain.)

In another proof that sobriety does not make right, von Baer’s mystical and oracular colleague Lorenz Oken hit upon the “correct” argument in 1809, while von Baer was led astray a few years later. “Man by the upright walk obtains his character,” writes Oken, “the hands become free and can achieve all other offices.… With the freedom of the body has been granted also the freedom of the mind.” But the champion of the upright posture during the nineteenth century was Darwin’s German bulldog Ernst Haeckel. Without a scrap of direct evidence, Haeckel reconstructed our ancestor and even gave it a scientific name. (Pithecanthropus, by the way, is probably the only scientific name given to an animal before it was discovered. When Eugène Dubois discovered Java-man in the 1890s, he adopted Haeckel’s generic name but he gave it the new specific designation Pithecanthropus erectus. We now usually include this creature in our own genus as Homo erectus.)

But why, despite Haeckel’s demurral, did the idea of cerebral primacy become so strongly entrenched? One thing is sure; it had nothing to do with direct evidence—for there was none for any position. With the exception of Neanderthal (a geographic variant of our own species, according to most anthropologists), no human fossils were discovered until the closing years of the nineteenth century, long after the dogma of cerebral primacy was established. But the debates based on no evidence are among the most revealing in the history of science, for in the absence of factual constraints, the cultural biases that affect all thought (and which scientists try so assiduously to deny) lie nakedly exposed.

Indeed, the nineteenth century produced a brilliant expose from a source that will no doubt surprise most readers—Frederick Engels. (A bit of reflection should diminish surprise. Engels had a keen interest in the natural sciences and sought to base his general philosophy of the dialectic of materialism upon a “positive” foundation. He did not live to complete his Dialectic of Nature, but he included long commentaries on science in such treatises as the Anti-Duhring.) In 1876, Engels wrote an essay entitled, “The Part Played by Labor in the Transition from Ape to Man.” It was published posthumously in 1896 and, unfortunately, had no visible impact upon Western science.

Engels considers three essential features of human evolution: speech, a large brain, and upright posture. He argues that the first step must have been descent from the trees, with subsequent evolution to upright posture by our ground-dwelling ancestors. “These apes when moving on level ground began to drop the habit of using their hands and to adopt a more and more erect gait. This was a decisive step in the transition from ape to man.” Upright posture freed the hand for using tools (labor, in Engels’s terminology); increased intelligence and speech came later.

Thus the hand is not only the organ of labor, it is also the product of labor. Only by labor, by adaptation to ever new operations…by the ever-renewed employment of these inherited improvements in new, more and more complicated operations, has the human hand attained the high degree of perfection that has enabled it to conjure into being the pictures of Raphael, the statues of Thorwaldsen, the music of Paganini.

Engels presents his conclusions as though they followed deductively from the premise of his materialist philosophy, but I am confident that he cribbed them from Haeckel. The two formulations are almost identical, and Engels cites the relevant pages of Haeckel’s work for other purposes in an earlier essay written in 1874. But no matter. The importance of Engels’s essay lies not in its substantive conclusions, but in its trenchant political analysis of why Western science was so hung up on the a priori assertion of cerebral primacy.

As humans learned to master their material surroundings, Engels argues, other skills were added to primitive hunting—agriculture, spinning, pottery, navigation, arts and sciences, law and politics, and finally, “the fantastic reflection of human things in the human mind: religion.” As wealth accumulated, small groups of men seized power and forced others to work for them. Labor, the source of all wealth and the primary impetus for human evolution, assumed the same low status of those who labored for the rulers.* Since rulers governed by their will (that is, by feats of mind), actions of the brain appeared to have a motive power of their own. The profession of philosophy followed no unsullied ideal of truth. Philosophers relied on state religious patronage. Even if Plato did not consciously conspire to bolster the privileges of rulers with a supposed abstract philosophy, his own class encouraged an emphasis on thought as primary, dominating, and all together more important than the labor it supervised This idealistic tradition dominated philosophy right down through Darwin’s day. Its influence was so subtle and pervasive that even scientific but apolitical materialists like Darwin fell under its sway. A bias must be recognized before it is challenged. Cerebral primacy seemed so obvious and natural that it was accepted as given, rather than recognized as a deep-seated social prejudice related to the class position of the professional thinkers and their patrons. Engels writes:

All merit for the swift advance of civilization was ascribed to the mind, the development and activity of the brain. Men became accustomed to explain their actions from their thoughts, instead of from their need.… And so there arose in the course of time that idealistic outlook on the world which, especially since the downfall of the ancient world, has dominated men’s minds. It still rules them to such a degree that even the most materialistic natural scientists of the Darwinian school are still unable to form any clear idea of the origin of man, because under that ideological influence they do not recognize the part that is played therein by labor.

The importance of Engels’s essay does not lie in the happy result that Australopithecusconfirmed a specific theory posed by him—via Haeckel—but rather in his perceptive analysis of the political role of science and of the social biases that must affect all thought.

Indeed, Engels’s theme of separation of the head and hand has done much to set and limit the course of science throughout history. Academic science, in particular, has been constrained by an idea of “pure” research, which in former days barred a scientist from extensive experimentation and empirical testing. Ancient Greek science labored under the restriction that patrician thinkers could not perform the manual work of plebeian artists. Medieval barber-surgeons who had to deal with battlefield casualties did more to advance the practice of medicine than academic physicians who rarely examined patients and who based their treatment on a knowledge of Galen and other learned texts. Even today, “pure” researchers tend to disparage the practical, and terms such as “aggie school” and “cow college” are heard with distressing frequency in academic circles. If we took Engels’s message to heart and recognized our belief in the inherent superiority of pure research for what it is—namely a social prejudice—then we might forge among scientists the union between theory and practice that a world teetering dangerously near the brink so desperately needs.

Note

* Editors’ note: Marx and Engels did not propose that labor was the source of all wealth, as Gould suggests here. Instead, as Marx wrote in Critique of the Gotha Program: “Labour is not the source of all wealth. Nature is just as much the source of use values (and it is surely of such that material wealth consists!) as labour, which itself is only the manifestation of a force of nature, human labor power.”

3037. Moroccan Fossil Find Rearranges Homo sapiens Family Tree

By Marriëtte Le Roux, phys.org, June 8, 2017

French paleoanthropologist Jean-Jacques Hublin, who led research on an exciting fossil discovery in Morocco, says the resulting findings see a move "further and further away" from "a linear vision of human evolution with a succession of species."

This week's unveiling of the oldest-known Homo sapiens remains has painted an excitingly chaotic picture of what Earth was like 300,000 years ago—bustling with hominin species that included a very early version of our own, experts say.

The story of human evolution, this shows, does not follow a straight line from monkey to ape-man to architect.

Rather than emerging from a single "Garden of Eden" 200,000 years ago before spreading throughout Africa and the world, early modern humans were already scattered across the Mother Continent a hundred millennia earlier.

Even then, homo sapiens were living in distinct groupings that met occasionally, trading technology and genes.

They also rubbed shoulders with rival Homo species, which may have included their own direct ancestor, according to the analysis of the sensational findings.

Africa, at the time, would have resembled "a kind of human zoo", said Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology, who led the research on five human fossils from Jebel Irhoud in Morocco.

"We are moving further and further away from this linear vision of human evolution with a succession of species, one replacing the other," he said.

"There were probably several groups of hominins existing, overlapping in time... and having, I would say, complex relationships."

Two studies published in the journal Nature on Wednesday, extended our species' recorded existence by a third, from 200,000 to 300,000 years ago, and torpedoed the long-held theory that we emerged from an East African "cradle of humankind."

Graphic showing timeline relating to the discovery of the oldest Homo sapiens

"The origin of our species likely involved numerous populations spread across Africa with periodic gene flow between them," said Matthew Skinner of the University of Kent's School of Anthropology, who did not take part in the study.

For Lawrence Barham of the University of Liverpool, the dating of the Moroccan site helps us to see our species more clearly in time and in space.

The previous oldest Homo sapiens remains ever found, in Ethiopia, were 195,000 years old.

"An earlier date of 300,000 years is significant from the perspective of human evolution in Africa itself, where Homo sapiens may have co-existed with at least two other species—Homo heidelbergensis and Homo naledi," Barham commented.

Who taught whom?

Many scientists hypothesise that the large-brained H. heidelbergensis was the common ancestor from which H. sapiens and our cousins the Neanderthals split around half-a-million years ago.

Contemporary H. naledi had a smaller brain and retained some ape-like features—it likely climbed trees as well as made tools.

Now the question arises: did these different African species compete?

"Or did each have its own niche enabling them to coexist?" asked Barham.

French paleoanthropologist Jean-Jacques Hublin and Abdelouahed Ben-Ncer of Morocco's National Institute of Archaeology and Heritage Sciences in Morocco mull research which has advanced human origins by a hundred millennia, undermining …more

Another unknown is when our species started encountering members of Homo groups from further afield—Neanderthals from Europe and Denisovans in Asia, for example.

The new findings, Barham told AFP, "raises the possibility that there may have been even earlier movements of Homo sapiens out of Africa."

The consensus today is that our species left Africa about 80,000-100,000 years ago.

At the time that Hublin's ancient Moroccans were hunting and cooking gazelle and zebra meat not far from modern-day Marrakesh, Africa was a very different place—easier to navigate on foot.

For long periods between 330,000 and 300,000 years ago, the desert was replaced by a greener, more hospitable landscape.

According to the research team, the discovery means that Homo sapiens—not members of a rival or ancestor species—were the ones who left behind Middle Stone Age hand tools that have since been unearthed all over Africa.

As our species was previously thought to be much younger, it was not considered plausible that they could have made these implements.

For Barham, the new dates will revive a theory that Neanderthals learnt tool-making from Homo sapiens, not the other way round.

3004. Early humans Living At Least 500,000 Years Ago Had Anatomically Modern Human-Like Hands

By David Keys, Independent, August 23, 2018

A beautifully crafted flint hand axe made by prehistoric toolmakers at Boxgrove, West Sussex, half a million years ago.

Evidence from a quarry in southern England is shedding extraordinary new light on the evolution of human intelligence.

Arguably, the most important driving force that enabled early humans to evolve into ever more intelligent creatures was the human hand, which gave us the physical ability to make things.

Without that crucial ability, there would never have been the need to imagine and visualise complex objects purely in the mind, or the ability to then invent, manufacture and use them.

Stone Age Britons may have had prehistoric secret code

Now archaeologists have demonstrated for the first time that a particular type of stone tool used some half a million years ago could not have been made without modern human-like hands.

The study – based on beautifully made prehistoric tools found at Boxgrove in West Sussex – reveals for the first time that early Stone Age humans had modern-style human hands, despite the fact that they belonged to a human species ancestral to our own but which became extinct more than 300,000 years ago.

Research in the UK and the US supports the concept that early human intellectual ability was largely developed in tandem with, and to a considerable extent courtesy of, hand evolution – and that eventually we (Homo sapiens) inherited our super-dextrous hands from prehistoric humans, which existed before the Neanderthals.

The specific stone tools which were analysed as part of the study were sophisticated flint hand axes, which had required a special technique to shape them.

The technique is known to prehistorians as ‘platform preparation’. In most very early stone tools, the manufacturing process is a simple single-stage affair in which the toolmaker merely hits a lump of flint with a stone repeatedly to systematically knock bits off it until the lump has been reduced to a desired shape.

However, more sophisticated toolmakers employed a two-stage approach. First they would successively "soften up" small portions of the flint’s surface, so as to then be able to more accurately remove flakes from it, thus creating a much more sophisticated and effective tool with a better and more refined cutting edge.

By attaching electronic sensors to the hands of skilled modern flint knappers, archaeologists from the University of Kent were able to demonstrate that "platform preparation" – and thus more sophisticated stone tools – was only achievable by prehistoric people equipped with anatomically modern human-like hands.

The study, led by Dr Alastair Key of the university’s School of Anthropology and Conservation, and funded by the British Academy, investigated how hands were used during the production of different types of early stone tools.

The research demonstrates that the Boxgrove early humans probably had significantly stronger grips compared to earlier populations.

It reveals that by 500,000 BC, humans had the physical capability needed to make sophisticated hand axes.

This in turn implies that they were also theoretically able to make a large range of other artefacts that required strong, dextrous hands – things made out of wood, antler and bone, as well as stone.

“Our experimental research not only suggests that early humans at least 500,000 years ago had anatomically modern human-like hands, but, when combined with other recent research, can also help us understand the way in which the human hand, brain and other anatomical elements co-evolved,” said Dr Key.

Although the fact that sophisticated tool manufacture could only be done with modern-human-like hands was demonstrated by the Boxgrove research, another set of similarly sophisticated tools have recently been found in South Africa (also dating from around 500,000 years ago) – and there are indications that "platform preparation" (the crucial diagnostic sophisticated technique) was being used for stone tool manufacture in Ethiopia as early as 850,000 years ago.

So the Boxgrove, the South African and the Ethiopian evidence now helps demonstrate quite clearly that humanity developed its manual dexterity, its intelligence and its manufacturing ability as part of a long interactive process across at least two and probably three continents.

Early (and indeed modern) humans were (and still are) not physically the strongest or even the fastest animals around. So, in order to survive, they had to evolve ways of administering physical force through their hands in ever more efficient ways. They needed to do that in order to hunt and gather more efficiently, in order to butcher prey more efficiently and in order to defend themselves against other animals (including other humans).

Over thousands of generations, the need to apply physical force more efficiently drove changes, through natural selection, in the shape and design of their hands.

Ultimately the process resulted in hands that could make sophisticated tools, weapons and other artefacts – and, in time, that physical ability to make things in turn allowed and drove additional evolutionary changes in their brains to enable them to even more effectively envisage and invent the ever more sophisticated items they needed to help them survive and flourish. The rest was history, as they say.

Just how intellectually able they had become by 500,000BC has been revealed by a recent experiment at Emory University in Atlanta, Georgia. Using the Boxgrove hand-axes as exemplars, 20 students and others were tasked with learning the tool-making skills to replicate them. It took, on average, 200-250 hours for each modern novice toolmaker to learn how to do it.

2925. Tiny Brains of Extinct Human Relative Had Complex Features

By Nicholas St. Fleur, The New York Times, May 14, 2018

Researchers say that the skull of Homo naledi, a hominin that lived 236,000 to 335,000 years ago, contained a brain the size of an orange that had a similar shape and structure with that of modern humans.  Photo: John Hawks.

Credit

What makes humans so smart? For a long time the answer was simple: our big brains.

But new research into the tiny noggins of a recently discovered human relative called Homo naledi may challenge that notion. The findings, published Monday, suggest that when it comes to developing complex brains, size isn’t all that matters.

In 2013 scientists excavating a cave in South Africa found remains of Homo naledi, an extinct hominin now thought to have lived  236,000 to 335,000 years ago. Based on the cranial remains, the researchers concluded it had a small brain only about the size of an orange or your fist. Recently, they took another look at the skull fragments and found imprints left behind by the brain. The impressions suggest that despite its tiny size, Homo naledi’s brain shared a similar shape and structure with that of modern human brains, which are three times as large.

“We’ve now seen that you can package the complexity of a large brain in a tiny packet,” said Lee Berger, a paleoanthropologist at Wits University in South Africa and an author of the paper published in the journal Proceedings of the National Academy of Sciences. “Almost in one fell swoop we slayed the sacred cow that complexity in the hominid brain was directly associated with increasing brain size.”

Not every scientist agrees with their interpretation.

Since its remains were first retrieved, Homo naledi has puzzled scientists. From head to toe the ancient hominin displays a medley of primitive, apelike features and more advanced, humanlike characteristics.

“It’s this mosaic that is unlike anything we have seen or expected,” said Dr. Berger who first discovered Homo naledi in the Dinaledi Chamber in South Africa’s Rising Star cave system. So far, researchers have found more than 2,000 fossils belonging to the human relatives which have provided a portrait of what the species once looked like.

Homo naledi had small teeth like a human’s, but their shape more closely resembles that of an ape’s. Its shoulders are also apelike, but the arms, wrists and hands more humanlike. The fingers, though, were long and curved, and the thumbs appeared particularly strong. The spine was a combination of primitive and Neanderthal-like, the pelvis resembled that of another more distant human relative, Australopithecus afarensis (dubbed Lucy), and the thighs also looked primitive. But below the knee, the legs were long and thin like a human’s and the feet were nearly identical to our own.

Now, researchers have found that Homo naledi’s similarities with modern humans extend into the brain. After examining the imprints, or endocasts, from five Homo naledi skull fragments, the team found that the species had a frontal lobe that was very similar to that of modern humans and unlike that of an ape’s. The scientists also found that Homo naledi had an asymmetrical brain, with the left brain appearing more forward than the right, which is also seen in humans. Asymmetry in the brain is associated with higher levels of behavioral complexity, the team said.

Based on the regions of the brain that Homo naledi shared with modern humans, the authors suggested that it may have exhibited complex behavior. But what they did not say was what those behaviors may have been, said John Hawks, an paleoanthropologist at the University of Wisconsin, Madison, and an author on the paper.

“Is that aspect of the brain evolution central to talking or stone tool making? We don’t know enough to say that,” he said. He added that the finding does not mean that brain size is not important to creating a complex brain — it is. Rather, size alone does not tell the whole story. “There’s something about shape that actually matters too,” he said.

“These new fossil hominids show that the evolution of hominins is much more complex than we thought before,” said Ralph Holloway, a paleoanthropologist at Columbia University and lead author of the paper.  

Emiliano Bruner, a paleoneurobiologist at Centro Nacional de Investigación sobre la Evolución Humana in Spain, said the finding still needs to be confirmed from a wider fossil record of the species that comes from outside the Dinaledi Chamber fossil site. That would help with understanding any variation that appears within the species.

Simon Neubauer, a physical anthropologist at the Max Planck Institute for Evolutionary Anthropology in Germany, said the finding did support the idea that both brain size and brain organization are important to human evolution. But he added that because of its age, the tiny-brained Homo naledi might be an outlier in a general hominin trend toward increasing brain sizes.

Dr. Bruner agreed.

“It is not reasonable to forget all that evidence because of a couple of outliers,” he said. “Exceptions are, as always, expected. But this does not break the rule.”