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ARIZONA STATE UNIVERSITY—Scientists have long been able to measure and analyze the fossil skulls of our ancient ancestors to estimate brain volume and growth. The question of how these ancient brains compare to modern human brains and the brains of our closest primate cousin, the chimpanzee, continues to be a major target of investigation.

A new study published in Science Advances used CT-scanning technology to view three-million-year old brain imprints inside fossil skulls of the species Australopithecus afarensis (famous for “Lucy” and “Selam” from Ethiopia’s Afar region) to shed new light on the evolution of brain organization and growth. The research reveals that while Lucy’s species had an ape-like brain structure, the brain took longer to reach adult size, suggesting that infants may have had a longer dependence on caregivers, a human-like trait.

The CT-scanning enabled the researchers to get at two long-standing questions that could not be answered by visual observation and measurement alone: Is there evidence for human-like brain reorganization in Australopithecus afarensis, and was the pattern of brain growth in this species more similar to that of chimpanzees or that of humans?

To study brain growth and organization in A. afarensis, the researchers, including ASU paleoanthropologist William Kimbel, scanned eight fossil crania from the Ethiopian sites of Dikika and Hadar using high-resolution conventional and synchrotron-computed tomography. Kimbel, leader of the field work at Hadar, is director of the Institute of Human Origins and Virginia M. Ullman Professor of Natural History and the Environment in the School of Human Evolution and Social Change.

Lucy’s species inhabited eastern Africa more than three million years ago–“Lucy” herself is estimated to be 3.2 million years old–and occupies a key position in the hominin family tree, as it is widely accepted to be ancestral to all later hominins, including the lineage leading to modern humans.

“Lucy and her kin provide important evidence about early hominin behavior–they walked upright, had brains that were around 20 percent larger than those of chimpanzees, and may have used sharp stone tools,” explains coauthor Zeresenay Alemseged (University of Chicago), who directs the Dikika field project in Ethiopia and is an International Research Affiliate with the Institute of Human Origins.

Brains do not fossilize, but as the brain grows and expands before and after birth, the tissues surrounding its outer layer leave an imprint on the inside of the bony braincase. The brains of modern humans are not only much larger than those of our closest living ape relatives but are also organized differently and take longer to grow and mature. Compared with chimpanzees, modern human infants learn longer and are entirely dependent on parental care for longer periods of time. Together, these characteristics are important for human cognition and social behavior, but their evolutionary origins remain unclear.

The CT scans resulted in high-resolution digital “endocasts” of the interior of the skulls, where the anatomical structure of the brains could be visualized and analyzed. Based on these endocasts, the researchers could measure brain volume and infer key aspects of cerebral organization from impressions of the brain’s structure.

A key difference between apes and humans involves the organization of the brain’s parietal lobe–important in the integration and processing of sensory information–and occipital lobe in the visual center at the rear of the brain. The exceptionally preserved endocast of “Selam,” a skull and associated skeleton of an Australopithecus afarensis infant found at Dikika in 2000, has an unambiguous impression of the lunate sulcus–a fissure in the occipital lobe marking the boundary of the visual area that is more prominent and located more forward in apes than in humans–in an ape-like position. The scan of the endocranial imprint of an adult A. afarensis fossil from Hadar (A.L. 162-28) reveals a previously undetected impression of the lunate sulcus, which is also in an ape-like position.

Some scientists had conjectured that human-like brain reorganization in australopiths was linked to behaviors that were more complex than those of their great ape relatives (e.g., stone-tool manufacture, mentalizing, and vocal communication). Unfortunately, the lunate sulcus typically does not reproduce well on endocasts, so there was unresolved controversy about its position in Australopithecus.

“A highlight of our work is how cutting-edge technology can clear up long-standing debates about these three million-year-old fossils,” notes coauthor Kimbel. “Our ability to ‘peer’ into the hidden details of bone and tooth structure with CT scans has truly revolutionized the science of our origins.”

A comparison of infant and adult endocranial volumes also indicates more human-like protracted brain growth in Australopithecus afarensis, likely critical for the evolution of a long period of childhood learning in hominins.

In infants, CT scans of the dentition make it possible to determine an individual’s age at death by counting dental growth lines. Similar to the growth rings of a tree, virtual sections of a tooth reveal incremental growth lines reflecting the body’s internal rhythm. Studying the fossilized teeth of the Dikika infant, the team’s dental experts calculated an age at death of 2.4 years.

The pace of dental development of the Dikika infant was broadly comparable to that of chimpanzees and therefore faster than in modern humans. But given that the brains of Australopithecus afarensis adults were roughly 20 percent larger than those of chimpanzees, the Dikika child’s small endocranial volume suggests a prolonged period of brain development relative to chimpanzees.

“The combination of apelike brain structure and humanlike protracted brain growth in Lucy’s species was unexpected,” says Kimbel. “That finding supports the idea that human brain evolution was very much a piecemeal affair, with extended brain growth appearing before the origin of our own genus, Homo.”

Among primates, different rates of growth and maturation are associated with different infant-care strategies, suggesting that the extended period of brain growth in Australopithecus afarensis may have been linked to a long dependence on caregivers. Alternatively, slow brain growth could also primarily represent a way to spread the energetic requirements of dependent offspring over many years in environments where food is not always abundant. In either case, protracted brain growth in Australopithecus afarensis provided the basis for subsequent evolution of the brain and social behavior in hominins and was likely critical for the evolution of a long period of childhood learning.

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Brain imprints in fossil skulls of the species Australopithecus afarensis (famous for “Lucy” and the “Dikika child” from Ethiopia pictured here) shed new light on the evolution of brain growth and organization. The exceptionally preserved endocranial imprint of the Dikika child reveals an ape-like brain organization, and no features derived towards humans. Philipp Gunz, MPI EVA Leipzig.

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Article Source: ARIZONA STATE UNIVERSITY news release

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UNIVERSITY OF COPENHAGEN THE FACULTY OF HEALTH AND MEDICAL SCIENCES—Genetic information from an 800,000-year-old human fossil has been retrieved for the first time. The results from the University of Copenhagen shed light on one of the branching points in the human family tree, reaching much further back in time than previously possible.

An important advancement in human evolution studies has been achieved after scientists retrieved the oldest human genetic data set from an 800,000-year-old tooth belonging to the hominin species Homo antecessor.

The findings by scientists from the University of Copenhagen (Denmark), in collaboration with colleagues from the CENIEH (National Research Center on Human Evolution) in Burgos, Spain, and other institutions, are published April 1st in Nature.

“Ancient protein analysis provides evidence for a close relationship between Homo antecessor, us (Homo sapiens), Neanderthals, and Denisovans. Our results support the idea that Homo antecessor was a sister group to the group containing Homo sapiens, Neanderthals, and Denisovans”, says Frido Welker, Postdoctoral Research Fellow at the Globe Institute, University of Copenhagen, and first author on the paper.

Reconstructing the human family tree

By using a technique called mass spectrometry, researchers sequenced ancient proteins from dental enamel, and confidently determined the position of Homo antecessor in the human family tree.

The new molecular method, palaeoproteomics, developed by researchers at the Faculty of Health and Medical Sciences, University of Copenhagen, enables scientists to retrieve molecular evidence to accurately reconstruct human evolution from further back in time than ever before.

The human and the chimpanzee lineages split from each other about 9-7 million years ago. Scientists have relentlessly aimed to better understand the evolutionary relations between our species and the others, all now extinct, in the human lineage.

“Much of what we know so far is based either on the results of ancient DNA analysis, or on observations of the shape and the physical structure of fossils. Because of the chemical degradation of DNA over time, the oldest human DNA retrieved so far is dated at no more than approximately 400.000 years”, says Enrico Cappellini, Associate Professor at the Globe Institute, University of Copenhagen, and leading author on the paper.

“Now, the analysis of ancient proteins with mass spectrometry, an approach commonly known as palaeoproteomics, allow us to overcome these limits”, he adds.

Theories on human evolution

The fossils analyzed by the researchers were found by palaeoanthropologist José María Bermúdez de Castro and his team in 1994 in stratigraphic level TD6 from the Gran Dolina cave site, one of the archaeological and paleontological sites of the Sierra de Atapuerca, Spain.

Initial observations led to conclude that Homo antecessor was the last common ancestor to modern humans and Neanderthals, a conclusion based on the physical shape and appearance of the fossils. In the following years, the exact relation between Homo antecessor and other human groups, like ourselves and Neanderthals, has been discussed intensely among anthropologists.

Although the hypothesis that Homo antecessor could be the common ancestor of Neanderthals and modern humans is very difficult to fit into the evolutionary scenario of the genus Homo, new findings in TD6 and subsequent studies revealed several characters shared among the human species found in Atapuerca and the Neanderthals. In addition, new studies confirmed that the facial features of Homo antecessor are very similar to those of Homo sapiens and very different from those of the Neanderthals and their more recent ancestors.

“I am happy that the protein study provides evidence that the Homo antecessor species may be closely related to the last common ancestor of Homo sapiens, Neanderthals, and Denisovans. The features shared by Homo antecessor with these hominins clearly appeared much earlier than previously thought. Homo antecessor would therefore be a basal species of the emerging humanity formed by Neanderthals, Denisovans, and modern humans”, adds José María Bermúdez de Castro, Scientific Co-director of the excavations in Atapuerca and co-corresponding author on the paper.

World class-expertise

Findings like these are made possible through an extensive collaboration between different research fields: from paleoanthropology to biochemistry, proteomics and population genomics.

Retrieval of ancient genetic material from the rarest fossil specimens requires top quality expertise and equipment. This is the reason behind the now ten-years-long strategic collaboration between Enrico Cappellini and Jesper Velgaard Olsen, Professor at the Novo Nordisk Foundation Center for Protein Research, University of Copenhagen and co-author on the paper.

“This study is an exciting milestone in palaeoproteomics. Using state of the art mass spectrometry, we determine the sequence of amino acids within protein remains from Homo antecessor dental enamel. We can then compare the ancient protein sequences we ‘read’ to those of other hominins, for example Neanderthals and Homo sapiens, to determine how they are genetically related”, says Jesper Velgaard Olsen.

“I really look forward to seeing what palaeoproteomics will reveal in the future”, concludes Enrico Cappellini.

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Homo antecessor, incomplete skull from “Gran Dolina” (ATD6-15 & ATD6-69), in Atapuerca, Spain. Locutus Borg, Wikimedia Commons

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Article Source: UNIVERSITY OF COPENHAGEN THE FACULTY OF HEALTH AND MEDICAL SCIENCES news release

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MASSACHUSETTS INSTITUTE OF TECHNOLOGY—When Spanish invaders arrived in the Americas, they were generally able to subjugate the local peoples thanks, in part, to their superior weaponry and technology. But archeological evidence indicates that, in at least one crucial respect, the Spaniards were quite dependent on an older indigenous technology in parts of Mesoamerica (today’s Mexico, Guatemala, Belize, and Honduras).

The invaders needed copper for their artillery, as well as for coins, kettles, and pans, but they lacked the knowledge and skills to produce the metal. Even Spain at that time had not produced the metal domestically for centuries, relying on imports from central Europe. In Mesoamerica they had to depend on local smelters, furnace builders, and miners to produce the essential material. Those skilled workers, in turn, were able to bargain for exemption from the taxes levied on the other indigenous people.

This dependence continued for at least a century, and perhaps as long as two centuries or more, according to new findings published in the journal Latin American Antiquity, in a paper by Dorothy Hosler, professor of archeology and ancient technology at MIT, and Johan Garcia Zaidua, a researcher at the University of Porto, in Portugal.

The research, at the site of El Manchón, in Mexico, made use of information gleaned from more than four centuries worth of archeological features and artifacts excavated by Hosler and her crew over multiple years of fieldwork, as well as from lab work and historical archives in Portugal, Spain, and Mexico analyzed by Garcia.

El Manchón, a large and remote settlement, initially displayed no evidence of Spanish presence. The site consisted of three steep sectors, two of which displayed long house foundations, some with interior rooms and religious sanctuaries, patios, and a configuration that was conceptually Mesoamerican but unrelated to any known ethnic groups such as the Aztec. In between the two was an area that contained mounds of slag (the nonmetallic material that separates out during smelting from the pure metal, which floats to the surface).

The Spanish invaders urgently needed enormous quantities of copper and tin to make the bronze for their cannons and other armaments, Hosler says, and this is documented in the historical and archival records. But “they didn’t know how to smelt,” she says, whereas archaeological data suggest the indigenous people had already been smelting copper at this settlement for several hundred years, mostly to make ritual or ceremonial materials such as bells and amulets. These artisans were highly skilled, and in Guerrero and elsewhere had been producing complex alloys including copper-silver, copper-arsenic, and copper-tin for hundreds of years, working on a small scale using blowpipes and crucibles to smelt the copper and other ores.

But the Spanish desperately required large quantities of copper and tin, and in consultation with indigenous smelters introduced some European technology into the process. Hosler and her colleagues excavated an enigmatic feature that consisted of two parallel courses of stones leading toward a large cake of slag in the smelting area. They identified this as the remains of a thus-far-undocumented hybrid type of closed furnace design, powered by a modified hand-held European bellows. A small regional museum in highland Guerrero illustrates just such a hybrid furnace design, including the modified European-introduced bellows system, capable of producing large volumes of copper. But no actual remains of such furnaces had previously been found.

The period when this site was occupied spanned from about 1240 to 1680, Hosler says, and may have extended to both earlier and later times.

The Guerrero site, which Hosler excavated over four field seasons before work had to be suspended because of local drug cartel activity, contains large heaps of copper slag, built up over centuries of intensive use. But it took a combination of the physical evidence, analysis of the ore and slags, the archaeological feature in the the smelting area, the archival work, and reconstruction drawing to enable identification of the centuries of interdependence of the two populations in this remote outpost.

Earlier studies of the composition of the slag at the site, by Hosler and some of her students, revealed that it had formed at a temperature of 1150 degrees Celsius, which could not have been achieved with just the blowpipe system and would have required bellows. That helps to confirm the continued operation of the site long into the colonial period, Hosler says.

Years of work went into trying to find ways to date the different deposits of slag at the site. The team also tried archaeomagnetic data but found that the method was not effective for the materials in that particular region of Mexico. But the written historical record proved key to making sense of the wide range of dates, which reflected centuries of use of the site.

Documents sent back to Spain in the early colonial period described the availability of the locally produced copper, and the colonists’ successful tests of using it to cast bronze artillery pieces. Documents also described the bargains made by the indigenous producers to gain economic privileges for their people, based on their specialized metallurgical knowledge.

“We know from documents that the Europeans figured out that the only way they could smelt copper was to collaborate with the indigenous people who were already doing it,” Hosler says. “They had to cut deals with the indigenous smelters.”

Hosler says that “what’s so interesting to me is that we were able to use traditional archeological methods and data from materials analysis as well as ethnographic data” from the furnace in a museum in the area, “and historical and archival material from 16th century archives in Portugal, Spain, and Mexico, then to put all the data from these distinct disciplines together into an explanation that is absolutely solid.”

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European colonists cooperated with indigenous people to smelt copper. Alexas Fotos, Pixabay, Public Domain

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Article Source: MASSACHUSETTS INSTITUTE OF TECHNOLOGY news release

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UNIVERSITY OF KENT—A new study led by the University of Kent has found evidence that human ancestors as recent as two million years ago may have regularly climbed trees.

Walking on two legs has long been a defining feature to differentiate modern humans, as well as extinct species on our lineage (aka hominins), from our closest living ape relatives: chimpanzees, gorillas and orangutans. This new research, based on analysis of fossil leg bones, provides evidence that a hominin species (believed to be either Paranthropus robustus or early Homo) regularly adopted highly flexed hip joints; a posture that in other non-human apes is associated with climbing trees.

These findings came from analyzing and comparing the internal bone structures of two fossil leg bones from South Africa, discovered over 60 years ago and believed to have lived between 1 and 3 million years ago. For both fossils, the external shape of the bones were very similar showing a more human-like than ape-like hip joint, suggesting they were both walking on two legs. The researchers examined the internal bone structure because it remodels during life based on how individuals use their limbs. Unexpectedly, when the team analyzed the inside of the spherical head of the femur, it showed that they were loading their hip joints in different ways.

The research project was led by Dr Leoni Georgiou, Dr Matthew Skinner and Professor Tracy Kivell at the University of Kent’s School of Anthropology and Conservation, and included a large international team of biomechanical engineers and palaeontologists. These results demonstrate that novel information about human evolution can be hidden within fossil bones that can alter our understanding of when, where and how we became the humans we are today.

Dr Georgiou said: ‘It is very exciting to be able to reconstruct the actual behavior of these individuals who lived millions of years ago and every time we CT scan a new fossil it is a chance to learn something new about our evolutionary history.’

Dr Skinner said: ‘It has been challenging to resolve debates regarding the degree to which climbing remained an important behavior in our past. Evidence has been sparse, controversial and not widely accepted, and as we have shown in this study the external shape of bones can be misleading. Further analysis of the internal structure of other bones of the skeleton may reveal exciting findings about the evolution of other key human behaviors such as stone tool making and tool use. Our research team is now expanding our work to look at hands, feet, knees, shoulders and the spine.’

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Photograph of the fossil and artifact-bearing surface exposed deposits of the Sterkfontein Cave site. View looking towards the west. Dominic Stratford

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Article Source: UNIVERSITY OF KENT news release

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UNIVERSITY OF GÖTTINGEN—Over 80,000 years ago, Neanderthals were already feeding themselves regularly on mussels, fish and other marine life. The first robust evidence of this has been found by an international research team with the participation of the University of Göttingen during an excavation in the cave of Figueira Brava in Portugal. Dr Dirk Hoffmann at the Göttingen Isotope Geology Department dated flowstone layers – calcite deposits that form like stalagmites from dripping water – using the uranium-thorium method, and was thus able to determine the age of the excavation layers to between 86,000 and 106,000 years. This means that the layers date from the period in which the Neanderthals settled in Europe. The use of the sea as a source of food at that time has so far only been attributed to anatomically modern humans (Homo sapiens) in Africa. The results of the study* were published in the journal Science.

The cave of Figueira Brava is located 30 kilometers south of Lisbon on the slopes of the Serra da Arrábida. Today it is located directly on the waterfront, but at that time it was up to two kilometers from the coast. The research team, coordinated by the first author of the study, Professor João Zilhão from the University of Barcelona, found that the Neanderthals living there were able to routinely harvest mussels and fish, and to hunt seals. Their diet included mussels, crustaceans and fish as well as waterfowl and marine mammals such as dolphins and seals. Food from the sea is rich in omega-3 fatty acids and other fatty acids that promote the development of brain tissue.

The cave yielded remains of this marine life associated with the excavation layers dated to the time period between 86,000 and 106,000 years. The site also yielded tens of thousands of stone tools identified with Middle Paleolithic technology, and a tooth that exhibited features typically characteristic of neanderthals.

Until now, it has always been suspected that this consumption increased the cognitive abilities of the human populations in Africa. “Among other influences, this could explain the early appearance of a culture of modern people that used symbolic artifacts, such as body painting with ochre, the use of ornaments or the decoration of containers made of ostrich eggs with geometric motifs,” explains Hoffmann. “Such behavior reflects human’s capacity for abstract thought and communication through symbols, which also contributed to the emergence of more organized and complex societies of modern humans”.

The recent results of the excavation of Figueira Brava now confirm that if the habitual consumption of marine life played an important role in the development of cognitive abilities, this is as true for Neanderthals as it is for anatomically modern humans. Hoffmann and his co-authors previously found that Neanderthals made cave paintings in three caves on the Iberian Peninsula more than 65,000 years ago and that perforated and painted shells must also be attributed to the Neanderthals.

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View on the Figueira Brava cave with its three entrances. João Zilhão

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Horizontal exposure of a mussel shell bed. João Zilhão

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Cracked-open and burnt fragments of pincers of the edible crab (cancer pagurus). João Zilhão

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Article Source: Edited and adapted from the UNIVERSITY OF GÖTTINGEN news release

*J. Zilhão et al., Last Interglacial Iberian Neandertals as fisher-hunter-gatherers, Science, 10.1126/science.aaz7943

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Science Advances—New artifacts uncovered at the Waim archaeological site in the highlands of New Guinea – including a fragment of the earliest symbolic stone carving in Oceania – illustrate a shift in human behavior between 5050 and 4200 years ago in response to the widespread emergence of agriculture, ushering in a regional Neolithic Era similar to the Neolithic in Eurasia. The location and pattern of the artifacts at the site suggest a fixed domestic space and symbolic cultural practices, hinting that the region began to independently develop hallmarks of the Neolithic about 1000 years before Lapita farmers from Southeast Asia arrived in New Guinea. While scientists have known that wetland agriculture originated in the New Guinea highlands between 8000 and 4000 years ago, there has been little evidence for corresponding social changes like those that occurred in other parts of the world. To better understand what life was like in this region as agriculture spread, Ben Shaw et al. excavated and examined a trove of artifacts from the recently identified Waim archaeological site. “What is truly exciting is that this was the first time these artifacts have been found in the ground, which has now allowed us to determine their age with radiocarbon dating,” Shaw said. The researchers analyzed a stone carving fragment depicting the brow ridge of a human or animal face, a complete stone carving of a human head with a bird perched on top (recovered by Waim residents), and two ground stone pestle fragments with traces of yam, fruit and nut starches on their surfaces. They also identified an obsidian core that provides the first evidence for long-distance, off-shore obsidian trade, as well as postholes where house posts may have once stood.

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The first pestle found during initial spade pitting, the find that started it all. Ben Shaw

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Ben recording postholes in the excavated section. Judith Field

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Complex stone artefacts recovered by Waim residents which initiated excavations. Ben Shaw

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Waim base camp where the team stayed during excavation. Judith Field

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Article Source: Science Advances news release

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WELLCOME TRUST SANGER INSTITUTE—A new study has provided the most comprehensive analysis of human genetic diversity to date, after the sequencing of 929 human genomes by scientists at the Wellcome Sanger Institute, the University of Cambridge and their collaborators. The study uncovers a large amount of previously undescribed genetic variation and provides new insights into our evolutionary past, highlighting the complexity of the process through which our ancestors diversified, migrated and mixed throughout the world.

The resource, published in Science (20 March), is the most detailed representation of the genetic diversity of worldwide populations to date. It is freely available to all researchers to study human genetic diversity, including studies of genetic susceptibility to disease in different parts of the world.

The consensus view* of human history tells us that the ancestors of present-day humans diverged from the ancestors of extinct Neanderthal and Denisovan groups around 500,000-700,000 years ago, before the emergence of ‘modern’ humans in Africa in the last few hundred thousand years.

Around 50,000-70,000 years ago, some humans expanded out of Africa and soon after mixed with archaic Eurasian groups. After that, populations grew rapidly, with extensive migration and mixture as many groups transitioned from hunter-gatherers to food producers over the last 10,000 years.

This study is the first to apply the latest high-quality sequencing technology to such a large and diverse set of humans, covering 929 genomes from 54 geographically, linguistically and culturally diverse populations from across the globe. The sequencing and analysis of these genomes, which are part of the Human Genome Diversity Project (HGDP)-CEPH panel**, now provides unprecedented detail of our genetic history.

The team found millions of previously unknown DNA variations that are exclusive to one continental or major geographical region. Though most of these were rare, they included common variations in certain African and Oceanian populations that had not been identified by previous studies.

Variations such as these may influence the susceptibility of different populations to disease. However, medical genetics studies have so far predominantly been conducted in populations of European ancestry, meaning that any medical implications that these variants might have are not known. Identifying these novel variants represents a first step towards fully expanding the study of genomics to underrepresented populations.

However, no single DNA variation was found to be present in 100 per cent of genomes from any major geographical region while being absent from all other regions. This finding underlines that the majority of common genetic variation is found across the globe.

Dr Anders Bergström, of the Francis Crick Institute and an alumnus of the Wellcome Sanger Institute, said: “The detail provided by this study allows us to look deeper into human history, particularly inside Africa where less is currently known about the timescale of human evolution. We find that the ancestors of present-day populations diversified through a gradual and complex process mostly during the last 250,000 years, with large amounts of gene flow between these early lineages. But we also see evidence that small parts of human ancestries trace back to groups that diversified much earlier than this.”

Hélène Blanché, Head of the Biological Resource Centre at the Centre d’Etude du Polymorphisme Humain (CEPH) in Paris, France, said: “The Human Genome Diversity Project resource has facilitated many new discoveries about human history in the past two decades. It is exciting to see that with the latest genomic sequencing technology, these genomes will continue to help us understand our species and how we have evolved.”

The study also provides evidence that the Neanderthal ancestry of modern humans can be explained by just one major ‘mixing event’, most likely involving several Neanderthal individuals coming into contact with modern humans shortly after the latter had expanded out of Africa. In contrast, several different sets of DNA segments inherited from Denisovans were identified in people from Oceania and East Asia, suggesting at least two distinct mixing events.

The discovery of small amounts of Neanderthal DNA in west African people, most likely reflecting later genetic backflow into Africa from Eurasia, further highlights how human genetic history is characterized by multiple layers of complexity. Until recently, it was thought that only people outside sub-Saharan Africa had Neanderthal DNA.

Dr Chris Tyler-Smith, recently retired from the Wellcome Sanger Institute, said: “Though this resource is just the beginning of many avenues of research, already we can glimpse several tantalizing insights into human history. It will be particularly important for better understanding human evolution in Africa, as well as facilitating medical research for the full diversity of human ancestries.”

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The latest technology and techniques are being used to sequence the human genome, allowing scientists to peer into our deep evolutionary history. Courtesy Kenneth Rodrigues, Pixabay

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Article Source: WELLCOME TRUST SANGER INSTITUTE news release

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UNIVERSITY OF THE WITWATERSRAND—High-resolution micro-CT scanning of the skull of the fossil specimen known as “Little Foot” has revealed some aspects of how this Australopithecus species used to live more than 3 million years ago.

The meticulous excavation, cleaning and scanning of the skull of the ~3.67 million-year-old fossil specimen has revealed the most complete Australopithecus adult first cervical vertebra yet found. A description of the vertebra by Wits University researchers Dr Amélie Beaudet and the Sterkfontein team was published in the Scientific Reports. This research program is supported by the the Centre of Excellence in Palaeosciences, Scientific Palaeontological Trust, National Research Foundation, University of the Witwatersrand and the French National Centre for Scientific Research through the French Institute of South Africa.

The first cervical vertebra (or atlas) plays a crucial role in vertebrate biology. Besides acting as the connection between the head and the neck, the atlas also plays a role in how blood is supplied to the brain via the vertebral arteries.

By comparing the atlas of “Little Foot” with other fossils from South and East Africa as well as living humans and chimpanzees, the Wits University team shows that Australopithecus was capable of head movements that differ from modern humans.

“The morphology of the first cervical vertebra, or atlas, reflects multiple aspects of an organism’s life,” says Beaudet, the lead author of the study. “In particular, the nearly complete atlas of ‘Little Foot’ has the potential to provide new insights into the evolution of head mobility and the arterial supply to the brain in the human lineage.”

The shape of the atlas determines the range of head motions while the size of the arteries passing through the vertebrae to the skull is useful for estimating blood flow supplying the brain.

“Our study shows that Australopithecus was capable of head movements that differ from us. This could be explained by the greater ability of Australopithecus to climb and move in the trees. However, a southern African Australopithecus specimen younger than ‘Little Foot’ (probably younger by about 1 million years) may have partially lost this capacity and spent more time on the ground, like us today.”

The overall dimensions and shape of the atlas of “Little Foot” are similar to living chimpanzees. More specifically, the ligament insertions (that could be inferred from the presence and configuration of bony tubercles) and the morphology of the facet joints linking the head and the neck all suggest that “Little Foot” was moving regularly in trees.

Because “Little Foot” is so well-preserved, blood flow supply to the brain could also be estimated for the first time, using evidence from the skull and vertebrae. These estimations demonstrate that blood flow, and thus the utilization of glucose by the brain, was about three times lower than in living humans, and closer to the those of living chimpanzees.

“The low investment of energy into the brain of Australopithecus could be tentatively explained by a relatively small brain of the specimen (around 408cm3), a low quality diet (low proportion of animal products) or high costs of other aspects of the biology of Australopithecus (such as upright walking). In any case, this might suggest that the human brain’s vascular system emerged much later in our history.”

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Pictures of the ‘Little Foot’ skull. The view from the bottom (right) shows the original position of the first cervical vertebra still embedded in the matrix. R.J. Clarke

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Comparison of the nearly intact first cervical vertebra of ‘Little Foot’ and two other Australopithecus from Sterkfontein in South Africa and from Hadar in Ethiopia showing how complete ‘Little Foot’ is compared to the rest of the fossil record. Amélie Beaudet/Wits University

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Article Source: UNIVERSITY OF THE WITWATERSRAND news release

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If you liked this article, you may like this one:

Sterkfontein: A History of Evolution in the Cradle of Humanity

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UNIVERSITY OF EXETER—Mysterious bone circles made from the remains of dozens of mammoths have revealed clues about how ancient communities survived Europe’s ice age.

About 70 of these structures are known to exist in Ukraine and the west Russian Plain.

New analysis shows the bones at one site are more than 20,000 years old, making it the oldest such circular structure built by humans discovered in the region. The bones were likely sourced from animal graveyards, and the circle was then hidden by sediment and is now a foot below current surface level.

The majority of the bones found at the site investigated, in the Russian Plains, are from mammoths. A total of 51 lower jaws and 64 individual mammoth skulls were used to construct the walls of the 30ft by 30ft structure and scattered across its interior. Small numbers of reindeer, horse, bear, wolf, red fox and arctic fox bones were also found.

Archaeologists from the University of Exeter have also found for the first time the remains of charred wood and other soft non-woody plant remains within the circular structure, situated just outside the modern village of Kostenki, about 500km south of Moscow. This shows people were burning wood as well as bones for fuel, and the communities who lived there had learned where to forage for edible plants during the Ice Age. The plants could also have been used for poisons, medicines, string or fabric. More than 50 small charred seeds were also found – the remains of plants growing locally or possibly food remains from cooking and eating.

Dr Alexander Pryor, who led the study, said: “Kostenki 11 represents a rare example of Palaeolithic hunter-gatherers living on in this harsh environment. What might have brought ancient hunter gatherers to this site? One possibility is that the mammoths and humans could have come to the area on masse because it had a natural spring that would have provided unfrozen liquid water throughout the winter – rare in this period of extreme cold.

“These finds shed new light on the purpose of these mysterious sites. Archaeology is showing us more about how our ancestors survived in this desperately cold and hostile environment at the climax of the last ice age. Most other places at similar latitudes in Europe had been abandoned by this time, but these groups had managed to adapt to find food, shelter and water.”

The last ice age, which swept northern Europe between 75-18,000 years ago, reached its coldest and most severe stage at around 23-18,000 years ago, just as the site at Kostenki 11 was being built. Climate reconstructions indicate at the time summers were short and cool and winters were long and cold, with temperatures around -20 degrees Celsius or colder. Most communities left the region, likely because of lack of prey to hunt and plant resources they depended upon for survival. Eventually the bone circles were also abandoned as the climate continued to get colder and more inhospitable.

Previously archaeologists have assumed that the circular mammoth bone structures were used as dwellings, occupied for many months at a time. The new study suggests this may not always have been the case as the intensity of activity at Kostenki 11 appears less than would be expected from a long term base camp site.

Other finds include more than 300 tiny stone and flint chips just a few millimeters in size, debris left behind the site’s inhabitants as they knapped stone nodules into sharp tools with distinctive shapes used for tasks such as butchering animals and scraping hides.

The research, conducted by academics from the University of Exeter, University of Cambridge, Kostenki State Museum Preserve, University of Colorado Boulder and the University of Southampton, is published in the journal Antiquity.

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Above and below: The majority of the bones found at the site investigated, in the Russian Plains, are from mammoths. A total of 51 lower jaws and 64 individual mammoth skulls were used to construct the walls of the 30ft by 30ft structure and scattered across its interior. Alex Pryor

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Article Source: UNIVERSITY OF EXETER news release

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Science Advances—Archaeologists have excavated a 3400-year-old ballcourt in the mountains of Oaxaca, Mexico. The discovery challenges current assumptions about the origin and evolution of the ballgame that held ritual and political importance across Mesoamerica, a pre-Columbian cultural region encompassing Guatemala, Belize, most of Mexico, and parts of Honduras and El Salvador. Researchers have found more than 2300 probable ballcourts, and to the region’s best-known civilizations, the Maya and the Aztec, the game symbolized the regeneration of life and the maintenance of cosmic order. Because chemical analysis of several Aztec balls showed that their rubber came from Castilla elastica, a tree species associated with the plains of southern Mesoamerica, archaeologists have favored the lowlands as the place of origin and primary evolution of the ballgame. Additionally, the oldest known ballcourt, dated to 1650 B.C., is at Paso de la Amada in the coastal lowlands of southern Chiapas, Mexico. At the site of Etlatongo in Oaxaca, Mexico, however, Jeffrey Blomster and Victor Chavez discovered two ballcourts, the older of which dates to 1374 B.C., pushing back the appearance of such structures in the Mesoamerican highlands by approximately 800 years. Based on this finding, Blomster and Chavez argue that both lowland and highland societies contributed to the evolution of the Mesoamerican ballgame. Because nearly a millennium separates the Paso de la Amada and Etlatongo sites from the next ballcourts documented in their respective regions, future research could provide context by uncovering ballcourts at more highland and lowland sites.

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Location of Etlatongo in Mesoamerica and the setting of its ballcourt. (A) Map showing location of Etlatongo in the Mixteca Alta and other referenced sites in Mesoamerica. (B) Aerial view of the ballcourt on Mound 1-1 (colored blue) in relation to domestic space excavated in Operations G & I (purple) to the north. Blomster and Salazar Chávez, Sci. Adv. 2020; 6 : eaay6964

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The surface of Mound 1-1 at Etlatongo before excavations began in 2015. Deep below the surface, the project found the ballcourts. Note the old threshing floor on the surface, no longer in use, from the time when these lands belonged to an hacienda. Formative Etlatongo Project

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Excavations beginning on Etlatongo Mound 1-1 in the early morning. A small pile of dirt from the excavations has already accumulated on the southern portion of the mound. The modern town of San Mateo Etlatongo is at the foot of the hill in the background of the photo, obscured by the low hanging cloud. Formative Etlatongo Project

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Etlatongo’s ballcourts, Structure 1-2 and Structure 1-3, reconstructed plan views and related cross-sections, with separate scales, based on the excavations. Photograph shows architectural details of both ballcourts; the white rectangles over the plan views show excavation locations. Formative Etlatongo Project

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Early ballcourts in Mesoamerica. Comparison of early ballcourt cross-sections (to scale), with earliest on top, with plan views (not to scale) from Paso de la Amada (Chiapas) and La Laguna (Tlaxcala). Blomster and Salazar Chávez, Sci. Adv. 2020; 6 : eaay6964

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Etlatongo ballplayer figurine. One of numerous ceramic ballplayers from the termination event, front view shows a thick belt or yoke with a loincloth project from it, while the profile view illustrates broken tripod support at bottom, which allowed the figurine to stand, and whistle chamber above it. Blomster and Salazar Chávez, Sci. Adv. 2020; 6 : eaay6964

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Additional ceramic ballplayer figurines found above the ballcourt. Both wear thick belts or yokes with a loincloth; the figure on the left also has an additional costume element, a collar or pectoral, over the chest. Formative Etlatongo Project

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Article Source: Science Advances news release

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PLOS—The El Algar society thrived in complex hilltop settlements across the Iberian Peninsula from 2200-1550 cal BCE, and gravesites and settlement layouts provide strong evidence of a marked social hierarchy.

Knipper and colleagues conducted carbon and nitrogen isotope analysis at two different El Algar hilltop settlements: the large fortified urban site La Bastida (in present-day Totana, Murcia), and the smaller settlement Gatas (Turre, Almería). Their sample included remains of 75 human individuals from across social strata, 28 bones from domestic animals and wild deer, charred barley (75 grains total), and charred wheat (29 grains) from the middle and late phases of El Algar civilization across the two sites.

The sampled human individuals showed no significant difference between isotope values for males and for females, suggesting that diets may have been similar between genders. However, “elite” individuals at La Bastida showed higher levels of both carbon and nitrogen. This might have implied that the people of La Bastida consumed higher levels of animal-based food, but the authors suggest that the isotope value differences between La Bastida and Gatas could in fact have resulted from similar dietary compositions. Nitrogen values are similar at both sites for barley, but higher for the domestic animals at La Bastida, meaning that diets with similar relative contributions of barley and meat/dairy products would have led to higher nitrogen values in the humans at La Bastida compared to Gatas.

The researchers found a strong reliance on cereal farming, supplemented by livestock, in the El Algar economy. The range and values of carbon in the barley and wheat sample reflect what was likely a dry, unirrigated landscape, though nitrogen levels in the cereal crops suggest the El Algar people applied animal manure to their fields. Cereals and their by-products appear to have contributed substantially to the forage of domesticated sheep/goats, cattle and pigs.

Though the sample used in this study* is relatively small, and there are limitations to what can be sampled with this type of isotope analysis, this study shows the importance of considering the complete trophic chain in order to adequately interpret isotope data from human remains–and also demonstrates the sophistication of El Algar farming techniques.

Knipper adds: “It is essential to not only investigate human remains, but also comparative samples of different former food stuffs as well as to interpret the data in the light of the archaeological and social historical context.”

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La Bastida 3D reconstruction. Dani Méndez-REVIVES

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Article Source: PLOS One news release

*Knipper C, Rihuete-Herrada C, Voltas J, Held P, Lull V, Micó R, et al. (2020) Reconstructing Bronze Age diets and farming strategies at the early Bronze Age sites of La Bastida and Gatas (southeast Iberia) using stable isotope analysis. PLoS ONE 15(3): e0229398. https://doi.org/10.1371/journal.pone.0229398

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UNIVERSITY OF MICHIGAN—ANN ARBOR–A clump of grass grows on an outcrop of shale 33,000 years ago. An ostrich pecks at the grass, and atoms taken up from the shale and into the grass become part of the eggshell the ostrich lays.

A member of a hunter-gatherer group living in southern Africa’s Karoo Desert finds the egg. She eats it, and cracks the shell into dozens of pieces. Drilling a hole, she strings the fragments onto a piece of sinew and files them into a string of beads.

She gifts the ornaments to friends who live to the east, where rainfall is higher, to reaffirm those important relationships. They, in turn, do the same, until the beads eventually end up with distant groups living high in the eastern mountains.

Thirty-three thousand years later, a University of Michigan researcher finds the beads in what is now Lesotho, and by measuring atoms in the beads, provides new evidence for where these beads were made, and just how long hunter-gatherers used them as a kind of social currency.

In a study published in the Proceedings of the National Academy of Science, U-M paleolithic archeologist Brian Stewart and colleagues establish that the practice of exchanging these ornaments over long distances spans a much longer period of time than previously thought.

“Humans are just outlandishly social animals, and that goes back to these deep forces that selected for maximizing information, information that would have been useful for living in a hunter-gatherer society 30,000 years ago and earlier,” said Stewart, assistant professor of anthropology and assistant curator of the U-M Museum of Anthropological Archaeology.

“Ostrich eggshell beads and the jewelry made from them basically acted like Stone Age versions of Facebook or Twitter ‘likes,’ simultaneously affirming connections to exchange partners while alerting others to the status of those relationships.”

Lesotho is a small country of mountain ranges and rivers. It has the highest average of elevation in the continent and would have been a formidable place for hunter-gatherers to live, Stewart says. But the fresh water coursing through the country and belts of resources, stratified by the region’s elevation, provided protection against swings in climate for those who lived there, as early as 85,000 years ago.

Anthropologists have long known that contemporary hunter-gatherers use ostrich eggshell beads to establish relationships with others. In Lesotho, archeologists began finding small ornaments made of ostrich eggshell. But ostriches don’t typically live in that environment, and the archeologists didn’t find evidence of those ornaments being made in that region–no fragments of unworked eggshell, or beads in various stages of production.

So when archeologists began discovering eggshell beads without evidence of production, they suspected the beads arrived in Lesotho through these exchange networks. Testing the beads using strontium isotope analysis would allow the archeologists to pinpoint where they were made.

Strontium-87 is the daughter isotope of the radioactive element rubidium-87. When rubidium-87 decays it produces strontium-87. Older rocks such as granite and gneiss have more strontium than younger rocks such as basalt. When animals forage from a landscape, these strontium isotopes are incorporated into their tissues.

Lesotho is roughly at the center of a bullseye-shaped geologic formation called the Karoo Supergroup. The supergroup’s mountainous center is basalt, from relatively recent volcanic eruptions that formed the highlands of Lesotho. Encircling Lesotho are bands of much older sedimentary rocks. The outermost ring of the formation ranges between 325 and 1,000 kilometers away from the Lesotho sites.

To assess where the ostrich eggshell beads were made, the research team established a baseline of strontium isotope ratios–that is, how much strontium is available in a given location–using vegetation and soil samples as well samples from modern rodent tooth enamel from museum specimens collected from across Lesotho and surrounding areas.

According to their analysis, nearly 80% of the beads the researchers found in Lesotho could not have originated from ostriches living near where the beads were found in highland Lesotho.

“These ornaments were consistently coming from very long distances,” Stewart said. “The oldest bead in our sample had the third highest strontium isotope value, so it is also one of the most exotic.”

Stewart found that some beads could not have come from closer than 325 kilometers from Lesotho, and may have been made as far as 1,000 kilometers away. His findings also establish that these beads were exchanged during a time of climactic upheaval, about 59 to 25 thousand years ago. Using these beads to establish relationships between hunter-gatherer groups ensured one group access to others’ resources when a region’s weather took a turn for the worse.

“What happened 50,000 years ago was that the climate was going through enormous swings, so it might be no coincidence that that’s exactly when you get this technology coming in,” Stewart said. “These exchange networks could be used for information on resources, the condition of landscapes, of animals, plant foods, other people and perhaps marriage partners.”

Stewart says while archeologists have long accepted that these exchange items bond people over landscapes in the ethnographic Kalahari, they now have firm evidence that these beads were exchanged over huge distances not only in the past, but for over a long period of time. This study places another piece in the puzzle of how we persisted longer than all other humans, and why we became the globe’s dominant species.

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Above and below: Archeologists work at rock shelters at Sehonghong and Melikane in southern Africa. Brian Stewart

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Above and below: Ostrich eggshell beads have been used to cement relationships in Africa for more than 30,000 years. John Klausmeyer, Yuchao Zhao and Brian Stewart

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Article Source: University of Michigan news release

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Science Advances—Scientists have discovered new fragments of two Homo erectus skulls alongside different types of stone tool technologies, helping to dispel the assumption that these different technologies were used by different species of hominins or in different eras. The skull fragments also hold clues to possible differences between male and female members of H. erectus, a species of human ancestor that appeared about two million years ago, as well as to the lifestyle and diet of the species. Archaeologists and paleoanthropologists classify stone tools by their complexity and the time period in which they were used. “Mode I” tools are those with simple modifications—a few pieces chipped off to make sharp edges. Mode II tools are created by removing flakes on both sides of the stone resulting in more refined, “pear-shaped” hand axes. It was previously assumed that H. erectus invented Mode II tools, which succeeded Mode I tools used by earlier hominins, though some researchers have proposed a more complex history. Now, Sileshi Semaw and colleagues have discovered H. erectus skulls in close association with both kinds of tools in Ethiopia. They date one skull to 1.26 million years ago and the other to 1.6 to 1.5 million years ago. They interpret these findings to mean H. erectus used both technologies concurrently over hundreds of thousands of years, indicating the species was behaviorally flexible and diverse. The researchers also analyzed the features of the skulls, one male and the other female. The female skull was smaller and slimmer, indicating H. erectus may have been sexually dimorphic. The isotope data point to these individuals as having a broad, varied diet – consisting of plants, eggs, insects and more – but additional isotopic data from more samples over a larger geographic range would be needed to confirm this, the authors say.

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The DAN5 cranium, held by Dr. S. Semaw.
Michael J. Rogers, Southern Connecticut State University

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The DAN5 cranium, view from the front and above. Michael J. Rogers, Southern Connecticut State University

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Two opposing views of Oldowan stone tools from DAN5. Michael J. Rogers, Southern Connecticut State University

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Two opposing views of Acheulian stone tools from DAN5. Michael J. Rogers, Southern Connecticut State University

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Map of the Gona Study Area. Michael J. Rogers, Southern Connecticut State University

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Article Source: Science Advances news release

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MAX PLANCK INSTITUTE FOR THE SCIENCE OF HUMAN HISTORY—The historic economies of Mongolia are among the least understood of any region in the world. The region’s persistent, extreme winds whisk away signs of human activity and prevent the buildup of sediment which archaeologists rely on to preserve the past. Today crop cultivation comprises only a small percent of Mongolia’s food production, and many scholars have argued that Mongolia presents a unique example of dense human populations and hierarchical political systems forming without intensive farming or stockpiling grains.

The current study*, led by Dr. Shevan Wilkin of the Max Planck Institute for the Science of Human History provides, for the first time, a detailed glimpse into the diets and lives of ancient Mongolians, underscoring the importance of millets during the formation of the earliest empires on the steppe.

Isotopic analysis and the imperial importance of millets

Collaborating with archaeologists from the National University of Mongolia and the Institute of Archaeology in Ulaanbaatar, Dr. Wilkin and her colleagues from the MPI SHH sampled portions of teeth and rib bones from 137 previously excavated individuals. The skeletal fragments were brought back to the ancient isotope lab in Jena, Germany, where researchers extracted bone collagen and dental enamel to examine the ratios of stable nitrogen and carbon isotopes within. With these ratios in hand, scientists were able to reconstruct the diets of people who lived, ate, and died hundreds to thousands of years ago.

Researchers tracked the trends in diet through the millennia, creating a “dietscape” which clearly showed significant differences between the diets of Bronze Age peoples and those who lived during the Xiongnu and Mongol Empires. A typical Bronze Age Mongolian diet was based on milk and meat, and was likely supplemented with small amounts of naturally available plants. Later, during the Xiongnu Empire, human populations displayed a larger range of carbon values, showing that some people remained on the diet common in the Bronze Age, but that many others consumed a high amount of millet-based foods. Interestingly, those living near the imperial heartlands appear to have been consuming more millet-based foods than those further afield, which suggests imperial support for agricultural efforts in the more central political regions. The study also shows an increase in grain consumption and increasing dietary diversity through time, leading up to the well-known Mongolian Empire of the Khans.

Rethinking Mongolian prehistory

The new discoveries presented in this paper show that the development of the earliest empires in Mongolia, like in other parts of the world, was tied to a diverse economy that included the local or regional production of grain. Dr. Bryan K. Miller, a co-author who studies the historical and archaeological records of Inner Asian empires, remarks that “these regimes were like most empires, in that they directed intricate political networks and sought to amass a stable surplus – in this case a primarily pastoral one that was augmented by other resources like millet.”

“In this regard,” Dr. Miller adds, “this study brings us one step closer to understanding the cultural processes that led humanity into the modern world.”

The view that everyone in Mongolian history was a nomadic herder has skewed discussions concerning social development in this part of the world. Dr. Wilkin notes that “setting aside our preconceived ideas of what prehistory looked like and examining the archaeological record with modern scientific approaches is forcing us to rewrite entire sections of humanity’s past.” Dr. Spengler, the director of the archaeobotany labs at the MPI SHH, emphasizes the importance of this discovery, noting that “this study pulls the veil of myth and lore off of the real people who lived in Mongolia millennia ago and lets us peak into their lives.”

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Mongolian landscape with pastoral herd of sheep and goats. Alicia Ventresca Miller

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Cultivated land in northern Mongolia. Alicia Ventresca Miller

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Horses are still used by many for transport across Mongolia. Shevan Wilkin

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Article Source: MAX PLANCK INSTITUTE FOR THE SCIENCE OF HUMAN HISTORY news release

*Shevan Wilkin, Alicia Ventresca Miller, Bryan K. Miller, Robert N. Spengler, William T. T. Taylor, Ricardo Fernandes, Madeleine Bleasdale, Jana Zech, S. Ulziibayar, Erdene Myagmar, Nicole Boivin, Patrick Roberts, Economic Diversification Supported the Growth of Mongolia’s Nomadic Empires, Scientific Reports, DOI: 10.1038/s41598-020-60194-0

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UNIVERSITY OF VIENNA—The Mediterranean Sea has been a major route for maritime migrations as well as frequent trade and invasions during prehistory, yet the genetic history of the Mediterranean islands is not well documented despite recent developments in the study of ancient DNA. An international team led by researchers from the University of Vienna, Harvard University and University of Florence, Italy, is filling in the gaps with the largest study* to date of the genetic history of ancient populations of Sicily, Sardinia and the Balearic Islands, increasing the number of individuals with reported data from 5 to 66.

The results reveal a complex pattern of immigration from Africa, Asia and Europe which varied in direction and its timing for each of these islands. For Sicily the article reports on a new ancestry during the Middle Bronze Age that chronologically overlaps with the Greek Mycenaean trade network expansion.

Sardinians descend from Neolithic farmers

A very different story is unraveled in the case of Sardinia. Despite contacts and trade with other Mediterranean populations, ancient Sardinians retained a mostly local Neolithic ancestry profile until the end of the Bronze Age. However, during the second half of the 3rd millennium BC, one of the studied individuals from Sardinia has a large proportion of North African ancestry. Taken together with previous results of a contemporary central Iberian individual and a later 2nd mill. BC Bronze Age individual from Iberia, it clearly shows prehistoric maritime migrations across the Mediterranean Sea from North Africa to locations in southern Europe, affecting more than 1 percent of individuals reported in the ancient DNA literature from this region and time to date.

“Our results show that maritime migrations from North Africa started long before the era of the eastern Mediterranean seafaring civilizations and moreover were occurring in multiple parts of the Mediterranean”, says Ron Pinhasi, a co-senior author of the Department of Evolutionary Anthropology, University of Vienna.

During the Iron Age expansion and establishment of Greek and Phoenician colonies in the West Mediterranean islands, the two Sardinian individuals analyzed from that period had little, if any, ancestry from the previous long-established populations. “Surprisingly, our results show that despite these population fluxes and mixtures, modern Sardinians retained between 56-62 percent of ancestry from the first Neolithic farmers that arrived in Europe around 8000 years ago”, says David Caramelli a co-senior author, and Director of Department of Biology at the University of Florence.

Migration from the Iberian Peninsula documented

“One of the most striking findings is about the arrival of ancestry from the Steppe north of the Black and Caspian Seas in some of the Mediterranean islands. While the ultimate origin of this ancestry was Eastern Europe, in the Mediterranean islands it arrived at least in part from the west, namely from Iberia”, says David Reich, a co-senior author at Harvard University, who is also an investigator of the Howard Hughes Medical Institute and at the Broad Institute of MIT and Harvard. “This was likely the case for the Balearic Islands, in which some early residents probably derived at least part of their ancestry from Iberia”, says first author Daniel Fernandes, of the Department of Evolutionary Anthropology, University of Vienna.

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The largest study to date of the genetic history of ancient populations of Sicily, Sardinia and the Balearic Islands shows a complex pattern of migration from Africa, Asia and Europe. David Caramelli

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Researchers found a large proportion of North African ancestry in one of the studied individuals who lived in Sardinia during the second half of the 3rd millennium BC. David Caramelli

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Article Source: UNIVERSITY OF VIENNA news release

*The study was published in Nature Ecology & Evolution: Fernandes, Daniel M. et al.: “The spread of steppe and Iranian-related ancestry in the islands of the western Mediterranean”. Nature Ecology & Evolution 2020. DOI: 10.1038/s41559-020-1102-0

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MAX PLANCK INSTITUTE FOR THE SCIENCE OF HUMAN HISTORY—The Toba super-eruption was one of the largest volcanic events over the last two million years, about 5,000 times larger than Mount St. Helen’s eruption in the 1980s. The eruption occurred 74,000 years ago on the island of Sumatra, Indonesia, and was argued to have ushered in a “volcanic winter” lasting six to ten years, leading to a 1,000 year-long cooling of the Earth’s surface. Theories purported that the volcanic eruption would have led to major catastrophes, including the decimation of hominin populations and mammal populations in Asia, and the near extinction of our own species. The few surviving Homo sapiens in Africa were said to have survived by developing sophisticated social, symbolic and economic strategies that enabled them to eventually re-expand and populate Asia 60,000 years ago in a single, rapid wave along the Indian Ocean coastline.

Fieldwork in southern India conducted in 2007 by some of this study’s authors challenged these theories, leading to major debates between archaeologists, geneticists and earth scientists about the timing of human dispersals Out of Africa and the impact of the Toba super-eruption on climate and environments. The current study continues the debate, providing evidence that Homo sapiens were present in Asia earlier than expected and that the Toba super-eruption wasn’t as apocalyptic as believed.

The Toba volcanic super-eruption and human evolution

The current study* reports on a unique 80,000 year-long stratigraphic record from the Dhaba site in northern India’s Middle Son Valley. Stone tools uncovered at Dhaba in association with the timing of the Toba event provide strong evidence that Middle Palaeolithic tool-using populations were present in India prior to and after 74,000 years ago. Professor J.N. Pal, principal investigator from the University of Allahabad in India notes that “Although Toba ash was first identified in the Son Valley back in the 1980s, until now we did not have associated archaeological evidence, so the Dhaba site fills in a major chronological gap.”

Professor Chris Clarkson of the University of Queensland, lead author of the study, adds, “Populations at Dhaba were using stone tools that were similar to the toolkits being used by Homo sapiens in Africa at the same time. The fact that these toolkits did not disappear at the time of the Toba super-eruption or change dramatically soon after indicates that human populations survived the so-called catastrophe and continued to create tools to modify their environments.” This new archaeological evidence supports fossil evidence that humans migrated out of Africa and expanded across Eurasia before 60,000 years ago. It also supports genetic findings that humans interbred with archaic species of hominins, such as Neanderthals, before 60,000 years ago.

Toba, climate change and human resilience

Though the Toba super-eruption was a colossal event, few climatologists and earth scientists continue to support the original formulation of the “volcanic winter” scenario, suggesting that the Earth’s cooling was more muted and that Toba may not have actually caused the subsequent glacial period. Recent archaeological evidence in Asia, including the findings unearthed in this study, does not support the theory that hominin populations went extinct on account of the Toba super-eruption.

Instead, archaeological evidence indicates that humans survived and coped with one of the largest volcanic events in human history, demonstrating that small bands of hunter-gatherers were adaptable in the face of environmental change. Nevertheless, the peoples who lived around Dhaba more than 74,000 years ago do not seem to have significantly contributed to the gene pool of contemporary peoples, suggesting that these hunter-gatherers likely faced a series of challenges to their long-term survival, including the dramatic environmental changes of the following millennia. In summarizing the wider implications of this study, Professor Michael Petraglia of the Max Planck Institute says, “The archaeological record demonstrates that although humans sometimes show a remarkable level of resilience to challenges, it is also clear that people did not necessarily always prosper over the long term.”

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Stone tools found at the Dhaba site corresponding with the Toba volcanic super-eruption levels. Pictured here are diagnostic Middle Palaeolithic core types. Chris Clarkson

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Standing on the Dhaba site, overlooking the Middle Son Valley, India. Note the archaeological trench location on the left hand side of the photo. Christina Neudorf

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Article Source: MAX PLANCK INSTITUTE FOR THE SCIENCE OF HUMAN HISTORY news release

*Chris Clarkson, Clair Harris, Bo Li, Christina M. Neudorf, Richard G. Roberts, Christine Lane, Kasih Norman, Jagannath Pal, Sacha Jones, Ceri Shipton, Jinu Koshy, M.C. Gupta, D.P. Mishra, A.K. Dubey, Nicole Boivin, and Michael Petraglia; Human occupation of northern India spans the Toba super-eruption ~74,000 years ago. Nature Communications, DOI: 10.1038/s41467-020-14668-4.

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UNIVERSITY OF UTAH—For three years, anthropologist Alan Rogers has attempted to solve an evolutionary puzzle. His research untangles millions of years of human evolution by analyzing DNA strands from ancient human species known as hominins. Like many evolutionary geneticists, Rogers compares hominin genomes looking for genetic patterns such as mutations and shared genes. He develops statistical methods that infer the history of ancient human populations.

In 2017, Rogers led a study which found that two lineages of ancient humans, Neanderthals and Denisovans, separated much earlier than previously thought and proposed a bottleneck population size. It caused some controversy–anthropologists Mafessoni and Prüfer argued that their method for analyzing the DNA produced different results. Rogers agreed, but realized that neither method explained the genetic data very well.

“Both of our methods under discussion were missing something, but what?” asked Rogers, professor of anthropology at the University of Utah.

The new study has solved that puzzle and in doing so, it has documented the earliest known interbreeding event between ancient human populations—a group known as the “super-archaics” in Eurasia interbred with a Neanderthal-Denisovan ancestor about 700,000 years ago. The event was between two populations that were more distantly related than any other recorded. The authors also proposed a revised timeline for human migration out of Africa and into Eurasia. The method for analyzing ancient DNA provides a new way to look farther back into the human lineage than ever before.

“We’ve never known about this episode of interbreeding and we’ve never been able to estimate the size of the super-archaic population,” said Rogers, lead author of the study. “We’re just shedding light on an interval on human evolutionary history that was previously completely dark.”

The paper was published on Feb. 20, 2020, in the journal Science Advances.

Out of Africa and interbreeding

Rogers studied the ways in which mutations are shared among modern Africans and Europeans, and ancient Neanderthals and Denisovans. The pattern of sharing implied five episodes of interbreeding, including one that was previously unknown. The newly discovered episode involves interbreeding over 700,000 years ago between a distantly related “super-archaic” population which separated from all other humans around two million years ago, and the ancestors of Neanderthals and Denisovans.

The super-archaic and Neanderthal-Denisovan ancestor populations were more distantly related than any other pair of human populations previously known to interbreed. For example, modern humans and Neanderthals had been separated for about 750,000 years when they interbred. The super-archaics and Neanderthal-Denisovan ancestors were separated for well over a million years.

“These findings about the timing at which interbreeding happened in the human lineage is telling something about how long it takes for reproductive isolation to evolve,” said Rogers.

The authors used other clues in the genomes to estimate when the ancient human populations separated and their effective population size. They estimated the super-archaic separated into its own species about two million years ago. This agrees with human fossil evidence in Eurasia that is 1.85 million years old.

The researchers also proposed there were three waves of human migration into Eurasia. The first was two million years ago when the super-archaics migrated into Eurasia and expanded into a large population. Then 700,000 years ago, Neanderthal-Denisovan ancestors migrated into Eurasia and quickly interbred with the descendants of the super-archaics. Finally, modern humans expanded to Eurasia 50,000 years ago where we know they interbred with other ancient humans, including with the Neanderthals.

“I’ve been working for the last couple of years on this different way of analyzing genetic data to find out about history,” said Rogers. “It’s just gratifying that you come up with a different way of looking at the data and you end up discovering things that people haven’t been able to see with other methods.”

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Neanderthal-Denisovan ancestor interbred with an unknown super-archaic human species. Chloedancer99, Pixabay

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Article Source: UNIVERSITY OF UTAH news release

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AARHUS UNIVERSITY—Symbolic behavior – such as language, account keeping, music, art, and narrative – constitutes a milestone in human cognitive evolution. But how, where and when did these complex practices evolve? This question is very challenging to address; human cognitive processes do not fossilize, making it very difficult to study the mental life of our Stone Age ancestors. However, in a new study published in the Proceedings of the National Academy of Sciences journal PNAS, an interdisciplinary team of cognitive scientists and archaeologists from Denmark, South Africa and Australia takes up the challenge. They used engravings on ochre nodules and ostrich eggshells made between about 109 000 and 52 000 years ago in a series of five cognitive science experiments to investigate their potential symbolic function.

The engravings originate from the South African Middle Stone Age sites of Blombos Cave and Diepkloof Rock Shelter, and are considered among the earliest examples of human symbolic behavior. They were found in different layers of the cave sediments, which has made it possible to reconstruct the approximate time and order in which they were produced. Lead scientist Kristian Tylén, Associate Professor at the Department of Linguistics, Cognitive Science and Semiotics and at the Interacting Minds Centre, Aarhus University, Denmark, explains:

“It is remarkable that we have a record of a practice of making engravings spanning more than 40 000 years. This allows us to observe how the engraved patterns have been developed and refined incrementally over time to become better symbols – that is – tools for the human mind, similar to the way instrumental technologies, such as stone tools, are honed over time to do their job more efficiently”.

In the experiments, participants were shown the engraved patterns while the researchers measured their responses in terms of visual attention, recognition, memory, reaction times, and discrimination of patterns belonging to different points in time. The experiments suggest that over the period of more than 40 000 years, the engravings evolved to more effectively catch human visual attention, they became easier to recognize as human-made, easier to remember and reproduce, and they evolved elements of group-specific style. However, they did not become easier to discriminate from each other within or between each of the two sites.

Several previous studies have presented speculations on the possible symbolic function of the Blombos and Diepkloof engravings. Some have suggested that they should be regarded as fully-developed symbols pointing to distinct meanings, more or less like written glyphs. This suggestion is, however, not supported by the present study:

“It is difficult to make well-grounded interpretations of these ancient human behaviors”, says archaeologist and co-author Niels N. Johannsen, Associate Professor at the Department of Archaeology and Heritage Studies and at the Interacting Minds Centre, Aarhus University, “and we have been missing a more systematic, scientific approach. The main advantage of our experimental procedure is that we work directly with the archaeological evidence, measuring cognitive consequences of the changes that these engravings have undergone through time – and from these data, we argue, we are in a better position to understand the possible function of the engravings made by our ancestors tens of thousands of years ago.”

The experimental findings suggest that the engravings from Blombos and Diepkloof were created and refined over time to serve an aesthetic purpose, for instance as decorations. However, they also evolved elements of style that could have worked to mark the identity of the group, that is, they could be recognized as coming from a particular group.

The experiments make use of contemporary participants and concerns could be raised that the measurements say little about cognitive processes unfolding in the minds of stone age humans 100 000 years ago.

Kristian Tylén explains:

“Previous investigations have relied exclusively on studies of archaeological artifacts, the size and shape of cranial casts, or the mapping of genes. These are very indirect measures of human cognitive processes. While our experimental approach is also indirect in the sense that we cannot travel back in time and directly record the cognitive processes of our Stone Age ancestors, it is, on the other hand, dealing directly with those basic cognitive processes critically involved in human symbolic behavior.”

The study can thus inform foundational discussions of the early evolution of human symbolic behavior. Not unlike manual tools, the findings suggest that the engravings were incrementally refined over a period of more than 40 000 years to become more effective ‘tools for the mind’ as their producers became more skilled symbol makers and users. In the challenging pursuit of understanding human cognitive evolution, the approach and findings provide novel insights into the minds of our Stone Age ancestors that cannot be achieved through the traditional methods of archaeology and genetics, or by theoretical work alone.

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Blombos Cave ochre fragment engravings. https://commons.wikimedia.org/wiki/File:Blombos_Cave_-_3.jpg. https://originalrockart.wordpress.com/. Attribution-Share Alike 4.0 International license 

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Article Source: AARHUS UNIVERSITY news release

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UNIVERSITY OF ARKANSAS—Analysis of Paleolithic-era teeth from a 28,500-year-old fossil site in the Czech Republic provides supporting evidence for two groups of canids – one dog-like and the other wolf-like – with differing diets, which is consistent with the early domestication of dogs.

The study, published in the Journal of Archaeological Science, was co-directed by Peter Ungar, Distinguished Professor of anthropology at the University of Arkansas.

The researchers performed dental microwear texture analysis on a sample of fossils from the Předmostí site, which contains both wolf-like and dog-like canids. Canids are simply mammals of the dog family. The researchers identified distinctive microwear patterns for each canid morphotype. Compared to the wolf-like canids, the teeth of the early dog canids – called “protodogs” by the researchers – had larger wear scars, indicating a diet that included hard, brittle foods. The teeth of the wolf-like canids had smaller scars, suggesting they consumed more flesh, likely from mammoth, as shown by previous research.

This greater durophagy – animal eating behavior suggesting the consumption of hard objects – among the dog-like canids means they likely consumed bones and other less desirable food scraps within human settlement areas, Ungar said. It provides supporting evidence that there were two types of canids at the site, each with a distinct diet, which is consistent with other evidence of early-stage domestication.

“Our primary goal was to test whether these two morphotypes expressed notable differences in behavior, based on wear patterns,” said Ungar. “Dental microwear is a behavioral signal that can appear generations before morphological changes are established in a population, and it shows great promise in using the archaeological record to distinguish protodogs from wolves.”

Dog domestication is the earliest example of animal husbandry and the only type of domestication that occurred well before the earliest definitive evidence of agriculture. However, there is robust scientific debate about the timing and circumstances of the initial domestication of dogs, with estimates varying between 15,000 and 40,000 years ago, well into the Ice Age, when people had a hunter-gatherer way of life. There is also debate about why wolves were first domesticated to become dogs. From an anthropological perspective, the timing of the domestication process is important for understanding early cognition, behavior and the ecology of early Homo sapiens.

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Peter Ungar with the jaw of a dog-like canid at the Moravian Museum in the Czech Republic. Peter Ungar

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Article Source: UNIVERSITY OF ARKANSAS news release

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UNIVERSITY OF QUEENSLAND—Australia’s first plant foods – eaten by early populations 65,000 years ago – have been discovered in Arnhem Land.

Preserved as pieces of charcoal, the morsels were recovered from the debris of ancient cooking hearths at the Madjedbebe archaeological site, on Mirarr country in northern Australia.

University of Queensland archaeobotanist Anna Florin said a team of archaeologists and Traditional Owners identified 10 plant foods, including several types of fruits and nuts, underground storage organs (‘roots and tubers’), and palm stem.

“By working with Elders and co-authors May Nango and Djaykuk Djandjomerr, the team was also able to explain how the plants were likely used at Madjedbebe,” Ms Florin said.

“Many of these plant foods required processing to make them edible and this evidence was complemented by grinding stone technology also used during early occupation at the site.”

“The First Australians had a great deal of botanical knowledge and this was one of the things that allowed them to adapt to and thrive in this new environment.

“They were able to guarantee access to carbohydrates, fat and even protein by applying this knowledge, as well as technological innovation and labour, to the gathering and processing of Australian plant foods.”

Madjedbebe is a sandstone rock shelter at the base of the Arnhem Land escarpment, and is Australia’s oldest documented site.

Excavation director Professor Chris Clarkson from UQ’s School of Social Science said he was surprised and delighted by the quantity of archaeobotanical evidence recovered from the site.

“Madjedbebe continues to provide startling insights into the complex and dynamic lifestyle of the earliest Australian Aboriginal people,” Professor Clarkson said.

The oldest occupation layer at Madjedbebe also holds evidence for the oldest edge ground stone axes in the world, the earliest grindstone technology outside Africa, the early shaping of stone spearheads, many kilograms of ground ochre, and the first recorded use of reflective pigments in the world.

“The site is an important cultural place to Mirarr people today who strive to protect their heritage from numerous threats, including mining,” Ms Florin said.

Justin O’Brien, CEO of Gundjeihmi Aboriginal Corporation which represents the Mirarr Traditional Owners, said that research on country – working in meaningful partnership with Traditional Owners – was a powerful way to share Mirarr’s enduring culture with a broader audience.

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Madjedbebe is a sandstone rock shelter at the base of the Arnhem Land escarpment, and is Australia’s oldest documented site. University of Queensland

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A team of archaeologists and Traditional Owners identified 10 plant foods. University of Queensland

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The study is published in Nature Communications (DOI: 10.1038/s41467-020-14723-0).

Article Source: UNIVERSITY OF QUEENSLAND news release

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