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NORTHWESTERN UNIVERSITY, EVANSTON, Ill.—A new study may resolve an old debate about how tough the Vikings actually were.

Although TV and movies paint Vikings as robust souls, braving subzero temperatures in fur pelts and iron helmets, new evidence indicates they might have been basking in 50-degree summer weather when they settled in Greenland.

After reconstructing southern Greenland’s climate record over the past 3,000 years, a Northwestern University team found that it was relatively warm when the Norse lived there between 985 and 1450 C.E., compared to the previous and following centuries.

“People have speculated that the Norse settled in Greenland during an unusually, fortuitously warm period, but there weren’t any detailed local temperature reconstructions that fully confirmed that. And some recent work suggested that the opposite was true,” said Northwestern’s Yarrow Axford, the study’s senior author. “So this has been a bit of a climate mystery.”

Now that climate mystery finally has been solved.

The study is published in the journal Geology. Axford is an associate professor of Earth and planetary sciences in Northwestern’s Weinberg College of Arts and Sciences. The study is a part of Northwestern Ph.D. candidate G. Everett Lasher’s dissertation research, based in Axford’s lab.

To reconstruct past climate, the researchers studied lake sediment cores collected near Norse settlements outside of Narsaq in southern Greenland. Because lake sediment forms by an incremental buildup of annual layers of mud, these cores contain archives of the past. By looking through the layers, researchers can pinpoint climate clues from eons ago.

For this study, Lasher analyzed the chemistry of a mix of lake fly species, called chironomids, trapped inside the layers of sediment. By looking at the oxygen isotopes within the flies’ preserved exoskeletons, the team pieced together a picture of the past. This method allowed the team to reconstruct climate change over hundreds of years or less, making it the first study to quantify past temperature changes in the so-called Norse Eastern Settlement.

“The oxygen isotopes we measure from the chironomids record past lake water isotopes in which the bugs grew, and that lake water comes from precipitation falling over the lake,” said Lasher, first author of the paper. “The oxygen isotopes in precipitation are partly controlled by temperature, so we examined the change in oxygen isotopes through time to infer how temperature might have changed.”

Because recent studies concluded that some glaciers were advancing around Greenland and nearby Arctic Canada during the time Vikings lived in southern Greenland, Axford and Lasher expected their data to indicate a much colder climate. Instead, they found that a brief warm period interrupted a consistent cooling climate trend driven by changes in Earth’s orbit. Near the end of the warm period, the climate was exceptionally erratic and unstable with record high and low temperatures that preceded Viking abandonment of Greenland. Overall, the climate was about 1.5-degrees Celsius warmer than the surrounding cooling centuries. This warmer period was similar to southern Greenland’s temperatures today, which hover around 10-degrees Celsius (50-degrees Fahrenheit) in summer.

In another surprise, Axford and Lasher found that the North Atlantic Oscillation (NAO)—a natural fluctuation in atmospheric pressure that is often responsible for climate anomalies in the region—probably was not in a dominantly positive phase for multiple Medieval centuries as had been hypothesized. (When the NAO is in its positive phase, it brings cold air to much of Greenland.)

“We found that the NAO could not explain Medieval climatic changes at our site,” Lasher said. “That might call into question its use in explaining long-term climate change over the last 3,000 years elsewhere.”

So what did cause the Vikings’ fortuitously warm climate? Lasher and Axford aren’t sure but speculate it might have been caused by warmer ocean currents in the region. The new data will be useful for climate modelers and climate researchers as they seek to understand and predict what might be in store for Greenland’s ice sheet as Earth warms rapidly in the future.

“Unlike warming over the past century, which is global, Medieval warmth was localized,” Axford said. “We wanted to investigate what was happening in southern Greenland at that time because it’s a climatically complex part of the world where counterintuitive things can happen.”

The Norse settlements in Greenland collapsed as local climate apparently became exceptionally erratic, and then ultimately consistently cold. But Axford and Lasher will leave it to the archaeologists to determine whether or not climate played a role in their departure.

“We went in with a hypothesis that we wouldn’t see warmth in this time period, in which case we might have had to explain how the Norse were hearty, robust folk who settled in Greenland during a cold snap,” Lasher said. “Instead, we found evidence for warmth. Later, as their settlements died out, apparently there was climatic instability. Maybe they weren’t as resilient to climate change as Greenland’s indigenous people, but climate is just one of many things that might have played a role.”

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Recovering a sediment core. Amanda Morris

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Article Source: Northwestern University news release

YALE UNIVERSITY—Long before human ancestors began hunting large mammals for meat, a fatty diet provided them with the nutrition to develop bigger brains, posits a new paper* in Current Anthropology.

The paper argues that our early ancestors acquired a taste for fat by eating marrow scavenged from the skeletal remains of large animals that had been killed and eaten by other predators. The argument challenges the widely held view among anthropologists that eating meat was the critical factor in setting the stage for the evolution of humans.

“Our ancestors likely began acquiring a taste for fat 4 million years ago, which explains why we crave it today,” says Jessica Thompson, the paper’s lead author and an anthropologist at Yale University. “The reservoirs of fat in the long bones of carcasses were a huge calorie package on a calorie-poor landscape. That could have been what gave an ancestral population the advantage it needed to set off the chain of human evolution.”

Thompson, who recently joined Yale’s faculty, completed the paper while on the faculty at Emory University.

While focusing on fat over meat may seem like a subtle distinction, the difference is significant, Thompson says. The nutrients of meat and fat are different, as are the technologies required to access them. Meat eating is traditionally paired with the manufacture of sharp, flaked-stone tools, while obtaining fat-rich marrow only required smashing bones with a rock, Thompson notes.

The authors review evidence that a craving for marrow could have fueled not just a growing brain size, but the quest to go beyond smashing bones with rocks to make more sophisticated tools and to hunt large animals.

“That’s how all technology originated — taking one thing and using it to alter something else,” Thompson says. “That’s the origin of the iPhone right there.”

Co-authors of the paper include anthropologists Susana Carvalho of Oxford University, Curtis Marean of Arizona State University, and Zeresenay Alemseged of the University of Chicago.

The human brain consumes 20% of the body’s energy at rest, or twice that of the brains of other primates, which are almost exclusively vegetarian. It’s a mystery to scientists how our human ancestors met the calorie demands to develop and sustain our larger brains.

A meat-centered paradigm for human evolution hypothesizes that an ape population began more actively hunting and eating small game, which became an evolutionary stepping stone to the human behavior of hunting large animals.

The paper argues that this theory does not make nutritional sense. “The meat of wild animals is lean,” Thompson says. “It actually takes more work to metabolize lean protein than you get back.”

In fact, eating lean meat without a good source of fat can lead to protein poisoning and acute malnutrition. Early Arctic explorers, who attempted to survive on rabbit meat exclusively, described the condition as “rabbit starvation.”

This protein problem, coupled with the energy required for an upright ape with small canines to capture and eat small animals, would seem to rule out eating meat as a pathway to fueling brain growth, Thompson says.

The new paper presents a new hypothesis, going back about 4 million years, to the Pliocene. As the human ancestor began walking primarily on two legs, heavily forested regions of Africa were breaking into mosaics, creating open grasslands.

“Our human ancestors were likely awkward creatures,” Thompson says. “They weren’t good in trees, like chimpanzees are, but they weren’t necessarily all that good on the ground either. So, what did the first upright walking apes in our lineage do to make them so successful? At this stage, there was already a small increase in the size of the brains. How were they feeding that?”

Thompson and her co-authors propose that our early ancestors wielded rocks as they foraged on open grassland. After a predator had finished eating a large mammal, these upright apes explored the leftovers by smashing them and discovered the marrow hidden in the limb bones.

“The bones sealed up the marrow like a Tupperware container, preventing bacterial growth,” Thompson says. And the only things that could crack open these containers, she adds, were the bone-cracking jaws of hyenas or a clever ape wielding a rock.

The hypothesis offers an explanation for how the human ancestor may have garnered the extra calories needed to foster a larger brain, long before there is evidence for controlled fire, which could have mitigated the problem of bacteria in rotting, scavenged meat. The fat hypothesis also predates by more than 1 million years most evidence for even basic toolmaking of simple stone flakes.

Scientists ought to begin looking for evidence of bone-smashing behavior in early human ancestors, Thompson said.

“Paleoanthropologists are looking for mostly complete bones, and then concentrating on identifying the animal that died,” Thompson says. “But instead of just wondering about the bone’s creature of origin, we should be asking, ‘What broke this bone?’ We need to start collecting tiny pieces of shattered bone to help piece together this kind of behavioral information.”

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An African grassland environment like this formed a typical backdrop for early human scavenging.

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Article Source: Yale University news release

*https://www.journals.uchicago.edu/doi/full/10.1086/701477

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AKSON RUSSIAN SCIENCE COMMUNICATION ASSOCIATION—Scientists from Russia and Uzbekistan found a unified fortification system on the northern border of ancient Bactria. This country existed in the 3rd century BC. The fortress found blocked the border and protected the oases of Bactria from nomadic raids. During the excavations, scientists revealed the fortress citadel, drew up a detailed architectural plan and collected rich archaeological material providing evidence for the construction, life, and the death of the fortress as a result of the assault.

In the 4th century BC, a significant part of the Central Asia territory belonged to Bactria, which, as a separate satrapy, was part of the Achaemenid Empire. In 329 BC Bactria became part of the Alexandrian empire and after his death joined the kingdom of Seleucid: the largest Hellenistic state in the East, created by the commander Alexander Seleucius I Nicator and his son Antiochus I Soter. Gradually, the state became weakened by numerous military campaigns and the struggle for power. As a result, once flourishing Bactria ceased to exist in the 2nd century BC when Iranian-speaking nomads from the northern territories, the Saki and Yuadzhi, invaded the country.

Recently, Russian scientists completed excavations in this area and determined the fortress construction time: about 95-90 years of the 3rd century BC, the time of the Antiochus I reign and the very beginning of the formation of the Seleucid state. The fortress was inhabited for about 150 years.

The fortress consisted of a diamond-shaped main quadrangle, a triangular citadel (phylacterion) surrounded by powerful double walls with an internal gallery about nine meters wide, and extension walls, which were fortified with 13 rectangular bastions-towers, three of which were also outboards. Outside the fortress there was a marketplace where local residents brought goods needed by the garrison soldiers.

The archaeologists recorded the location of each item using a total station or GPS, and then created a single plan tied to the terrain. As a result, the scientists managed to establish where the marketplace was, the road to the entrance to the fortress, and determined the location of the assault: there were more than 200 arrowheads, combat darts and troops. It is curious that the proposed battlefield is located to the east of the fortress, which suggests a possible environment or the breakthrough of the enemy through a system of border fortifications.

The warriors who defended Uzundar wore armor: in the inside-wall room of the south-western fortified wall, archaeologists discovered armor-clad plates and two right-handed iron heads from helmets. So far, scientists can not exactly determine what type of helmets these patches represented—a pseudoattical or Melos group, so it is still possible that these are the same helmets that the Alexandrian forces wore during the Antiochus I Soter period.

“This findings are sensational: direct analogies are known from the Takhti-Sanga temple, but there they were bronze, and we found iron fragments in Uzundar. To date, there are only a few specimens and sculptures with which to compare these cheeks and determine their type. We also found fastening details, which provide important information on manufacturing technology, according to tradition, but to answer these questions requires lengthy research,” says Nigora Dvurechenskaya, researcher at the Department of Classical Archaeology, Head of the Bactrian detachment of the Central Asian Archaeological Expedition.

In addition to weapons, archaeologists have collected a large number of ceramics, as well as a rich numismatic collection: about 200 coins of very good preservation identified as coins of Antiochus I and all the rulers of the Greco-Bactrian kingdom from Diodot to Heliocles of very different denominations: from silver drachmas to copper mites. Such a variety proves that Bactria at the very beginning of the Seleucid kingdom formation was part of a developed monetary circulation system. Thus, the materials of Uzundara allow us o study and reconstruct all spheres of life of the Seleucid and Greco-Bactrian fortresses.

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View of the Uzundara citadel from above. Nigora Dvurechenskaya et al.

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Article Source:Edited from the Akson Russion Science Communication Association news release.

If you liked this article, you may like Lady Moon, a previously published Popular Archaeology premium article (now free) about the discovery of a lost ancient city in the kingdom of Bactria. 

PLOS—Ancient cremated human remains, despite being deformed, still retain sexually diagnostic physical features, according to a study released January 30, 2019 in the open-access journal PLOS ONE by Claudio Cavazzuti of Durham University, UK and colleagues. The authors provide a statistical approach for identifying traits that distinguish male and female remains within a population.

The ability to determine the sex of ancient human remains is essential for archaeologists tracking demographic data and cultural practices across civilizations. Large burial assortments can provide representative samples of ancient populations, but the process of cremation, which has been popular for millennia, warps and fragments bone, altering skeletal measurements that archaeologists might otherwise use to sex an individual. Few studies have attempted to identify skeletal traits that are sexually diagnostic after cremation. Thus, archaeologists lack a reliable method to sex cremated remains in the absence of external clues such as gendered grave goods.

Cavazzuti and colleagues aimed to resolve this deficiency by measuring 24 skeletal traits across 124 cremated individuals with clearly engendered grave goods (such as weapons for men and spindle whorls for women) from five Italian necropolises dating between the 12th and 6th centuries BCE. Assuming that gender largely correlates to sex, the authors statistically compared sex to variation in anatomical traits. Of the 24 traits examined, eight predicted sex with an accuracy of 80% or more, a reliability score similar to those obtained for uncremated ancient remains.

The authors conclude that anatomical sex determination is possible in cremated remains, though they caution that the measurements identified in this study differ from those used to sex modern cremated remains, indicating that sexually diagnostic traits differ between populations across time and space. Nonetheless, they suggest that, for ancient populations with large sample sizes, the statistical methods used in this study may be able to differentiate male and female remains.

Cavazzuti adds: “This is a new method for supporting the sex determination of human cremated remains in antiquity. Easy, replicable, reliable.”

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Bone fragments used for diagnostic study. Claudio Cavazzuti, 2018

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Article Source: PLOS news release

*Cavazzuti C, Bresadola B, d’Innocenzo C, Interlando S, Sperduti A (2019) Towards a new osteometric method for sexing ancient cremated human remains. Analysis of Late Bronze Age and Iron Age samples from Italy with gendered grave goods. PLoS ONE 14(1): e0209423. https://doi.org/10.1371/journal.pone.0209423

UNIVERSITY OF OXFORD—A much debated ancient human skull from Mongolia has been dated and genetically analyzed, showing that it is the earliest modern human yet found in the region, according to new research from the University of Oxford. Radiocarbon dating and DNA analysis have revealed that the only Pleistocene hominin fossil discovered in Mongolia, initially called Mongolanthropus, is in reality a modern human who lived approximately 34 – 35 thousand years ago.

The skullcap, found in the Salkhit Valley northeast Mongolia is, to date, the only Pleistocene hominin fossil found in the country.

The skullcap is mostly complete and includes the brow ridges and nasal bones. The presence of archaic or ancient features have led in the past to the specimen being linked with uncharacterized archaic hominin species, such as Homo erectus and Neanderthals. Previous research suggested ages for the specimen ranging from the Early Middle Pleistocene to the terminal Late Pleistocene.

The Oxford team re-dated the specimen to 34,950 – 33,900 years ago. This is around 8,000 years older than the initial radiocarbon dates obtained on the same specimen.

To make this discovery, the Oxford team employed a new optimized technique for radiocarbon dating of heavily contaminated bones. This method relies on extracting just one of the amino acids from the collagen present in the bone. The amino acid hydroxyproline (HYP), which accounts for 13% of the carbon in mammalian collagen, was targeted by the researchers. Dating this amino acid allows for the drastic improvement in the removal of modern contaminants from the specimens.

The new and reliable radiocarbon date obtained for the specimen shows that this individual dates to the same period as the Early Upper Palaeolithic stone tool industry in Mongolia, which is usually associated with modern humans. The age is later than the earliest evidence for anatomically modern humans in greater Eurasia, which could be in excess of 100,000 years in China according to some researchers.

This new result also suggests that there was still a significant amount of remaining contamination in the sample during the original radiocarbon measurements. Additional analyses performed in collaboration with scientists at the University of Pisa (Italy) confirmed that the sample was heavily contaminated by the resin that had been used to cast the specimen after its discovery.

“The research we have conducted shows again the great benefits of developing improved chemical methods for dating prehistoric material that has been contaminated, either in the site after burial, or in the museum or laboratory for conservation purposes.” said Dr Thibaut Devièse first author on the new paper and leading the method developments in compound specific analysis at the University of Oxford. “Robust sample pretreatment is crucial in order to build reliable chronologies in archaeology.”

DNA analyses were also performed on the hominin bones by Professor Svante Pääbo’s team at the Max-Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Diyendo Massiliani and colleagues reconstructed the complete mitochondrial genome of the specimen. It falls within a group of modern human mtDNAs (haplogroup N) that is widespread in Eurasia today, confirming the view of some researchers that the cranium is indeed a modern human. Further nuclear DNA work is underway to shed further light on the genetics of the cranium.

‘This enigmatic cranium has puzzled researchers for some time”, said Professor Tom Higham, who leads the PalaeoChron research group at the University of Oxford. “A combination of cutting edge science, including radiocarbon dating and genetics, has now shown that this is the remains of a modern human, and the results fit perfectly within the archaeological record of Mongolia which link moderns to the Early Upper Palaeolithic industry in this part of the world.’

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The Salkhit skullcap © Maud Dahlem, Muséum de Toulouse (France).

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This is a view of the find spot in the Salkhit Valley, Mongolia © Institute of History and Archaeology & Academy of Sciences (Mongolia).

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Article Source: University of Oxford news release

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MAX PLANCK INSTITUTE FOR THE SCIENCE OF HUMAN HISTORY—Investigations into what it means to be human have often focused on attempts to uncover the earliest material traces of ‘art’, ‘language’, or technological ‘complexity’. More recently, however, scholars have begun to argue that more attention should be paid to the ecological uniqueness of our species. A new study, published in Archaeological Research in Asia, reviews the palaeoecological information associated with hominin dispersals into Southeast Asia and Oceania throughout the Pleistocene (1.25 Ma to 12 ka). Our species’ ability to specialize in the exploitation of diverse and ‘extreme’ settings in this part of the world stands in stark contrast to the ecological adaptations of other hominin taxa, and reaffirms the utility of exploring the environmental adaptations of Homo sapiens as an avenue for understanding what it means to be human.

The paper, published by scientists from the Max Planck Institute for the Science of Human History focuses on hominin movements across the supposed ‘Movius Line’ a boundary previously argued to separate populations with different cultural and cognitive capacities. While such divisions and assumptions are now clearly outdated, the authors argue that focus on this part of the world may, instead, be used to study the different patterns of colonization of diverse tropical and maritime habitats by different members of our ancestral line. As Noel Amano, co-author on the study states, ‘analysis of biogeochemical records, animal assemblages, and fossil plant records associated with hominin arrival can be used to reconstruct the degree to which novel or specialized adaptations were required at a given place and time’.

Southeast Asia offers a particularly exciting region in this regard as such records can be linked to a variety of hominins throughout the Pleistocene, including Homo erectus, Homo floresiensis(or ‘the Hobbit’), and Homo sapiens. As Patrick Roberts, lead author of the study states the accumulated evidence shows, ‘While earlier members of our genus appear to have followed riverine and lacustrine corridors, Homo sapiens specialized in adaptations to tropical rainforests, faunally depauperate island settings, montane environments, and deep-water marine habitats.’ The authors hope that, in the future, the growth of new methods and records for determining past hominin ecologies will enable similar comparisons to be undertaken in different parts of the world, further testing the unique capacities of our species during its global expansion.

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Lowland Palawan, the Philippines — Southeast Asia offers a particularly exciting region in regard to early hominin movements across the supposed “Movius Line”, a boundary previously argued to separate populations. Records from the region can be linked to a variety of hominins throughout the Pleistocene, including Homo erectus, Homo floresiensis (or “the Hobbit”), and Homo sapiens. Noel Amano

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Article Source: Max Planck Institute for the Science of Human History news release

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UNIVERSITY COLLEGE LONDON—Neanderthals have been imagined as the inferior cousins of modern humans, but a new study by archaeologists at UCL reveals for the first time that they produced weaponry advanced enough to kill at a distance.

The study, published in Scientific Reports, examined the performance of replicas of the 300,000 year old Schöningen spears – the oldest weapons reported in archaeological records – to identify whether javelin throwers could use them to hit a target at distance.

Dr Annemieke Milks (UCL Institute of Archaeology), who led the study, said: “This study is important because it adds to a growing body of evidence that Neanderthals were technologically savvy and had the ability to hunt big game through a variety of hunting strategies, not just risky close encounters. It contributes to revised views of Neanderthals as our clever and capable cousins.”

The research shows that the wooden spears would have enabled Neanderthals to use them as weapons and kill at distance. It is a significant finding given that previous studies considered Neanderthals could only hunt and kill their prey at close range.

The Schöningen spears are a set of ten wooden throwing spears from the Palaeolithic Age that were excavated between 1994 and 1999 in an open-cast lignite mine in Schöningen, Germany, together with approximately 16,000 animal bones.

The Schöningen spears represent the oldest completely preserved hunting weapons of prehistoric Europe so far discovered. Besides Schöningen, a spear fragment from Clacton-on-Sea, England dating from 400,000 years ago can be found at the Natural History Museum, London.

The study was conducted with six javelin athletes who were recruited to test whether the spears could be used to hit a target at a distance. Javelin athletes were chosen for the study because they had the skill to throw at high velocity, matching the capability of a Neanderthal hunter.

Owen O’Donnell, an alumnus of UCL Institute of Archaeology, made the spear replicas by hand using metal tools. They were crafted from Norwegian spruce trees grown in Kent, UK. The surface was manipulated at the final stage with stone tools, creating a surface that accurately replicated that of a Pleistocene wooden spear. Two replicas were used, weighing 760g and 800g, which conform to ethnographic records of wooden spears.

The javelin athletes demonstrated that the target could be hit at up to 20 meters, and with significant impact which would translate into a kill against prey. This is double the distance that scientists previously thought the spears could be thrown, demonstrating that Neanderthals had the technological capabilities to hunt at a distance as well as at close range.

The weight of the Schöningen spears previously led scientists to believe that they would struggle to travel at significant speed. However, the study shows that the balance of weight and the speed at which the athletes could throw them produces enough kinetic energy to hit and kill a target.

Dr Matt Pope (UCL Institute of Archaeology), co-author on the paper, said: “The emergence of weaponry – technology designed to kill – is a critical but poorly established threshold in human evolution.

“We have forever relied on tools and have extended our capabilities through technical innovation. Understanding when we first developed the capabilities to kill at distance is therefore a dark, but important moment in our story.”

Dr Milks concluded: “Our study shows that distance hunting was likely within the repertoire of hunting strategies of Neanderthals, and that behavioral flexibility closely mirrors that of our own species. This is yet further evidence narrowing the gap between Neanderthals and modern humans.”

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A Schoningen spear in situ. P. Pfarr NLD

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This is a replica spear produced by Owen O’Donnell, an alumnus of UCL Institute of Archaeology. Annemieke Milks (UCL)

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The spear fragment from Clacton-on-Sea, England dating from 400,000 years ago. Annemieke Milks (UCL)

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Article Source: University College London news release

*Annemieke Milks, David Parker & Matt Pope. ‘External ballistics of Pleistocene hand-thrown spears: experimental performance data and implications for human evolution’ is published in Scientific Reports on Friday 25 January 2019.

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UNIVERSITY OF SEVILLE—A new study of Bajondillo Cave (Málaga) by a team of researchers based in Spain, Japan and the UK, coordinated from the Universidad de Sevilla, reveals that modern humans replaced Neanderthals at this site approximately 44,000 years ago. The research, to be published in Nature Ecology and Evolution, shows that the replacement of Neanderthals by modern humans in southern Iberia began early, rather than late, in comparison to the rest of Western Europe.

Western Europe is a key area for understanding the timing of the replacement of Neanderthals by early modern humans (AMH). Typically in Western Europe, late Neanderthals are associated with stone tools belonging to Mousterian industries (named after the Neanderthal site of Le Moustier in France), while the earliest modern humans are associated with succeeding Aurignacian industries (named after the French site of Aurignac).

The final replacement of Neanderthals by AMH in western Europe is usually dated to around 39,000 years ago. However, it’s claimed that the southern Iberian region documents the late survival of the Mousterian, and therefore Neanderthals, to about 32,000 years ago, with no evidence for the early Aurignacian found elsewhere in Europe.

This new dating study of Bajondillo Cave instead calibrates the replacement of Mousterian industries by Aurignacian ones there to between ~45-43,000 years ago, raising questions about the late survival of Neanderthals in southern Iberia. Further research is necessary to determine whether the new Bajondillo dating indicates an earlier replacement of Neanderthals across the whole of southern Iberia, or in fact, an altogether more complex scenario of co-existence over several millennia.

Co-author Jimenez-Espejo explains that the takeover by modern humans at the site at Bajondillo was not associated with a Heinrich (severe cooling) event. “Heinrich events represent the harshest and most variable climate conditions in Western Europe at the millennial scale, but at least in this Mediterranean coastal region, they did not control the Mousterian to Aurignacian transition.”

This research also highlights coastal corridors as the favored routes for early AMH.

Professor Chris Stringer, Research Leader at the Natural History Museum and co-author of the study, said ‘Finding such an early Aurignacian from a cave so close to the sea adds to speculation that the Mediterranean coast could have been used by modern humans dispersing into Europe. This dating also fits with growing evidence that Homo sapiens had already spread rapidly across much of Eurasia more than 40,000 years ago’.

Considering the importance of coastal regions, co-author Arturo Morales-Muñiz suggested that the Bajondillo evidence also revives the idea that the Strait of Gibraltar could have been a potential dispersal route for early modern humans out of Africa.

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Bajondillo Cave and Malága Bay (Spain) at the end of the 1950s. Foreground images show Neanderthal (La Chapelle-aux-Saints, France, left) and early Modern Human (from Abri Cro-Magnon, France, right) skulls. Left lithic tool corresponds to Mousterian technology, and right Aurignacian, both recovered at Bajondillo Cave. University of Seville

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These are selected archaeological sites in Western Europe with Aurignacian industries actually or potentially older than 42,000 years, including Bajondillo Cave (Spain). Orange arrows indicate potential expansion routes across Europe at low sea level. Images on the left show a Neanderthal skull (La Chapelle-aux-Saints, France) and a Mousterian tool recovered at Bajondillo Cave. On the right the images show a Modern Human skull (Abri-Cro-Magnon, France) and an Aurignacian tool recovered at Bajondillo Cave. University of Seville

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Article Source: University of Seville news release

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UNIVERSITY COLLEGE LONDON—Skin color is one of the most visible and variable traits among humans and scientists have always been curious about how this variation evolved. Now, a study* of diverse Latin American populations led by UCL geneticists has identified new genetic variations associated with skin color.

The study, published in the journal Nature Communications, found that the variation of light skin among Eurasian people evolved independently from different genetic backgrounds.

The genetic study analyzed pigmentation in over 6,000 Latin Americans, who have a mix of Native American, European and African ancestry.

It is well established that Native Americans are genetically closely related to East Asians, the initial settlement of the Americas occurring some 15-20,000 years ago, through migration from Eastern Siberia into North America. As a consequence, genetic variations in Native Americans are often shared with East Asians.

This study identifies five new associated regions involving skin, eye and hair color. Genes affecting skin color in Europeans have been extensively studied, but here researchers identified an important variation in the gene MFSD12 seen uniquely in East Asians and Native Americans.

They show it was under natural selection in East Asians after they split from Europeans around 40,000 years ago, and was then carried over to America by ancient migrations of Native Americans. It is the first time this gene has been linked to skin color in Native Americans and East Asians.

Dr Kaustubh Adhikari (UCL Genetics Institute), said: “Our work demonstrates that lighter skin color evolved independently in Europe and East Asia. We also show that this gene was under strong natural selection in East Asia, possibly as adaptation to changes in sunlight levels and ultraviolet radiation.”

Human physical diversity has fascinated biologists for centuries and despite the discovery of hundreds of genes related to such variation, there is still a lot to be understood in order to gain a fuller picture. Scientists have been calling for more diversity in genetics research to ensure that everyone benefits from the medical outcomes of research.

Only recently scientists published the first major study on the genes linked to skin tone diversity in Africa. Latin Americans are similarly underrepresented in genetics research, in particular in pigmentation research.

“It is commonly thought that variation in pigmentation, such as skin color, in Latin Americans primarily arises due to people’s varying degree of European or African ancestry. But our new study shows that there is variation inherited from their Native ancestors as well”, said Dr Javier Mendoza-Revilla (UCL Genetics Institute).

Professor Desmond Tobin (Charles Institute of Dermatology, University College Dublin) explained: “The pigment melanin determines our hair, skin and eye color. This gene MFSD12 influences how melanin is produced and stored in the skin, thus affecting our skin color. A darker skin produces more melanin, which can help prevent UV light from damaging our DNA and so offers protection against skin cancer.”

“Interestingly, this gene also turned up in the skin color study in Africans, but the variants were entirely different than those we observe in our study, highlighting the huge genetic diversity in humans and the need to diversify our study populations”, emphasized Professor Andres Ruiz-Linares (UCL Genetics Institute), who led the CANDELA project spanning participants from five countries: Brazil, Colombia, Chile, Mexico and Peru.

In addition to skin tone variation, the scientists also noted a wide variation in eye color among Latin Americans. “Just like skin color, early research on eye color was Europe-centric, and mostly focused on the distinction between blue vs. brown eyes. But we show that eye color is a broad continuum, and by studying the subtler variation within brown to black, we found two new genes linked to it”, said Dr Anood Sohail (University of Cambridge).

The study’s findings help explain the variation of skin, hair and eye color of Latin Americans, shed light on human evolution, and inform an understanding of the genetic risk factors for conditions such as skin cancer.

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Study sheds new light on the evolution of skin color. Image from Wikimedia Commons

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Article Source: University College London news release

*Kaustubh Adhikari, Javier Mendoza-Revilla, Anood Sohail, et.al. ‘A GWAS in Latin Americans highlights the convergent evolution of lighter skin pigmentation in Eurasia’ will be published in Nature on Monday 21st January

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DARTMOUTH COLLEGE—The fossil site of Malapa in the Cradle of Humankind, South Africa, discovered by Lee Berger of the University of the Witwatersrand, Johannesburg, in August 2008, has been one of the most productive sites of the 21st century for fossils of early human ancestors or hominins. A new hominin species, Australopithecus sediba (Au. sediba), was named by Berger and his colleagues, following the discovery of two partial skeletons just under two million years old, a juvenile male individual– Malapa Hominin 1 (MH1)– and an adult female, Malapa Hominin 2 (MH2). The skeletons are under the custodianship of the University of the Witwatersrand, where they are being kept. Each partial skeleton is more complete than the famous “Lucy,” an Australopithecus afarensis or early hominin species found in 1974 in Ethiopia. Now, 10 years later after the discovery of Malapa, full descriptions of the hominin fossil material, as well as raw measurement data and surface scans of the fossils, available at Morphosource.org, are published in a special issue of the open access journal, PaleoAnthropology.

“The anatomies we are seeing in Australopithecus sediba are forcing us to reassess the pathway by which we became human,” explained co-editor Jeremy DeSilva, an associate professor of anthropology at Dartmouth, and co-author of four of the papers, including ones on the lower limb and computer animation of the walking mechanics.

The special issue is comprised of nine separate papers analyzing: the skull; vertebral column and thorax; pelvis; upper limb: shoulder, arm and forearm; hand; and lower limb fossils of Au. sediba; along with descriptions of body size and proportions; and walking mechanics, including a 3D computer animation of Au. sediba walking. The papers are co-authored by leading anthropologists, who are members of the main group of researchers that Berger had assembled for the study of the Malapa material. The research draws on approximately 135 specimens from MH1, MH2 and what may be a third individual, all of which were uncovered between 2008 and 2016.

The researchers find that Au. sediba is in fact a unique species, refuting earlier critics who questioned its validity as a species. Au. sediba is distinct from both Australopithecus africanus, with which it shares a close geographic proximity, and from early members of the genus Homo (e.g., Homo habilis) in both East and South Africa; yet, it also shares features with both groups, suggesting a close evolutionary relationship.

“Our findings challenge a traditional, linear view of evolution. It was once thought that a fossil species a million years younger than Lucy would surely look more human-like. For some anatomies of Australopithecus sediba, like the knee, that is true. But, for others, like the foot, it is not. Instead, what we’re witnessing here are parallel lineages, illustrating how different hominin experiments were unfolding early in our complex evolutionary history,” explained DeSilva.

These new research papers address critiques of Au. sediba from other colleagues while correcting some initial observations and testing new ideas regarding this extraordinary collection. For example, other researchers hypothesized that this was more than one species due to the differences in the size and shape of the vertebrae. “The differences in these vertebrae can simply be attributed to their developmental age differences: the juvenile individual’s vertebrae have not yet completed growth, whereas the adult’s vertebra growth is complete,” explained co-editor Scott A. Williams, an associate professor of anthropology in the Center for the Study of Human Origins at New York University, and co-author of two of the papers, including the one on the vertebral column.

The special issue also finds that Au. sediba was well adapted to terrestrial bipedalism or walking on just two feet but also spent significant time climbing in trees, perhaps for foraging and protection from predators.

This larger picture sheds light on the lifeways of Au. sediba and also (whether directly or indirectly) on a major transition in hominin evolution, that of the largely ape-like species included broadly in the genus Australopithecus to the earliest members of our own genus, Homo.

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The cranium of Malapa hominid 1 (MH1) from South Africa, named “Karabo”. The combined fossil remains of this juvenile male is designated as the holotype for Australopithecus sediba. Photo by Brett Eloff. Courtesy Profberger and Wits University, Wikimedia Commons

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Lee Berger with the partial skeleton of Australopithecus sediba. Photo by Brett Eloff, courtesy Lee Berger and the University of the Witwatersrand. Lee Berger, Wikimedia Commons

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Article Source: Dartmouth College news release

The Papers

PaleoAnthropology (2018)

Guest Editors: Scott A. Williams, Jeremy M. DeSilva

1. Malapa at 10: Introduction to the special issue on Australopithecus sediba (Williams, S.A., DeSilva, J.M., and de Ruiter, D.J.)
2. The skull of Australopithecus sediba (de Ruiter, D.J., Carlson, K.B., Brophy, J.K., Churchill, S.E., Carlson, K.J., and Berger, L.R.)
3. The vertebrae, ribs, and sternum of Australopithecus sediba (Williams, S.A., Meyer, M.R., Nalla, S., García-Martínez, D., Nalley, T.K., Eyre, J., Prang, T.C., Bastir, M., Schmid, P., Churchill, S.E., and Berger, L.R.)
4. The shoulder, arm, and forearm of Australopithecus sediba (Churchill, S.E., Green, D.J., Feuerriegel, E.M., Macias, M.E., Mathews, S., Carlson, K.J., Schmid, P., and Berger, L.R.)
5. The hand of Australopithecus sediba (Kivell, T.L., Churchill, S.E., Kibii, J.M., Schmid, P., and Berger, L.R.)
6. The pelvis of Australopithecus sediba (Churchill, S.E., Kibii, J.M., Schmid, P., Reed, N.D., and Berger, L.R.)
7. The anatomy of the lower limb skeleton of Australopithecus sediba (DeSilva, J.M., Carlson, K.J., Claxton, A., Harcourt-Smith, W.E.H., McNutt, E.J., Sylvester, A.D., Walker, C.S., Zipfel, B., Churchill, S.E., and Berger, L.R.)
8. Body size and proportions of Australopithecus sediba (Holliday, T.W., Churchill, S.E., Carlson, K.J., DeSilva, J.M., Schmid, P., Walker, C.S., and Berger, L.R.)
9. Computer animation of the walking mechanics of Australopithecus sediba (Zhang, A.Y. and DeSilva, J.M.)

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CENTER FOR GENOMIC REGULATION—By combining deep learning algorithms and statistical methods, investigators from the Institute of Evolutionary Biology (IBE), the Centro Nacional de Análisis Genómico(CNAG-CRG) of the Centre for Genomic Regulation (CRG) and the Institute of Genomics at the University of Tartu have identified, in the genome of Asiatic individuals, the footprint of a new hominid who cross bred with its ancestors tens of thousands of years ago.

Modern human DNA computational analysis suggests that the extinct species was a hybrid of Neanderthals and Denisovans and cross bred with Out of Africa modern humans in Asia. This finding would explain that the hybrid found this summer in the caves of Denisova-the offspring of a Neanderthal mother and a Denisovan father-, was not an isolated case, but rather was part of a more general introgression process.

The study, published in Nature Communications, uses deep learning for the first time ever to account for human evolution, paving the way for the application of this technology in other questions in biology, genomics and evolution.

Humans had descendants with an species that is unknown to us

One of the ways of distinguishing between two species is that while both of them may cross breed, they do not generally produce fertile descendants. However, this concept is much more complex when extinct species are involved. In fact, the story told by current human DNA blurs the lines of these limits, preserving fragments of hominids from other species, such as the Neanderthals and the Denisovans, who coexisted with modern humans more than 40,000 years ago in Eurasia.

Now, investigators of the Institute of Evolutionary Biology (IBE), the Centro Nacional de Análisis Genómico (CNAG-CRG) of the Centre for Genomic Regulation (CRG), and the University of Tartu have used deep learning algorithms to identify a new and hitherto-unknown ancestor of humans that would have interbred with modern humans tens of thousands of years ago. “About 80,000 years ago, the so-called Out of Africa occurred, when part of the human population, which already consisted of modern humans, abandoned the African continent and migrated to other continents, giving rise to all the current populations”, explained Jaume Bertranpetit, principal investigator at the IBE and head of Department at the UPF. “We know that from that time onwards, modern humans cross bred with Neanderthals in all the continents, except Africa, and with the Denisovans in Oceania and probably in South-East Asia, although the evidence of cross-breeding with a third extinct species had not been confirmed with any certainty”.

Deep learning: deciphering the keys to human evolution in ancient DNA

Hitherto, the existence of the third ancestor was only a theory that would explain the origin of some fragments of the current human genome (part of the team involved in this study had already posed the existence of the extinct hominid in a previous study). However, deep learning has made it possible to make the transition from DNA to the demographics of ancestral populations.

The problem the investigators had to contend with is that the demographic models they have analysed are much more complex than anything else considered to date and there were no statistic tools available to analyse them. Deep learning “is an algorithm that imitates the way in which the nervous system of mammals works, with different artificial neurons that specialize and learn to detect, in data, patterns that are important for performing a given task”, stated Òscar Lao, principal investigator at the CNAG-CRG and an expert in this type of simulations. “We have used this property to get the algorithm to learn to predict human demographics using genomes obtained through hundreds of thousands of simulations. Whenever we run a simulation we are traveling along a possible path in the history of humankind. Of all simulations, deep learning allows us to observe what makes the ancestral puzzle fit together”.

It is the first time that deep learning has been used successfully to explain human history, paving the way for this technology to be applied in other questions in biology, genomics and evolution.

An extinct hominid could explain the history of humankind

The deep learning analysis has revealed that the extinct hominid is probably a descendant of the Neanderthal and Denisovan populations. The discovery of a fossil with these characteristics this summer would seem to endorse the study finding, consolidating the hypothesis of this third species or population that coexisted with modern human beings and mated with them. “Our theory coincides with the hybrid specimen discovered recently in Denisova, although as yet we cannot rule out other possibilities”, said Mayukh Mondal, an investigator of the University of Tartu and former investigator at the IBE.

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Jaume Bertranpetit, researcher at the Institute of Evolutionary Biology, and Oscar Lao, researcher at the Centre for Genomic Regulation, co-led the study. Pilar Rodriguez

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Article Source: Center for Genomic Regulation news release

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UNIVERSITY OF COPENHAGEN – FACULTY OF HUMANITIES—11,500 years ago in what is now northeast Jordan, people began to live alongside dogs and may also have used them for hunting, a new study from the University of Copenhagen shows. The archaeologists suggest that the introduction of dogs as hunting aids may explain the dramatic increase of hares and other small prey in the archaeological remains at the site.

Dogs were domesticated by humans as early as 14,000 years ago in the Near East, but whether this was accidental or on purpose is so far not clear. New research published in the Journal of Anthropological Archaeology by a team of archaeologists from the University of Copenhagen and University College London may suggest that humans valued the tracking and hunting abilities of early dogs more than previously known.

A study of animal bones from the 11,500 year old settlement Shubayqa 6 in northeast Jordan not only suggests that dogs were present in this region at the start of the Neolithic period, but that humans and dogs likely hunted animals together:

“The study of the large assemblage of animal bones from Shubayqa 6 revealed a large proportion of bones with unmistakable signs of having passed through the digestive tract of another animal; these bones are so large that they cannot have been swallowed by humans, but must have been digested by dogs,” explained zooarchaeologist and the study’s lead author Lisa Yeomans.

Lisa Yeomans and her colleagues have been able to show that Shubayqa 6 was occupied year round, which suggests that the dogs were living together with the humans rather than visiting the site when there were no inhabitants:

“The dogs were not kept at the fringes of the settlement, but must have been closely integrated into all aspects of day-to-day life and allowed to freely roam around the settlement, feeding on discarded bones and defecating in and around the site.”

Can new hunting techniques account for the increase in small prey?

When Yeomans and her co-authors sifted through the analyzed data, they also noted a curious increase in the number of hares at the time that dogs appeared at Shubayqa 6. Hares were hunted for their meat, but Shubayqa 6’s inhabitants also used the hare bones to make beads. The team think that it is likely that the appearance of dogs and the increase in hares are related.

“The use of dogs for hunting smaller, fast prey such as hares and foxes, perhaps driving them into enclosures, could provide an explanation that is in line with the evidence we have gathered. The long history of dog use, to hunt both small as well as larger prey, in the region is well known, and it would be strange not to consider hunting aided by dogs as a likely explanation for the sudden abundance of smaller prey in the archaeological record,” said Lisa Yeomans.

“The shift may also be associated with a change in hunting technique from a method, such as netting, that saw an unselective portion of the hare population captured, to a selective method of hunting in which individual animals were targeted. This could have been achieved by dogs.”

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Selection of gazelle bones from Space 3 at Shubayqa 6 displaying evidence for having been in the digestive tract of a carnivore. University of Copenhagen

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One of the excavated structures at the Shubayqa 6 site. University of Copenhagen

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Article Source: University of Copenhagen news release

Read the study, Close companions: Early evidence for dogs in northeast Jordan and the potential impact of new hunting methods, published in Journal of Anthropological Archaeology.

About Shubayqa 6

Shubayqa 6 is situated on the northern edge of the Qa’ Shubayqa, around 130 km northeast of the Jordanian capital, Amman. It is the ?rst substantial early Neolithic settlement identi?ed in the Black Desert and has been under investigation since 2012; this and previous studies demonstrate that settlement in this semi-arid to arid zone was more intensive than previously thought and that the area could sustain large populations of animals and humans.

The excavations were carried out in collaboration with the Department of Antiquities of Jordan as part of a project funded by the Danish Council for Independent Research, Danish Institute in Damascus and H.P. Hjerl Mindefondet for Dansk Palæstinaforsking.

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OHIO STATE UNIVERSITY, COLUMBUS, Ohio – A relative of modern humans that lived at least 104,000 years ago in northern China showed evidence of dental growth and development very similar to that of people today, a new study found.

An international team of scientists performed the first systematic assessment of dental growth and development in an East Asian archaic hominin fossil that is known as the Xujiayao juvenile. The fossil is of a 6 1/2-year-old who lived between 104,000 and 248,000 years ago found at the Xujiayao site in northern China.

The researchers were surprised to find that in most ways, this child’s dental development was very similar to what you would find in a child today, said Debbie Guatelli-Steinberg, co-author of the study and professor of anthropology at The Ohio State University. “The Xujiayao juvenile is the oldest fossil found in east Asia that has dental development comparable to modern humans,” Guatelli-Steinberg said.

“It may suggest that these archaic humans had a slow life history like modern humans, with a prolonged period of childhood dependency.”

The study was published today (1-16-19) in the journal Science Advances.

Teeth provide some of the best data anthropologists have about the growth and development of our ancient ancestors, she said. That’s because growth lines in teeth retain a record of dental development.

Compared to our primate cousins, modern humans – including their teeth – take a long time to form and develop. Anthropologists believe this characteristic is associated with humans’ longer periods of child dependency – how long a juvenile relies on support from a caregiver.

Among other techniques, the researchers used synchrotron X-ray imaging to look inside the fossil to see the internal structure of the teeth, including growth lines that revealed the rate of tooth development.

The results were surprising in part because so many other features of this hominin are not modern, such as the shape and thickness of the skull and the large size of the teeth, according to the researchers. “We don’t know exactly where this enigmatic East Asian hominin fits in human evolution,” said Song Xing, lead author of the study, who is at the Chinese Academy of Sciences in Beijing. “It has some affinities to archaic human relatives like the Denisovans and Neanderthals with, as we found, some more modern features. It is a strange mosaic.”

Using the growth lines in the teeth, the researchers estimated the death of the Xujiayao juvenile at about 6 1/2 years of age, said study co-author Mackie O’Hara, a graduate student in anthropology at Ohio State. The first molar of this juvenile – what we call the 6-year-molar today – had erupted a few months before death and had started to wear a bit. The root was about three-quarters complete, similar to humans today.

“We found that this juvenile was growing up – at least dentally – according to a schedule similar to that of modern people,” O’Hara said.

Another aspect that was similar to modern humans was the perikymata, which are the incremental growth lines that appear on the surface of the tooth. “We found that the way these perikymata were distributed on the Xujiayao juvenile teeth was close to what we see in modern humans, and not to Neanderthals,” Guatelli-Steinberg said.

Another interesting finding related to the long-period growth line, which is laid down about every eight days in modern humans. “This juvenile had a 10-day rhythm, which you don’t see very often in early hominins,” she said. “Most of the early hominins had a shorter rhythm, closer to seven days. This is another aspect that is much more modern.”

The one aspect of dental development in the Xujiayao juvenile that was not modern was the rate of growth in the roots of the teeth. Here, the juvenile showed relatively fast growth, compared to a slower growth in modern humans.

While the dental development of this juvenile suggested it had a slow life course similar to modern humans, Guatelli-Steinberg cautioned that we don’t know what happens in later childhood in hominins like this one. “It would be interesting to see if dental development in later childhood, such as the growth and development of third molars, was also similar to modern humans,” she said.

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The original Xujiayao fossil. Song Xing, Chinese Academy of Sciences

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The buccal view of the Xujiayao incisor and canine showing the pattern of perikymata distribution. Song Xing and Paul Tafforeau

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Article Sources: Ohio State University and Science Advances news releases

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UNIVERSITY OF SHEFFIELD—Scientists at the University of Sheffield studying ancient DNA have created a tool allowing them to more accurately identify ancient Eurasian populations, which can be used to test an individual’s similarity to ancient people who once roamed the earth.

Currently the study of ancient DNA requires a lot of information to classify a skeleton to a population or find its biogeographical origins.

Now scientists have defined a new concept called Ancient Ancestry Informative Markers (aAIMs) – a group of mutations that are sufficiently informative to identify and classify ancient populations.

The research, led by Dr Eran Elhaik, from the University of Sheffield’s Department of Animal and Plant Sciences, saw the identification of a small group of aAIMs that can be used to classify skeletons to ancient populations.

Dr Elhaik said: “We developed a new method that finds aAIMs efficiently and have proved that it is accurate.”

AIMs (Ancestry Informative Markers) have a long history in science and have been employed for the past decade by health and forensic experts.

But Dr Elhaik said that when his team applied traditional AIMs-finding tools to ancient DNA data, they were disappointed with their low accuracy.

“Ancient populations are much more diverse than modern ones,” he said. “Their diversity was reduced over the years following events such as the Neolithic revolution and the Black Death.

“Although we have many more people today they are all far more similar to each other than ancient people. In addition, the ancient data themselves are problematic due to the large amount of degraded DNA.”

To overcome these challenges, Dr Elhaik developed a specialized tool that identifies aAIMs by combining traditional methodology with a novel one that takes into account a mixture.

“Ancient genomes typically consist of hundreds of thousands and sometimes millions of markers. We demonstrated that only 13,000 markers are needed to make accurate population classifications for ancient genomes and while the field of ancient forensics does not exist yet, these aAIMs can help us get much closer to ancient people.”

He added: “Until now you couldn’t test people for ancient DNA ancestry because commercial microarrays, such as the ones used for genetic genealogy, don’t have a lot of markers relevant for paleogenomics – people could not study their primeval origins.

“This finding of aAIMs is like finding the fingerprints of ancient people. It allows testing of a small number of markers – that can be found in a commonly available array – and you can ask what part of your genome is from Roman Britons or Viking, or Chumash Indians, or ancient Israelites, etc.

“We can ask any question we want about these ancient people as long as someone sequenced these ancient markers. So this paper brings the field of paleogenomics to the public.”

Researchers said to make the study’s findings more accurate for identifying and classifying ancient people throughout the world, the framework and methods of the study should be applied again when more comprehensive ancient DNA databases are available.

The full study Ancient Ancestry Informative Markers for Identifying Fine-Scale Ancient Population Structure in Eurasians is published in the journal Genes.

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The Eurasian landmass, home to many ancient populations.

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Article Source: UNIVERSITY OF SHEFFIELD news release

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EUROPEAN SYNCHROTRON RADIATION FACILITY—Rembrandt van Rijn revolutionized painting with a 3D effect using his impasto technique, where thick paint makes a masterpiece protrude from the surface. Thanks to the ESRF, the European Synchrotron, Grenoble, France, three centuries later an international team of scientists led by the Materials Science and Engineering Department of the Delft University of Technology and the Rijksmuseum have found how he did it. The study is published in Angewandte Chemie.

Impasto is thick paint laid on the canvas in an amount that makes it stand from the surface. The relief of impasto increases the perceptibility of the paint by increasing its light-reflecting textural properties. Scientists know that Rembrandt, epitome of the Dutch Golden Age, achieved the impasto effect by using materials traditionally available on the 17thcentury Dutch colour market, namely lead white pigment (a mixture of hydrocerussite Pb3(CO3)2(OH)2 and cerussite PbCO3), and organic mediums (mainly linseed oil). The precise recipe was, however, unknown until today.

Plumbonacrite, Pb5(CO3)3O(OH)2 is the mysterious, missing ingredient of the impasto effect, researchers from The Netherlands and France have discovered. It is extremely rare in historic paint layers. It has been detected in some samples from 20th century paintings and in a degraded red lead pigment in a Van Gogh painting. “We didn’t expect to find this phase at all, as it is so unusual in Old Masters paintings”, explains Victor Gonzalez, main author of the study and scientist at the Rijksmuseum and Delft University of Technology. “What’s more, our research shows that its presence is not accidental or due to contamination, but that it is the result of an intended synthesis”, he adds.

The European Synchrotron, ESRF, played an essential role in these findings. The team sampled tiny fragments from the Portrait of Marten Soolmans (Rijksmuseum), Bathsheba (The Louvre) and Susanna (Mauritshuis), three of Rembrandt’s masterpieces. Using the ESRF’s beamlines, they quantified the crystalline phases in Rembrandt’s impasto and in the adjacent paint layers, modelled the pigment crystallites morphology and size and obtained crystalline phase distribution maps at the microscale.

The samples were less than 0.1mm in size, requiring the small and intense beam delivered by the synchrotron. The scientists analysed them on two ESRF beamlines, ID22 and ID13, where they combined High-angular Resolution X-Ray Diffraction (HR-XRD) and micro-X-Ray Diffraction (μ-XRD) . “In the past, we have already successfully used the combination of these two techniques to study lead-white based paints. We knew that the techniques can provide us with high quality diffraction patterns and therefore with subtle information about paint composition”, explains Marine Cotte, scientist at the ESRF, 2018 Descartes-Huygens Prize laureate for her research on art conservation.

The analysis of the data showed that Rembrandt modified his painting materials intentionally. “The presence of plumbonacrite is indicative of an alkaline medium. Based on historical texts, we believe that Rembrandt added lead oxide (litharge) to the oil in this purpose, turning the mixture into a paste-like paint”, explains Cotte.

The breakthrough yields the path for the long-term preservation and conservation of Rembrandt’s masterpieces. However, the number of samples studied is not extensive enough to assess if lead white impastos systematically contain plumbonacrite. “We are working with the hypothesis that Rembrandt might have used other recipes, and that is the reason why we will be studying samples from other paintings by Rembrandt and other 17th Dutch Masters, including Vermeer, Hals, and painters belonging to Rembrandt’s circle”, explains Annelies van Loon, scientist at the Rijksmuseum.

In addition to this, the team will reconstruct specific impasto-like samples, preparing and ageing them under CO2 rich and CO2 free atmospheres (to assess the origin of carbonates in plumbonacrite) and in humid and dry conditions (to assess the effect of water).

This work, led by the Materials Science and Engineering Department of the Delft University of Technology and the Rijksmuseum is a collaboration between academia (Institut de Recherche de Chimie Paris, Sorbonne University and University of Amsterdam), Cultural Heritage research institutes (C2RMF: Centre de Recherche et des Restauration des Musées de France), museums (Rijksmuseum and Mauritshuis) and the ESRF.

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The Portrait of Marten Soolmans by Rembrandt van Rijn, at the Rijksmuseum in Amsterdam, the Netherlands

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Article Source: EUROPEAN SYNCHROTRON RADIATION FACILITY news release

BINGHAMTON UNIVERSITY—BINGHAMTON, N.Y. – The ancient people of Rapa Nui (Easter Island, Chile) built their famous ahu monuments near coastal freshwater sources, according to a team of researchers including faculty at Binghamton University, State University of New York.

The island of Rapa Nui is well-known for its elaborate ritual architecture, particularly its numerous statues (moai) and the monumental platforms that supported them (ahu.) Researchers have long wondered why ancient people built these monuments in their respective locations around the island, considering how much time and energy was required to construct them. A team of researchers including Binghamton University anthropologist Carl Lipo used quantitative spatial modeling to explore the potential relations between ahu construction locations and subsistence resources, namely, rock mulch agricultural gardens, marine resources, and freshwater sources—the three most critical resources on Rapa Nui. Their results* suggest that ahu locations are explained by their proximity to the island’s limited freshwater sources.

“The issue of water availability (or the lack of it) has often been mentioned by researchers who work on Rapa Nui/Easter Island,” said Lipo. “When we started to examine the details of the hydrology, we began to notice that freshwater access and statue location were tightly linked together. It wasn’t obvious when walking around—with the water emerging at the coast during low tide, one doesn’t necessarily see obvious indications of water. But as we started to look at areas around ahu, we found that those locations were exactly tied to spots where the fresh groundwater emerges—largely as a diffuse layer that flows out at the water’s edge. The more we looked, the more consistently we saw this pattern. Places without ahu/moai showed no freshwater. The pattern was striking and surprising in how consistent it was. Even when we find ahu/moai in the interior of the island, we find nearby sources of drinking water. This paper reflects our work to demonstrate that this pattern is statistically sound and not just our perception.”

“Many researchers, ourselves included, have long speculated associations between ahu/moai and different kinds of resources, e.g., water, agricultural land, areas with good marine resources, etc.,” said lead author Robert DiNapoli of the University of Oregon. “However, these associations had never been quantitatively tested or shown to be statistically significant. Our study presents quantitative spatial modeling clearly showing that ahu are associated with freshwater sources in a way that they aren’t associated with other resources.”

According to Terry Hunt of the University of Arizona, the proximity of the monuments to freshwater tells us a great deal about the ancient island society.

“The monuments and statues are located in places with access to a resource critical to islanders on a daily basis—fresh water. In this way, the monuments and statues of the islanders’ deified ancestors reflect generations of sharing, perhaps on a daily basis–centered on water, but also food, family and social ties, as well as cultural lore that reinforced knowledge of the island’s precarious sustainability. And the sharing points to a critical part of explaining the island’s paradox: despite limited resources, the islanders succeeded by sharing in activities, knowledge, and resources for over 500 years until European contact disrupted life with foreign diseases, slave trading, and other misfortunes of colonial interests.”

The researchers currently only have comprehensive freshwater data for the western portion of the island and plan to do a complete survey of the island in order to continue to test their hypothesis of the relation between ahu and freshwater.

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Monumental Maois statues on Easter Island. Horacio Fernandez, Wikimedia Commons

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Binghamton University archaeologist Carl Lipo is part of an international team of researchers working to solve the ancient mysteries of Easter Island. Binghamton University, State University of New York

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Article Source: Binghamton University news release

Also contributing to this research were Matthew Becker and Tanya Brosnan (California State University, Long Beach); Sean Hixon (Pennsylvania State University); and Alex E. Morrison (University of Auckland).

*The paper, “Rapa Nui (Easter Island) monument locations explained by freshwater sources,” was published in PLoS One.

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