Archaeology News Report

Wednesday, January 22, 2020

First ancient DNA from West Africa illuminates the deep human past

A team of international researchers dug deep to find some of the oldest African DNA on record, in a new study published in Nature

Saint Louis University

**IMAGE:** The Shum Laka rock shelter in Cameroon, home to an ancient population that bears little genetic resemblance to most people who live in the region today. view more

Credit: Photo by Pierre de Maret.

A team of international researchers, which includes a Saint Louis University Madrid anthropologist, dug deep to find some of the oldest African DNA on record, in a new study published in Nature.
Africa is the homeland of our species and harbors greater human genetic diversity than any other part of the planet. Studies of ancient DNA from African archaeological sites can shed important light on the deep origins of humankind. The research team sequenced DNA from four children buried 8,000 and 3,000 years ago at Shum Laka in Cameroon, a site excavated by a Belgian and Cameroonian team 30 years ago.
The findings, "Ancient West African foragers in the context of African population history," published Jan. 22 in Nature, represent the first ancient DNA from West or Central Africa, and some of the oldest DNA recovered from an African tropical context. They enable a new understanding of the deep ancestral relationships among early Homo sapiens in sub-Saharan Africa.
This study was the product of collaboration among geneticists, archaeologists, biological anthropologists and museum curators based in North America (including Harvard Medical School and the Université de Montréal); Europe (Royal Belgian Museum of Natural Sciences, Royal Museum for Central Africa, Université Libre de Bruxelles and Saint Louis University's Madrid campus); Cameroon (University of Yaoundé, University of Buea); and China (Duke Kunshan University).
A unique archaeological site with exceptional preservation
Shum Laka is a rock shelter located in the 'Grassfields' region of Cameroon, a place long pinpointed by linguists as the probable cradle of Bantu languages, a widespread and diverse group of languages spoken by more than a third of Africans today.
"Linguists, archaeologists and geneticists have been studying the origin and spread of Bantu languages for decades, and the Grassfields region is key to this question," said Mary Prendergast, Ph.D., a professor of anthropology and chair of humanities at Saint Louis University's campus in Madrid, and a co-supervising author of the study. "The consensus is that the Bantu language group originated in west-central Africa, before spreading across the southern half of the continent after about 4,000 years ago."
This expansion is thought to be the reason why most people from central, eastern and southern Africa are genetically closely related to each other and to West Africans.
"Shum Laka is a reference point for understanding the deep history of west-central Africa," said Isabelle Ribot, Ph.D., a University of Montreal anthropologist who excavated and studied the burials, and is a key author of the study.
The Shum Laka rockshelter was excavated in the 1980s and 1990s by archaeologists from Belgium and Cameroon. It boasts an impressive and well-dated archaeological record, with radiocarbon dates spanning the past 30,000 years. Stone tools, plant and animal remains, and eventually pottery collectively indicate long-term forest-based hunting and gathering and an eventual transition to intensive tree fruit exploitation.
Shum Laka is emblematic of the 'Stone to Metal Age,' a critical era in west-central African history that ultimately gave rise to Iron Age metallurgy and farming. During this era, the site repeatedly served as a burial ground for families, with 18 individuals (mainly children) buried in two major phases at about 8,000 and 3,000 years ago.
"Such burials are unique for West and Central Africa because human skeletons are exceedingly rare here prior to the Iron Age," said Ribot. "Tropical environments and acidic soils are not kind to bone preservation, so the results from our study are really remarkable."
Scientists at Harvard Medical School sampled petrous (inner-ear) bones from six individuals buried at Shum Laka. Four of these samples produced ancient DNA, and were directly dated at the Pennsylvania State University Radiocarbon Laboratory. The molecular preservation was impressive given the burial conditions, and enabled whole-genome ancient DNA analysis.
A newly documented population of hunter-gatherers
Surprisingly, the ancient DNA sequenced from the four children - one pair buried 8,000 years ago, the other 3,000 years ago - reveals ancestry very different from that of most Bantu-speakers today. Instead, they are closer to central African hunter-gatherers.
"This result suggests that Bantu-speakers living in Cameroon and across Africa today do not descend from the population to which the Shum Laka children belonged," said Mark Lipson, Ph.D., Harvard Medical School, lead author of the study. "This underscores the ancient genetic diversity in this region and points to a previously unknown population that contributed only small proportions of DNA to present-day African groups."
The spreads of farming and herding in Africa - as in other parts of the world - were accompanied by many movements of people.
"If you go back 5,000 years ago, virtually everyone living south of the Sahara was a hunter-gatherer," said Prendergast. "But look at a map of Africa showing foraging groups today, and you'll see they are very few and far between."
This study contributes to a growing body of ancient DNA research demonstrating ancient genetic diversity and population structure that has since been erased by the demographic changes that accompanied the spread of food production.
A rare paternally inherited lineage with deep roots
One of the sampled individuals - an adolescent male - carried a rare Y chromosome haplogroup (A00) found almost nowhere outside western Cameroon today. A00 is best documented among the Mbo and Bangwa ethnic groups living not far from Shum Laka, and this is the first time it has been seen in ancient DNA. A00 is a deeply divergent haplogroup, having split from all other known human lineages about 300,000-200,000 years ago. This shows that this oldest known lineage of modern human males has been present in west-central Africa for more than 8,000 years, and perhaps much longer.
New light on human origins
While the findings do not speak directly to Bantu language origins, they do shed new light on multiple phases of the deep history of Homo sapiens. The researchers examined the DNA of the Shum Laka children alongside published DNA from ancient hunter-gatherers from eastern and southern Africa, as well as DNA from many present-day African groups. Combining these datasets, they could construct a model of diverging lineages over the course of the human past.
"Our analysis indicates the existence of at least four major deep human lineages that contributed to people living today, and which diverged from each other between about 250,000 and 200,000 years ago," said David Reich, Ph.D., of Harvard Medical School, senior author of the study.
These lineages are ancestral to present-day central African hunter-gatherers, southern African hunter-gatherers, and all other modern humans, with a fourth lineage being a previously unknown 'ghost population' that contributed a small amount of ancestry to both western and eastern Africans.
"This quadruple radiation--including the position of a deeply-splitting 'ghost' modern human lineage--had not been identified before from DNA," Reich said.
Previous models for human origins suggested that present-day southern African hunter-gatherers, who split from other populations about 250,000-200,000 years ago, represent the deepest known branch of modern human variation. However, Lipson said, "the new analysis suggests that the lineage contributing to central African hunter-gatherers is similarly ancient and diverged from other African populations around the same time."
This finding adds to a growing consensus among archaeologists and geneticists that human origins in Africa may have involved deeply divergent, geographically separated populations.
Analysis also revealed another set of four human lineages branching between 80,000 and 60,000 years ago, including the lineages contributing most the ancestry in present-day eastern and western Africans and all non-Africans.
Considering this new model of human population relationships, the authors could show that about one third of the ancestry of the Shum Laka children derived from a lineage closely related to central African hunter-gatherers, and about two thirds of their ancestry came from a distinctive lineage distantly related to a majority of present-day West Africans.
"These results highlight how the human landscape in Africa just a few thousand years ago was profoundly different from what it is today, and emphasize the power of ancient DNA to lift the veil over the human past that has been cast by recent population movements," Reich said.
International collaboration
The international research team plans to return to Shum Laka this year, in part to help communicate findings to the Cameroonian academic and broader communities. "Interdisciplinary collaborations like this one are an essential part of ancient DNA research," says Reich.
Key Take-Aways
The study examines DNA from four people buried in the Shum Laka rockshelter in Cameroon, about 8,000 years ago and 3,000 years ago, at the transition from the Stone to Iron Ages. This study reports the first ancient DNA recovered from West or Central Africa, and includes some of the oldest DNA recovered from the African tropics.
This part of west-central Africa - the 'Grassfields' region of Cameroon - has been identified as the probable cradle of Bantu languages, the most widespread and diverse group of languages in Africa today. For decades, linguists, archaeologists, and geneticists have investigated the origin of Bantu languages and their spread.
None of the sampled individuals from Shum Laka are closely related to most present-day Bantu-speakers. Instead, they were part of a separate population that lived in the region for at least five millennia, and was later almost completely replaced by very different populations whose descendants comprise most people living in Cameroon today.
The Shum Laka individuals harbored about two-thirds of their ancestry from a previously unknown lineage distantly related to present-day West Africans and about one-third of their ancestry from a lineage related to present-day central African hunter-gatherers. This finding reveals previously unknown genetic diversity prior to the spread of food production.
Analysis of whole-genome ancient DNA data from these individuals provided insights into the relationships among several early-branching African human lineages. Results suggest that lineages leading to today's central African hunter-gatherers, southern African hunter-gatherers, and all other modern humans diverged in close succession about 250,000-200,000 years ago.
Another set of genetic divergences was identified dating to about 80,000-60,000 years ago, including the lineage leading to all present-day non-Africans.
These findings strengthen arguments recently made by archaeologists and geneticists that human origins in Africa may have involved deeply divergent, geographically separated populations.

Monday, January 20, 2020

Gold bar found in Mexico was Aztec treasure

Complete article





The 1.93-kilogram bar was found by a construction worker during excavations for a new building along the Alameda. Photo: MNA-INAH.

A gold bar found in a Mexico City park in 1981 was part of the Aztec treasure looted by Hernan Cortes and the Spanish conquistadors 500 years ago, a new study says.

The 1.93-kilogram bar was found by a construction worker during excavations for a new building along the Alameda, a picturesque park in the heart of the Mexican capital.

For 39 years, its origins remained a mystery.

But thanks to specialized X-rays, Mexico's National Institute of Anthropology and History (INAH) says it has now confirmed where the bar came from: the Spaniards' hasty, though temporary, retreat during the so-called "Noche Triste," or "Sad Night."

That night -- June 30, 1520 -- the Aztecs, furious over the slaughter of their nobles and priests, drove the Spanish invaders from their capital, Tenochtitlan.

The conquistadors escaped with as much looted Aztec treasure as they could carry, including, apparently, the gold bar in question.

Friday, January 17, 2020

Beach-combing Neanderthals dove for shells

Did Neanderthals wear swimsuits? Probably not. But a new study suggests that some of these ancient humans might have spent a lot of time at the beach. They may even have dived into the cool waters of the Mediterranean Sea to gather clam shells.
The findings come from Grotta dei Moscerini, a picturesque cave that sits just 10 feet above a beach in what is today the Latium region of central Italy.
In 1949, archaeologists working at the site dug up some unusual artifacts: dozens of seashells that Neanderthals had picked up, then shaped into sharp tools roughly 90,000 years ago.
Now, a team led by Paola Villa of the University of Colorado Boulder has uncovered new secrets from those decades-old discoveries. In research published today in the journal PLOS ONE, she and her colleagues report that the Neanderthals didn't just collect shells that were lying out on the beach. They may have actually held their breath and went diving for the perfect shells to meet their needs.
Villa, an adjoint curator in the CU Museum of Natural History, said the results show that Neanderthals may have had a much closer connection to the sea than many scientists thought.
"The fact they were exploiting marine resources was something that was known," Villa said. "But until recently, no one really paid much attention to it."
Cave discoveries When archaeologists first found shell tools in Grotta dei Moscerini, it came as a surprise. While Neanderthals are well-known for crafting spear tips out of stone, few examples exist of them turning shells into tools.
But the find wasn't a fluke. The 1949 excavation of the cave unearthed 171 such tools, all valves from shell belonging to a local species of mollusk called the smooth clam (Callista chione). Villa explained that the ancient humans used stone hammers to chip away at these shells, forming cutting edges that would have stayed thin and sharp for a long time.
"No matter how many times you retouch a clam shell, its cutting edge will remain very thin and sharp," she said.
But did the Neanderthals, like many beachgoers today, simply collect these shells while taking a stroll along the sand?
To find out, Villa and her colleagues took a closer look at those tools. In the process, they found something they weren't expecting. Nearly three-quarters of the Moscerini shell tools had opaque and slightly abraded exteriors, as if they had been sanded down over time. That's what you'd expect to see, Villa said, on shells that had washed up on a sandy beach.
The rest of the shells had a shiny, smooth exterior.
Those shells, which also tended to be a little bit bigger, had to have been plucked directly from the seafloor as live animals.
"It's quite possible that the Neanderthals were collecting shells as far down as 2 to 4 meters," Villa said. "Of course, they did not have scuba equipment."
Researchers also turned up a large number of pumice stones from the cave that Neanderthals had collected and may have used as abrading tools. The stones, Villa and her colleagues determined, washed onto the Moscerini beach from volcanic eruptions that occurred more than 40 miles to the south.
Going for a dip She's not alone in painting a picture of beach-loving Neanderthals.
In an earlier study, for example, a team led by anthropologist Erik Trinkaus identified bony growths on the ears of a few Neanderthal skeletons. These features, called "swimmer's ear," can be found in people who practice aquatic sports today.
For Villa, the findings are yet more proof that Neanderthals were just as flexible and creative as their human relatives when it came to eking out a living--a strong contrast to their representation in popular culture as a crude cavemen who lived by hunting or scavenging mammoths.
"People are beginning to understand that Neanderthals didn't just hunt large mammals," Villa said. "They also did things like freshwater fishing and even skin diving."

The colors of the Pachacamac idol, an Inca god, finally revealed

CNRS

**IMAGE:** In the last picture, the red arrows mark the presence of red pigments containing mercury. view more

Credit: © Marcela Sepulveda/Rommel Angeles/Museo de sitio Pachacamac

The legend of Pachacamac will not soon die. Since the 16th century, Spanish chroniclers have said that Hernando Pizarro had destroyed the idol of the deity when he conquered the Inca Empire in the Andes. But a carved wooden post representing Pachacamac was discovered on the archaeological site of the same name in 1938, so it was considered that the Spaniards may have been wrong in thinking that the idol had been completely destroyed. Now we have a new mystery! What is the nature of the red colour observed on the object? Is it blood residue, the remnants of sacrificial practices?
Thanks to close collaboration with the museum at the Pachacamac archaeological site in Peru, an international research team* has been able to conduct never-before-seen analysis -- non-invasive and non-destructive analysis -- of the idol's polychromy. They first revealed that red was not the only colour present on the piece of wood: we see white on the teeth of a personage and yellow on some headdresses.
What is even more interesting is that the researchers were able to determine the chemical composition of the pigments and show that red is not blood but mercury, no doubt from cinnabar, a mercury mineral known in that region for over 2000 years. Cinnabar sources in the Andes are 400 km from Pachacamac, at high altitude. So the idol was painted intentionally, no doubt to show economic and political power by carrying a pigment from a faraway region even though others were available on site.
Finally, the Pachacamac idol was carbon-14 dated for the first time. The object was made around 731 AD, probably by the Waris, i.e. about 700 years before the height of the Incan empire. This confirms that the Pachacamac site already had local ritual importance before the Incas arrived. They then made it one of their main pilgrimage centres, to the point that it housed an oracle that advised the emperor himself.
These results are part of a broad study of painted objects and walls at the Pachacamac archaeological site that aims to better understand the materials, practices and knowledge related to colour in the Andes during the pre-Hispanic period.

Thursday, January 9, 2020

Early humans arrived in Southeast Asia later than previously believed

American Association for the Advancement of Science

New dates from the World Heritage archeological site at Sangiran on the island of Java suggest that that the first appearance of Homo erectus occurred more recently than previously thought, researchers report. The new findings place the arrival of the first hominins in Sangiran between 1.3-1.5 million years ago (Ma), suggesting that early humans migrated from Asia to Southeast Asia and Java nearly 300,000 years later than previously believed. The fossil-rich Sangiran dome in Java contains the oldest human fossils in Southeast Asia and is widely regarded as one of the most important sites in understanding the evolution of our early ancestors and their slow march across the globe. To date, more than 100 specimens from at least three different hominid species have been recovered from Sangrian sediments. However, despite decades of research, the site's chronology remains uncertain and controversial, particularly the timing of H. erectus' first appearance in the region, and the current widely accepted dates are difficult to reconcile with other early sites in Asia. An accurate understanding of the Sangiran chronology is crucial for understanding the earliest human migrations and settlements in Asia. To resolve this debate, Shuji Matsu'ura and colleagues used a combination of fission-track and Uranium/Lead (U/Pb) dating to determine the age of volcanic zircons found above, below and within the hominin-bearing layers of the Sangiran fossil deposit. While previous estimates have estimated hominin arrival as early as 1.7 Ma, Matsu'ura et al.'s findings suggest a much younger date; likely by 1.3 Ma, however no earlier than 1.5 Ma. In a related Perspective, Boris Brasseur discusses the study's findings in more detail.

###

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

The Vikings erected a runestone out of fear of a climate catastrophe

University of Gothenburg

**IMAGE:** Rök runes. view more

Credit: Helge Andersson

Several passages on the Rök stone - the world's most famous Viking Age runic monument - suggest that the inscription is about battles and for over a hundred years, researchers have been trying to connect the inscription with heroic deeds in war. Now, thanks to an interdisciplinary research project, a new interpretation of the inscription is being presented. The study shows that the inscription deals with an entirely different kind of battle: the conflict between light and darkness, warmth and cold, life and death.
The Rök runestone, erected in Östergötland around 800 CE, is the world's most famous runestone from the Viking Age, but has also proven to be one of the most difficult to interpret. This new interpretation is based on a collaboration between researchers from several disciplines and universities.
"The key to unlocking the inscription was the interdisciplinary approach. Without these collaborations between textual analysis, archaeology, history of religions and runology, it would have been impossible to solve the riddles of the Rök runestone," says Per Holmberg, professor in Swedish at the University of Gothenburg, who led the study.
A previous climate catastrophe The study is based on new archaeological research describing how badly Scandinavia suffered from a previous climate catastrophe with lower average temperatures, crop failures, hunger and mass extinctions. Bo Gräslund, professor in Archaeology at Uppsala University, points to several reasons why people may have feared a new catastrophe of this kind:
"Before the Rök runestone was erected, a number of events occurred which must have seemed extremely ominous: a powerful solar storm coloured the sky in dramatic shades of red, crop yields suffered from an extremely cold summer, and later a solar eclipse occurred just after sunrise. Even one of these events would have been enough to raise fears of another Fimbulwinter," says Bo Gräslund.
Nine riddles According to the researchers' new interpretation now being published, the inscription consists of nine riddles. The answer to five of these riddles is "the Sun". One is a riddle asking who was dead but now lives again. The remaining four riddles are about Odin and his warriors.
Olof Sundqvist, professor in History of Religions at Stockholm University, explains the connection:
"The powerful elite of the Viking Age saw themselves as guarantors for good harvests. They were the leaders of the cult that held together the fragile balance between light and darkness. And finally at Ragnarök, they would fight alongside Odin in the final battle for the light."
Parallels with other Old Norse texts According to the researchers, several points in the inscription have clear parallels with other Old Norse texts that no one has previously noted.
"For me, it's been almost like discovering a new literary source from the Viking Age. Sweden's answer to the Icelandic Poetic Edda!" says Henrik Williams, professor in Scandinavian Languages with a specialty in Runology at Uppsala University.

Magnitude of Great Lisbon Earthquake may have been lower than previous estimates

The magnitude of the Great Lisbon Earthquake event, a historic and devastating earthquake and tsunami that struck Portugal on All Saints' Day in 1755, may not be as high as previously estimated.

In his study published in the Bulletin of the Seismological Society of America, Joao F. B. D. Fonseca at the Universidade de Lisboa used macroseismic data -- contemporaneous reports of shaking and damage -- from Portugal, Spain and Morocco to calculate the earthquake's magnitude at 7.7. Previous estimates placed the earthquake at magnitude 8.5 to 9.0.
Fonseca's analysis also locates the epicenter of the 1755 earthquake offshore of the southwestern Iberian Peninsula, and suggests the rupture was a complicated one that may have involved faulting onshore as well. This re-evaluation could have implications for the seismic hazard map of the region, he said.
The current maps are based on the assumption that most of the region's crustal deformation is contained in large offshore earthquakes, without a significant onshore component. "While the current official map assigns the highest level of hazard to the south of Portugal, gradually diminishing toward the north, the interpretation now put forward concentrates the hazard in the Greater Lisbon area," said Fonseca.
The 1755 Lisbon earthquake and tsunami event, along with the fires it caused that burned for hours in the city, is considered one of the deadliest earthquake events in history, leading to the deaths of about 12,000 people. The devastation had a significant impact on Portugal's economy and its political power within Europe, and its philosophical and theological implications were widely discussed by Enlightenment scholars from Voltaire to Immanuel Kant.