'Little Foot' skull reveals how this more than 3 million year old human ancestor lived

Micro-CT scanning of 'Little Foot' skull reveals new aspects of the life of this more than 3-million year-old-human ancestor

IMAGE: COMPARISON OF THE NEARLY INTACT FIRST CERVICAL VERTEBRA OF 'LITTLE FOOT' AND TWO OTHER AUSTRALOPITHECUS FROM STERKFONTEIN IN SOUTH AFRICA AND FROM HADAR IN ETHIOPIA SHOWING HOW COMPLETE 'LITTLE FOOT'... view more 

CREDIT: AMÉLIE BEAUDET/WITS UNIVERSITY

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

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

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

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

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

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

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

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

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

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

Bronze Age diet and farming strategy reconstructed using integrative isotope analysis

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

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

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

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

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

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

PLOS ONE: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0229398

Eggshell beads exchanged over 30,000 years

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Neanderthal migration to Southern Siberia

At least two different groups of Neanderthals lived in Southern Siberia and an international team of researchers including scientists from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have now proven that one of these groups migrated from Eastern Europe. The researchers have now published their findings in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).

Neanderthals were widespread in Europe and also migrated to Southern Siberia, but the origins of these Siberian Neanderthals and when they migrated was not known.

An international team of researchers including archaeologist Thorsten Uthmeier, professor of Prehistory and Protohistory at FAU, have now examined tools found in the Chagyrskaya cave in the Altai mountains in Russia in order to find the answer.

Parallels to sites in Central and Eastern Europe

The site has been excavated since 2019 as part of a DFG research project in conjunction with the Siberian Branch of the Russian Academy of the Sciences in Novosibirsk. In addition to stone tools and bones from hunting remains, two main find layers yielded numerous Neanderthal fossils. After discovering that the stone tools did not resemble any of the tools from groups living in the Altai during the same period, the team searched for comparable finds in a larger radius.

Geometric morphological analyses of 3D models of scanned tools showed that the stone tools found in the Chagyrskaya cave were very similar to artefacts from the Micoquien, which is the name given to the corresponding stone tool industry in Central and Eastern Europe. The comparative scans originate among others from find sites in Bavaria including FAU's own Sesselfelsgrotte cave, in which most of the artefacts used in the comparison were found.

The researchers were able to reconstruct the route of migration of the Siberian Neanderthals using DNA analyses of Neanderthal bones and sediments from the Chagyrskaya cave. The route led the groups during the course of several generations via Croatia and the North Caucasus to the Altai.

Several groups of Neanderthals migrated to Siberia

The DNA analyses also showed that the Neanderthals from the Chagyrskaya cave differ significantly in terms of their DNA from a second Altai group found in the Denisova cave. This discovery fits with the observation that the Denisova Neanderthals were apparently not familiar with tools from the Micoquien. The research team therefore presumes that several groups of Neanderthals migrated to Siberia.

The interdisciplinary examinations of the Neanderthals found in the Chagyrskaya cave, in which Bavarian find sites investigated by FAU play an important role, clearly show that the wave of migration of groups of this species of human 60,000 years ago originated in Central and Eastern Europe.

At the same time, the researchers from Novosibirsk led by Professor Ksenia Kolobova and from FAU found rare evidence that artefacts are culturally informative indicators of population movements.

Violence accompanied the growth of agriculture in Eastern North America 7,500 to 5,000 years ago

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The growth of agriculture led to unprecedented cooperation in human societies, a team of researchers, has found, but it also led to a spike in violence, an insight that offers lessons for the present.

A new study out today in Environmental Archaeology by collaborators from UConn, the University of Utah, Troy University, and California State University, Sacramento examines the growth of agriculture in Eastern North America 7,500 to 5,000 years ago, and finds that while the domestication of plants fostered new cooperation among people, it also saw the rise of organized, intergroup violence.

"We were interested in understanding why people would make the shift from hunting and gathering to farming," says Elic Weitzel, a UConn Ph.D. student in anthropology. "Then I started to get interested in what happened in society after they made that shift and started farming on a larger scale."

The team used the "ideal free distribution" model to look at patterns of how individuals distribute themselves in an area, meaning places where people will begin occupying the best locations first. A number of factors make an area more suitable such as access to food, water, raw materials, and shelter. To measure suitability, the team looked at an indicator called "net primary productivity," which is a measure of available energy based on the plants in the area. In areas of higher net primary productivity, there were more people clustered together - and more conflict.

"If you are living in a suitable area, you can lay claim and keep others from accessing what you have. That becomes a cooperative process, because one person is not as effective as a whole group is at defending a territory," says Weitzel.

A growing population can decrease the suitability of a location over time, but that does not always mean declining quality of life. To study this, the team also took into consideration the concept known as Allee's Principle, which states that individual fitness, or likelihood of survival and reproduction, increases as the density of the population increases due to cooperative behaviors. Weitzel explains that for something like a crop of plants, they represent something valuable, and the value of cooperative behavior becomes apparent.

"The transition from a hunting and gathering society to an agricultural society is dependent on collaboration," says co-author Stephen Carmody, of Troy University. "The development of agriculture appears to only have happened in nine places around the world so Eastern North America is a unique part of the world to study. Agriculture was one of the most consequential transitions that happened in the past. It changed our whole economic situation."

Developments such as combined efforts for harvesting and defense, and possibly even sharing seeds among groups, could happen with interpersonal cooperation, which leads to greater chances of survival for the group.

As the saying goes, many hands make for lighter work and, Weitzel says, the research is about cooperation and competition at the same time.

"When a resource like domesticated crops is dense and predictable, that is when we expect that it would be defendable," he says. "Other groups may want access to your crop in case their crop failed, for example. There is cooperation and there are aspects of competition. Harvesting and defending."

Weitzel explains that this time period - 7,500 to 5,000 years ago - is not only when researchers found people aggregating and living cooperatively in high-quality locations, it is also when they saw an uptick in intergroup violence, as shown by skeletons showing the effects of "trophy-taking."

"Of course there are signs of violence throughout history, but trophy-taking is a different type of violence," Weitzel says. "The victor removes a part of the loser as a signal they won. They took scalps, hands, feet, heads - that first evidence appears to have happened at the same time as plant management."

This reflects the Allee Principle's limit: a point at which population density surpasses an optimum number, and suitability declines as a result.

"As the ideal free distribution and Allee effects predict, at a certain point, the benefits of cooperation start to wane and you see dispersal again. There are incentives to be around other people, but not too many other people," says Weitzel.

After the spike in trophy-taking violence, there was a period of time when the populations dispersed once again, although populations still aggregated. During the dispersal period, researchers found a corresponding decrease in trophy-taking violence.

"We see a lot of things that look modern to us, for example social inequality and climate change," Carmody says. "However, these are fundamental processes and large-scale issues. A lot of these issues tie back to the origin of agriculture."

By understanding early human interactions, Weitzel says this knowledge can help understand our present and even influence the way we think about the future.

"This is one of the ways archaeology is relevant to contemporary and future society," he says. "The modeling of human behaviors in society and our relationships can help us overcome current collective action problems. We are all better off if we cooperate."

How millets sustained Mongolia's empires

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

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

Isotopic analysis and the imperial importance of millets

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

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

Rethinking Mongolian prehistory

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

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

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

5,000-year-old milk proteins point to the importance of dairying in eastern Eurasia

Today dairy foods sustain and support millions around the world, including in Mongolia, where dairy foods make up to 50% of calories consumed during the summer. Although dairy-based pastoralism has been an essential part of life and culture in the eastern Eurasian Steppe for millennia, the eastward spread of dairying from its origin in southwest Asia and the development of these practices is little understood. The current study, led by Shevan Wilkin and Jessica Hendy of the Max Planck Institute for the Science of Human History, presents the earliest evidence for dairy consumption in East Asia, circa 3000 BCE, and offers insights into the arrival and evolution of dairy pastoralism in prehistoric Mongolia.

Earliest dairy consumption & a possible path of entry

The highly mobile nature of pastoralist societies and the severe winds of the Eastern Steppe make detecting occupied sites with direct evidence into the lives and culture of ancient Mongolians exceedingly rare. Instead, the researchers looked for clues in ritual human burial mounds, often marked by stone monuments and occasionally featuring satellite animal graves.

In collaboration with the National University of Mongolia, researchers analyzed dental calculus from individuals ranging from the Early Bronze Age to the Mongol Period. Three-quarters of all individuals contained evidence that they had consumed dairy foods, which demonstrates the widespread importance of this food source in both prehistoric and historic Mongolia. The study's results include the earliest direct evidence for dairy consumption in East Asia, identified in an individual from the Afanasievo site of Shatar Chuluu, which dates to roughly 3000 BCE. Previous DNA analysis on this individual revealed non-local genetic markers consistent with Western Steppe Herder populations, presenting Early Bronze Age Afanasievo migrations westward via the Russian Altai as a viable candidate for the introduction of dairy and domestic livestock into eastern Eurasia.

Multiple different animal species were used for their milk

By sequencing the milk proteins extracted from the dental calculus, the scientists were able to determine which animal species were being used for dairy production, and thereby help to trace the progression of domestication, dairying, and pastoralism in the region. "Modern Mongolians use cow, sheep, goat, yak, camel, horse and reindeer for milk today, yet when each of these species were first utilized for dairy in Mongolia remains unclear," says Shevan Wilkin, lead author of the study. "What is clear is that the crucial renewable calories and hydration made available through the incorporation of dairying would have become essential across the arid and agriculturally challenging ancient Eastern Steppe."

The earliest individuals to show evidence of dairy consumption lived around 5000 years ago and consumed milk from ruminant species, such as cattle, sheep, and goats. A few thousand years later, at Bronze Age sites dated to after 1200 BCE, the researchers find the first evidence of horse milk consumption, occurring at the same time as early evidence for horse bridling and riding, as well as the use of horses at ritual burial sites. In addition, the study shows that during the Mongol Empire circa 1200-1400 CE, people also consumed the milk of camels. "We are excited that through the analysis of proteins we are able to see the consumption of multiple different animal species, even sometimes in the same individual. This gives us a whole new insight into ancient dairying practices" says Jessica Hendy, senior author of the study.

Millenia after the first evidence of horse milk consumption, horses remain vital to the daily lives of many in modern Mongolia, where mounted pastoralists rely on them to manage large herds of livestock, transport people and supplies, and provide a primary source of meat and milk. "Our findings suggest that the incorporation of horses into dairy pastoralism in Eastern Eurasia was closely linked to a broader economic transformation in the use of horses for riding, movement, and diet," says William Taylor of the University of Colorado-Boulder, one of the study's coauthors.

Although the earliest individual sampled in this study showed evidence of dairy consumption, the researchers hope future studies will examine individuals from previous time periods. "In order to form a clearer picture of the origins of dairying in this region, we need to understand the impact of western steppe herder migrations and confirm whether dairying was occurring in Mongolia prior to their arrival," Shevan Wilkin concludes.