Drier, less predictable environment may have spurred human evolution

A progressively drying climate punctuated by variable wetter episodes may have precipitated the transition from our hominin ancestors to anatomically modern humans, according to research published on Oct. 8 in the online edition of the Proceedings of the National Academy of Science (PNAS).

Since the discovery of a rich assemblage of human fossils as well as stone tools and other archeological evidence in the rift valley of East Africa, a region often referred to as the cradle of humanity, scientists have attempted to piece together the complex puzzle that is the history of our human origins, including the environmental context of that history.

The study, based on lake sediment cores, is the first to provide a continuous environmental context for the diverse archeological evidence recovered from nearby localities in the rift valley basins of southern Kenya. The cores were sampled from Lake Magadi as part of the Hominin Sites and Paleolakes Drilling Project, or HSPDP, which is directed by University of Arizona professor Andrew Cohen.

Lake Magadi, a shallow, periodically dry lake, is close to the Olorgesailie basin in Kenya, one of the most productive sites for archaeological evidence of human evolution in Africa. The authors suggest that the profound climatic changes may have been driving forces behind hominin evolution, the origins of modern Homo sapiens and the onset of the Middle Stone Age.

While previous hypotheses have related hominin evolution to climate change, most prior studies lack regional-scale evidence for a link between environment and hominin evolution, the authors write in the paper, "Progressive aridification in East Africa over the last half million years and implications for human evolution." According to the study, a trend toward intense aridification in the area began 575,000 years ago. The change, not previously documented in continuous continental cores from East Africa, corresponds with faunal extinctions and a major transformation in stone tool technology documented in the Olorgesailie region.

"Much evidence for human evolution has been gathered from the area, but linking those records to detailed environmental records was missing until now," said the study's lead author, Richard Owen, of Hong Kong Baptist University. "There is a big gap in the records between the last Early Stone Age tools 500,000 years ago and the appearance of Middle Stone Age tools about 320,000 years ago. Our results plugged that gap with a continuous environmental record."

A critical transition occurred sometime during this gap, a period for which archeologists have unearthed evidence of a leap in early humans' abilities to make, use and trade stone tools.

The cores from Lake Magadi provide the first detailed link between climate change and events known from the region's archeological record.

"We have known for a while that the climate at the time was very varied, but the key here is that the records are in proximity to the archeological evidence for this transition," says Cohen, a professor in the University of Arizona's Department of Geosciences. "The older stone tools found at Olorgesailie did not change much between 1.2 million and a half-million years ago. And suddenly, after 500,000 and before 320,000 years ago - we don't know exactly when, but in that timespan - there was a critical transition in archeology when tools became more sophisticated and were transported over longer distances."
At the same time the lake core records point to the climate becoming drier and more variable, there is evidence elsewhere in Africa of the appearance of modern Homo sapiens, prompting much speculation whether the two are connected, Cohen said.

"Whether the evolution of bigger brains goes hand in hand with new toolkits is not entirely clear," he said. "But the earliest modern Homo sapiens fossils from Morocco date back 325,000 years, the same time we see this transition of tools. And both happened around the same time that our core record indicates severe drying very close to the archeological sites."

The deepest core drilled at Lake Magadi reached 200 meters (650 feet), penetrating all sedimentary layers down to the volcanic bedrock of the lake. The core samples, each about 10 feet long and 2 1/2 inches in diameter, are cut into manageable 5-foot segments, packaged and air-freighted to the National Lake Core Facility at the University of Minnesota for curation, analysis and storage.

According to the hypothesis of variability selection, a rapidly changing environment creates selective pressure that forces species to adapt to rapid change, Owen said. Under that scenario, the larger brains of anatomically modern humans would have allowed our ancestors to adapt quickly to an increasingly less predictable world.

"Now we have evidence that at the same time the toolkits were changing, the mammal fauna changed and the climate became more arid," Owen said. "So you have a series of coincidences that makes you think, 'This could be real.' Now we can say when the environment changed and then compare that to the archeological evidence of the region."

Drilling at other nearby sites by HSPDP has been completed as researchers gather more of the region's climate data to continue studying the importance of environmental variability in the course of human evolution.

Bone knife from Morocco is oldest specialized tool associated with Aterian culture

A single bone artefact found in a Moroccan cave is the oldest well-dated specialized bone tool associated with the Aterian culture of the Middle Stone Age, according to a study released October 3, 2018 in the open-access journal PLOS ONE by Abdeljalil Bouzouggar of the Institut National des Sciences de l'Archéologie et du Patrimoine in Morocco and colleagues. The make and manufacture of the tool are distinct from similarly-aged sub-Saharan artefacts, suggesting a unique technological industry in North Africa.

The tool was recovered in 2012 from Dar-es Soltan 1 cave, located about 260km inland from the Atlantic coast of Morocco. Upon close examination, Bouzouggar and colleagues were able to identify the origins of the bone as a large mammal rib with evidence of having been shaped and sharpened into a 122mm-long knife through a complex series of modifications. The layer containing the bone knife has been dated to approximately 90,000 years ago, approximately 55,000 years after the first appearance of the Aterian culture.

This tool and the technology used to create it are distinct from bone tools of similar age in southern Africa but similar to two tools known from the El Mnasra cave site in Morocco which is also of similar age, suggesting a unique North African Aterian bone technology. Specialized bone tools are considered a sign of cognitive complexity but have been poorly-understood with the Aterian technological complex, so this finding represents a new insight into the development of modern human cognition. The authors also suggest that this new technology may have come about in response to changing resources around 90,000 years ago but note that more study will be required to support this.

Silvia Bello, a co-author, adds: "Aterians were capable of a complex and controlled sequence of actions involved in the manufacture of specialised bone knives. Such distinctive bone technology implies the emergence of an independent modern techno-complex unique to the north Africa around 100,000 years ago."

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PLOS ONE: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0202021

Neanderthal-like features in 450,000-year-old fossil teeth from the Italian Peninsula

These teeth add to an emerging picture of complex human evolution in Middle Pleistocene Eurasia

PLOS

IMAGE: This is a virtual rendering of the Visogliano and Fontana Ranuccio teeth.

Credit: Zanolli et al., 2018

Fossil teeth from Italy, among the oldest human remains on the Italian Peninsula, show that Neanderthal dental features had evolved by around 450,000 years ago, according to a study published October 3, 2018 in the open-access journal PLOS ONE by Clément Zanolli of the Université Toulouse III Paul Sabatier in France and colleagues. These teeth also add to a growing picture of a period of complex human evolution that we are only beginning to understand.

Zanolli and colleagues examined dental remains from the sites of Fontana Fanuccio, located 50km southeast of Rome, and Visogliano, located 18km northwest of Trieste. At around 450,000 years old, these teeth join a very short list of fossil human remains from Middle Pleistocene Europe. Using micro-CT scanning and detailed morphological analyses, the authors examined the shape and arrangement of tooth tissues and compared them with teeth of other human species. They found that the teeth of both sites share similarities with Neanderthals and are distinct from modern humans.
There has been much debate over the identities and relationships of Middle Pleistocene ancient humans in Eurasia. The discovery of Neanderthal-like teeth so early in the record adds support to the suggestion of an early divergence of the Neanderthal lineage from our own, around the Early-Middle Pleistocene transition. The teeth are also notably different from other teeth known from this time in Eurasia, suggesting that there may have been multiple human lineages populating the region at this time, adding to a growing list of evidence that the Middle Pleistocene was a time of more complex human evolution than previously recognized.
Zanolli adds: "The remains from Fontana Ranuccio and Visogliano represent among the oldest human fossil remains testifying to a peopling phase of the Italian Peninsula. Our analyses of the tooth internal structural organization reveal a Neanderthal-like signature, also resembling the condition shown by the contemporary assemblage from Atapuerca Sima de los Huesos, indicating that an overall Neanderthal morphological dental template was preconfigured in Western Europe at least 430 to 450 ka ago."

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 PLOS ONE: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0189773

Cuisine of early farmers revealed by analysis of proteins in pottery from Çatalhöyük

Knowledge of the diet of people living in the prehistoric settlement of Çatalhöyük almost 8000 years ago has been complemented in astonishing scope and detail by analyzing proteins from their ceramic bowls and jars. Using this new approach, an international team of researchers has determined that vessels from this early farming site in central Anatolia, in what is now Turkey, contained cereals, legumes, dairy products and meat, in some cases narrowing food items down to specific species.

An international team led by researchers from the Max Planck Institute for the Science of Human History, the Freie Universität Berlin and the University of York has uncovered details about the diet of early farmers in the central Anatolian settlement of Çatalhöyük. By analyzing proteins from residues in ancient pots and jars excavated from the site, the researchers were able to find evidence of foods that were eaten there. Although previous studies have looked at pot residues from the site, this was the first to use proteins, which can be used to identify plants and animals more specifically, sometimes down to the species level.

One of the key early farming sites in the Old World

Çatalhöyük was a large settlement inhabited from about 7100 BC to 5600 BC by early farmers, and is located in what is now central Turkey. The site showcases a fascinating layout in which houses were built directly next to each other in every direction and stands out for its excellent preservation of finds. After over 25 years of excavation and analysis, it is considered one of the best-researched early farming sites in the Old World.

For this study, the researchers analyzed vessel sherds from the West Mound of Çatalhöyük, dating to a narrow timeframe of 5900-5800 BC towards the end of the site's occupation. The vessel sherds analyzed came from open bowls and jars, as shown by reconstructions and had calcified residues on the inside surfaces. In this region today, limescale residue on the inside of cooking pots is very common. The researchers used state-of-the-art protein analyses on samples taken from various parts of the ceramics, including the residue deposits, to determine what the vessels held.

Food proteins left behind in ceramic bowls and jars

The analysis revealed that the vessels contained grains, legumes, meat and dairy products. The dairy products were shown to have come mostly from sheep and goats, and also from the bovine (cattle) family. While bones from these animals are found across the site and earlier lipid analyses have identified milk fats in vessels, this is the first time researchers have been able to identify which animals were actually being used for their milk. In line with the plant remains found, the cereals included barley and wheat, and the legumes included peas and vetches. The non-dairy animal products, which might have included meat and blood, came primarily from the goat and sheep family, and in some cases from bovines and deer. Interestingly, many of the pots contain evidence of multiple food types in a single vessel, suggesting that the residents mixed foods in their cuisine, potentially as porridges or soups, or that some vessels were used sequentially for different food items, or both.

Early cheese-making

One particular vessel however, a jar, only had evidence for dairy products, in the form of proteins found in the whey portion of milk. "This is particularly interesting because it suggests that the residents may have been using dairy production methods that separated fresh milk into curds and whey. It also suggests that they had a special vessel for holding the whey afterwards, meaning that they used the whey for additional purposes after the curd was separated," states Jessica Hendy, lead author, of the Max Planck Institute for the Science of Human History.

These results show that dairying has been ongoing in this area since at least the 6th millennium BC, and that people used the milk of multiple difference species of animal, including cow, sheep and goat.

However, the researchers emphasize that based on the archaeological record an even greater variety of foods, especially plant foods, were likely eaten at Çatalhöyük, which either were not contained in the vessels they studied or are not present in the databases they use to identify proteins.

The "shotgun" proteomic approaches used by the researchers are heavily dependent on reference sequence databases, and many plant species are not represented or have limited representation. "For example, there are only 6 protein sequences for vetch in the databases. For wheat, there are almost 145,000," explains Hendy. "An important aspect of future work will need to be expanding these databases with more reference sequences."

The potential of protein analysis on archaeological ceramics

Other molecular techniques applied to ancient pottery can reveal broad classes of food - such as evidence of dairy or animal fat - but an analysis of proteins allows a much more detailed picture of past cuisine.

The results of this study show the power of protein analyses, which can identify foodstuffs in situ down to the species level, in samples as old as 8000 years. In particular, the residues on the insides of the ceramics were exceptionally well-preserved and contained a wealth of information. The removal of these residues can be a common practice among archaeologists as part of the preservation and cleaning process.

"These results highlight how valuable these deposits can be, and we encourage colleagues to retain them during post-excavation processing and cleaning," states Eva Rosenstock of the Freie Universität Berlin and the senior author of the study.

Broad genetic variation on the Pontic-Caspian Steppe

The genetic variation within the Scythian nomad group is so broad that it must be explained with the group assimilating people it came in contact with. This is shown in a new study on Bronze and Iron Age genetics of the Pontic-Caspian Steppe, situated in the Black Sea region. The article is published in the scientific journal Science Advances.

"There is so much genetic variation among the Scythians, it seems that you didn't have to be born a Scyth to be a part of their community", says Anders Götherström, Professor at the Department of Archaeology and Classical Studies, Stockholm University.

This is likely the strategy needed for the group to have been able to grow as fast, expand as vast and to remain established for as long as they did. The findings emphasize the importance of assimilation to maintain Scythian dominance around the Black Sea region.

"It also sheds light on their attitude towards conquered people. Scythians are often thought of as an extremely aggressive group, but their gradual genetic expansion show us that they were also a group prepared to interact with and take in new people. For example, in one burial ground we found individuals of different genetic background buried according to Scythian tradition. This tells us that Scythians seem to have incorporated people from other groups into their families and their community", says Maja Krzewi?ska researcher at the Department of Archaeology and Classical Studies, Stockholm University.

The Pontic-Caspian Steppe - a dynamic place

The vast area of the Pontic-Caspian Steppe region has worked as a motor for demographic events throughout Eurasia, especially in the western part of the meta-continent. Crucial events in European history and prehistory can be traced back to people of the Steppe. Including the invention of horseback riding, chariots, a new type of warfare and the spread of Indo-European languages.

"The Central Eurasian Steppe seems to have been a very dynamic place. An important geographical region which acted both as a melting-pot and a nursery of people, as well as communicative and technological innovations. This is where people met, shared ideas and genes. From this 'pit-stop' genes and ideas were spread from the East to the West", says Gül?ah Merve K?l?nç researcher at the Department of Archaeology and Classical Studies, Stockholm University.

A gradual genetic mix
 
An international research team, led from Stockholm University, have investigated genomic data from 35 individuals, spanning 2 200 years. The material mainly consists of human remains from the southern Urals and central Eurasian Steppe. The researchers have analyzed DNA from four different nomadic groups; Cimmerians, Scythians, Sarmatians and Bronze Age Srubanya individuals.

Even though a couple of the groups had an early history somewhere else all the groups share genetic background and follow each other chronologically. The Cimmerians were displaced by the Scythians and those in return were followed by the Sarmatians.

"It's not one group completely displacing another. The expansion process seems to have been more gradual. First from Altai to southern Urals, and thereafter further west. It suggests that the Pontic-Caspian Steppe served as a natural transition point and the source of w estern nomads, despite their cultural roots stretching further east", says Maja Krzewi?ska researcher at the Department of Archaeology and Classical Studies, Stockholm University.

Archaeologists find the earliest use of nutmeg as a food

IMAGE: Burke Museum Archaeology Curator Peter Lape (left) and Daud Tanudirjo (right) excavating a layer at the site with the earliest known cooking use of nutmeg. view more 

Credit: Andrew Lawless

As all things pumpkin spice arrive in grocery store aisles and on restaurant menus, a new study published in the journal Asian Perspectives describes the earliest-known use of nutmeg as a food ingredient.

Found at an archaeological site on Pulau Ay, a small island in the Banda Islands, central Maluku, Indonesia, the nutmeg was found as residue on ceramic potsherds and is estimated to be 3,500 years old -- about 2,000 years older than the previously known use of the spice.

The study and two excavations in 2007 and 2009 were led by Peter Lape, professor of anthropology at the University of Washington and curator of archaeology at the Burke Museum, in collaboration with colleagues from Universitas Gadjah Mada in Indonesia, the University of New South Wales in Australia and others.

The Pulau Ay archaeological site was occupied from 2,300 to 3,500 years ago, with animal bones, earthenware pottery, stone tools, and post molds of possible housing structures found. The variety of artifacts discovered provides evidence of changes in how people utilized marine food resources, pottery and domestic animals over time.

Over the first 500 years at the site, people shifted from a predominately fish-based diet to primarily eating domesticated pigs. In addition, pottery was initially thin-walled vessels adapted for storage of liquids that may have allowed people to survive on this water-poor island. A few hundred years later, thicker-walled pottery better adapted for cooking appears along with pig bones.

"This site shows us how people adapted to living on these small tropical islands in stages, from occasional use as fishing camps to permanent occupation," Lape said. "It's also fascinating to see such early use of nutmeg, a spice that changed the world a few thousand years later."

It was on the pottery where Lape's co-authors Judith Field and Adelle Coster found not only the nutmeg, but also residue from six other plants including sago and purple yam. These plants could have been collected from wild plants, or possibly cultivated through farming.

Pulau Ay is a small island lacking both indigenous land mammals and surface water. It likely would not have supported a permanent human population that did not have the technological advantages of domestic animals and water storage.

However, by surveying additional archaeological sites, the study's authors suggest that the island was regularly visited by people targeting its rich marine reef resources for several thousand years before more permanent populations were established in the early Neolithic, the later part of the Stone Age.

The most likely homeland for these visitors is the nearest large island of Seram, 100 kilometers to the east. People who possessed sufficient knowledge of Pulau Ay and the seafaring skills to make regular return trips there would seem to be likely candidates for the first Neolithic settlers as well.

Sometime around 2,300 years ago, the site was largely or totally abandoned, and no other sites in the

Banda Islands have so far been found that date to the period between 2,300 and 1,500 years ago. Future work aims to answer why these remote islands, which attracted the settlement of people who were quite connected to other places before and after this period, would have been abandoned for 800 years.

Studies of sites like this one can help illuminate the complex cultural processes at work during the Neolithic period, which saw the introduction of many new plants, animals and technologies to the islands of Southeast Asia. The results from this site show that these changes did not happen all at once, but rather were gradually adopted and adapted to allow people to utilize these tropical island seascapes in new ways.

As for the nutmeg, understanding its earliest origins of human use helps connect the dots to later international trades. By the 14th century (and possibly earlier), long-distance traders were traveling to Banda to obtain nutmeg; this valuable spice brought the Banda Islands international renown during the early modern era.

The find provides a new perspective on a key ingredient that is still a valuable commodity today--especially in a multi-billion dollar industry of fall-themed foods and beverages.

Neanderthal healthcare practices crucial to survival

Research at the University of York has suggested that Neanderthals embraced healthcare practices, such as assisting in cases of serious injury and the challenges of childbirth.

Healthcare practices in this period of human evolution have often been studied alongside complex cultural behaviour, mostly based around research into rituals and symbols associated with death. This new study, however, sets out, for the first time, that healthcare could have had a more strategic role in Neanderthal survival.

Previous research at the University of York has already suggested that compassion and caring for the injured and dying could have been a factor in the development of healthcare practices, but further investigation has now shown that there was evolutionary drivers behind it too.

Researchers investigated the skeletal remains of more than 30 individuals where minor and serious injuries were evident, but did not lead to loss of life. The samples displayed several episodes of injury and recovery, suggesting that Neanderthals must have had a well-developed system of care in order to survive.

Dr Penny Spikins, from the University of York's Department of Archaeology, said: "Neanderthals faced multiple threats to their lives, particularly from large and dangerous animals, but in popular culture Neanderthals have such a brutish and strong image that we haven't really thought too deeply about their vulnerabilities before now.

"We have evidence of healthcare dating back 1.6 million years ago, but we think it probably goes further back than this. We wanted to investigate whether healthcare in Neanderthals was more than a cultural practice; was it something they just did or was it more fundamental to their strategies for survival?

"The high level of injury and recovery from serious conditions, such as a broken leg, suggests that others must have collaborated in their care and helped not only to ease pain, but to fight for their survival in such a way that they could regain health and actively participate in the group again."

It is generally accepted that more than 80% of the skeletal remains known to archaeologists display several injuries, some of which may have required simple remedies, such as food and rest, and others that would have required serious levels of care due to a high risk to life.

Neanderthals lived in small groups, so any one loss of life was particularly significant to the survival of the whole community. Injury, over disease, was the most common threat, as Neanderthals didn't live in the type of environment, or in large enough communities, to be at high risk from pathogens.
Neanderthal women, however, were at risk from difficulties in childbirth. The shape of their pelvis and the size and shape of a child's head was similar to that of modern-day humans, so it is assumed that they would also have encountered some common issues in childbirth.

Dr Spikins said: "It is likely that they would have had assisted childbirth; the role that we now attribute to midwives. Without support, they probably could not have survived the toll that the death rate of mothers and babies could have taken on their communities.

"When we look at the daily risks and dangers involved in hunting and finding food, as well as in childbirth in respect to their small hunting communities, it is not surprising that they would develop practices to improve health and reduce mortality risk.

"We can start to see healthcare as a pattern of evolutionary significant collaborative behaviour, alongside hunting together, food sharing and parenting. In this we can see why providing healthcare to those in need today is such an important part of human life."

Researchers now aim to expand this work to look at potential methods of healthcare and how far back healthcare practices can be traced.