Movius Line explained?

500,000-year-old shell cutting tool could explain Acheulean hand-axe puzzle

The teardrop shaped Acheulean hand-axe is without doubt the signature artefact of the Lower Palaeolithic, remaining in use for nearly one and a half million years. The tools first came into use about 1.75 million years ago and persisted until around 250,000 years ago. While chiefly associated with Homo erectus, they remained in use into the time of the larger-brained Homo heidelbergensis.

What has long been a puzzle is that while the hand-axes are ubiquitous in Africa, Europe and Southwest Asia, they are very rare further east. The boundary between the two regions is known as the Movius Line, after the American archaeologist Hallam Movius who first noted the discontinuity in 1948. The Movius Line has largely stood the test of time: the occasional Acheulean-like artefacts that have been found in China and South Korea are probably due to an eastwards migration of later hominins about 250,000 years ago (Cameron & Groves, 2004). By this time, hand-axes had been abandoned in the West (Klein, 2005).

The simplest explanation is that the ancestors of Homo erectus living east of the Movius Line had already left Africa by the time the hand-axes were invented (Swisher, et al., 1994). Another possibility is that not every hominin group in Africa adopted Acheulean technology, and that the original migrants were among those lacking it (Lepre, et al., 2011). Both possibilities suppose that firstly, the hand-axes were only invented once (or were not re-invented by groups that had left Africa); and that secondly, after the initial colonisation of Southeast Asia and China, the migrants there had no significant contact with the Acheulean-using peoples living elsewhere. Another possibilities is that the population sizes at the extremities of the migration were too low to keep the skills necessary for hand-axe production alive from one generation to the next (Lycett & von Cramon-Taubadel, 2008). None of these explanations are very compelling, because it is now known that prepared-core techniques were independently invented in Africa and Eurasia (Adler, et al., 2014), and it therefore seems unlikely that the simpler Acheulean technology arose only once.

A more likely explanation is that migrants passed through a region lacking suitable raw materials to make the hand-axes and were forced to look to alternatives for tool-making. One suggestion is they switched to bamboo and either forgot how to make hand-axes or were happy to stick with bamboo even when suitable stone was available (Klein, 2005). It is also possible that they switched to bamboo because it is readily available and an excellent tool-making material in its own right (Cameron & Groves, 2004; Roberts, 2009; Lewin & Foley, 2004).

It has long been claimed that the theory cannot be proved because bamboo implements from such a long time ago are extremely unlikely to have survived – but there are other alternatives to stone that can survive for hundreds of thousands of years. The recently-discovered shell cutting tool from Trinil, Java, is around 500,000 years old, and it was found in a region where suitable stone is scarce (Joordens, et al., 2014). Although it is far more recent than the first eastwards migration of Homo erectus, it demonstrates that the species was capable of utilising alternative raw materials for tool-making where necessary. It therefore seems likely that the Movius Line represents a shift to the use of organic materials for tool-making when stone suitable for hand-axe manufacture was unavailable.

References:

1. Cameron, D. & Groves, C., Bones, Stones and Molecules: “Out of Africa” and Human Origins (Elsevier Academic Press, London, 2004).
2. Klein, R., in The Human Past, edited by Scarre, C. (Thames & Hudson, London, 2005), pp. 84-123.
3. Swisher, C. et al., Age of the earliest known hominids in Java, Indonesia. Science 263, 1118-1121 (1994).
4. Lepre, C. et al., An earlier origin for the Acheulian. Nature 477, 82-85 (2011).
5. Lycett, S. & von Cramon-Taubadel, N., Acheulean variability and hominin dispersals: a model-bound approach. Journal of Archaeological Science 35, 553-562 (2008).
6. Adler, D. et al., Early Levallois technology and the Lower to Middle Paleolithic transition in the Southern Caucasus. Science 345 (6204), 1609-1612 (2014).
7. Roberts, A., The Incredible Human Journey (Bloomsbury, London, 2009).
8. Lewin, R. & Foley, R., Principles of Human Evolution, 2nd ed. (Blackwell Science Ltd, Oxford, 2004).
9. Joordens, J. et al., Homo erectus at Trinil on Java used shells for tool production and engraving. Nature (2014).

Homo erectus engraved abstract patterns on seashells

500,000-year-old shells provide earliest yet evidence for symbolic behaviour

Archaeologists studying freshwater mussel shells excavated in the nineteenth century at Trinil, Java, have discovered geometric patterns carved by Homo erectus 500,000 years ago and unambiguous evidence that one shell had been sharpened and polished for use as a cutting tool. In addition, the number of large adults in the shell assemblage suggests that they were intentionally collected for eating.

The shells were excavated by Dutch anthropologist Eugene Dubois in 1891 during the course of his work in Java, which led to the discovery of Homo erectus. They now form part of the Dubois Collection in the Naturalis Biodiversity Centre in Leiden. Researchers dated sediments within the shells with argon-argon and luminescence methods to obtain an age range of 540,000 to 430,000 years old.

The engraved shell, designated DUB1006-fL, displays a geometric pattern of grooves. The pattern consists of a zigzag line with three sharp turns producing an ‘M’ shape, a set of more superficial parallel lines, and a zigzag with two turns producing an inverted ‘N’ shape. The grooves appear to have been intentionally produced, and comparison with experimentally-made grooves suggest that they were made with a shark tooth.

Previously, the earliest evidence for the carving of abstract patterns was the engraved ochres from Blombos Cave, South Africa, which date from the period 100,000 to 75,000 years ago, and the 60,000 year old engraved ostrich shells from Diepkloof Cave, South Africa. Neanderthals made abstract rock engravings at Gorham’s Cave, Gibraltar, 39,000 years ago. More controversially, it has been suggested that a 230,000 year old pebble found at Berekhat Ram in the Golan Heights is a representation of the female form.

The cutting tool is the earliest-known example of the use of shells for tool-making, and may have been a response to the lack of locally-available material for making stone tools. A similar explanation has been proposed for Neanderthal shell tools from Italy and Greece, but these are only around 110,000 years old.

Finally, seafood is a dietary adaptation was once thought to be exclusive to modern humans, beginning around 165,000 years ago. Subsequently it was discovered that Neanderthals were exploiting seafood on the Malaga coast 150,000 years ago. The Trinil shells show that the use of seafood by humans was a much earlier development.

Overall, the Trinil shells suggest that Homo erectus possessed a far greater behavioural flexibility than previously believed in terms of both tool-making technology and subsistence strategies. The engraved geometric pattern suggest that at least some capacity for symbolic thought was already present in early humans 500,000 years ago.

The findings are published in the journal Nature.

Reference:

1. Joordens, J. et al., Homo erectus at Trinil on Java used shells for tool production and engraving. Nature (2014).

Novel agro-pastoral package enabled settlement of Tibetan Plateau

Barley and sheep enabled agriculturalists to live at high altitude

A new study, published in the journal Science, has documented human adaptations to living at high altitudes on the Tibetan Plateau. This vast elevated region in Central Asia includes most of Tibet and Qinghai Province, together with a part of the Ladakh region of Jammu and Kashmir. Measuring 1,000 km (620 miles) from north to south and 2,500 km (1,600 miles) east to west, it has an area of 2,500,000 sq. km (970,000 sq. miles) or roughly five times the size of France. With an average elevation exceeding 4,500 m (14,800 ft.), the Tibetan Plateau is the world’s highest and largest plateau, for which reason it is popularly known as “the roof of the world”.

The first evidence for human presence on the Tibetan Plateau dates to around 20,000 years ago, reaching altitudes of up to 4,300 metres above sea level. Artefacts include stone tools, small hearths and animal remains. It is thought that these finds were associated with single-use campsites occupied by hunters in pursuit of game. The first farming villages appeared 5,200 years ago.

In order to ascertain when and at what altitude food production became sufficient to sustain a long-term presence, researchers recovered artefacts, animal remains and plant remains from 53 sites located on the northeastern corner of the plateau. They obtained radiocarbon dates for charred cereal grains recovered from each site, which suggested that the sites fell into two groups. The first group dated from between 5,200 to 3,600 years ago, and the second group from between 3,600 to 2,300 years ago. None of the first group of sites exceeded an altitude much above 2,500 metres above sea level, but the majority of second group of sites ranged in altitude from between 2,500 to 3,400 metres above sea level.

The first group of sites were interpreted as reflecting the widespread settlement of the region by farming communities of the Yellow River and its tributaries. Millet accounted for all but a tiny percentage of cereal grains recovered from these sites. By contrast, at the higher altitude sites in the second group, the dominant crop was barley, together with some. Barley was grown alongside millet at the lower altitude sites in the second group. Sheep remains were present at those sites lying at or higher than 3,000 meters above sea level.

The presence of crops and livestock suggests that there was now a more sustained human presence at high altitudes. Barley is more frost-resistant than millet, but it also has a longer growing season of typically six months. The presence of houses and tombs at these sites further supports a sustained and likely year-round human presence. Thus this second phase of settlement of the Tibetan Plateau saw the northern Chinese millet joined and in some cases replaced by two Southwest Asian crops – barley and wheat. The introduction of these new crops enabled Tibetan farmers to exploit the harsher conditions of the higher elevations of the Tibetan Plateau.

Some sites outside the study region were located at even greater altitudes. For example, Changguogou on the southern-central part of the plateau has an elevation of 3,600 metres above sea level. Southwest Asian crops included barley, wheat, oats, rye and peas, in addition to millet.

The changing patterns of exploitation of the Tibetan Plateau might have been driven by climate change. The warm, wet conditions of the Early and Middle Holocene enabled both early hunter-gatherer exploitation of the plateau and the subsequent expansion of millet agriculture into the region. These conditions gave way to a colder, dryer climate, which did not favour millet and forced farmers to look for hardier alternatives. Not only did barley and wheat do well in the cooler conditions, they also grew at the higher elevations the farmers had previously been unable to exploit.

References:

1. Chen, F. et al., Agriculture facilitated permanent human occupation of the Tibetan Plateau after 3600 BP. Science (2014).

Neanderthals may have used projectile spears

Bone abnormality suggests repetitive movements similar to those documented for professional throwing athletes

Three long bones from a Neanderthal left arm have been found at Tourville-la-Rivière, Normandy. The bones are somewhere between 183,000 and 236,000 years old and paleo-ecological indicators suggest an date towards the end of the MIS 7 interglacial (245,000 to 190,000 years ago).

An abnormal crest has been found on the humerus, which is thought to represent a deltoid muscle enthesis. The abnormality could have resulted from trauma connected to repetitive movements similar to those seen for professional throwing athletes.

It has long been assumed that Neanderthals used only thrusting rather than projectile spears, but the Tourville-la-Rivière findings provide evidence,albeit inderect, that this might not have been the case. Such a suggestion is consistent with the recent discovery of 280,000-year-old projectile points in Ethiopia.Though these were not made by Neanderthals, they nevertheless indicate that archaic humans could master projectile technology.

The findings are published in the open-access journal PLoS One.

Reference:

1. Faivre, J. et al., Middle Pleistocene Human Remains from Tourville-la-Rivière (Normandy, France) and Their Archaeological Context. PLoS One 9 (10), e104111 (2014).

Cave art from Sulawesi was contemporary with Upper Palaeolithic European cave-painting tradition

U-series re-dating suggests that Indonesian cave art is almost 40,000 years old

The arrival of modern humans in Europe is marked by the appearance in the archaeological record of a sophisticated artistic tradition, which includes portable art objects and cave art. Archaeologists have long been puzzled by an apparent lack of antecedents for this artwork, either in Africa or on early modern human migration routes. It is difficult to see how a seemingly mature artistic tradition could arise de novo in Upper Palaeolithic Europe – but if the 40,000 year old cave paintings at sites such as Altamira and El Castillo really were the earliest cave art anywhere in the world, this must have been the case.

In the 1950s, rock art was reported from limestone caves in the Maros and Pangkep regions of the island of Sulawesi, Indonesia. Over 90 rock art sites are known, which have been extensively studied by Indonesian scholars and appear to belong two distinct periods. The art of the earlier period comprises hand stencils produced by spraying pigment over hands pressed against rock surface, together with a smaller number of large, naturalistic paintings of large Sulawesi mammals, including the anoa (a small bovid), the Celebes warty pig and the babirusa (a member of the pig family). The artwork of the later period is typified by small anthropomorphic depictions and a wide range of geometric signs, typically drawn using a black pigment. This later period has been associated with Austronesian migrants on stylistic grounds, and is thought to be no more than a few thousand years old.

The art of earlier period, though much older than that of the later period, was still thought to be less than 10,000 years old. However, recently-reported uranium series dates obtained for 14 paintings (12 hand stencils and two animal paintings) located at seven different sites indicate that it is much older. The oldest hand stencil was at least 39,900 years old and the oldest animal painting was at least 35,700 years old. The most recent hand stencil was no older than 27,200 years old, suggesting a tradition that endured for at least 13,000 years – comparable to the duration of the European cave painting tradition.

That contemporary traditions of cave art occurred in two regions as far apart as Europe and Indonesia implies either independent development or a common origin dating much further back in time. If the latter was the case, we can hope that even earlier depictions of human hands, figurative art and other images await discovery.

Reference:

1. Aubert, M. et al., Pleistocene cave art from Sulawesi, Indonesia. Nature 514, 223-227 (2014).

Levallois technology originated independently in Africa and Eurasia

Armenian findings provide insight into Lower to Middle Palaeolithic transition

The Middle Stone Age/Middle Palaeolithic saw a shift in emphasis from hand-axe (biface) manufacture to prepared-core methods. In the former, flakes detached from a stone core are regarded as waste products; in the latter, flakes detached from a pre-shaped stone core are the desired products. The shift to prepared-core industries probably came about as toolmakers began to recognise that debitage (waste flakes) could often be useful tools in their own right. Such methods are economical in their use of raw materials, because many flakes may be struck from the same core.

Prepared-core techniques include the Levallois method. It is named after the Parisian suburb of Levallois-Perret, where examples of prepared cores were found in the nineteenth century. The Levallois method involves at least five or six clearly separate stages, each of which requires careful preplanning. Flakes were first struck off around the periphery of a raw stone nodule; the scars from this process were then used as striking platforms (the point where a stone core is struck by a hammerstone) to remove flakes from one surface of the nodule. From the resulting core, one or more flakes could now be detached, the shape and size of which being predetermined by the core preparation. Flakes so produced were fashioned into as many as forty distinct tool types, each with its own specific cutting, scraping or piercing function. There was a much greater standardisation in the form of the tools made, indicating a clearer mental template and greater manipulative skill applied to their manufacture.

What has been unclear is whether this method was developed just once, and spread with populations, or whether it was independently invented on multiple occasions. In Africa, the Early to Middle Stone Age transition is characterised by the gradual replacement of bifaces by flakes, points, and blades produced through various prepared-core methods, principally the Levallois method. On the single-invention picture, such a gradual transition would not be seen elsewhere; rather there would be a discontinuity as human groups dumped their outmoded Acheulean hand-axes and adopted the new technology.

However, recent findings from the site of Nor Geghi 1, Armenia (NG1) suggest that this was not the case. A mixture of Acheulean and Levallois artefacts have been recovered, 316 in all, made from locally-available obsidian. The artefacts are around 300,000 years old and are the earliest examples of this technology to be found outside of Africa.

The findings support the hypothesis that Levallois technology arose gradually from Acheulean technology on multiple occasions and its presence in Africa and Eurasia represents technological convergence rather than a ‘technical breakthrough’ that spread from a single point of origin.

Reference:

1. Adler, D. et al., Early Levallois technology and the Lower to Middle Paleolithic transition in the Southern Caucasus. Science 345 (6204), 1609-1612 (2014).

Neanderthal rock engraving

Important evidence for symbolic behaviour from Gorham’s Cave, Gibraltar

Archaeologists from the Gibraltar Caves project have found a rock engraving at Gorham’s Cave on the eastern side of Gibraltar. The deeply-etched cross-hatched pattern is carved into the dolomite bedrock of the cave, and was wholly-covered by an undisturbed archaeological level containing Mousterian artefacts. Thus its association with Neanderthals is secure.

The engraving is at least 39,000 years old and although modern humans were in Europe by that time, they had not yet reached the southern Iberian Peninsula. Furthermore, the Gibraltar rock engraving predates the earliest Aurignacian cave art, suggesting that it was an independent Neanderthal development.

Researchers carried out a number of tests to demonstrate that the engraving was intentional. They used a variety of tools and cutting actions on blocks of dolomite rock similar to the rock face at Gorham's cave and found that results best matching the engraving were achieved by using a pointed tool to create and enlarge a groove. Considerable care and physical effort was required to produce similar markings. The researchers also used the sharp tools to cut pork skin on a dolomite slab to rule out the possibility that the pattern had been produced accidentally while cutting meat or working animal hides.

The Gorham’s Cave rock engraving is only the latest in a series of recent discoveries that clearly demonstrate that the Neanderthals were not the dimwits of popular imagination. It is possibly the strongest indication yet that they were capable of symbolic behaviour

References:

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1.            Rodríguez-Vidal, J. et al., A rock engraving made by Neanderthals in Gibraltar. PNAS (Early edition) (2014).

Link:

http://www.pnas.org/content/early/2014/08/27/1411529111

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Neolithic boom-to-bust

Transition to agriculture triggered demographic growth followed by collapse

Researchers have used two sets of data from the period 6000 to 2000 BC to investigate the demographics of the transition to agriculture in Europe: data from cemeteries, and radiocarbon dates from 24 well-documented archaeological regions across Europe.

The juvenility index is the proportion of a population aged between 5 and 19 years old: in an increasing population, this is high; in a declining population it is low. Researchers obtained data from 212 cemeteries, weighting results by settlement size. They then considered the Summed Calibrated Radiocarbon Date Probability Distribution (SCDPD) of 8,032 radiocarbon dates, which can be used as a proxy for population density and indicate whether populations are rising or falling at a given time.

Both sets of data gave similar results. The transition from Mesolithic to Neolithic in each region was accompanied by a sharp increase in the population, but after a period of stability there was a decline. The cemetery data indicated a period of growth lasting for about 720 years, a period of stability lasting for just under 1,000 years, followed by a decline. The use of radiocarbon dates is less proven as a proxy, but because far more data is available it should provide higher resolution results. The radiocarbon dates indicated that the period of growth had lasted for 420 years before a decline set in, lasting for 840 years for a complete boom to bust cycle of 1,260 years. That the two sets of results are reasonably consistent confirms SCDPD as a valid demographic proxy.

References:

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1.            Downey, S., Bocaege, E., Kerig, T., Edinborough, K. & Shennan, S., Correlation with Juvenility Index Supports Interpretation of the Summed Calibrated Radiocarbon Date Probability Distribution (SCDPD) as a Valid Demographic Proxy. PLoS One 9 (8), e105730 (2014).

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Link:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0105730

Prehistory of New World Arctic investigated in major new genetic study

Paleo-Eskimos were independent of Inuit and Native American expansions

In the 1980s, the American linguist Joseph Greenberg proposed that Native American languages could be classified within three families: Eskimo-Aleut, Na Dene and Amerind. He further suggested that each family corresponded to a separate migration into the New World from Siberia and concluded, therefore, that the New World had been peopled by three migrations. Greenberg’s views remained controversial for many years as most mitochondrial and Y-chromosomal genetic studies indicated that there had been no more than two migrations. In 2012, however, he was apparently vindicated when David Reich and his colleagues presented a high resolution study of 52 Native American and 17 Siberian groups genotyped at 364,470 single nucleotide polymorphisms. The results indicated that there had indeed been three migrations broadly corresponding to the three language families: specifically (i) First Americans, (ii) Eskimo-Aleuts and, (iii) Saqqaq and Na Dene speakers.

These results are built on by a major new study conducted by an international team numbering over fifty researchers led by geneticist Maanasa Raghavan from the University of Copenhagen. The study focussed on mitochondrial and genome-wide sequences obtained from ancient bone, hair and teeth samples of Arctic Siberia, Alaska, Canada, and Greenland, and high-coverage genomes of two present-day Greenlandic Inuit, two Siberian Nivkhs, one Aleutian Islander, and two Athabascan Native Americans.

From this data, researchers hoped to resolve issues regarding the complex archaeological record of the Early Paleo-Eskimos (Pre-Dorset/Saqqaq), the Late Paleo-Eskimos (Early Dorset, Middle Dorset, and Late Dorset), and the Thule cultures. They were able to show that the Paleo-Eskimos reached the New World in a single migration from Siberia around 3000 BC and displayed genetic continuity for more 4,000 years. About 700 years ago they were replaced by the Thule people, who were the ancestors of the present day Inuit.

While supporting Reich et al overall, the results indicated that the Saqqaq tradition and Na Dene speakers were not part of the same migratory wave: accordingly the Paleo-Eskimos must have arrived in a separate migration to the three waves identified by Reich et al, implying that the New World was populated by four migrations in all.

References:

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1.  Reich, D. et al., Reconstructing Native American population history. Nature 488, 370–374 (2012).

2.  Greenberg, J., Turner, C. & Zegura, S., The Settlement of the Americas: A Comparison of the Linguistic, Dental, and Genetic Evidence. Current Anthropology 27 (5), 477-497 (1986).

3.  Raghavan, M. et al., The genetic prehistory of the New World Arctic. Science 345 (620), 1020,1255832 (2014).

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Neanderthals coexisted with modern humans for up to 5,000 years

New radiocarbon dates point to longer coexistence but earlier extinction

A new study published in the journal Nature suggests that Neanderthals persisted alongside modern humans in Europe for as long as 5,000 years after the arrival of the latter. A team lead by Tom Higham at Oxford obtained 196 AMS radiocarbon dates from 40 sites across Europe, relying on improved techniques to remove young carbon contamination. The results also indicate that the Neanderthals were probably extinct no later than 41,000 to 39,000 years ago.

Although it was once believed that Neanderthals and modern humans had coexisted for up to 10,000 years, work in the middle of the last decade suggested that the overlap was very brief.  The new results represent a reversion to the earlier position, albeit pushed further back in time since it is now believed that modern humans first reached Europe about 46,000 years ago (Higham’s team suggest the date was around 45,000 years ago).

The new dates may resolve long-running controversy over the Châtelperronian culture, with is believed to be of Neanderthal origin but incorporates elements associated with modern human behaviour. The dates indicate that the Châtelperronian began around 45,000 years ago, suggesting that it was influenced by interaction with modern humans. The Châtelperronian comes to an end at about the same time as the Mousterian, about 41,000 to 39,000 years ago

.

The researchers were unfortunately unable to obtain any dates for remains from Gorham’s Cave, Gibraltar, where Neanderthal survival after 30,000 years ago has been claimed.

The lengthy overlap rules out the in any case improbable hypothesis that modern humans hunted down and exterminated the Neanderthals. It is more likely that a combination of increased competition for limited resources and the Heinrich Event 4 climatic downturn 40,000 years ago was responsible.

References: 

Higham, T. et al., The timing and spatiotemporal patterning of Neanderthal disappearance. Nature 512, 306-309 (2014). 

Gibraltar Neanderthals ate roasted pigeons

Further evidence of Neanderthal sophistication at Gorham’s Cave

Gorham’s Cave, Gibraltar, was occupied by Neanderthals for thousands of years and was one of the last known sites of Neanderthal occupation before their final disappearance. Researchers have been working at the cave site for the past 25 years, and it has yielded a wealth of data about Neanderthal technology and patterns of subsistence.

In a survey published online in Nature Scientific Reports, researchers examined 1,724 Rock dove (common pigeon) bones from the cave, spanning the period from 67,000 to 28,000 years ago. All but the most recent part of this time period is associated with Mousterian technology, implying that the occupants of the cave at that time were Neanderthals. Modern human Upper Palaeolithic technology does not appear until near the end of the sequence.

Some of the bones were unevenly discoloured, consistent with roasting over a fire or glowing embers. Bones with less meat on them would have been more intensely affected by the heat, and would consequently undergo more discoloration than meatier bones. Some bones also displayed cut marks and/or tooth marks.

The exploitation of the pigeons was not sporadic: there is repeated evidence for the practice throughout the time that Neanderthals were resident in the cave. Furthermore, they could not have learned about it from modern humans as the earlier evidence substantially predates the arrival of modern humans in Europe.

That the Gorham’s Cave Neanderthals were able to regularly exploit this reliable and sustainable source of food is further evidence of their sophistication.

References:

1. Blasco, R. et al., The earliest pigeon fanciers. Nature Scientific Reports online (2014).

Link:
http://www.nature.com/srep/2014/140807/srep05971/full/srep05971.html

Is Homo floresiensis a valid species?

New papers revive ‘hobbit’ controversy

The announcement in 2003 that dwarf hominins had been discovered at Liang Bua Cave on the Indonesian island of Flores was one of the major news stories of that year. The type specimen, LB1, a female inevitably dubbed ‘Flo’ had lived had lived just 18,000 years ago at a time when all archaic hominins were believed to be long extinct. Estimated to have been around thirty years old at the time of her death, ‘Flo’ stood just 1.06 m (3 ft. 6 in.) tall, weighed 16 and 36 kg (35 and 79 lb), and had an estimated cranial capacity of just 380 cc, comparable to that of an australopithecine.

Rapidly dubbed the ‘hobbit people’ on the grounds of their diminutive stature, the hominins were recognised as a new human species, Homo floresiensis. It was suggested that in the absence of natural enemies on an island where food is fairly scarce, ‘Flo’s’ people had undergone a process known as insular dwarfism, where smaller individuals are positively selected for and over several generations, the entire population ‘downsizes’.
Not everybody accepted this explanation. In 2006, the late Teuku Jacob claimed that Flo was a modern human of Australomelanesian extraction, who had suffered from a developmental disorder leading to a smaller brain known as microcephaly. Jacob found little support for his views and was also criticised for allegedly damaging the specimens while they were on loan to him from the Indonesian National Archaeological Research Center.

The controversy had been revived by the publication of two companion papers in the journal PNAS. Two of the authors of these new papers were also involved with Jacob’s original study. The first paper, Henneberg, et al (2014), argues that Flo was suffering from Down syndrome. This can result in atavism, where developmental characteristics of an earlier ancestral condition appear alongside undisrupted characteristics. This pattern could explain what has been otherwise interpreted as a mosaic of primitive and derived features. As a teratological specimen, the authors note that LB1 is not eligible to be designated the type specimen of a new species.

In the second paper, Eckhardt, et al (2014) suggest that based on an examination of the Flores specimens made in 2005, both the stature and brain size of LB1 have been underestimated. LB1, they argue, possessed abnormalities such as craniofacial asymmetry and a thigh bone disproportionately short in relation to its other long bones. Such abnormalities are indicative of Down syndrome and a number of other developmental conditions.

 References:
1. Jacob, T. et al., Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities. PNAS 103 (36), 13421–13426 (2006).
2. Henneberg, M., Eckhardt, R., Chavanaves, S. & Hsüc, K., Evolved developmental homeostasis disturbed in LB1 from Flores, Indonesia, denotes Down syndrome and not diagnostic traits of the invalid species Homo floresiensis. PNAS (Early Edition) (2014).
3. Eckhardt, R., Henneberg, M., Weller, A. & Hsüc, K., Rare events in earth history include the LB1 human skeleton from Flores, Indonesia, as a developmental singularity, not a unique taxon. PNAS (Early Edition) (2014).

Links (all papers are open access):
Jacob, et al http://www.pnas.org/content/103/36/13421.short
Henneberg, et al http://www.pnas.org/content/early/2014/07/31/1407382111.abstract
Eckhardt, et al http://www.pnas.org/content/early/2014/07/31/1407385111.abstract

Craniofacial changes after 80,000 years ago may reflect increased social tolerance

Did technology boom result from reduced male aggression?

An ambitious study published in the journal Current Anthropology has proposed a link between craniofacial changes and technological advances occurring after around 80,000 years ago. The authors suggest that a reduction in browridge projection and a shortening of the upper facial skeleton (referred to by the authors as ‘feminization’) was the result of either reduced testosterone levels or reduced androgen receptor densities. This reduced male aggression and increased social tolerance, in turn enabling larger groups to live together and the building of long-distance social networks. The consequence was that between around 80,000 and 30,000 years ago, there was acceleration of cumulative technological evolution or ‘cultural ratcheting’ where innovations accumulate over time as a result of cooperation between individuals and groups.

Robert Cieri and his colleagues considered over 1,400 skulls from prehistoric people living before and after 80,000 years ago, and from recent foragers and farmers. They found that a trend towards browridge reduction and facial shortening is apparent from after 80,000 years ago, consistent with the hypothesised higher testosterone levels or androgen receptor densities prior to that time.

The study is the latest attempt to resolve an apparent lag in the archaeological record between the appearance of anatomically modern humans and clear evidence for modern human behaviour in the form of symbolic expression, innovation and planning depth. Such evidence does not become apparent until after 80,000 years ago, leading some anthropologists to postulate a ‘smartness mutation’ occurring at about that time that somehow ‘rewired’ the human brain and enabled it function far more efficiently.

In the last fifteen years or so, the trend has been to look for demographic rather than cognitive explanations. The African Middle Stone Age has examples of seemingly precocious technological traditions such as Stillbay and Howieson’s Poort that were relatively short-lived and were replaced by more conservative traditions. It is argued that periodically, population levels fell to below the level needed to preserve the complex technological traditions from one generation to the next. It has also been suggested that evidence for symbolic behaviour in the form of beads and ornaments is indicative of more complex societies rather than more complex brains. Both fit well with the idea of more tolerant societies emerging after 80,000 years ago.

However, the most recent archaeological data has failed to correlate the disappearance of advanced technological traditions with demographic collapse, and indeed the extent to which such technologies were repeatedly lost has been questioned. For example, microliths are now known to have first appeared 165,000 years ago and their periodic disappearance from the archaeological record may be apparent rather than actual.    

References:

1. Cieri, R., Churchill, S., Franciscus, R., Tan, J. & Hare, B., Craniofacial Feminization, Social Tolerance, and the Origins of Behavioral Modernity. Current Anthropology 55 (4), 419-443 (2014).

Evidence for Neolithic dairy farming in Finland

Lipid residues from prehistoric sherds reveal transition around 2500 BC 

It has long been debated whether Neolithic farming economies were ever established at the limits of modern agriculture around the 60th parallel north. Thanks to the warming effects of the Gulf Stream, sustainable farming economies were established slightly to the south, in Britain, southern Norway and Sweden. In Finland, however, agriculture is problematic even today due to lower temperatures and a snow cover for several months of the year.

Corded Ware was a pan-European phenomenon during the third millennium BC. Corded Ware reached Finland, but despite the firm association of this culture with pastoral farming elsewhere in Europe, there is no evidence for it in Finland. A problem for archaeologists is the poor survival rate of archaeological remains in the acidic soils of the region.

Fortunately, these same conditions favour the preservation of certain classes of ancient biomolecules such as lipids in the walls of ancient ceramic cooking vessels. Carbon isotope analysis can then be used to determine the origins of such organic residues.

In a new study published in Proceedings of the Royal Seciety B, researchers took advantage if the availability of abundant sherds representing prehistoric cooking vessels to investigate the economy of prehistoric hunter–fisher–foragers using so-called Comb Ware, and possible early farmers associated with Corded Ware, Final Neolithic Kiukainen Ware, and Early Metal Age people.

Seventy prehistoric sherds were investigated, from sites in southern and southwestern Finland; 19 yielded residues amenable to analysis. Residues recovered from Comb Ware dating from 3900 to 3300 BC were found to be associated exclusively with marine products suggesting specialised subsistence strategies and/or the storage of marine commodities for exchange. By contrast, residues recovered from Corded Ware dating to around 2500 BC display isotopic signatures suggesting fats of ruminants. While these could indicate either domestic cattle or wild elk or reindeer, around half the residues are from milk, suggesting the former possibility. Notably, these milk residues were found in drinking beakers rather than storage amphorae. Only one Corded Ware vessel was found to contain residues of a marine origin despite the proximity of the sites investigated to the coast.

Unlike the other two, Final Neolithic Kiukainen Ware sherds revealed a mixed-economy of marine and ruminant products. Possibly marine elements were reintroduced to the economy as a hedge against deteriorating climate. The Early Metal Age residues were exclusively of dairy origin, suggesting the intensification of agriculture despite the continued deterioration of the climate.

The sharp contrast between the marine products associated with Comb Wares and domesticated products associated with Corded Wares supports the view that Corded Ware pottery represents the successful introduction of farming into Finland and also places the origins of farming and milk consumption at this northerly latitude at 4,500 years ago.

References:

1. Cramp, L. et al., Neolithic dairy farming at the extreme of agriculture in northern Europe. Proceedings of the Royal Seciety B 281 (2014).

Link:

http://rspb.royalsocietypublishing.org/content/281/1791/20140819.full

Chimpanzee gestures decoded

Study may throw light on origins of human language

The use of gestures by chimpanzees was first demonstrated by field studies carried out in the 1960s and 1970s, and work on captive animals has shown that these gestures are part of an intentional, goal-orientated behaviour common to all the great apes. While this behaviour overlaps with human language, it is absent from most animal communication systems and evidence for it is also lacking for the vocalisations of great apes.

There has been considerable interest in a potential common origin of great ape gestures and components of human language and, therefore, in the actual meaning of the gestures. Surprisingly, little work has been carried out in this area. In a new report, published in the journal Current Biology, researchers Catherine Hobaiter and Richard Byrne from the School of Psychology & Neuroscience, University of St Andrews, have presented the first systematic study of meaning in wild chimpanzee gestural communication. They have found that individual gestures have specific meanings, independently of who is making them, as is the case with words in human language. They have also provided a partial ‘lexicon’.

The field studies were conducted in the Budongo Forest in Uganda, and more than 80 chimpanzees were observed. The researchers recorded the interactions of the chimpanzees and analysed 4,531 instances of gestural communications between the animals, noting the motions they used and how other chimpanzees responded. Some 36 gestures were analysed, and some 15 different meanings were identified.

Some of the gestures are unambiguous: for example ‘leaf-clipping’ is only used to signal sexual attraction. 

However, many are associated with up to three meanings: for example, ‘grab’ is used for ‘stop that’, ‘’climb on me’, and ‘move away’. This ambiguity may be apparent rather than real, and may arise in part from the difficulty for human observers in discerning subtle variations in the nature of the gesture. It is evident to a human recipient whether or not a gentle touch is intended to make them move or stay where they are, but such distinctions are very difficult to perceive visually. Gestures were also employed towards two or three very similar outcomes:  for example, ‘push’ is used for both ‘move away’ and ‘stop that’.

Researchers found considerable variation in whether an intended meaning was signalled by a single gesture type or several gestures of apparently equivalent meaning. This was particularly common in social negotiations, where a degree of persuasion was required. By contrast, meanings typically conveyed by a single gesture were often well defined: for example ‘initiate grooming’ is signalled by a big loud scratch.

References:

x

1.  Hobaiter, C. & Byrne, R., The Meanings of Chimpanzee Gestures. Current Biology 24, 1-5 (2014).

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Neanderthals ate their greens

Analysis of 60,000 – 45,000 year old coprolites provides insight into Neanderthal diet

Neanderthal dietary reconstructions have, to date, been based on archaeological evidence, stable isotope data and studies of dental calculus. These suggest that they were predominantly meat eaters, although plant foods made a contribution to their diet. Hitherto, there has been no direct evidence for an omnivorous diet.

A new study, published in the open access journal PLoS One has presented direct evidence of Neanderthal diet using faecal biomarkers, which are a valuable analytical tool for identifying diet. Researchers applied gas chromatography and mass spectroscopy techniques to coprolites (fossil faeces) from the Neanderthal site of El Salt at Alicante, Spain. The coprolites were recovered from sediments gathered from a number of levels at the site, which was repeatedly occupied by Neanderthals between 60,000 and 45,000 years ago.

The team focussed on chemical processes associated with the action of bacteria in the gut. They found a high proportion of coprostanol, which the gut bacteria produce from cholesterol and which is associated with the consumption of meat. However, they also recorded significant quantities of 5β-stigmastanol, which is associated with plant consumption.

Further tests were necessary to confirm that the coprolites were of human origin. The conversion of cholesterol into coprostanol is not unique to humans, but related molecules were also identified in proportions that ruled out other omnivores.

   

References:

x

1.  Ainara Sistiaga, A., Mallol, C., Galván, B. & Everett Summons, R., The Neanderthal Meal: A New Perspective Using Faecal Biomarkers. PLoS One 9 (6), e101045 (2014).

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Link:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0101045

Sima de los Huesos hominins are proto-Neanderthals

New study supports ‘accretion’ model

A new study, published in the journal Science, has provided support for the ‘accretion’ model of Neanderthal evolution. ‘Classic’ Neanderthals, i.e. humans possessing the full suite of Neanderthal characteristics, do not appear in the fossil record until 130,000 years ago. However, French palaeoanthropologist Jean-Jacques Hublin has proposed that Neanderthal characteristics appeared gradually over time, in a piecemeal fashion.

Thus, for example if Feature X appeared in one population and Feature Y in another, then interbreeding between the two populations would have resulted in a population possessing both Features X and Y. Over time, populations gradually acquired the full suite of Neanderthal characteristics by a process of accretion, resulting in a gradual transition from Homo heidelbergensis to Neanderthal. The accretion model explains ‘proto-Neanderthal’ features seen on certain fossils dating to the period prior to the appearance of the ‘classic’ Neanderthals. These include a 400,000-year-old fragmentary skull from Swanscombe in England and the 225,000-year-old Steinheim skull from Stuttgart, Germany.

Much of the evidence we have regarding Neanderthal origins comes from a single site in the Sierra de Atapuerca of northern Spain, near the city of Burgos: a Middle Pleistocene human burial pit known as Sima de los Huesos. The name translates – rather appropriately – as ‘the Pit of Bones’. Sima de los Huesos is a small muddy chamber lying at the bottom of a 13 m (43 ft.) chimney, lying deep within the Cueva Mayor system of caves. Investigation of the site has proved to be long and difficult. The most immediate problems are logistical. The cramped site is located more than 500 m (⅓ mile) from the mouth of the Cueva Mayor and is hard to access, necessitating at times crawling on the stomach. Another problem is the disturbance to the site caused by the many generations of souvenir and fossil hunters. Systematic excavation commenced in 1984 and has continued ever since. To date, over 2,000 fragmentary hominin fossils have been recovered, including three skulls. In total, the remains are thought to represent at least 32 individuals of both sexes. It is likely that the site was simply used for the hygienic disposal of the dead, because there is no evidence to suppose that any of the individuals were deliberately killed and the bones show no sign of injuries caused by spears or clubs.

Study of this enormous collection of bones is still in progress, and is likely to continue for some time yet as the site yields further fossils. However, it has become clear that the fossils show a mixture of Homo heidelbergensis and Neanderthal characteristics, just as would be expected if the accretion model is correct. The key question is how old is the site? Uranium series dates obtained in 2007 suggested that they were at least 530,000 years old, making the Sima people older than some Homo heidelbergensis remains from southern Europe and the Balkan region that show no incipient Neanderthal characteristic features.

The new study considered 17 crania, including seven new specimens. The sample shows a consistent morphological pattern with derived Neanderthal features present in the face and anterior of the cranial vault, many of which are adaptations to aid chewing of food. This suggests that facial modification was the first step in the evolution of the Neanderthal lineage, consistent with the accretion model evolution, with different anatomical features evolving at different rates.

The researchers also used a variety of techniques including combined electron spin resonance/uranium series to obtain a revised date of 430,000 years old, which gives a far better fit with the accretion model.

References:

x

1.  Arsuaga, J. et al., Neandertal roots: Cranial and chronological evidence from Sima de los Huesos. Science 344 (6190), 1358-1363 (2014).

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Interbreeding between Neanderthals and modern humans

What we know now

Whether or not modern humans interbred with Neanderthals is a question that has long been of interest to both scholars and lay people alike, but it was not until May 2010 that strong evidence emerged that the answer to the question was ‘yes, probably’.

A project to sequence the Neanderthal genome was commenced in 2006 at the Max Planck Institute for Evolutionary Anthropology (Green, et al., 2006; Green, et al., 2008), and in May 2010, researchers published a first draft of the Neanderthal genome (Green, et al., 2010). With the initial announcement came the dramatic news that made headlines around the world. It turned out that between one and four percent of the genome of modern non-Africans was derived from Neanderthals. In other words, the answer to the million dollar question was ‘yes, they did interbreed – but not in Africa’. The researchers compared the Neanderthal genome with those of five present-day individuals: two indigenous Africans (one San from South Africa and one Yoruba from West Africa) and three Eurasians (one from Papua New Guinea, one from China and one from France). The results showed that Neanderthals were more closely related to non-Africans than to Africans. This is not particularly surprising, as Neanderthals are not known to have lived in Africa. Any interbreeding has generally been supposed to have occurred within the known range of the Neanderthals, in Europe and western Asia. What was unexpected was that no difference was found between Papua New Guinean, Chinese and European individuals in terms of their degree of relatedness to Neanderthals.

The implication is that the interbreeding must have occurred before the ancestors of the present-day Asian, Australasian and European populations diverged from one another – presumably in Southwest Asia soon after modern humans first left Africa, and long before they reached Europe. If the population that left Africa was small, only limited interbreeding would be necessary to leave the Neanderthal contribution fixed in the modern non-African genome for all time, as numbers increased during the subsequent peopling of the world.

Interbreeding was not the only way to interpret these initial results, and the authors of the report said that they could not rule out the possibility that their results reflected substructure in the early modern human populations. In fact, a later independent study favoured this possibility, using a mathematical model to represent a connected string of regional populations spanning Africa and Eurasia. After the string split, the Eurasian and African parts of the range subsequently evolved into Neanderthals and modern humans respectively. For the latter, groups geographically closest to the split (i.e. in North Africa) remained more closely related to Neanderthals than those further south. It was assumed that the non-African world was subsequently populated by a dispersal of one of these northerly groups from Africa (Eriksson & Manica, 2012).

Subsequent work by independent researchers ruled out this substructure scenario (Sankararaman, et al., 2012; Yang, et al., 2012), and appeared to back the view that there had been a single episode of interbreeding very early on in the Out of Africa expansion that led to the peopling of the non-African world (Yotova, et al., 2011). The findings that some Africans do after all carry a Neanderthal genetic signature (Sánchez-Quinto, et al., 2012; Wall, et al., 2013) is not a major problem, as this can be accounted for in terms of a pre-Neolithic ‘Back to Africa’ migration of modern humans from Southwest Asia (Olivieri, et al., 2006; González, et al., 2007; Hodgson, et al., 2014).

A complication is that studies have found no trace of a Neanderthal component in mitochondrial DNA (Caramelli, et al., 2003; Serre, et al., 2004; Caramelli, et al., 2008). On the ‘brief encounter’ picture, this could mean crossbred women were sterile, and thus their mitochondrial DNA was never passed to subsequent generations. Another possibility is that interbreeding between Neanderthals and modern humans was very rare, with only one such event every couple of centuries. The reason could be limited biological compatibility, or it could be that the two mostly avoided interspecific mating. Such a low rate of interbreeding would account for the absence of Neanderthal mitochondrial DNA from the present-day gene pool, but it would still be sufficient to account for the observed levels of Neanderthal DNA in the nuclear genome. However, it would require interbreeding to occur across the whole of the Neanderthal range, not just in Southwest Asia (Currat & Excoffier, 2011; Neves & Serva, 2012).

Between 2012 and 2014, further studies showed that the original conclusion that all non-African populations were related equally to Neanderthals was incorrect, and that the proportion of Neanderthal ancestry in East Asians is 20 to 40 percent higher than it is in Europeans. This implies that interbreeding could not all have happened at a single time and place; some of it must have happened after the ancestral East Asian and European populations separated (Meyer, et al., 2012; Wall, et al., 2013; Vernot & Akey, 2014). Given that Neanderthals lived in Europe but are not known from East Asia, this is unexpected. However, their known range extents to the Altai region north of the Himalayas and a subsequent episode of interbreeding might have occurred there. Alternatively, it is possible that the Neanderthal range actually extended further south, as we know to have been the case for the Denisovans.

The latest work suggests that around 20 percent of the Neanderthal genome survives in the present-day population, albeit individuals each only possess a small fraction of this amount (Vernot & Akey, 2014). 

Many useful Neanderthal genes have been incorporated into the modern genome; for example those involved with the production of keratin, a protein that is used in skin, hair and nails. Possibly the Neanderthal versions of these genes were more suited to the harsh conditions of Ice Age Europe (Sankararaman, et al., 2014). In East Asian populations, many genes involved with protection from UV are of Neanderthal origin (Ding, et al., 2014).

Some deleterious genes also have a Neanderthal connection, including those implicated in Type 2 diabetes and Crohn’s disease. Significantly, Neanderthal DNA was largely absent from the X chromosome and genes associated with modern testes. The implication is that Neanderthal DNA in these regions led to reduced male fertility, or sterility (Sankararaman, et al., 2014), consistent with the view that Neanderthals and modern humans were at the limits of biological compatibility.

These results show that natural selection had a significant role, with both positive and negative selection determining Neanderthal gene frequencies. It is entirely possible that selective factors could be at least partially responsible for the higher incidence of Neanderthal DNA in East Asian populations.

It is now clear that the interactions between Neanderthal and modern populations were complex; and that we are still at a very early stage of understanding them.

References:

1. Green, R. et al., Analysis of one million base pairs of Neanderthal DNA. Nature 444, 330-336 (2006).

2. Green, R. et al., A Complete Neandertal Mitochondrial Genome Sequence Determined by High-Throughput Sequencing. Cell 134, 416–426 (2008).

3. Green, R. et al., A Draft Sequence of the Neandertal Genome. Science 328, 710-722 (2010).

4. Eriksson, A. & Manica, A., Effect of ancient population structure on the degree of polymorphism shared between modern human populations and ancient hominins. PNAS 109 (35), 13956–13960 (2012).

5. Sankararaman, S., Patterson, N., Li, H., Pääbo, S. & Reich, D., The Date of Interbreeding between Neandertals and Modern Humans. PLoS Genetics 8 (10) (2012).

6. Yang, M., Malaspinas, A., Durand, E. & Slatkin, M., Ancient Structure in Africa Unlikely to Explain Neanderthal and Non-African Genetic Similarity. Molecular Biology and Evolution 29 (10), 2987–2995 (2012).

7. Yotova, V. et al., An X-Linked Haplotype of Neandertal Origin Is Present Among All Non-African Populations. Molecular Biology and Evolution 28 (7), 1957-1962 (2011).

8. Sánchez-Quinto, F. et al., North African Populations Carry the Signature of Admixture with Neandertals. PLoS One 7 (10) (2012).

9.  Wall, J. et al., Higher levels of Neanderthal ancestry in East Asians than in Europeans. Genetics 194, 199-209 (2013).

10. Olivieri, A. et al., The mtDNA Legacy of the Levantine Early Upper Palaeolithic in Africa. Science 314, 1757-1770 (2006).

11. González, A. et al., Mitochondrial lineage M1 traces an early human backflow to Africa. BMC Genomics 8 (223) (2007).

12. Hodgson, J., Mulligan, C., Al-Meeri, A. & Raaum, R., Early Back-to-Africa Migration into the Horn of Africa. PLoS Genetics 10 (6), e1004393 (2014).

13. Caramelli, D. et al., Evidence for a genetic discontinuity between Neandertals and 24,000-year-old anatomically modern Europeans. PNAS 100 (11), 6593–6597 (2003).

14.  Serre, D. et al., No Evidence of Neandertal mtDNA Contribution to Early Modern Humans. PLoS Biology 2 (3), 0313-0317 (2004).

15.  Caramelli, D. et al., A 28,000 Years Old Cro-Magnon mtDNA Sequence Differs from All Potentially Contaminating Modern Sequences. PLoS One 3 (7) (2008).

16.  Currat, M. & Excoffier, L., Strong reproductive isolation between humans and Neanderthals inferred from observed patterns of introgression. PNAS 108 (37), 15129-15134 (2011).

17.  Neves, A. & Serva, M., Extremely Rare Interbreeding Events Can Explain Neanderthal DNA in Living Humans. PLoS One 7 (10) (2012).

18.  Meyer, M. et al., A High-Coverage Genome Sequence from an Archaic Denisovan Individual. Science 338, 222-226 (2012).

19. Vernot, B. & Akey, J., Resurrecting Surviving Neandertal Lineages from Modern Human Genomes. Science 343, 1017-1021 (2014).

20.  Sankararaman, S. et al., The genomic landscape of Neanderthal ancestry in present-day humans. Nature 507, 354–357 (2014).

21.  Ding, Q., Hu, Y., Xu, S., Wang, J. & Jin, L., Neanderthal Introgression at Chromosome 3p21.31 Was Under Positive Natural Selection in East Asians. Molecular Biology and Evolution 31 (3), 683-695 (2014).

Neolithic was brought to Europe by maritime colonists

Ancient and modern mitochondrial DNA study links PPNB to modern populations of Cyprus and Crete

In recent years, ancient DNA has been obtained from Neolithic human remains, and this has provided a more reliable picture of the genetic impact of the European Neolithic than was possible with genetic studies of living populations. However, researchers have been hampered by the lack of data from the original farmers of Southwest Asia.

In a new study, published in the open access journal PLoS One Genetics, researchers report the successful extraction of mitochondrial DNA from fifteen out of 63 skeletons recovered from the Pre Pottery Neolithic B (PPNB) sites of Tell Halula, Tell Ramad and Dja’de El Mughara, dating from between 8700 to 6600 BC. 

The genetic profiles were compared with data obtained from human remains associated with the LBK and Cardial/Epicardial European Neolithic cultures. The researchers also looked for possible signatures of the original Neolithic expansion in the gene pools of present-day Southwest Asian and southern European populations, and tried to infer possible routes of the expansion by comparison with the ancient samples. They were able to identify K and N-derived mitochondrial DNA haplogroups as potential markers of the Neolithic expansion, whose genetic signature would have reached both the Iberian coasts and the Central European plain.

They also observed genetic affinities between the PPNB samples and the modern populations of Cyprus and Crete. However, no such link was found to modern populations of western Anatolia, suggesting that the Neolithic was first introduced into Europe by maritime colonists.

References:

1. Fernández, E. et al., Ancient DNA Analysis of 8000 B.C. Near Eastern Farmers Supports an Early Neolithic Pioneer Maritime Colonization of Mainland Europe through Cyprus and the Aegean Islands. PLoS One Genetics 10 (6), e1004401 (2014).

 Link:
 http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1004401

KwaZulu-Natal findings refutes technological hiatus during African Middle Stone Age

Post-Howieson’s Poort Sibudan tradition was not ‘unstructured and unsophisticated’

Archaeologists have long believed that the later part of the African Middle Stone Age (MSA) was characterised by conservative technologies punctuated by the appearance of technologically-sophisticated but short-lived technocomplexes such as the Stillbay and Howieson’s Poort traditions of South Africa. These traditions are noted for finely-worked stone points, microliths, tools made from bone, and innovative technologies including pressure flaking and compound adhesives. Various theories involving population collapses have been put forward to account for their disappearance and the reversion to comparatively unsophisticated prepared-core industries.

However, it has been suggested that this phenomenon may be more apparent than real, as the Stillbay and Howieson’s Poort eras have been studied far more closely than the supposed hiatus periods that followed. Recent work at the archaeological site Sibudu, KwaZulu-Natal supports the view. Archaeologists have identified a new technocomplex, which they have named the Sibudan, from the six uppermost lithic assemblages at the site. The new technocomplex dates from around 58,000 years ago, placing its’ beginning just after the end of the Howieson’s Poort era.

While the Sibudan has technological parallels with other contemporary MSA industries, it is typologically and technologically distinct. The six stratified tool assemblages are linked by common features, which identify them as a distinct tradition. Many of these features are considered to be hallmarks of a sophisticated stone tool-making technology, including characteristic tool assemblages with standardised forms and reduction cycles, and the production of standardised blades with soft stone hammers. Overall, the Sibudan refutes the notion that post-Howieson’s Poort stone-knapping technologies were rudimentary or unsophisticated.

The report is published in the open access journal PLoS One.

References:

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1.  Will, M. B. G. & Conard, N., Characterizing the Late Pleistocene MSA Lithic Technology of Sibudu, KwaZulu-Natal, South Africa. PLoS One 9 (5), e98359 (2014).

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Link:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0098359

Human evolution favoured brain over brawn

Metabolite study demonstrates human muscle and brain tissue underwent disproportionate evolutionary change

A new study, published in the open access journal PLoS One Biology, has used metabolites to track evolutionary changes in brain and skeletal muscle tissues. Metabolites are metabolic products or intermediated of low molecular weight (1,500 amu or less), which are associated with the physiological processes that maintain the functionality of body tissues. Changes in the concentrations of these metabolites are thought to be closely related to evolutionary changes in the associated tissues.

Researchers measured the concentrations of more than 10,000 metabolites in the prefrontal cortex, primary visual cortex, cerebellar cortex, skeletal muscles and kidneys of humans, chimpanzees, macaque monkeys and mice using mass spectrometry-based techniques. They found that in most cases the differences reflected genetic distances between the species rather than environmental differences.

The striking exception was found in the human lineage. The concentration profiles of metabolites associated with the human prefrontal cortex, cerebellar cortex and skeletal tissues showed far greater changes than could be accounted for by genetic difference: by a factor of four for the brain tissue, and eight for the muscle tissue. In fact the muscle tissue is implied to have undergone more evolutionary change in the 6 to 7 million years since the divergence from chimpanzees than it did during the 130 or so million years separating mice from the common ancestor of the apes and Old World monkeys. No comparable differences were noted for the primary visual cortex or kidneys. Nor were significant differences to any of these results found after controlling for differences in diet and levels of physical activity.

It is well known that humans are physically quite weak in comparison to chimpanzees, despite weighing in at around twice the size. Surprisingly, this is largely based on anecdotal observations mostly predating the 1950s. Accordingly, the researchers set macaque, chimpanzee and human subjects a ‘pulling task’, which tested both upper and lower body strength. These tests confirmed the anecdotal observations.

The researchers concluded that the metabolic changes in human muscle tissue were associated with a drastic reduction in muscle strength; and that these changes might be linked to the changes in brain metabolism and enhanced cognitive abilities.

The findings are an extension of Aiello and Wheeler’s ‘expensive tissue’ hypothesis, which proposed that the considerable energy requirements of the human brain (around 20 percent of the total energy budget) could only be met by making savings elsewhere. Aiello and Wheeler (1995) proposed these savings were made by downsizing other energetically-expensive organs, principally the gut. Apparently, though, this was insufficient and further savings were required in the form of a decrease in the energy expenditure of skeletal muscle.

References:

x

1.  Bozek, K. et al., Exceptional Evolutionary Divergence of Human Muscle and Brain Metabolomes Parallels Human Cognitive and Physical Uniqueness. PLoS One Biology 12 (5), e1001871 (2014).

2.  Aiello, L. & Wheeler, P., The expensive tissue hypothesis: the brain and the digestive system in human and primate evolution. Current Anthropology 36, 199-221 (1995).

x

Link (open access):

http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001871.

The Venus of Willendorf

The Venus of Willendorf is a small 11.1 cm (4 3/8 in) high figurine carved from oolitic limestone and tinted with red ochre.

The 25,000-year-old figurine dates to the Gravettian period and is one of the most iconic artefacts of the European Upper Palaeolithic. It was discovered in 1908 by archaeologist Josef Szombathy near the village of Willendorf in Austria, and since then it has resided in the Naturhistorisches Museum, Vienna. It is currently on display in the Mineralogy galleries, having been relocated there while the Prehistory galleries undergo refurbishment. I took the photographs of the front, side and rear views when I visited the museum during a recent trip to Vienna. From a personal point of view, the enigmatic figurine did much to spark my interest in prehistory, so I was very keen to see it in person for the first time.

With its large breasts, full figure and exaggerated sexual characteristics, the contrast between the Venus of Willendorf and the classical portrayal of the Roman goddess could not be greater. Yet there is nothing crude or primitive about its execution; it is immediately obvious that the figurine is as finely-worked as anything from classical times.

The face is concealed behind rows of plaited hair, which comprise seven concentric bands surrounding the head, with two more semi-circular bands below at the back of the neck. Another interpretation is that the figurine is wearing a woven fibre hat.
Female figurines with similar attributes are known dating to throughout the European Upper Palaeolithic, though most are from the Gravettian period. Despite its obvious inaccuracy, the term ‘Venus figurines’ has been used to describe them since the first examples were found in the nineteenth century. They are often interpreted as fertility figures or mother goddesses, although their real function remains unknown.

13,000 year old skull and mtDNA reinforces continuity between Paleoindians and Native Americans

Teenaged girl ‘Naia’ shared craniofacial features with earliest-known Americans, but genetic profile is common among today’s Native Americans 

The first people to reach the New World arrived around 15,000 years ago, having migrated across the Beringia land bridge that then linked Siberia to Alaska. The Paleoindians, as they are known, possessed craniofacial features that differ markedly to those of present-day Native Americans. Their skulls were long and narrow, the face narrow and the forehead prominent. By contrast, present-day Native Americans are broad-faced, with rounder skulls. A facial reconstruction of Kennewick Man – an 8,400 year old skull found in the Columbia River, Kennewick, WA – is said to bear startling a resemblance to the actor Sir Patrick Steward.

It has therefore been suggested that there were two migrations to the New World, with the Paleoindians arriving first and later being replaced by the ancestors of the present-day Native Americans. However, others argue that the differences arose in situ, possibly as a result of changes in diet when the Paleoindians adopted agriculture during the period between 8,000 and 2,000 years ago. Another possibility is that the changes are simply the result of genetic drift.

The ‘two migrations’ theory has received a significant setback with the recovery of a near-complete human skeleton of a female aged 15 to 16 years from Hoyo Negro, a submerged collapsed chamber in the Sac Actun cave system in the Yucatan Peninsula, Mexico. The skeleton has been nicknamed ‘Naia’ (Greek for ‘water nymph’), and it has been dated to between 12,000 and 13,000 years old. Naia’s craniofacial features are typical of the Paleoindian morphology, but mitochondrial DNA extracted from a molar teeth has been identified as belonging to the haplogroup D1, which occurs only among present-day Native Americans. This is consistent with the view that there was continuity between Paleoindians and present-day Native Americans.

Researchers now intend to sequence Naia’s nuclear DNA, which they hope will shed further light on the origins of the first Americans.

References:

1. Chatters, J. et al., Late Pleistocene Human Skeleton and mtDNA Link Paleoamericans and Modern Native Americans. Science 344, 750-754 (2014).

Rice versus wheat agriculture could explain cultural differences within China, claim researchers

Greater interdependency found in rice-growing regions

People living in the rice-growing regions of southern China are more interdependent, loyal, and nepotistic, and less likely to divorce than their counterparts in the wheat-growing regions north of the Yangtze, according to a study published in the journal Science.

Han Chinese students from various regions in the country underwent a series of tests, including the ‘triad task’, which shows subjects lists of three items, such as train, bus, and tracks. They then decide which two items should be paired together. Two of the items (trains and buses) can be paired because they belong to the same category (trains and buses are forms of transport), and two (trains and tracks) because they share a functional relationship (trains run on tracks). Participants from rice-growing regions were more likely to pair the train and the track, whereas those from wheat-growing regions tended to pair the train and the bus.

The so-called ‘rice theory’ is an extension of subsistence style theory, which argues that some forms of subsistence (such as farming) require more functional interdependence than other forms (such as herding). Over time, societies that have to cooperate intensely become more interdependent, whereas societies that do not have to depend on each other as much become more individualistic. Previous studies have tended to focus on farming versus herding rather than differences between types of farming.

The two major differences between farming rice and wheat are irrigation and labour. Rice paddies require the construction and maintenance of elaborate irrigation systems, in turn requiring cooperation between farmers – often at village level. Farmers also need to coordinate their use of water so as not to adversely affect the supplies of their neighbours. Overall, growing paddy rice is at least twice as labour intensive as wheat farming.

The rice theory predicts that a Unus pro omnibus, omnes pro uno mentality will apply to anybody living in a region where rice has been farmed for thousands of years, not just those directly involved with its production. This prediction was borne out by the study, as few if any of the participants had actually farmed rice or wheat for a living.

My feelings are that while this is an interesting study, one should always be cautious about cultural determinism.

References:

1. Talhelm, T. et al., Large-Scale Psychological Differences Within China Explained by Rice Versus Wheat Agriculture. Science 344, 603-608 (2014).

Link:
http://www.sciencemag.org/content/344/6184/603

Study traces origins of Neolithic in South Asia

Eastward dispersal from Southwest Asia was slower than that unto Europe

A new study, published in the open-access journal PLoS One, has considered the eastwards spread of agriculture from Southwest Asia. This has been less well studied than the westwards expansion into Anatolia and Europe.

Researchers conducted a statistical analysis of radiocarbon dates for 160 Neolithic sites in western and southern Asia. The locations of these sites suggest that the dispersal of farmers eastwards from the Zagros followed two routes: a northern route via northern Iran, southern Central Asia and Afghanistan, and a southern route via Fars through the interior of southern Iran.

Analysis of the radiocarbon dates indicated an eastwards expansion at an average speed of 0.65 km per year, rather slower than the 1 km per year documented for Europe. The authors of report considered this to be unsurprising. Firstly, the arid climate and complicated topography of the region are less favourable for agriculture. Because of this, the early Neolithic settlements in Iran were relatively small and widely separated. Secondly, the European expansion was aided by the Danube, the Rhine and the Mediterranean coastline, but there are no major rivers in Afghanistan or Iran that could play a similar role.

The authors were encouraged that the fairly simple ‘wave of advance’ model used captured the salient features of the data studied, but stressed the need for a more detailed analysis that would consider local environments and climatic conditions.

References:

1. Gangal, K., Sarson, G. & Shukurov, A., The Near-Eastern Roots of the Neolithic in South Asia. PLoS One 19 (5), e95714 (2014).

Link:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0095714

How to think like a Neandertal, by Thomas Wynn and Frederick Coolidge

Of all early humans, none have captured the public imagination to anywhere near the extent of the Neanderthals. Indeed, with the possible exception of the dinosaurs, no extinct species is so deeply rooted in our popular culture. The idea that tens of thousands of years ago, people very much like ourselves shared the planet with another human species is one that intrigues many, although the term ‘Neanderthal’ is all too often used in a pejorative sense, and there is a widespread perception of the Neanderthals as dimwits.

In this engaging and accessible book, which is nevertheless as rigorous as any textbook, anthropologist Thomas Wynn and psychologist Frederick Coolidge paint a very different picture of the Neanderthals and their way of life. Drawing on archaeological and fossil evidence, they go beyond reconstructing the Neanderthal world and attempt to deduce their underlying thought processes.

In the first chapter, we are given an introduction to the world of the Neanderthals. From the start, Wynn and Coolidge refer to the Neanderthals as ‘people’, which is entirely correct as they were every bit as human as we are. The name comes from Neander Tal (‘Neander Valley’) near Dusseldorf, where Neanderthal remains were first identified in the 1850s (it was originally spelled ‘Neander Thal’, hence the more commonly-used spelling, but it has always been pronounced ‘tal’ and not ‘thal’). We learn that the Neanderthals were short, stocky, powerfully-built folk, with chinless, protruding faces, pronounced browridges over their eyes, and long, broad noses. The braincase was long and low, rather than the globular shape of modern people. Many features of their distinctive anatomy were adaptations to the harsh conditions of Ice Age Europe, but in comparison to very early humans it turns out that modern people are actually far more distinctive than Neanderthals.

An important difference is the shape of the braincase, which reflects the actual shape of the brain itself. Neanderthal brains were differently shaped to ours, and about ten percent larger. Does this mean that they were ten percent smarter than us? Wynn and Coolidge believe that they were neither more nor less intelligent than us – just different. This conclusion provides a focus for the rest of the book.

Neanderthals lived hard and died hard. Shanidar 1 lived in Iraq about 50,000 years ago, and was in his late 30s when he was killed by a rock fall. But long before his death he had suffered a number of major injuries, any one of which could have killed him. He owed his survival to caring companions, who nursed him back to health – and a dogged ability to cope with pain and life-changing injuries. Nor was Shanidar 1 particularly unusual: the pattern of healed injuries suffered by Neanderthals is very similar to those suffered by rodeo riders, suggesting that were regularly pitted against large, dangerous animals.

Each subsequent chapter focusses on a different aspect of Neanderthal life, and uses the evidence to build on this initial picture of them as tough but compassionate folk. Topics include hunting, spear making, family life, burial traditions and language. Wynn and Coolidge even examine Neanderthal humour before characterising them as pragmatic, stoical, risk-taking, empathic (in that they cared for their sick and injured), hard-hearted (in that they were prepared to leave the sick and injured behind if they needed to move camp), conservative (from the point of their extremely static technology, not their voting intentions), and xenophobic (in that they rarely met strangers and distrusted them when they did).

The final chapter plays a game of ‘Trading Places’ and speculates how a Neanderthal might fare in our modern world, and how a modern human in theirs. Wynn and Coolidge suggest that Neanderthals would do well in our world, and would excel as doctors, mechanics or soldiers. On the other hand, they suggest that a modern human would struggle to make a go of Neanderthal living.

The demise of the Neanderthals is covered fairly briefly. The arrival of modern humans in Ice Age Europe is viewed from the Neanderthal perspective. It is surmised that the end came when the climate began to deteriorate 30,000 years ago. This had happened before, and the Neanderthals had able to cope – but now they had competition. The modern humans were more adaptable and inventive when it came to finding new sources of food and developing new hunting methods. The Neanderthals retreated south to the Iberian Peninsula, where they held out for a while, but in the end they died out.

Wynn and Coolidge suggest that the Neanderthals may survive as dim cultural memories. Possibly some European folk traditions have their origins in ancient encounters with Neanderthals. More plausibly, they also suggest that our enduring fascination with the Neanderthals is that they were humans who led very different lives to ourselves, yet were still somehow like us. The Neanderthals live on as “inexact mirrors of ourselves”, Wynn and Coolidge conclude.

How to think like a Neandertal, by Thomas Wynn and Frederick Coolidge is published in the USA by Oxford University Press © 2012