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).

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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

Reference:
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