Study suggests Neanderthals could speak like modern humans

Kebara 2 hyoid bone suggests similar linguistic abilities.

Whether or not Neanderthals could speak like modern humans has been the subject of a long-running debate. For a long time, it was believed that they did not. Based on the analysis of Neanderthal specimen from La Chapelle-aux-Saints, France, it was claimed that the Neanderthal larynx was positioned high in the throat, like a chimpanzee (or a modern human baby), making it impossible for Neanderthals to produce the modern range of vocalisations (d’Errico, et al., 2003).

However, the hyoid bone of Kebara 2, a fossil Neanderthal from Mt. Carmel in Israel, has provided new evidence. The hyoid is a small U-shaped bone that lies between the root of the tongue and the larynx, anchoring the muscles required for speech. The Kebara 2 hyoid is within the modern range in form. Furthermore, by analysis of patterns of muscle attachment, researchers were able to show that the placement of the larynx was similar to that of a modern human, low in the throat (Arensburg, et al., 1989; Arensburg, et al., 1990).

3d modelling work has supported these conclusions. Data from a number of Neanderthal skulls was used to reconstruct the vocal tract. The estimated hyoid position fell within the modern range and acoustic analysis shows that Neanderthals were able to make the quantal vowel sounds (/a/, /i/ and /u/) that are present in all modern human languages. The Neanderthal /i/ and /u/ sounds are within the modern range; /a/ falls just outside (Barney, et al., 2012).

The latest study follows on from this work and used X-ray microtomography to map the internal structure of the Kebara 2 hyoid. It was found that this, too, was within the modern range. Mechanical modelling showed that the micro-biomechanical performance of the hyoid under the loadings it would experience when in use was very similar to that of modern humans. Thus the Kebara 2 hyoid doesn’t just resemble a modern hyoid both externally and internally, it was used in a very similar way (D’Anastasio, et al., 2013).
These results show that from a biomechanical point of view, Neanderthals were fully capable of modern speech. It leaves unresolved the issue as to whether or not they possessed the cognitive abilities, but there is a mounting body of evidence to suggest that their subsistence strategies and other behaviours were far more advanced than previously believed.

References:

1. d’Errico, F. et al., Archaeological Evidence for the Emergence of Language, Symbolism, and Music — An Alternative Multidisciplinary Perspective. Journal of World Prehistory 17 (1), 1-70 (2003).

2. Arensburg, B., Tillier, A., Vandermeersch, B., Duday, H. & Rak, Y., A middle Palaeolithic human hyoid bone. Nature 338, 758–760 (1989).

3. Arensburg, B., Schepartz, L., Tillier, A., Vandermeersch, B. & Rak, Y., A reappraisal of the anatomical basis for speech in Middle Palaeolithic hominids. American Journal of Physical Anthropology 83 (2), 137-146 (1990).

4. Barney, A., Martelli, S., Serrurier, A. & Steele, J., Articulatory capacity of Neanderthals, a very recent and human-like fossil hominin. Philosophical Transactions of the Royal Society B 367, 88–102 (2012).

5. D’Anastasio, R. et al., Micro-Biomechanics of the Kebara 2 Hyoid and Its Implications for Speech in Neanderthals. PLoS One 8 (12) (2013).

530,000 years old Spanish hominins were closely related to Denisovans

Mystery of Sima de los Huesos ‘proto-Neanderthal’ mitochondrial genome.

Sima de los Huesos – ‘the Pit of Bones’ –  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 in the Sierra de Atapuerca of northern Spain. Human remains dating to the Middle Pleistocene were first discovered there in 1976, and systematic excavation has been in progress since 1984. Investigation of the cramped site has proved to be long and difficult – it 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. 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. Many of the remains are of adolescents and young adults, though, the pattern of mortality was probably quite normal for the time, and a similar peak in adolescence has been found at a site at Krapina in Croatia. There is no evidence for violence and the deaths could simply be the result of hunting accidents and childbirth complications. Hunting accidents were probably not uncommon among inexperienced young hunters and women likely fell pregnant soon after commencing menstruation (Pettitt, 2005).
Uranium-series dating suggests that the remains are least 530,000 years old (Bischoff, et al., 2007), and display a mixture of Homo heidelbergensis and Neanderthal features. For this reason, the  Sima de los Huesos hominins are often described as ‘proto-Neanderthal’ (Klein, 2009), although it has also been argued that they were a species distinct from both Neanderthals and Homo heidelbergensis rather than an intermediate between the two (Tattersall, 2002).

In a newly-published study, researchers at the Max Planck Institute for Evolutionary Anthropology have reported the sequencing of the almost-complete mitochondrial genome of one of the Sima de los Huesos hominins. The mitochondrial DNA was extracted from a thigh bone. An estimated age of 400,000 years was obtained by comparison with other, younger ancient DNA sequences dated by direct means. This is rather more recent than the uranium series dates for the site, but still by far the oldest hominin DNA ever recovered. The previous record-holder was no more than 100,000 years old.

Given the geographical location of the Sima de los Huesos and the apparent affinities of the hominins to Neanderthals, it was expected that the material would show affinity to genetic sequences obtained from later Neanderthal remains. Instead, it more closely resembled ancestral Denisovan mitochondrial DNA (Meyer, et al., 2013).

The Denisovan genome, first identified Denisova Cave in the Altai Mountains of southern Siberia, has been found in the modern populations of New Guinea and Island Southeast Asia, implying that the Denisovan range had once extended from the deciduous forests of Siberia to the tropics. This is a wider ecological and geographic region than any other hominin species, with the exception of modern humans (Reich, et al., 2011); but could their range have extended all the way to Europe?

It is likelier that the Sima de los Huesos hominins were the common ancestors of both the Neanderthals and the Denisovans. Mitochondrial lineages originally present in both lineages subsequently disappeared from the Neanderthals, but persisted in the Denisovans. They could have been lost from the Neanderthal line as a result of a population bottleneck of the type known to have affected later Neanderthal populations (Dalén, et al., 2012).

References:

1. Pettitt, P., in The Human Past, edited by Scarre, C. (Thames & Hudson, London, 2005), pp. 124-173.

2. Bischoff, J. et al., High-resolution U-series dates from the Sima de los Huesos hominids yields 600 +/-66 kyrs: implications for the evolution of the early Neanderthal lineage. Journal of Archaeological Science 34, 763-770 (2007).

3. Klein, R., The Human Career, 3rd ed. (University of Chicago Press, Chicago, IL, 2009).

4. Tattersall, I., in The Speciation of Modern Homo sapiens, edited by Crow, T. (Oxford University Press, Oxford, 2002), pp. 49-59.

5. Meyer, M. et al., A mitochondrial genome sequence of a hominin from Sima de los Huesos. Nature (Published online) (2013).

6. Reich, D. et al., Denisova Admixture and the First Modern Human Dispersals into Southeast Asia and Oceania. American Journal of Human Genetics 89, 1-13 (2011).

7. Dalén, L. et al., Partial genetic turnover in neandertals: continuity in the east and population replacement in the west. Molecular Biology and Evolution 29 (8), 1893-1897 (2012).

The Denisovans

In 2008, a distal manual phalanx of from a hominin little finger was recovered from Denisova Cave in the Altai Mountains of southern Siberia. The cave is named for a hermit called Dionisij (Denis) who is supposed to have lived there in eighteenth century, but if this is true he was only the latest in a long line of inhabitants. In April 2010, it was reported that the phalanx had belonged to a hitherto-unknown human species (Krause, et al., 2010).

The small bone was dated by stratigraphic methods and found to be in the region of 30,000 to 48,000 years old. It was believed to have belonged to a child aged between five and seven years old, but other than that no morphological classification could be made. Due to the cool, dry climate, it proved to be possible to extract DNA from the bone, isolate mtDNA fragments, and sequence the entire mitochondrial genome. As we inherit our mtDNA solely from our mothers, this led to the find being dubbed X Woman, despite being a juvenile of unknown gender.

At the time in question, Neanderthals, identified as such by their mtDNA, were living less than 100 km (60 miles) away. The presence of an Upper Palaeolithic industry at Siberian sites such as Kara-Bom and Denisova itself has been taken as evidence for the appearance of modern humans in the Altai before 40,000 years ago. The expectation, therefore, was that the mitochondrial DNA from the bone would match that of either Neanderthals or modern humans, but neither turned out to be the case. Instead, sequencing revealed that X Woman had last shared a common ancestor with Neanderthals and modern humans about a million years ago.

X Woman clearly wasn’t a Neanderthal or a modern human, but what was she (if indeed she was a ‘she’)? One possibility was Homo heidelbergensis, the presumptive common ancestor of the Neanderthals and modern humans, but this species probably appeared no earlier than 600,000 years ago, and was too recent to be associated with X Woman’s ancestors. On the other hand, one million years ago was too recent for X Woman to be a late-surviving descendant of the first wave of Homo erectus to reach Southeast Asia and China.

Towards the end of 2010, it was reported that X Woman’s nuclear genome had been sequenced (Reich, et al., 2010). It turned out that X-Woman lacked a Y-chromosome and therefore was indeed female. The discovery of an upper molar tooth from a young adult was also reported. The sequencing of mtDNA from the tooth confirmed that it belonged to a different individual to the phalanx. For this reason, the term ‘X-Woman’ was dropped in favour of ‘Denisovan’.

The nuclear data allowed more detailed estimates to be made regarding the relatedness of Denisovans, Neanderthals and modern humans. It was found that the Denisovans diverged from Neanderthals 640,000 years ago, and from present-day Africans 804,000 years ago. This meant that the Denisovans were more closely related to the Neanderthals than to modern humans, and may thus be considered a sister group of the former. The most remarkable finding was that 4.8 percent of the nuclear genome of present-day New Guineans derives from Denisovans, greater than the Neanderthal contribution of 2.5 percent (Reich, et al., 2010). The implication was that the Denisovan range had once extended from the deciduous forests of Siberia to the tropics. This is a wider ecological and geographic region than any other hominin with the exception of modern humans (Reich, et al., 2011). Overall, the data was consistent with a scenario in which modern humans, on leaving Africa, interbred with Neanderthals and then, at some subsequent point, the ancestors of present-day New Guineans interbred with Denisovans.

Follow-up studies confirmed the presence of Denisovan genetic material in some other modern populations of island Southeast Asia, and also in Aboriginal Australians, Fijians and Polynesians. Significantly, though, it was absent from mainland populations. The only logical explanation is that the present-day population of Mainland Southeast Asia are descended from a second group of migrants that arrived after the Denisovans had become extinct (Reich, et al., 2011; Skoglund & Jakobsson, 2011; Meyer, et al., 2012).

Interbreeding with Denisovans might have boosted the immune systems of some modern populations. The human leucocyte antigen (HLA) helps the immune system to recognise and combat pathogens. There are three genes known as HLA-A, HLA-B and HLA-C, and it believed that a number of variants of these genes are of Denisovan origin. These variants could have conferred immunity to pathogens to which the incoming modern population had not been previously exposed, and given a survival to those acquiring them from the Denisovans. It is possible that the modern immune system has thus been shaped by ‘importing’ advantageous genes from archaic populations throughout Eurasia (Abi-Rached, et al., 2011).

It has been suggested, on the basis of allele comparison, that the Denisovans were dark-skinned, with brown eyes and hair (Meyer, et al., 2012). Other than that, and beyond their genetic impact on modern populations, we still know very little about them. The Middle Pleistocene fossil record of Southeast and East Asia is very sparse and the Denisova tooth, probably a third or possibly second left upper molar, fails to support a connection with any of the few remains that have been found. The tooth is fairly large, lying within the size range of Homo erectus and Homo habilis. It is above the size range typical for Neanderthals, early modern humans, and the very few third upper molars that have been recovered from other late archaic hominins in the region. The tooth shares no derived morphological features with Neanderthals or modern humans, hinting at the distinctiveness of the Denisovans (Reich, et al., 2010). On the other hand, the report failed to note that some early modern human teeth are also very large, such as those associated with the 35,000-year-old lower jawbone from Peştera cu Oase in Romania (Trinkaus, et al., 2003; Trinkaus, et al., 2003). Size alone probably does not tell us very much (Hawks, 2010).

Recently, it has been suggested that the Denisovans interbred with yet another archaic human species. Given that the Denisovans and Neanderthals diverged from one another after they diverged from modern humans, one would expect the two species to be equally genetically distinct from our own species. However, this is not the case; the Denisovans are more genetically distinct than the Neanderthals. It turns out that scattered fragments amounting to around one percent of their genome is much older than the rest of it. This is best explained by the Denisovans interbreeding with an as yet unidentified human species, possibly Homo heidelbergensis or Homo erectus. We do not yet have genetic material from either species, so this cannot be confirmed (Marshall, 2013).

At all events, it is now clear that the view of modern humans entirely replacing archaic populations is not correct, either in or out of Africa. There is certainly an element of truth to the multiregional model. It is, however, only an element. The range of morphological variation between modern and archaic humans is greater than that in any existing primate species. We should not think of Denisovans and Neanderthals as simply variant forms of Homo sapiens (Stringer, 2012).

References:

Abi-Rached, L. et al., 2011. The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans. Science, 25 August.

Hawks, J., 2010. The Denisova genome FAQ. [Online]
Available at: http://johnhawks.net/weblog/reviews/neandertals/neandertal_dna/denisova-nuclear-genome-reich-2010.html
[Accessed 14 November 2011].

Krause, J. et al., 2010. The complete mitochondrial DNA genome of an unknown hominin from southern Siberia. Nature, 8 April, Volume 464, pp. 894-897.

Marshall, M., 2013. Mystery human species emerges from Denisovan genome. [Online]
Available at: http://www.newscientist.com/article/dn24603-mystery-human-species-emerges-from-denisovan-genome.html#.Uo5FQMTk-m5
[Accessed 21 November 2013].

Meyer, M. et al., 2012. A High-Coverage Genome Sequence from an Archaic Denisovan Individual. Science, 30 August.

Reich, D. et al., 2010. Genetic history of an archaic hominin group from Denisova Cave in Siberia. Nature, 23/30 December, Volume 468, pp. 1053-1060.

Reich, D. et al., 2011. Denisova Admixture and the First Modern Human Dispersals into Southeast Asia and Oceania. The American Journal of Human Genetics, 7 October, Volume 89, pp. 1-13.

Skoglund, P. & Jakobsson, M., 2011. Archaic human ancestry in East Asia. PNAS.

Stringer, C., 2012. What makes a modern human. Nature, 3 May, Volume 485, pp. 33-35.

Trinkaus, E. et al., 2003. Early modern human cranial remains from the Pestera cu Oase, Romania. Journal of Human Evolution, Volume 45, p. 245–253.

Trinkaus, E. et al., 2003. An early modern human from Peştera cu Oase, Romania. PNAS, 30 September, 100(20), p. 11231–11236.

Projectile weapons invented almost 280,000 years ago, by pre-modern humans

Study suggests Ethiopian Rift stone points were used as hafted javelin tips.

The invention of projectile weaponry was clearly an important advance for early humans, enabling large mammals or enemies to be killed or wounded at a distance, without the dangers of a confrontation at close quarters.

The earliest humans probably hunted to an extent, but unequivocal evidence for the hunting of large mammals does not appear in the archaeological record until the Middle Pleistocene. In 1995, four wooden spears were discovered at an open cast mine near the town of Schöningen in Germany. The 400,000-year-old weapons were found with the carcasses of the horses they had been used to kill: the earliest-known association of hunting weapon with quarry. Each spear was over 2 m (6 ft. 6 in.) long, sharpened at both ends, and scraped smooth with stone tools (Thieme, 1997). However, these were unlikely to have been projectile weapons. They are closer in thickness to ethnographically-recorded thrusting spears rather than throwing spears, and if thrown would have had a killing radius of less than 8 m (26 ft.) (Shea, 2006).

Even earlier are the 500,000-year-old stone points from the site of Kathu Pan 1 (KP 1) in South Africa. Some exhibit fractures to their ends, bases and edges that are consistent with a short-ranged weapon striking a target – but not with use for cutting or scraping. The points are shaped near the base in a way that suggests that they were hafted to wooden spears. Experiments with replicas of the KP 1 points, made from similar raw materials, suggest that they made effective spear tips. This makes them the earliest-known multi-component tools; however, they were thrusting spears rather than projectile weapons (Wilkins, et al., 2012).

Throwing spears or javelins were once thought to be a technology unique to modern humans. However, a newly-published study suggests that they predate the emergence of Homo sapiens by 80,000 years. The Gademotta Formation is an archaeological site located on the flanks of an ancient volcanic caldera in the Ethiopian Rift. Investigations since 2010 have yielded over two hundred intact or fragmentary stone points, nearly all of which made from locally-available obsidian. Obsidian is a naturally-occurring volcanic glass that is well-suited to the production of implements with a sharp cutting edge. Argon-argon dating suggests that the oldest of the artefacts are 279,000 years old. Many of the points were found to bear fracture patterns on their tips consistent with impact damage arising from their use as hafted javelin tips, rather than as thrusting weapons (Sahle, et al., 2013).

The pre-modern humans living in Africa at this time are commonly referred to as Homo heidelbergensis. It is commonly supposed that they lacked the cognitive abilities of modern humans (Klein & Edgar, 2002), but the emerging view is that the sophistication of Middle Pleistocene humans has been severely underestimated. The Gademotta projectile tips are an important piece of evidence in this new picture.

References:

1. Thieme, H., Lower Paleolithic hunting spears from Germany. Nature 385, 807-810 (1997).

2. Shea, J., The origins of lithic projectile point technology: evidence from Africa, the Levant, and Europe. Journal of Archaeological Science 33, 823-846 (2006).

3. Wilkins, J., Schoville, B., Brown, K. & Chazan, M., Evidence for Early Hafted Hunting Technology. Science 338, 942-946 (2012).

4. Sahle, Y. et al., Earliest Stone-Tipped Projectiles from the Ethiopian Rift Date to.279,000 Years Ago. PLoS One 8 (11) (2013).

5. Klein, R. & Edgar, B., The Dawn of Human Culture (John Wiley & Sons, Inc., New York, NY, 2002).

Mesolithic hunter-gatherers persisted in Central Europe for 2,000 years after arrival of farmers

Study indicates that foragers maintained way of life alongside farming communities.

Farming spread across Europe from Southwest Asia between 6500 and 4000 BC, but interactions between the indigenous Mesolithic hunter-gatherers and incoming Neolithic farmers are poorly understood. The general view is that hunter-gathering disappeared soon after the arrival of agriculture, but whether the hunter-gatherers took up farming themselves or simply died out remains uncertain.

In order to investigate relationships between foragers and farmers, researchers examined Mesolithic and Neolithic samples from Blätterhöhle, a cave site near Hagen in North Rhine-Westphalia, Germany (Bollongino, et al., 2013). The cave contained the remains of around 450 Neolithic and Mesolithic individuals. It is likely that it was a burial ground, and that these individuals were deposited there deliberately. Radiocarbon dating has revealed two phases of occupation: a Mesolithic occupation from 9210 to 8340 BC, and a Late Neolithic occupation from 3986 to 2918 BC.

Stable isotope analysis and ancient mitochondrial DNA extraction was carried out on the bones and teeth of 29 individuals. Isotopic ratios of sulphur, nitrogen and carbon in human remains can provide an insight into the diet of an individual while they were alive. Mitochondrial DNA can trace maternal ancestry.

Of the 29 individuals sampled, 25 yielded usable mitochondrial DNA; five from the Mesolithic occupation and 20 from the Late Neolithic occupation. The five Mesolithic-era individuals all belonged to mitochondrial haplogroup U, in common with other pre-Neolithic hunter-gatherers of central, eastern and northern Europe. More unexpectedly, twelve of the Neolithic-era individuals also belonged to haplogroup U. This haplogroup is rare among Late Neolithic farmers, and suggests a surprising persistence of Mesolithic maternal ancestry. The remaining eight individuals belonged to typical Neolithic haplogroups.

Stable isotope analysis indicated the existence of three distinct groups. The first, comprising the Mesolithic-era individuals, subsisted on a diet of wild foods typical of that found at other inland Mesolithic sites. The second group comprised Late Neolithic individuals with a diet of domesticated animals typical of German Neolithic sites. The third group was also from the Late Neolithic, but diet was unusual: low in plant and animal protein and high in freshwater fish.

The members of this third group all belonged to mitochondrial haplogroup U, whereas members of the contemporary second group were a mixture of Mesolithic and Neolithic haplogroups. Thus it appears that a group of fisher-foragers were living alongside a group of farmers in the fourth millennium BC, which is around 2,000 years after agriculture reached central Europe. That both groups used the Blätterhöhle cave site at the same time indicates that they were near-neighbours.

Ethnographic data shows that such communities do live side by side, commonly exchanging food; for example cereals for fish. While forager women do marry into farming communities, the reverse is very rare as women from farming communities regard it as marrying down. The mitochondrial results are consistent with the ethnographic picture: no Neolithic haplogroups were found among the fisher-foragers; but the Mesolithic haplogroup U was present among the farmers.

It is unclear just how prevalent such forager communities were in Late Neolithic Europe, but the Blätterhöhle results are the strongest indication yet that such genetically-distinct communities persisted long after the arrival of farming. The ultimate fate of these communities remains uncertain. The authors of the study suggest that some groups may have eventually changed over to farming, although it has been suggested that incoming farmers would rapidly appropriate all the prime farmland, making such a switch problematic (Bellwood, 2005).

References:

1. Bollongino, R. et al., 2000 Years of Parallel Societies in Stone Age Central Europe. Science 342, 479-481 (2013).

2. Bellwood, P., First Farmers (Blackwell Publishing, Oxford, 2005).

First came the temple, then the city

What was the purpose of 11,000 year old monument at Göbekli Tepe?

Located on a limestone ridge 15 km (9 miles) from the town of Şanlıurfa in southeastern Turkey is a site unlike any other known in the early Neolithic world of Southwest Asia. Göbekli Tepe is thought to be the world’s oldest temple. It comprises a series of stone circles that draw superficial comparison to Stonehenge, but it predates the well-known Salisbury Plain monument by seven millennia.

Göbekli Tepe was noted as far back as the early 1960s, but was largely ignored for thirty years. Not until 1994 was it visited by German archaeologist Klaus Schmidt, who believed that the site was Neolithic. He began excavating there the following year, and work has been ongoing ever since.

At the lowest level of the site, Layer III, Schmidt discovered series of semi-submerged circular or oval enclosures. Each comprises a dry-stone wall, into which up to twelve T-shaped limestone pillars are set, often joined to one another by stone benches. At the centre of each enclosure are two more pillars, which tend to be larger than the surrounding ones. The pillars range in height from 3 to 5 m (10 to 16 ft.) and weigh up to 10 tonnes. They were quarried from limestone plateaus close to the site, where a number of incomplete pillars remain in situ. One weighs over 50 tonnes, larger than any of the finished pillars so far excavated. Currently, four enclosures, designated A to D, are undergoing excavation, but geomagnetic surveys suggest that least twenty exist. Many of the pillars are carved with bas-reliefs of animals, including snakes, wild boar, foxes, lions, aurochs, wild sheep, gazelle, onager, birds, various insects, spiders, and scorpions. Where sexual characteristics are present, they are always male. The images are large, often life-size, and semi-naturalistic in style. Some pillars exhibit pairs of human arms and hands, suggesting that they represent stylised anthropomorphic beings. However, it is unclear as to whether they represent gods, shamans, ancestors, or even demons. There are also a number of mysterious abstract symbols that have been interpreted as pictograms (Schmidt, 1995; Schmidt, 1998; Schmidt, 2000; Schmidt, 2003; Peters & Schmidt, 2004).

Pictograms are graphic symbols used to convey meaning, often by pictorial resemblance to a physical object. They are widely used in present-day road and other public signage to denote traffic lights, pedestrian crossings, speed cameras, etc. If the Göbekli Tepe symbols were indeed pictograms, then the origins of writing may extend back into the early Neolithic, thousands of years before the appearance of writing systems such as cuneiform and hieroglyphic script.

No traces of houses have been found and there is little doubt that Göbekli Tepe was a ritual centre, possibly the first of its kind anywhere in the world (Schmidt, 1998). Unlike Stonehenge, the people who built Göbekli Tepe lacked a mixed farming economy. This overturned the conventional wisdom that such major projects could only be realised by fully-established farming communities. “First came the temple, then the city”, as Schmidt put it. How are we to interpret this temple?

One possibility is that the animals depicted in the various enclosures are totemic. It could be that the site was frequented by a number of groups, each of which identified itself with a different animal or animals and travelled to the site to perform rituals in its own particular enclosure (Peters & Schmidt, 2004). Another possibility is that Göbekli Tepe was associated with shamanistic practices (Lewis-Williams & Pearce, 2005).

A project on the scale of Göbekli Tepe would have required a large number of labourers and craftsmen. Coordinating the activities of all these people, to say nothing of providing them all with food and shelter, would have been a major undertaking. It should also be remembered that unlike the builders of Stonehenge, the Göbekli Tepe people were still not yet full agriculturalists. Such an undertaking was almost certainly beyond the capabilities of a few shamans and their communities. Instead, it seems likely that the monument was constructed by a hierarchical, stratified society, with powerful rulers. The shamans might have had more in common with priests (Peters & Schmidt, 2004). The link between rulers and religion, so prevalent in later times, might have already started to take shape.

The totemic and shamanistic explanations are not necessarily mutually exclusive, and if the totemic view is correct, then it possible that animals depicted in each enclosure could provide clues as to the origins of particular groups. For example, wild boar depictions predominate in Enclosure C. This suggests a group originating from the north, where pigs account for up to 40 percent of the animal remains found at PPNA sites. Combinations of wild boar with aurochs and cranes, as seen in Enclosure D, suggest an ecotone of steppe and river valley, such as along most water courses in the Euphrates and Tigris drainage regions (Peters & Schmidt, 2004).

Eventually, the enclosures at Göbekli Tepe complex were filled in and buried with debris. Animal remains and stone artefacts mixed in with the soil suggest that the filling material came from a typical late PPNA settlement refuse dump. The settlement has not been found, but the amount of debris involved suggests that it was not far away. Subsequently, a far less impressive complex was constructed over the first, comprising rectangular pits with smaller pillars, averaging about 1.5 m (5 ft.) (Peters & Schmidt, 2004).

Establishing a chronology for the site is difficult. Plant remains from the settlement debris have been dated to around 9000 BC (Kromer & Schmidt, 1998), but this does not tell us when the site was first occupied. Assuming that the debris accumulated while the Layer III site was in use, the first occupation of the site would be no later than this date. Based on dates for soil overlaying the filling debris, the Layer III complex was probably buried around 8000 BC (Peters & Schmidt, 2004). Dates for carbonates formed on the stone walls as a result of their burial suggest it could have been no later than 7700 BC (Pustovoytov, 2002).

Just why the Layer III complex was buried and the Layer II complex built over it is not known. A possible clue comes from the site of Nevali Çori, 30 km (18 miles) away. Unfortunately, this site was submerged following the construction of the Atatürk Dam. Prior to flooding, the site was excavated between 1983 and 1991 by Harold Hauptmann from the University of Heidelberg. The site was first occupied around 8500 BC, at the start of the PPNB, and occupation spanned three phases before final abandonment around 7600 BC ( Ex Oriente eV Scientific Society, 2011). It comprised some 29 rectangular multi-roomed houses and a ‘cult building’ – marking a shift from circular houses to the rectangular constructions that have largely characterised human dwellings ever since. The cult building dates to the site’s second and third phases. It was approximately square, measuring 13.9 by 13.5 m (45 ft. 7 in. by 45 ft. 4 in.), and was cut about 3 m (10 ft.) into the slope behind it. Access was via two downward steps. A stone bench ran all the way around the interior, broken by pillars similar to those at Göbekli Tepe and again surrounding a central pair, although they resembled the Hebrew letter ד (daleth) rather than the letter T (Peters & Schmidt, 2004; Lewis-Williams & Pearce, 2005). There is clearly a connection between the two sites, and possibly the shift to rectangular architecture is why Göbekli Tepe was filled in and rebuilt along rectangular lines.

References:

1. Schmidt, K., Investigations in the early Meospotamian Neolithic: Göbekli Tepe and Gürcütepe. Neo-Lithics (2/95), 9-10 (1995).

2. Schmidt, K., Beyond Daily Bread: Evidence of Early Neolithic Ritual from Göbekli Tepe. Neo-Lithics (2/98), 1-5 (1998).

3. Schmidt, K., Göbekli Tepe, Southeastern Turkey A Preliminary Report on the 1995-1999 Excavations. Paléorient 26 (1), 45-54 (2000).

4. Schmidt, K., The 2003 Campaign at Göbekli Tepe (Southeastern Turkey). Neo-Lithics (2/03), 3-8 (2003).

5. Peters, J. & Schmidt, K., Animals in the symbolic world of Pre-Pottery Neolithic Göbekli Tepe, south-eastern Turkey: a preliminary assessment. Anthropozoologica 39 (1), 179-218 (2004).

6. Lewis-Williams, D. & Pearce, D., Inside the Neolithic Mind (Thames & Hudson, London, 2005).

7. Kromer, B. & Schmidt, K., Two Radiocarbon Dates from Göbekli Tepe, South Eastern Turkey. Neo-Lithics (3/98), 8-9 (1998).

8. Pustovoytov, K., 14 C Dating of Pedogenic Carbonate Coatings on Wall Stones at Göbekli Tepe (Southeastern Turkey). Neo-Lithics (2/02), 3-4 (2002).

9. Ex Oriente eV Scientific Society, PPND - the platform for Neolithic Radiocarbon Dates, Available at http://www.exoriente.org/associated_projects/ppnd.php (2011).

Did Neanderthals invent tool used by present-day leather-workers?

Specialist bone tool predates arrival of Homo sapiens in Europe.

Two sites in the Dordogne Valley in southern France have yielded four nearly identical deer rib fragments with smoothed edges. These have been interpreted as being a type of tool known as a lissoir (French ‘to make smooth’) used for preparing animal hides. The lissoir is used by present-day leather-workers to make hides softer, tougher and more waterproof. No other known artefact from the Middle or Upper Palaeolithic could be used for such a task. To manufacture such an implement, it is necessary to polish and grind rib fragments to a predetermined size and shape.

A date of 51,500 years old has been obtained for one of the artefacts using optically stimulated luminescence, making these tools the earliest-known specialised bone tools in Europe. Crucially, this date is around 5,000 years before modern humans reached Europe, implying that the tools were manufactured by Neanderthals. This is further proof of Neanderthal sophistication: they clearly knew how to exploit the specific properties of bone both for shaping and for use as a tool.

Even if there were some long-range interactions between Neanderthals and modern humans at this early stage, there is no evidence that the latter used such tools until much later. The Dordogne implements are therefore likely to be of independent Neanderthal invention.

Furthermore, it is entirely possible that modern humans did not reinvent the lissoir but learned about it from the Neanderthals. When present-day leather-workers use such a tool, they could actually be using a Neanderthal invention.

Reference:

1. Soressi, M. et al., Neandertals made the first specialized bone tools in Europe. PNAS 110 (35), 14186-14190 (2013).

The ancestry of Homo floresiensis

Did ‘hobbit people’ of Flores evolve from Homo erectus or a more primitive hominin?

Homo floresiensis is an extinct Late Pleistocene hominin species known only from the Indonesian island of Flores. The type specimen LB 1 is a diminutive 30-year-old female who stood just 1.06 m (3 ft. 6 in.) tall. Nicknamed ‘Flo’, she had a cranial capacity initially estimated to be just 380 cc, comparable to that of an australopithecine. Her weight was estimated to be somewhere between 16 and 36 kg (35 and 79 lb.). Yet she was apparently human: she lacked the large back teeth of an australopithecine, the proportions of her facial skeleton were those of a human, and she appeared to be a humanlike fully-committed biped (Brown, et al., 2004; Morwood, et al., 2004).

The extremely small cranial capacity has been hotly debated since the species was first described in 2004. Some have claimed that Flo was a modern human suffering from microcephaly, a developmental disorder leading to a smaller brain (Jacob, et al., 2006; Martin, et al., 2006), but the majority reject this view and recognise Homo floresiensis as a new human species with a long, low cranial vault and other features characteristic of archaic humans (Argue, et al., 2006; Falk, et al., 2005; Falk, et al., 2007; Tocheri, et al., 2007; Lyras, et al., 2008).

Two principle theories have emerged as to the origin of these hominins. The first is that Homo floresiensis was a dwarf form of Homo erectus (approximate cranial capacity 1,000 cc) which underwent a dramatic reduction in size as a result of a phenomenon known as insular dwarfism. Animals living on an island where food is relatively scarce and predators are few or absent will ‘downsize’ over many generations, in order to reduce calorific requirements. What is actually happening is that evolution is favouring the smaller offspring in each generation. If predators do not pose a threat, any advantages in being large will be outweighed by poorer fuel-economy. What has to be questioned is whether insular dwarfism could lead to brain size reduction of the extent seen in Homo floresiensis.

The second theory is that Homo floresiensis is derived from a hominin species more primitive and smaller-brained than Homo erectus such as Homo habilis (approximate cranial capacity 600 cc) or even an australopithecine (approximate cranial capacity 400 cc). This second model implies that Homo erectus was not the first hominin species to leave Africa, contrary to the widely-accepted Out of Africa 1 hypothesis.

Two studies, one published in 2010 and the other earlier this year, have focussed on decreases in brain size. The first study considered the decreases in body mass and brain size that have been documented for a number of other primate lineages. Researchers tested putative ancestors for Homo floresiensis against these, using the high, medium and low estimates of its body mass. Results suggested that Homo erectus is only feasible as an ancestor for Homo floresiensis if the low estimate of 16 kg (35 lb.) is accepted. For the medium estimate of 24 kg (53 lb.), Homo habilis or the Dmanisi hominins are more feasible as ancestors. The high estimate is not compatible with any proposed scenario (Montgomery, et al., 2010).

The second study re-evaluated the brain size of Homo floresiensis using micro-CT scanning, and obtained an upwardly-revised estimate of 425 cc. This revised figure means that the degree of brain size reduction in relation to body mass is less, and therefore easier to explain. Nevertheless, if Homo erectus was the ancestor, the decrease in brain size is still too great to be explicable solely as a scaling downwards as body mass is downsized, and some other factor must have come into play. In an environment where food is scarce, and given that brain tissue is ‘expensive’ in metabolic terms, further reduction in brain size might have been advantageous. However, this could not be achieved without some loss of cognitive ability. The authors of the report suggested that cognitive abilities comparable to Homo habilis might have sufficed in an island habitat lacking dangerous predators (Kubo, et al., 2013).

While this ‘dumbing down’ scenario cannot be dismissed, it seems implausible. According to the widely-accepted ‘social brain hypothesis’ (Byrne & Whiten, 1988), the large primates of primates evolved in response to a need to predict the likely future social behaviour of their fellows, and base relationships upon these predictions. While Homo floresiensis would not have had to face dangerous predators, individuals would still need to interact with other group members. It is difficult to see that being less smart than one’s fellows could be anything over than a severe disadvantage, regardless of other circumstances.

I would therefore be inclined to the view that Homo erectus was not the ancestor of Homo floresiensis, and this view is supported by a number of studies considering the skeletal evidence. These have noted that while the cranial metrics were consistent with Homo erectus, the limb proportions of Homo floresiensis had more in common with Australopithecus garhi (Argue, et al., 2006) and the feet were a mosaic of primitive apelike and derived humanlike features. The big toe was fully in-line, albeit short, and the metatarsals followed a humanlike sequence in which the 1st (innermost) was the most robust (sturdily-built), followed by the 5th (outermost), then 4th, 3rd, and finally 2nd. The foot, though, was disproportionately long in comparison to that of a modern human; the lesser metatarsals (2nd to 5th) were long; and the outer toes were long and curved, unlike the short, straight toes of a modern human (Jungers, et al., 2009). The fact that the feet and limb proportions of Homo erectus were modern suggests that Homo floresiensis evolved from a species that was more primitive, such as Homo habilis.

References:

1. Brown, P. et al., A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia. Nature 431, 1055-1061 (2004).

2. Morwood, M. et al., Archaeology and age of a new hominin from Flores in eastern Indonesia. Nature 431, 1087-1091 (2004).

3. 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).

4. Martin, R. et al., Comment on ‘‘The Brain of LB1, Homo floresiensis’’. Science 312, 999b (2006).

5. Argue, D., Donlon, D., Groves, C. & Wright, R., Homo floresiensis: Microcephalic, pygmoid, Australopithecus, or Homo? Journal of Human Evolution 51, 360-374 (2006).

6. Falk, D. et al., The Brain of LB1, Homo floresiensis. Science 308, 624-628 (2005).

7. Falk, D. et al., Brain shape in human microcephalics and Homo floresiensis. PNAS 104 (7), 2513–2518 (2007).

8. Tocheri, M. et al., The Primitive Wrist of Homo floresiensis and Its Implications for Hominin Evolution. Science 317, 1743-1745 (2007).

9. Lyras, G., Dermitzakis, M., Van der Geer, A., Van der Geer, S. & De Vos, J., The origin of Homo floresiensis and its relation to evolutionary processes under isolation. Anthropological Science (2008).

10. Montgomery, S., Capellini, I., Barton, R. & Mundy, N., Reconstructing the ups and downs of primate brain evolution: implications for adaptive hypotheses and Homo floresiensis. BMC Biology 8 (9), 1-19 (2010).

11. Kubo, D., Kono, R. & Kaifu, Y., Brain size of Homo floresiensis and its evolutionary implications. Proceedings of the Royal Society B 280 (1760) (2013).

12. Byrne, R. & Whiten, A., Machiavellian Intelligence (Oxford University Press, Oxford, 1988).

13. Jungers, W. et al., The foot of Homo floresiensis. Nature 459, 81-84 (2009).

The Mesoamerican ballgame

A matter of life and death

The term ‘ballgame’ refers to a wide variety of ball sports widely played in ancient Mesoamerica. These sports were a key element in ancient Mesoamerican religious, ritual and political life. Rubber balls have been found at the early Olmec site of El Manatí, dating to around 1600 BC (Ortíz & Rodríguez, 1999), and are the earliest known example of the use of rubber in Mesoamerica. Rubber was also used to make figurines and bands for hafting axe heads, and in liquid form it was used for painting and for medicinal purposes. It was obtained by tapping the indigenous Castilla elastica tree. Latex from this source dries into a brittle substance that is of little use, but Mesoamerican people improved its elastic properties by adding an extract from the vine Ipomoea alba to produce a solid white mass. Modern researchers have found that a ball formed from such material exhibits typical rubbery behaviour, and can bounce to a height of 2 m (6 ft. 6 in.). The technique alters the mechanical properties of latex and predates the modern vulcanising process by 3,500 years (Hosler, et al., 1999).

At least three variants of the ballgame continue to be played to this day, although the rules of the original pre-Columbian games are not known. The pivotal role of the ballgame in ancient Mesoamerican life is reflected in the large number of known ball courts – almost 1,300 – located at around 1,000 sites. The earliest-known ball court is that at Paso de la Amada, Chiapas, dating to 1600 BC (Blomster, 2012).

Much early evidence of the game comes from ceramic figurines and other images of ballplayers. The earliest such figurines date to 1700 BC and were recovered from a tomb at El Opeño, Michoacan. An arranged scene portrays five male ballplayers and three female spectators. Three of the ballplayers are equipped with bats. All five are wearing shin-pads and short helmets, and some wear mitts over their hands. A small yoke-shaped basalt piece was also found in the tomb. It was probably worn on the hand to protect it or for hitting the ball, and is the earliest example of ballgame equipment found so far. However, the ballplayers lack the elaborate costumes that characterise later depictions. It is likely that the ballgame had yet to assume its later significance (Blomster, 2012). Notably, the ball court at Paso de la Amada predates the emergence of a hierarchical society there by about a century (Lesure, 1997). Perhaps at this stage, the ballgame was still primarily a recreational activity.

Soon however, it would become linked to conflict, completion, hereditary leadership, and emerging political inequality. Ballgame costume is present on several pieces of monumental sculpture from the Olmec site of San Lorenzo. Monument 34 depicts a half-kneeling male figure wearing shorts, with a thick protective belt and loincloth. The monument has been interpreted as an Olmec ruler in his role as a ballplayer. At one of the San Lorenzo satellite towns, a monument features a similarly-clad ballplayer straddling a bound captive probably destined for sacrifice. Figurines from San Lorenzo depict ballplayers equipped with headdresses and helmets that mask the whole of the face, except for the eyes. They are wearing wide, thick padded belts and loincloths, and round pendants interpreted as mirrors. Similar imagery is seen with ballplayer figurines recovered at Etlatongo in Oaxaca and Cantón Corralito in Chiapas (Blomster, 2012). The latter site has been interpreted as an Olmec colony due to the similarity of its ceramic assemblage with that of San Lorenzo (Cheetham, 2007).

Figurines from the central Mexican sites of Tlatilco and Tlapacoya show distinct differences to Olmec figurines. The differences may reflect regional variations of either the game itself or the attendant rituals. Some examples from Tlapacoya wear a protective yoke supported by vertical or crossed suspenders on the front torso, probably related to the thick padded belts from San Lorenzo and Cantón Corralito. Some central Mexican figurines also wear tall, elaborate headdresses and ear flares, again distinct from their Olmec counterparts. These elaborate costumes were probably worn during ceremonies taking place before or after the game, rather than during the game itself (Blomster, 2012).

It is generally accepted that the ballgame was closely associated with elite power. It represented institutionalised ritual combat, possibly serving as an alternative to actual warfare. The ballgame might also have served a role in local dispute resolution. Some versions of the game were associated with human sacrifice and others were of great cosmological significance. The Maya text Popol Vuh describes the ballgame as a contest between mortals and sinister underworld deities. The play of the ball in the court symbolised the movements of the sun and moon, in turn representing the regeneration of life and the maintenance of cosmic order; the ball court itself represented a portal to the underworld (Blomster, 2012). The former Liverpool F.C. manager Bill Shankly allegedly described football as much more important than life and death: the same, apparently, was true of the Mesoamerican ball game.

References:

1. Ortíz, M. & Rodríguez, M., in Social Patterns in Pre-Classic Mesoamerica, edited by Grove, D. & Joyce, R. (Dumbarton Oaks Research Library and Collection, Washington, DC, 1999), pp. 225-254.

2. Hosler, D., Burkett, S. & Tarkanian, M., Prehistoric Polymers: Rubber Processing in Ancient Mesoamerica. Science 284, 1988-1991 (1999).

3. Blomster, J., Early evidence of the ballgame in Oaxaca, Mexico. PNAS 109 (21), 8020–8025 (2012).

4. Lesure, R., Early Formative Platforms at Paso de la Amada, Chiapas, Mexico. Latin American Antiquity 8 (3), 217-235 (1997).

5. Cheetham, D., Cantón Corralito: Objects from a Possible Gulf Olmec Colony, Crystal River, FL:Foundation for the Advancement of Mesoamerican Studies Inc. (2007).

The Mesoamerican Calendar

Mesoamerican calendrical systems have become well-known to the general public in recent years as a result of the Maya Long Count, which ended on 21 December 2012. There is no reason to suppose that the Maya expected anything untoward to occur on that day, but that did not stop the doomsday industry from working overtime. As the supposed day of reckoning approached, groups camped out by a mountain in the south of France to await rescue by flying saucer. There was much nonsense about a rogue planet called Nibiru and other supposed perils. The cinema industry cashed in on the hoo-hah with the disaster movie 2012 and the rather more thoughtful Melancholia. Neither movie paid much heed to the laws of physics. In fact, periodic end of the world ‘scares’ are nothing new, and go back at least a thousand years (Moore, 1999).

The Long Count was actually only one of three calendars in use in pre-Columbian Mesoamerica. For day-to-day reckoning, there was a solar calendar or haab cycle of 365 days, and there was a ritual calendar of 260-days known as the tzolkin or sacred almanac. All three calendars made use of the vigesimal or base-20 system of counting, rather than our familiar decimal or base-10 system. The system employed a place-value notation and a zero, long before the Hindu-Arabic system introduced these concepts. It may have come about through the practice of counting the digits on the feet as well as on the hands. Numbers were represented by combinations of ones (dots), fives (bars) and zeros (various characters) stacked vertically, with place value increasing from bottom to top (Aventi, 2001). The other number that featured prominently in Mesoamerican calendrical systems was 13, representing the number of levels of heaven in Mesoamerican cosmology (cf. the seven levels of heaven in the Jewish, Islamic and Hindu traditions).

The haab cycle comprised 18 ‘months’ of 20 days each, plus 5 intercalary days. Each date denoted by one of 20 day names paired with one of 18 month names. Like the pre-Ptolemaic Egyptian calendar, it did not take leap years into consideration, and thus did not accurately track the solar year. Days in the tzolkin were denoted by a number from 1 to 13 and one of 20 names, for a total of 260 days. The haab and tzolkin cycles were combined into the Calendar Round, which repeats every 18980 days (52 years). The 52-year cycle was a period of great significance throughout Mesoamerica. The termination was celebrated by the New Fire ceremony, in which fires everywhere were extinguished and domestic implements and statues were discarded (Aventi, 2001).

The Long Count calendar generated dates from a fixed start point that were to all intents and purposes unique (as are Gregorian dates). The basic unit of time was the tun of 360 days, which was subdivided into 18 uinals of 20 kins (days) each. The tun was multiplied by successive powers of 20 (the vigesimal equivalent of decades and centuries) named katuns and baktuns. Thus a katun is 360 x 20 = 7200 days and a baktun is 360 x 20 x 20 = 144,000 days or just over 394 years. The Maya did not invent the Long Count, but by Classic times (AD 250 – 800), only they were using it (Webster & Evans, 2005). The Maya implementation of the Long Count began on a date corresponding to 11 August 3114 BC in the Gregorian calendar. The 13th baktun from that date ended on 21 December 2012. There is some dispute as to what is supposed to follow. The usual view is that 13 baktuns (just over 5125 years) represents a creation epoch and the count returns to zero (Aventi, 2001). However, there is some evidence that the Maya intended the count to continue. There may be higher-order units beyond the baktun which scholars (in the absence of the original Maya terms) have named the piktun, kalabtun, kinchiltun and alautun.

The reason for a 260-day ritual count remains uncertain. One suggestion is that it originated at a location between 14°42' and 15 N., where the Sun crosses the zenith at 260 and 105-day intervals. A possible candidate is the Late Formative Period site of Izapa, which is located on the Pacific Coast of Mexico (Malmstrom, 1973). One objection to this interpretation is that the 260-day cycle simply repeats and does not factor in the concomitant 105-day cycle (Henderson, 1973). Another problem is that the 260-day cycle may have been in use at Monte Albán around 500 BC, considerably earlier than Izapa (Henderson, 1973; Marcus & Flannery, 2004). There are also Olmec inscriptions that suggest that the cycle might date to as early as 650 BC (Pohl, Pope, & von Nagy, 2002; Stokstad, 2002).

Other suggestions are a link to the average human gestation period of 266 days, or to various astronomical cycles. Two tzolkin (520 days) corresponds closely to three eclipse half-years (519.93 days). The eclipse half-year of 173.31 days is the period between successive eclipse seasons, i.e. a period of around 33 days when the Earth, Moon and Sun can line up to produce an eclipse. There is also a close correspondence between the tzolkin and the average of 263 days that Venus remains visible as either a morning or evening star, before it disappears into the dawn or twilight skies. Links to Mars have also been suggested. The synodic period of the Red Planet (i.e. the interval between successive close approaches to Earth) is almost exactly three tzolkin, or 780 days (Aventi, 2001).

References:
Aventi, A. (2001). Skywatchers. Austin, TX: University of Texas Press.
Henderson, J. (1973). Origin of the 260-Day Cycle in Mesoamerica. Science, 185, 542.
Malmstrom, V. (1973). Origin of the Mesoamerican 260-Day Calendar. Science, 181, 939-940.
Marcus, J., & Flannery, K. (2004). The coevolution of ritual and society: New 14C dates from ancient Mexico. PNAS, 101(52), 18257–18261.
Moore, P. (1999). Countdown!... or how nigh is the end? London: Pan.
Pohl, M., Pope, K., & von Nagy, C. (2002). Olmec Origins of Mesoamerican Writing. Science, 298, 1984-1987.
Stokstad, E. (2002). Oldest New World Writing Suggests Olmec Innovation. Science, 298, 1873-1874.
Webster, D., & Evans, S. (2005). Mesoamerican civilization. In C. Scarre, The human past (pp. 594-639). London: Thames & Hudson.

Archaeological evidence for carcass processing at Kanjera, Kenya, 2 million years ago.

Earliest unambiguous evidence for meat-eating by early hominins.

Modern humans are the only existent primates anatomically adapted for the regular consumption of significant quantities of meat. The human gut is reduced compared with that of other primates, a configuration more suited to a meat-eating diet than the predominantly vegetarian diet of other primates. Although crucial to many models of hominin evolution, however, the timing of and circumstances in which early hominins began to include significant quantities of meat in their diet remain poorly understood.

The earliest-known stone tools, from Gona, Ethiopia, are 2.6 million years old and are often taken to be early evidence for meat eating (Semaw, et al., 1997; Semaw, 2000). No hominin remains were recovered in association with the tools, but in 1999, anthropologists working at the nearby Bouri Formation reported the discovery of large mammal bones bearing cut-marks apparently made by stone tools, possibly as a result of dismembering and filleting carcasses. Animals appeared to have been defleshed, and their long bones broken open, presumably to extract marrow. The bones were found in association with 2.5 million-year-old australopithecine remains, thought to be of Australopithecus garhi (de Heinzelin, et al., 1999).

It has also been claimed that 3.39 million-year-old animal bones from Dikika, Ethiopia, show stone tool cut-marks for flesh removal, and signs of having been struck with hammerstones to extract bone marrow (McPherron, et al., 2010). In the absence of any associated tools, there is no way to tell whether the cut-marks were produced with specially-made tools or naturally-sharp pieces of stone. Some are sceptical and argue that as the bones were buried in coarse-grained, sandy deposits, it is likely that trampling by animals produced the marks (Domınguez-Rodrigo, et al., 2011).

Even if the above is accepted as evidence of carcass-processing by early hominins, it is too insubstantial to show whether these were one-off forays into meat-eating or part of a more substantial shift in hominin dietary adaptations. To demonstrate ‘persistent carnivory’ requires a geologically-stratified series of relatively large assemblages of animal remains, each showing extensive signs of persistent hominin activity. The sum of the assemblages must demonstrate that this activity persisted over the course of at least a thousand years (Ferraro, et al., 2013).

Although rather more recent than the above dates, such evidence has now been reported from Kanjera South, a small site located on the shores of Lake Victoria, southwestern Kenya (Ferraro, et al., 2013). Three excavations along 50 metres have yielded several thousand well-preserved animal remains, approximately 2 million years old, and associated with stone tools. There is a consistent record of hominin activities throughout the stratified sequence, which spans hundreds or possibly thousands of years.

The animal remains included gazelle and other small bovids, together with a smaller number of medium-sized bovids. The remains showed clear evidence of butchery by hominins in the form of cut-marks and damage caused by hammerstones. Patterns of tooth-marks made by carnivores such as lions and hyenas suggest that these animals only had access to the carcasses after the hominins had removed the bulk of the meat and bone marrow. Carnivores typically chew on the mid-shafts of long bones, but the percentage of bones that were so marked was low.

Small bovids are invariably wholly consumed by carnivores within hours of death, implying that the hominins acquired and butchered them very soon after death. A possible implication is that these animals were hunted rather than scavenged, and that Kanjera represents the earliest archaeological record of hunting activities by hominins.

The skeletal remains of the small bovids suggest that they were transported to the site for butchery more or less intact. However, in the case of the medium-sized bovids, head and limb parts predominate. These animals were too large to transport intact, so the hominins removed the limb parts, leaving the rest of the body behind. Although head contents are nutritious, they are difficult to exploit and would thus be ignored by other scavengers. They therefore represent a niche that tool-using hominins could exploit. It is therefore likely that hominins scavenged leftover head parts from carnivore kills and transported them to the site for processing.

The Kanjera data not only provides the required evidence of hominin meat-eating over a period of many centuries: it also provides clues about specific activities. Thus, it seems, the hominins obtained much of their meat by hunting small bovids, but they also scavenged medium-sized bovid heads as a separate by complimentary activity. The date of 2 million years ago is somewhere between 200,000 and 500,000 years earlier than the previous earliest evidence for persistent hominin carnivory.

References:

1. Semaw, S. et al., 2.5-million-year-old stone tools from Gona, Ethiopia. Nature 385, 333-336 (1997).

2. Semaw, S., The World’s Oldest Stone Artefacts from Gona, Ethiopia: Their Implications for Understanding Stone Technology and Patterns of Human Evolution Between 2.6–1.5 Million Years Ago. Journal of Archaeological Science 27, 1197–1214 (2000).

3. de Heinzelin, J. et al., Environment and Behavior of 2.5-Million-Year-Old Bouri Hominids. Science 284, 625-629 (1999).

4. McPherron, S. et al., Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia. Nature 466, 857-860 (2010).

5. Domınguez-Rodrigo, M., Pickering, T. & Bunn, H., Reply to McPherron et al.: Doubting Dikika is about data, not paradigms. PNAS 108 (21), E117 (2011).

6. Ferraro, J. et al., Earliest Archaeological Evidence of Persistent Hominin Carnivory. PLoS One 8 (4) (2013).

Australopithecus sediba: a possible human ancestor

Australopithecus sediba is a possible human ancestor discovered in South Africa in 2010. The discovery was made at Malapa, a fossil-bearing cave located about 15 km (9.3 miles) NE of the well-known South African hominid-bearing sites of Sterkfontein and Swartkrans and about 45 km (28 miles) NNW of Johannesburg  (Berger, et al., 2010). It is situated within the Cradle of Humankind World Heritage Site. The recovery effort was led by Lee Berger, a paleoanthropologist at the University of the Witwatersrand, Johannesburg. The find was made when Matthew, Lee’s 9 year old son, discovered hominin collar bone embedded in a rock (Balter, 2010).

The find comprised two extremely well-preserved partial skeletons that were initially thought be somewhere between 1.78 and 1.95 million years old (Dirks, et al., 2010), later revised to 1.977 million years (Pickering, et al., 2011). These belonged to a juvenile male (MH1) aged 12 to 13 at time of his death and an adult female (MH2) (Berger, et al., 2010). They were found together buried in alluvial sediment, deep within the Malapa cave, part of an eroded cave system. Also found were the remains of wildcats, hyenas and a number of other mammals. On the ground above the cave are a number of ‘death traps’, or long vertical shafts. The smell of damp issuing from the shaft would have attracted animals. The pair – possibly mother and son – may have fallen to their deaths while searching for water. The sediments imply that subsequent high-volume water inflow, perhaps the result of a large storm, caused a debris flow. This carried the still partially articulated bodies deeper into the cave, to deposit them along a subterranean stream (Dirks, et al., 2010).

MH1 and MH2 were assigned to a new australopithecine species, Australopithecus sediba. The word ‘sediba’ means ‘fountain’ or ‘wellspring’ in the Sotho language. The more complete cranium of the juvenile MH1 has a capacity of 420cc, probably at least 95 percent of adult size. The remains share numerous similarities with Australopithecus africanus in the cranial vault, facial skeleton, lower jawbone and teeth, but there are also significant differences in the cranial, dental and postcranial anatomy. Homo-like features include smaller molars and premolars and less pronounced cheekbones. Certain features of the pelvis are similar to those seen in Homo erectus. The lower-to-upper limb bone proportions are also similar to those of later Homo, and unlike the more apelike proportions of Homo habilis. The anatomy of its hip, knees and ankles suggest that Australopithecus sediba was a habitual biped. Overall, it was claimed that Australopithecus sediba shares more derived features with early Homo than it does with other australopithecines. However, Berger was reluctant to place the new discovery within Homo, preferring to classify it as an australopithecine (Berger, et al., 2010).

The initial announcement of Australopithecus sediba attracted extensive news coverage, but not everybody was convinced by the claims made for it. Australian anthropologist Darren Curnoe was reported (MacKnight, 2010) as claiming that Australopithecus sediba is in the wrong place at the wrong time to be a human ancestor. He noted that Homo habilis emerged in East Africa well before the time of Australopithecus sediba. However, his argument does assume that Homo habilis is indeed an early human.  This may not be the case. It is also possible that at least some of Australopithecus sediba’s humanlike features could have evolved independently, and may not necessarily imply shared ancestry (Wood & Harrison, 2011).

Nevertheless, subsequent studies do support Berger’s initial claims. They suggest that aspects of the brain, dental morphology, pelvis, hand and foot of Australopithecus sediba could be interpreted as incipient humanlike features. A virtual endocast of the brain, obtained from synchrotron scanning, revealed an australopithecine-like size and pattern of convolutions. However, the orbitofrontal region showed possible development towards a humanlike frontal lobe. Possibly some neural reorganization of the brain preceded its later size increase in early humans (Carlson, et al., 2011).

The teeth of MH1 and MH2 are a mosaic of primitive and derived traits. Cladistic analysis of 22 dental traits suggest that Australopithecus sediba was a sister species of Australopithecus africanus (i.e. the two shared a common ancestor) and that the two were further evolved in the direction of Homo than were the australopithecines from East Africa (Irish, Guatelli-Steinberg, Legge, de Ruiter, & Berger, 2013). The lower jawbone morphology reduced dentition (especially canines and premolars) confirms that Australopithecus sediba was a distinct species to Australopithecus africanus and not merely a late-surviving form of that species (de Ruiter, et al., 2013).

The upper ribcage of Australopithecus sediba exhibits an apelike funnel shape, unlike the barrel shape associated with Homo. The funnel shape, as noted above, may be an adaptation to under-branch suspensory locomotion. The barrel shape may be associated with the increased chest volume and lung function necessary for endurance walking and running. The lower thorax, however, appears less flared than that of apes and more closely approximates the morphology found in humans (Schmid, et al., 2013). The spine is long and flexible, a form that has more in common with early Homo than with other australopithecines. Curvature of the lower spine is a hallmark of walking upright (Williams, Ostrofsky, Frater, Churchill, Schmid, & Berger, 2013).

The upper limbs were still predominantly apelike, suggesting the retention of substantial climbing and suspensory abilities (Churchill, et al., 2013). The hands show a mixture of australopithecine and human features. They retained adaptations for tree-climbing, but there was also a long thumb and shorter fingers. These suggest precision gripping of the type associated with tool manufacture and use (Kivell, Kibii, Churchill, Schmid, & Berger, 2011).

The pelvis and foot presented a mosaic of apelike and humanlike characteristics. These suggested adaptations to a more efficient (albeit not entirely human) form of bipedalism, at the expense of reduced arboreal efficiency (Kibii, et al., 2011; Zipfel, DeSilva, Kidd, Carlson, Churchill, & Berger, 2011). The bipedal mechanics differed from those reconstructed for other australopithecines, suggesting that there may have been several forms of hominin bipedalism at this time. The adaptations of Australopithecus sediba may have enabled it to both walk and climb reasonably well and thus survive in a dual arboreal/terrestrial world (DeSilva, et al., 2013).

References:

Balter, M. (2010, April 9). Candidate Human Ancestor From South Africa Sparks Praise and Debate. Science, 328, 154-155.

Berger, L., de Ruiter, D., Churchill, S., Schmid, P., Carlson, K., Dirks, P., et al. (2010, April 9). Australopithecus sediba: A New Species of Homo-Like Australopith from South Africa. Science, 328, 195-204.

Carlson, K., Stout, D., Jashashvili, T., de Ruiter, D., Tafforeau, P., Carlson, K., et al. (2011, September 9). The Endocast of MH1, Australopithecus sediba. Science, 333, 1402-1407.

Churchill, S., Holliday, T., Carlson, K., Jashashvili, T., Macias, M., Mathews, S., et al. (2013, April 12). The Upper Limb of Australopithecus sediba. Science, 340.

de Ruiter, D., DeWitt, T., Carlson, K., Brophy, J., Schroeder, L., Ackermann, R., et al. (2013, April 12). Mandibular Remains Support Taxonomic Validity of Australopithecus sediba. Science, 340.

DeSilva, J., Holt, K., Churchill, S., Carlson, K., Walker, C., Zipfel, B., et al. (2013). The Lower Limb and Mechanics of Walking in Australopithecus sediba. Science, 340.

Dirks, P., Kibii, J., Kuhn, B., Steininger, C., Churchill, S., Kramers, J., et al. (2010, April 9). Geological Setting and Age of Australopithecus sediba from Southern Africa. Science, 328, 205-208.

Irish, J., Guatelli-Steinberg, D., Legge, S., de Ruiter, D., & Berger, L. (2013, April 12). Dental Morphology and the Phylogenetic “Place” of Australopithecus sediba. Science(340).

Kibii, J., Churchill, S., Schmid, P., Carlson, K., Reed, M., de Ruiter, D., et al. (2011, September 9). A Partial Pelvis of Australopithecus sediba. Science, 333, 1407-1411.

Kivell, T., Kibii, J., Churchill, S., Schmid, P., & Berger, L. (2011, September 9). Australopithecus sediba Hand Demonstrates Mosaic Evolution of Locomotor and Manipulative Abilities. Science, 333, 1411-1417.

MacKnight, H. (2010, April 8). Experts reject new human species theory. Retrieved September 12, 2012, from Independent: http://www.independent.co.uk/news/science/experts-reject-new-human-species-theory-1939512.html

Pickering, R., Dirks, P., Jinnah, Z., de Ruiter, D., Churchil, S., Herries, A., et al. (2011, September 9). Australopithecus sediba at 1.977 Ma and Implications for the Origins of the Genus Homo. Science, 333, 1421-1423.

Schmid, P., Churchill, S., Nalla, S., Weissen, E., Carlson, K., de Ruiter, D., et al. (2013). Mosaic Morphology in the Thorax of Australopithecus sediba. Science, 340.

Williams, S., Ostrofsky, K., Frater, N., Churchill, S., Schmid, P., & Berger, L. (2013, April 12). The Vertebral Column of Australopithecus sediba. Science, 340.

Wood, B., & Harrison, T. (2011, February 17). The evolutionary context of the first hominins. Nature, 470, 347-352.

Zipfel, B., DeSilva, J., Kidd, R., Carlson, K., Churchill, S., & Berger, L. (2011, September 9). The Foot and Ankle of Australopithecus sediba. Science, 333, 1417-1420.

Fossil evidence for interbreeding between Neanderthals and modern humans

Lower jawbone discovered in 1957 could be from Neanderthal/modern human hybrid.

Although interbreeding between Neanderthals and modern humans has been inferred from genetic data, convincing fossil evidence for hybridisation has hitherto been lacking. Claims that the 24,500-year-old skeleton of a 4-year-old child found at Abrigo do Lagar Velho, Portugal in 1998 is an example of a hybrid (Duarte, et al., 1999) have not been widely accepted. Notably, the burial was typical of the Gravettian, a culture that is firmly associated with modern humans. It is possible that the infant was simply an unusually stocky modern human juvenile, or a ‘chunky child’ as one critic put it (Tattersall & Schwartz, 1999).

A newly-published report has claimed that a better case may be made for a lower jawbone from the Riparo Mezzena rocks helter, northern Italy. The jawbone was found in 1957, along with stone artefacts of the Mousterian tradition. As this tradition is firmly associated with Neanderthals in Europe, the 34,500-year-old jawbone was assumed to be Neanderthal. Mitochondrial DNA extracted from the jawbone confirms it to be Neanderthal. However, the Mezzena lower jawbone shows a number of modern features, including an incipient chin, which contrasts with the chinless jaws of ‘classic’ Neanderthals. The authors of the report claim that these features demonstrate hybridisation between Neanderthals and modern humans (Condemi, et al., 2013).

It is possible that the interbreeding occurred with a modern population thought to have been living at the nearby site of Grotta di Fumane (Longo, et al., 2012).

References:

1. Duarte, C. et al., The Early Upper Paleolithic Human Skeleton from the Abrigo do Lagar Velho (Portugal) and Modern Human Emergence in Iberia. PNAS 96, 7604–7609 (1999).

2. Tattersall, I. & Schwartz, J., Hominids and hybrids: The place of Neanderthals in human evolution. PNAS 96, 7117–7119 (1999).

3. Condemi, S. et al., Possible Interbreeding in Late Italian Neanderthals? New Data from the Mezzena Jaw (Monti Lessini, Verona, Italy). PLoS One 8 (3) (2013).

4. Longo, L. et al., Did Neandertals and anatomically modern humans coexist in northern Italy during the late MIS 3? Quaternary International 259, 102–112 (2012).

Study highlights differences in brain organisation between Neanderthals and modern humans

Neanderthals focussed on vision at expense of social networking.

A new study has suggested that there were significant differences in the neurological organisation of Neanderthals and modern humans, reflecting physiological differences between the two species. Neanderthals, as has long been known, were larger and more powerfully-built than modern humans. Consequently, it is suggested that they required proportionately more ‘brain power’ to carry out body maintenance ‘housekeeping’ tasks and control functions. In addition, it is suggested that Neanderthals had larger eyes than modern humans, which also used up brain power. They lived at high latitudes in Eurasia, where they experienced lower light levels than people living in the tropics.

Researchers considered the remains of 21 Neanderthals and 38 modern humans dating from between 27 to 200 thousand years ago. They adjusted brain sizes to compensate for the greater Neanderthal body size, and estimated the size of the visual cortex from eye socket measurements. The average size of the Neanderthal eye socket was found to 44 by 36 mm (1.73 by 1.42 in.) compared with 42 by 30 mm (1.65 by 1.18 in.) for the modern humans. This equates to an eyeball volume of 34 cc against 29.5 cc; a 15 percent difference.

With more brain power required for housekeeping and visual functions, less would have been available for social interactions, and it has been suggested the Neanderthal maximum social group size was smaller than the ‘Dunbar Number’ of 150 associated with modern humans. The area covered by extended Neanderthal communities would have been smaller than those of modern humans. Their ability to trade would have been reduced, as would their capacity to learn of distant foraging areas potentially unaffected by local shortages. Furthermore, their ability to acquire and pass on innovations may have been limited in comparison to modern humans.

In the high latitudes of Eurasia, far from their African homeland, modern humans were disadvantaged in as much as they lacked the enhanced visual acuity, as well as other Neanderthal adaptations to the colder climate. Unable to adapt their bodies, modern humans adapted their technology, and thus became more reliant on it than were the Neanderthals. However, technological change can greatly outpace evolutionary change. The combination of adaptable technology and enhanced social networks gave the first modern humans in Europe a competitive advantage over the physically-adapted Neanderthals, eventually bringing about the demise of the latter.

References:

1. Pearce, E., Stringer, C. &  Dunbar, R., New insights into differences in brain organization between Neanderthals and anatomically modern humans. Proceedings of the Royal Society B 280 (1758) (2013).