Tag Archives: Neanderthal

Detecting the presence of hominins in ancient soil samples

Out on the plains countless herbivores fertilise the ground by continual urination and defecation. A friend’s sheep are doing just that in the small field that came with my current home while they are keeping the grass under control.  Millions of hectares of prime agricultural land in China are kept fertile through disposal of human night soil from ‘honey wagons’ every day; it is even fed to fishes in small ponds. Such a nice economy also donates the DNA of the animal and plant inhabitants to the soil system. In 2015 analysis of environmental DNA from permafrost in Siberia and Alaska produced ‘bar codes’ for the now vanished ecosystems of what was  mammoth steppe during the climate decline to the last glacial maximum and the subsequent warming. The study revealed mammoth and pre-Columbian horse DNA and changes in the steppe vegetation, from which it was concluded that the steppe underwent regional extinction pulses of its megafauna linked to rapid climate ups and downs connected with Dansgaard-Oeschger cycles. It was but a small step to see the potential for studying distribution and timing of various hominins’ occupation of caves from the soils preserved within them, without depending on generally very rare occurrences of human skeletal remains.

Tourists at the entrance to Denisova Cave, Rus...

Tourists at the entrance to Denisova Cave, Russia (credit: Wikipedia)

The Max Planck Institute for Evolutionary Anthropology in Leipzig, now famous for extracting DNA from Neanderthal, Denisovan and possibly H. antecessor fossils, has applied the environmental DNA approach to sediments from 7 caves in France, Belgium, Spain, Croatia and Russia that span the period from 550 to 14 ka (Slon, V. and 30 others 2017.  Neandertal and Denisovan DNA from Pleistocene sediments. Science, v. 356 (online publication); doi:10.1126/science.aam9695). The sites had previously yielded fossils and/or artefacts. All of them contained mitochondrial DNA from diverse large mammals, four including archaic human genetic material supplied by Neanderthal individuals and Denisovans in the case of the Denisova cave. A key finding was Neanderthal mtDNA in one sedimentary layer that contained no skeletal remains – decay of a body was probably not involved. In two cases the DNA was from more than one individual. A variety of tests showed that surprisingly large quantities of DNA survive in soil and that it is spread evenly in sediment rather than being present in spots – an indication of derivation from urine, excreta or decayed soft tissue.

Although the study does not add to knowledge of hominin genetics, it confirms that the methodology is sufficiently advanced and efficient to detect hominin presence in fossil-free sediment. So this approach seems set to become a standard for many sites, such as that from California reported in the previous post, which suggest a human influence, or any cave sediments for that matter. Although skeletal remains are essential for reconstruction of bodily characteristics, hominin phylogeny seems set to cut loose from fossils. Hitherto suspected species’ presence in the time period where DNA analysis is feasible may be detected, such as Asian H. erectus. It may become possible to map or extend the geographic ranges of Denisovans and Neanderthals. Perhaps species new to science will emerge.

More on late Pleistocene hominin genetics here

Wade, E. 2017. DNA from cave soil reveals ancient human occupants. Science, v. 356, p. 363.

Wade, E. 2017. DNA from cave soil reveals ancient human occupants. Science, v. 356, p. 363.

Pre-sapiens hominins reached North America?

In 1991-2 palaeontologists excavated a site near San Diego, California where broken bones had been found. These turned out to be the disarticulated remains of an extinct mastodon. One feature of the site was the association of several large cobbles with bones of large limbs that seemed to have been smashed either to extract marrow or as source of tool-making material. The cobbles showed clear signs or pounding, such as loss of flakes – one flake could be fitted exactly to a scar in a cobble – pitted surfaces and small radiating fractures. The damage to one cobble suggested that it had been used as an anvil, the others being hammer stones.  Broken pieces of rock identical to the hammer stones were found among the heap of bones. No other artefacts were found, and the bones show no sign of marks left by cutting meat from them with stone tools. The breakage patterns of the bones included spiral fractures that experimental hammering of large elephant and cow bones suggest form when bone is fresh. Other clear signs of deliberate breakage are impact notches and small bone flakes. Two detached, almost spherical heads of mastodon femora suggest that marrow was the target for the hammering and confirmed the breakage was deliberate.


Artist’s impression of American mastodon. (credit: Wikipedia)

Since the sediment stratum in which the remains occurred consists of fine sands and silt, typical of a low-energy river system, the chances that the cobbles had been washed into association with the mastodon are very small. The interpretation of the site is that it was the result of opportunistic exploitation of a partial carcase of a young adult mastodon by humans. In the early 1990s attempts were made to date the bones using the radiocarbon method, but failed due to insufficient preserved collagen. That the site may have been much older than the period of known occupation of North America by ancestors of native people (post 14.5 ka) emerged from attempts at optically stimulated luminescence dating of sand grains that can suggest the age of burial. These suggested burial by at least 60 to 70 ka ago. It was only when the uranium-series disequilibrium method was used on bone fragments that full significance of the site emerged. The results indicated that they had been buried at 130.7±9.4 ka (Holen, S.R. and 10 others 2017. A 130,000-year-old archaeological site in southern California, USA. Nature, v.  544, p. 479—493; doi:10.1038/nature22065 – full paper and supplements available free)

Not only is the date almost ten times that of the earliest widely accepted signs of Homo sapiens in the Americas, the earliest anatomically modern humans known to have left Africa are around the same age, but restricted to the Levant. The earliest evidence that modern humans had reached East Asia and Australasia through their eastward migration out of Africa is no more than 60 ka. The date from southern California is around the start of the interglacial (Eemian) before the one in which we live now. It may well have been possible then, as ~14 ka ago, to walk across the Bering Straits due to low sea level, or even by using coast-hugging boats – hominins had reached islands in the Mediterranean and the Indonesian peninsula certainly by 100 ka, and probably earlier. But whoever exploited the Californian mastodon marrow must have been cold-adapted to achieve such a migration. While the authors speculate about ‘archaic’ H. sapiens the best candidates would have been hominins known to have been present in East Asia: H. erectus, Neaderthals and the elusive Denisovans.

Surely there will be reluctance to accept such a suggestion without further evidence, such as tools and, of course, hominin skeletal remains. But these long-delayed findings seem destined to open up a new horizon for American palaeoanthropology, at least in California.

You can find more information on hominin migration here.


Denisovan(?) remains in the garden

On the edge of the small town of Lingjing near Xuchang City in Henan Province, China, local people have long practiced intensive vegetable gardening because the local soil is naturally irrigated by the water table beneath the flood plain deposits of the Yinghe River. In the mid 1960s, around a small spring, they began to find dozens of small stone tools together with animal bones. Only in 2005, after the spring had stopped flowing, did systematic excavation begin (Li, Z.-Y. et al. 2017. Late Pleistocene archaic human crania from Xuchang, China. Science, v. 355, p. 969-972; doi: 10.1126/science.aal2482) About 3.5 m below the surface tools and bone fragments, including one with a carved representation of a bird, occurred just above the base of the modern soil profile. Radiocarbon dating of charcoal from the layer clustered around 13 500 years ago, just before the start of the Younger Dryas cooling episode; probably products of modern humans, although no human remains were found in the layer. Continued excavation penetrated sediments free of fossils and tools down to a depth of 8 m, when stone tools and bone fragments began to turn up again through the lowest 2 m of sediment. Optically stimulated luminescence (OSL) dating of mineral grains, which shows the last time that sediments were exposed to sunlight, produced much older dates between 78 to 123 ka. The thousands of stone flakes and cores, and cut marks on the animal bones found through the fossil-rich layer suggests that this was a site long used for tool making and food preparation, that had begun in the last interglacial period. Among the bones were fragments of the crania of as many as five individual humans.

Who were they? Their age range is tens of thousands of years before anatomically modern humans began to migrate into east Asia, so they are likely to have been an earlier human group. Homo erectus is known to have inhabited China since as early as 1.6 Ma ago and may be a possibility. The other possible group are the Denisovans, known only from their DNA in a small finger bone from a cave in eastern Siberia. Fragments of Denisovan DNA are famously present in that of many living indigenous people from eastern Asia, Melanesia and the Americas, but hardly at all in west Asians and Europeans. They also interbred with Neanderthals and may share a common ancestor with us and them, who lived about 700 ka ago.

Map showing the proportion of the genome inferred to be Denisovan in ancestry in diverse non-Africans. The color scale is not linear to allow saturation of the high Denisova proportions in Oceania (bright red) and better visualization of the peak of Denisova proportion in South Asia. (Credit: Sankararaman et al./Current Biology 2016;  http://dx.doi.org/10.1016/j.cub.2016.03.037)

Map showing the proportion of the genome inferred to be Denisovan in ancestry in non-Africans. The color scale ranges from black – 0, through greens – present to red – highest . (Credit: Sankararaman et al./Current Biology 2016; http://dx.doi.org/10.1016/j.cub.2016.03.037)

Unfortunately the human bones are completely fragmented and lack any teeth, jaw bones or elements of the face. However, the Chinese-US team used sophisticated computer refitting of CT-scanned fragments to reconstruct two of the crania, revealing one individual with prominent brow ridges and a flat-topped skull extended towards the back, similar to that of Neanderthals but with a much larger brain than H. erectus. The semi-circular canals associated with the ears, but used in balancing, are well preserved and also resemble those of Neanderthals. Yet east Asia has yielded not a single Neanderthal fossil. Could these be the elusive Denisovans? Even if more diagnostic bones turn up, especially teeth, such is the state of late hominin taxonomy that only DNA will provide definitive results: the Denisovans are defined entirely by DNA. The authors, perhaps wisely, do not speculate, but others may not be able to resist the temptation.

For more information on recent human evolution see here.

Gibbons, A. 2017. Close relative of Neandertals unearthed in China. Science, v. 355, p. 899; doi: 10.1126/science.355.6328.899

Neanderthal culture confirmed

The Châtelperronian material culture represents the earliest sign of the Upper Palaeolithic in Europe and its products span a period from about 45 to 40 ka. It includes stone tools, such as points and long, thin blades with a single cutting edge and a blunt back, reminiscent of a modern knife, and others with notched, or denticulate edges that resemble saw blades. A great many of the tools, including ivory and bone ones, are probably designed for working and stitching skins. But the most revealing worked objects are animal teeth, shells and fossils that are either bored or grooved to be strung together. The best have been found in the Grotte du Renne in eastern France. The most controversial aspect of the Châtelperronian is that its artefacts are sometimes found with the fossil remains of Neanderthals who had previously produced less sophisticated, Mousterian tools since around 160 ka. The controversy centres on whether or not Neanderthals created the Châtelperronian culture, and if so, did they develop them independently or through cultural exchange with or copying from the newly arrived anatomically modern humans (AMH).

Science Magazine

Châtelperronian ornaments from the Grotte du Renne eastern France, probably parts of a necklace. (Credit: ©Marian Vanhaeren, CNRS, University of Bordeaux)

The Grotte du Renne material is especially rich in ornaments, but insufficient fossil material is present to tell from anatomical characteristics whether or not they were made by AMH or Neanderthals. It has now become possible using traces of bone proteins to detect hominin bone fragments and DNA to assess which group is implicated (Welker, F. and 127 others, 2016. Palaeoproteomic evidence identifies archaic hominins associated with the Châtelperronian at the Grotte du Renne. Proceedings of the National Academy of Science, www.pnas.org/cgi/doi/10.1073/pnas.1605834113). Analyses of mtDNA and radiometric dating of the bones that yielded it show that the Grotte du Renne tools and ornaments link with Neanderthals who lived there about 37 ka ago. Interestingly, the stratigraphic horizon beneath the definite Neanderthal occupation level contains their earlier, Mousterian artefacts. So it seems that they developed new manufacturing techniques and material culture. Yet, the findings do not resolve the issue of independent invention or copying AMH methodology.

Importantly, Grotte du Renne shows that Neanderthals, even if they copied AMH techniques, were capable of appreciating, producing and using personal ornamentation: they could learn and transmit ideas. In that respect, here is support for the notion that, apart from significant anatomical differences from AMH they were not that different intellectually.

More on Neanderthals, Denisovans and anatomically modern humans

Wade, L. 2016. Neandertals made jewelry, proteins confirm. Science, v. 353, p. 1350.

Breaking news: Cave structures made by Neanderthals

Neanderthals were well equipped and undoubtedly wore clothing, made shelters, hunted, used fire and famously lived in caves. Deliberate burial of their dead, in some cases arguably with remains of flowers, indicates some form of ritual and belief system. Those in Spain wore necklaces and pendants of bivalve shells, some of which retain evidence of having been painted. Excavators there even found a paint container and painting tools made of small bones from a horse’s foot. The container and tools retain traces of the common iron colorants goethite, jarosite and hematite. One large, perforated scallop shell, perhaps used as a pectoral pendant, shows that its white interior was painted to match its reddish exterior. Given the evidence for adornment by earlier hominins, to find that Neanderthals created art should not be surprising. In May 2016 it emerged that about 177 thousand years ago and earlier, they had broken stalagmites off the cave roof to create curious semi-circular structures in Bruniquel Cave near Montauban in southern France (Jaubert, J. and 19 others, 2016. Early Neanderthal constructions deep in Bruniquel Cave in southwestern France. Nature, v. 533,  online publication, doi:10.1038/nature18291). Each of the structures contains incontrovertible evidence that fires were made within them. Rather than being near the well-lit cave entrance the structures are more than 300 m deep within the cave system surrounded by spectacular stalagmites and stalactites that are still in place. Were the structures younger than 42 ka they would probably have been attributed to the earliest anatomically modern Europeans and to some ritual function. Instead they were made during the climatic decline to the last but one glacial maximum.

Related article

Neanderthals built mystery underground circles 175,000 years ago


Neanderthal news

Increasingly sophisticated analysis of existing genomes from Neanderthal and Denisovan fossil bone, together with new data on single-chromosome DNA extracted from Croatian and Spanish Neanderthals continues to break new ground.

Artistic reconstruction of Neanderthal woman (credit: Natural History Museum, http://www.nhm.ac.uk/natureplus/blogs/tags/human_evolution)

Artistic reconstruction of Neanderthal woman (credit: Natural History Museum, http://www.nhm.ac.uk/natureplus/blogs/tags/human_evolution)

According to genome comparison between a Siberian specimen and modern humans, a population from which Neanderthals emerged separated from that which led to anatomically modern humans (AMH) sometime between 550 and 765 ka, although the fossil record can only confirm that divergence was before 430 ka. The comparison famously showed that Neanderthals contributed to modern, non-African humans between 47 and 75 ka, that is after the exodus of AMH from Africa that spread our species throughout all continents except Antarctica. This genetic exchange is thought to have taken place somewhere in the Middle East, which seems to have been a major staging post for our spread further east and also westward to Europe. A similar indication of liaison between Denisovans and AMH migrants is restricted to modern Melanesians, and probably took place in eastern Asia before 45 ka, when modern people began crossing from Eurasia to New Guinea and Australia. Neanderthal-Denisovan comparison suggests that those distinct groups separated between 380 and 470 ka ago (recently revised from an earlier estimate).

In both cases the gene flow was from the older groups to humans. Further examination of Siberian Neanderthal genomes now indicates that a reverse exchange occurred more than 100 ka ago (Kuhlwilm, M. and 21 others 2016. Ancient gene flow from early modern humans into Eastern Neanderthals. Nature, v. 530, p. 429-433). But the single-chromosome DNA from Croatian and Spanish Neanderthals shows no such sign This instance of two-way exchange is significant in another way: it took place before direct evidence of the generally accepted departure of African migrants to populate the rest of the world. At about 100 ka there is fossil evidence of possible AMH-Neanderthal cohabitation of the Levant, followed by a period with fossil evidence for Neanderthal presence there but not modern humans. Because stone tools from northern Arabia are dated as far back as 125 ka and closely resemble those associated with archaic modern humans, there is a possibility that AMH migration was far earlier than previously thought and passed through the Levant en route to points east.

Another tantalizing aspect of Neanderthal-modern human genetics is the tangible legacy of interbreeding with non-African humans. The first sign was that the gene (mc1r) that confers red hair on those of us blessed, or otherwise, with it may have Neanderthal origins, thus making us extremely proud of that heritage. The same gene is implicated in northern modern humans having developed pale skin, which might embarrass ‘white supremacists’! Similar studies in Svante Paabo’s lab at the Max Planck Institute for Evolutionary Anthropology in Leipzig also suggested 15 genome regions that include those involved in energy metabolism, possibly associated with type 2 diabetes; cranial shape and cognitive abilities, perhaps linked to Down’s syndrome, autism and schizophrenia; wound healing; skin, sweat glands, hair follicles and skin pigmentation; and barrel chests. There is more…

Joshua Akey of the University of Washington, Seattle, and evolutionary genomicist Tony Capra of Vanderbilt University in Nashville hit on the idea of ‘mining’ archived genetic information from more than 28 thousand living people for traces of 6000 Neanderthal DNA variants and comparing the results with physical traits and diseases logged in the human database (reported by Gibbons, A. 2016. Neanderthal genes linked to modern diseases. Science, v. 351, p. 648-9). On the plus side, Neanderthal ancestry may help boost immune responses to fungi, parasites and bacteria. Inheritance of enhanced blood coagulation, although greatly assisting recovery from wounds and hemorrhage when giving birth, confers a proclivity to heart attacks and strokes. Neanderthals also passed on ‘weak bladders’, solar keratoses that confer skin cancer risk, a tendency to malnutrition from modern diets low on meat and nuts, depression triggered by jet lag(!) and even a tendency to nicotine addiction. But a ‘pure’ line of modern human descent, shared by most Africans, also has its positive and negative heritable traits.

More on Neanderthals, Denisovans and anatomically modern humans

Our ancestors parted from other humans earlier than expected

Despite the excitement raised by the discovery of remnants of 15 individuals of Homo naledi in a South African Cave the richest trove of hominin fossils remains that of Sima de los Huesos (‘pit of bones’) in northern Spain. In 2013 bone found in that cave from one of 28 or more individuals of what previous had been regarded as H. heidelbergensis, dated at around 400 ka, yielded mitochondrial DNA. It turned out to have affinities with mtDNA of both Neanderthals and Denisovans, especially the second. The data served to further complicate the issue of our origins, but were insufficient to do more than throw some doubt on the significance of H. heidelbergensis as a distinct species: nuclear DNA would do better, it was hoped by the palaeo-geneticists of the Max Planck Institute for Evolutionary Anthropology in Leipzig. Now a small fragment of those data (about 1 tro 2 million base pairs) have been presented to a London meeting of the European Society for the Study of Human Evolution – though not yet in a peer-reviewed journal. Anne Gibbons summarised the formal presentation in the 18 September 2015 issue of Science (Gibbons, Ann 2015. Humanity’s long, lonely road. Science, v. 349, p. 1270).

English: Cranium 5 is one of the most importan...

One of the best preserved discoveries in the Sima de los Huesos, Atapuerca (Spain). (credit: Wikipedia)

The partial nuclear DNA is a great deal more like that of Neanderthals from much more recent times than it is of either Denisovans and modern humans. It seems most likely that the Sima de los Huesos individuals are early Neanderthals, which implies that the Neanderthal-Denisovan split was earlier than 400 ka. That might seem to be just fine, except for one thing: Neanderthal and Denisovan DNA are much more closely related to each other than to that of ourselves. That implies that the last common ancestor of the two archaic human species must have split from the ancestral line leading to modern humans even further back in time: maybe 550 to 765 ka ago and 100 to 400 ka earlier than previously surmised. This opens up several interesting possibilities for our long and separate development. Since Neanderthals and perhaps Denisovans emigrated from Africa to Eurasia several glacial cycles ago, maybe people genetically en route to anatomically modern humans did so too. The Neanderthal and Denisovan genomes suggest that they interbred with each other and that could have been at any time after the genetic split between them. Famously, they also interbred with direct ancestors of living Eurasians, but there is no genetic sign of that among living Africans. The evidence suggests that the insertion of archaic genetic material was into new migrants from Africa around 100 to 60 ka ago at different points along their routes to Europe and East Asia. But, obviously, it is by no means clear cut what passed between all three long-lived groups nor when. It is now just as possible that surviving, earlier Eurasians on the road to modern humans passed on their own inheritance from relationships with Neanderthal and Denisovan to newcomers from Africa. But none of these three genetic groups ever made their way back to Africa, until historic times.

More on Neanderthals, Denisovans and anatomically modern humans

Human-Neanderthal cohabitation of the Levant

The earliest known remains of anatomically modern humans outside of Africa were found unearthed from the Skhul and Qafzeh caves in what is now northern Israel. Their context was that of deliberate burial at a time when climate was cooling from the last interglacial, between 90 to 120 ka. The Levant was also the repository for a number of well-preserved Neanderthal skeletons, most dating to between 35-65 ka, including ten individuals at Shanidar in today’s northern Iraq, some of whom were also deliberately buried including one whose grave reputedly contained evidence for a floral tribute. The 25 ka gap between the two populations has previous been regarded as evidence for lack of contact between them. However, the Tabun Cave in modern Israel has yielded tools attributed to Neanderthal Mousterian culture that may indicate their intermittent presence from 200 to 45 ka, and fossils of two individuals dated at ~122 and ~90 ka. The remains at Skhul and Qafzeh are significantly more rugged or robust than African contemporaries and have been considered possible candidates for Neanderthal-modern human hybrids. But whatever their parentage, it seems they became extinct as the climate of the Levant dried to desert conditions around 80 ka.

View of the exterior of Shanidar Cave, taken d...

Entrance to the Shanidar Cave, northern Iraq, occupied by Neanderthals between 35-65 ka (credit: Wikipedia)

A more promising overlap between modern human and Neanderthal occupation comes with the discovery by a group of Israeli, US, Canadian, German and Austrian scientists of a much younger anatomically modern human cranium from the Manot Cave, also in northern Israel (Herschkovitz, I. and 23 others 2015. Levantine cranium from Manot Cave (Israel) foreshadows the first European modern humans. Nature (online) doi:10.1038/nature14134). The cranium has a U-Th radiometric age of ~55 ka, well within the time span of Neanderthal occupation. Moreover, Manot Cave is one of a cluster of occupied sites in northern Israel, with separations of only a few tens of kilometres: undoubtedly, this individual and companions more than likely met Neanderthals. The big question, of course, is did the neighbours interbreed? If so the Levant would be the confirmed as the probable source of hybridisation to which the DNA of non-African living humans points. There may be a insuperable difficulty in taking this further: it is thought that the high temperatures of the region, despite its dryness, may have destroyed any chance of reconstructing ancient genomes. Yet one of the first Neanderthal bones to yield useful genetic material was from Croatia, which is not a great deal cooler in summer.

Improved dating sheds light on Neanderthals’ demise

As Earth Pages reported in December 2011 a refined method of radiocarbon dating that removes contamination by younger carbon has pushed back the oldest accessible 14C dates. Indeed, materials previously dated using less sophisticated methods are found to be significantly older. This has led archaeologists to rethink several hypotheses , none more so than those concerned with the relationship in Europe between anatomically modern humans (AMH) and Neanderthals, especially the extinction of the latter.

The team of geochronologists at Oxford University who pioneered accelerator mass spectrometry (AMS) of carbon isotopes, together with the many European archaeologists whose research has benefitted from it, have now published results from 40 sites across Europe that have yielded either Neanderthal remains or the tools they are thought to have fashioned (Higham, T. and 47 others. The timing and spatiotemporal patterning of Neanderthal disappearance. Nature, v. 512, p. 306-309) . One such site is Gorham’s Cave in the Rock of Gibraltar where earlier dating suggested that Neanderthals clung on in southern Iberia until about 25 ka. Another hypothesis concerns the so called Châtelperronian tool industry which previous dating at the upper age limit of earlier radiocarbon methodology could not resolve whether or not it preceded AMH colonisation of Europe; i.e. it could either have been a Neanderthal invention or copied from the new entrants. Most important is establishing when AMH first did set foot in previously Neanderthal’s exclusive territory and for how long the two kinds of human cohabited Europe before the elder group met its end.

Deutsch: Rekonstruierter Neandertaler im Neand...

Reconstruction of Neanderthal life from the Neandertahl Museum(credit: Wikipedia)

The new data do not quash the idea of Neanderthals eking out survival almost until the last glacial maximum in the southernmost Iberian Peninsula, since material from Gorham’s Cave could not be dated. However, occupation levels at another site in southern Spain in which Neanderthal fossils occur and that had been dated at 33 ka turned out to be much older (46 ka). So it is now less likely that Neanderthals survived here any longer than they did elsewhere.

Neanderthal remains are generally associated with a tool kit known as the Mousterian that is not as sophisticated as that carried by AMH at the same time. Of the Mousterian sites that yielded AMS ages, the oldest (the Hyaena Cave in Devon, Britain) dates to almost 50 ka. The youngest has a 95% probability of being about 41 ka old. Of course, Neanderthals may have survived until later, but there is no age data to support that conjecture. The earliest known AMH remains in Europe are those associated with the so-called Uluzzian tool industry of the Italian peninsula. In southern Italy Mousterian tools are replaced by Uluzzian between about 44.8 and 44.0 ka, while Mousterian culture was sustained in northern Italy until between 41.7 to 40.5 ka.

Châtelperronian stone tools

Châtelperronian stone tools (credit: Wikipedia)

Mousterian tool from France

Mousterian blade tool from France (credit: Wikipedia)

Châtelperronian tools associated with Neanderthal remains occur in south-western France and the Pyrenees. The new AMS dating shows that the culture arose at about the same time (~45 ka) as the Uluzzian tool industry began in Italy and ended in those areas where it was used at about the same time (~41 ka) as did the more widespread Mousterian culture. So the question of whether Neanderthals copied stone shaping techniques from the earliest Uluzzian-making AMH more than 500 km to the east, or invented the methods themselves remains an open question. But does it matter as regards the cognitive abilities of Neanderthals? Copying methodology is part and parcel of the success and survival of succeeding AMH, but o too is the capacity to invent useful novelties from scratch. So, yes it does matter, for Neanderthals had sustained the Mousterian culture for tens to hundreds of thousand years with little change.

The upshot of these better data on timing is that AMH and Neanderthals co-existed in Europe for between 2.6 to 5.4 ka; as long as the time back from now to the Neolithic and early Bronze Age. Even allowing for low population density to make contacts only occasional, this is surely too long for systematic slaughter of Neanderthals by AMH. Yet it gives plenty of time for two-way transmission of cultural and symbolic activities, and even for genetic exchanges: assimilation as well as out-competition.

Incidentally, Scientific American’s September 2014 issue is partly devoted to broader issues of human evolution (Wong, K. (editor) The Human Saga. Scientific American, v. 311(No 3), p. 20-75) with a focus on new developments. These cover: a revised time line; the emerging complexity of hominin evolution  by veteran palaeoanthropologist Bernard Wood.; the influence of climate change; by Peter de Menocal; cultural evolution in the broad hominin context by Ian Tattersall; a discussion of hominin mating arrangements by Blake Edgar; two contributions on cooperation versus competition among hominins by Frans de Wall and GGry Stix; two articles on recent biological and future cultural  evolution by John Hawks and Sherry Turkle (interview).

Mitochondrial DNA from 400 thousand year old humans

The Sima de los Huesos (‘pit of bones’) site in the cave complex of Atapuerca in northern Spain has yielded one of the greatest assemblages of hominin bones. Well-preserved remains of at least 28 individuals date to the Middle Pleistocene (>300 ka). Anatomically the individuals have many Neanderthal-like features but also show affinities with earlier Homo heidelbergensis, who is widely considered to be the common ancestor for anatomically modern humans and Neanderthals, and perhaps also for the mysterious Denisovans. Most palaeoanthropologists have previously considered this Atapuerca group to be early Neanderthals, divergent from African lineages because they migrated to and became isolated in Europe.

English: Cranium 5 is one of the most importan...

Human cranium from the Sima de los Huesos, Atapuerca mountains (Spain). (credit: Wikipedia)

The riches of the Sima de los Huesos ossuary made it inevitable that attempts would be made to extract DNA that survived in the bones, especially as bear bones from the area had shown that mtDNA can survive more than 4300 ka. There has been an air of expectancy in hominin-evolution circles, and indeed among the wider public, since rumours emerged that the famous Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany had initiated genetic sequencing under the direction of Svante Pääbo: perhaps another ‘scoop’ to add to their reconstructing the first Neanderthal and Denisovan genomes. The news came out in the 5 December 2013 issue of Nature, albeit published on-line (Meyer, M. and 10 others 2013. A mitochondrial genome sequence of a hominin from Sima de los Huesos, Nature, v. 504; doi:10.1038/nature12788) with a discussion by Ewan Callaway (Callaway, E. 2013. Hominin DNA baffles experts Nature, v. 504, p. 16-17).

The bafflement is because the mtDNA from a femur of a 400 ka  individual does not match existing Neanderthal data as well as it does that of the Denisovan from Siberia by such a degree that the individual is an early Denisovan not a Neanderthal. Northern Spain being thousands of kilometres further west than the Denisova cave heightens the surprise.  Indeed, it may be on a lineage from an earlier hominin that did not give rise to Neanderthals. The full Neanderthal and Denisovan genomes suggest that they shared a common ancestor up to 700 ka ago. So the Sima de los Huesos individual presents several possibilities. It could be a member of an original population of migrants from Africa that occupied wide tracts of Eurasia, eventually to give rise to both Neanderthals and Denisovans. That genetic split may have arisen by the female line carrying it not surviving into populations that became Neanderthals – mtDNA is only present in the eggs of mothers. Mind you, that begs the question of who the Neanderthal females were. Another view is that the Sima de los Huesos individual may be descended from even earlier H. antecessor, whose 800 ka remains occur in a nearby cave. Pääbo’s team have even suggested that Denisovans interbred with a mysterious group: perhaps relics of the earlier H. antecessor colonists.

Established ideas of how humans emerged, based on bones alone and very few individuals to boot, are set to totter and collapse like a house of cards. Interbreeding has been cited three times from DNA data: modern human-Neanderthal; modern human-Denisovan and Denisovan with an unknown population. Will opinion converge on what seems to be obvious, that one repeatedly errant species, albeit with distinct variants, has been involved from far back in the human evolutionary journey?  There seems only one avenue to follow for an answer, which is to look for well preserved H. heidelbergensis. H. antecessor and H. erectus remains and apply ever improving techniques of genetic retrieval. Yet there is a chance that stretches of ancient DNA can be teased out of younger fossils.