Showing posts with label Neanderthal man. Show all posts
Showing posts with label Neanderthal man. Show all posts

Wednesday, 17 August 2022

Assessing the authenticity of Acheulean Porosphaera beads.

The appearance of symbolic thinking is considered to be one of the most important steps in the development of modern Human cognition, giving Humans the ability to pass on information by means of objects rather than direct communication, and thereby helping to build communities bound by common cultural traits rather than simple kinship. Evidence of this, however, is difficult to detect in the archaeological record, leading to intense debates as to when and where such behaviour first appeared.

The first shell beads appear over a hundred thousand years ago in Africa and the near east, at sites such as Skhul Cave in Israel, where beads have been dated to 135-100 000 years before the present, Qafzeh Cave, also in Israel, dated to 100-92 000 years ago, Blombos Cave in South Africa, 100-70 000 years ago, Sibudu Cave in South Africa, older than 70 000 to about 60 000 years ago, Border Cave, again in South Africa, 125-35 000 years ago,  Grotte des Pigeons in Morocco, 80 000 years ago, Bizmoune Cave in Morocco, at least 142 000 years old, Rhafas Cave, also in Morocco, 82 000 years ago, Contrabandiers Cave, once again in Morocco, 120-90 000 years ago, and Oued Djebbana in Algeria, 100-90 000 years ago. All of these sites are associated with early anatomically modern Humans, apparently confirming that beads were an innovation novel to this group. It has been suggested that symbolic thinking appeared in anatomically modern Humans, providing them with a cultural edge that enabled them to replace all other Hominins. However, recent evidence has suggested that some other Hominin species also used symbolism, which would indicate a far earlier origin within the genus Homo. This analysis has largely revolved around the use of personal ornaments, such as beads, pendants, bracelets and diadems, which are taken as evidence of symbolic thought.

One group particularly associated with bead-making are Neanderthals, something which ties into deeper questions about this group's abilities, and relationship to modern Humans. 

Neanderthals were for a long time (and often still are) classified as a separate Hominin species, Homo neanderthalensis, possibly the most advanced Human species other than ourselves, but nevertheless separate and inferior. However, more recent genetic studies have shown that many modern Humans, and probably all non-African Humans, carry some Neanderthal DNA, which challenges this view of separateness. 

This has led to differing views on the taxonomic status of Neanderthals; possibly they were still a separate species, Homo neandethalensis, but only recently diverged and still capable of interbreeding with us (which is tricky, because in biology populations are generally defined as different species when they are incapable of interbreeding). Alternatively, maybe they should be seen as a modern Humans, but belonging to a different subspecies, Homo sapiens neandethalensis (with all living Humans being classified as Homo sapiens sapiens), which acknowledges that they were different from us, but not that different. Finally, maybe they should be seen as completely modern Humans, but belonging to an ethnic group which has disappeared; making them no more different from living Humans than modern Europeans are from modern Africans.

Much of this debate revolves around the cognitive abilities of Neanderthals. As a group, Neanderthals are strongly associated with the Acheulean Palaeolithic technology. This technology first appeared in Africa about 1.76 million years ago (long before the appearance of Neanderthals), and spread across much of Africa and Eurasia, being used by a variety of Hominin groups. Neanderthals first appeared somewhere between 800 000 and 315 000 years ago, and used Acheulen technology throughout almost all of their history, although some later groups appear to have adopted different technologies learned from Modern Human neighbours. Thus, while Neaderthals are strongly associated with the Acheulean technology, particularly in Europe, not all Acheuleans were Neanderthals, and not all Neanderthals were Acheuleans. 

This long use of a single tool-making technology, apparently without any innovation, has been used to suggest that Neanderthals lacked the capacity for abstract imaginative thought; they were capable of copying what they had seen others make, but were quite incapable of coming up with new ideas for themselves. However, despite this apparent lack of innovation in tool-making, Neanderthals are also thought to have been capable of considerable artistic output, with material attributed to their output including pendants made from the claws of Birds of Prey, a bone flute, cave paintings, and numerous beads, some made from shells, but many of them made from fossils of the Cretaceous Sponge, Porosphaera globularis.

In a paper published in the journal Archaeological and Anthropological Sciences on 1 August 2022, Gabriele Luigi Francesco Berruti of the University of Ferrara, and of the Association 'P-Project Prehistory Piedmont', Dario Sigari, also of the University of Ferrara, and of the Geoscience Center of Coimbra University and the Archaeological Cooperative Society, Cristiana Zanasi of the Civic Museum of Modena,  Stefano Bertola and  Allison Ceresa, again of the University of Ferrara, and Marta Arzarello, once again of the University of Ferrara, and the Association 'P-Project Prehistory Piedmont', assess the authenticity of the Porosphaera globularis beads, and assess whether they were genuinely made by our Neanderthal forebears. 

Berruti et al.'s study concentrates on a collection of Porosphaera beads in the collection of the Civic Museums of Modena, which were obtained in 1891 from the French police commissioner and antiquarian  Charles Le Beuf, who collected them from Saint-Acheul in the Somme, the type locality for the Acheulian culture (i.e. the site from which that culture was named, and to which material from other locations is compared when deciding if it can be classified as 'Acheulian'.

Porosphaera beads were collected from Acheulian sites across northwest France and Southern England in the nineteenth century. They are clearly made from fossils of the Cretaceous calcareous Sponge Porosphaera globularis, which was naturally rounded, but have holes bored through them, which nineteenth century archaeologists interpreted as evidence of their use as beads. The problems with this are that the Sponge fossils are found in the same chalk layers that Acheuleans (and later people) excavated for flints from which to make tools (meaning that Acheuleans would have been digging them out whether they subsequently used them or not), and that about 9% of these fossils have 'natural' boreholes in them, made by Cretaceous Sipunculid Worms. 

Thus there could be three possible explanations for the 'beads' found by nineteenth century archaeologists. Firstly, they could be exactly what they were assumed to be; beads made by Acheuleans as personal ornamentation. Secondly, they could be Sponges with boreholes made by Cretaceous Worms, which were then collected and used as beads by the Acheuleans. Finally, it is possible that these Sponges were bored by Cretaceous Worms and overlooked by the Acheuleans, but collected by nineteenth century archaeologists, who had preconceived ideas about what beads looked like which the Acheuleans lacked.

Archaeological sites where Porosphaera globularis beads have been recovered. Berruti et al. (2022).

Whereas a modern site used as the type for an archaeological culture (or palaeontological species) would be recorded very precisely. The Saint Acheul 'site' actually refers to an entire region in the suburbs of Amiens, with several different locations producing material, some of them from several different layers. The earliest of these contains material dated to 670-650 000 years before the present, and marks the earliest spread of the Acheulian culture into northern Europe. Accurate recording of the level from which the Porosphaera beads  were obtained is lacking, but it is thought that they came from the same layers as flint tools recorded from the site.

In 1891 the then director of the Civic Museum of Modena, Carlo Boni, purchased a collection of beads and stone tools from Le Beuf for 400 Francs. The Porosphaera beads were assembled by Boni into four necklaces, three using raffia threads and one using metal wire, with each necklace having between 112 and 156 individual beads. These were then mounted on a cardboard panel for display purposes, using some red ribbon. The beads have remained on this mount to this day, with both the beads and the panel having gained a coating of dust and an organic crust derived from the breakdown of the cardboard.

One of the four Porosphaera globularis necklaces of the Modena collection assembled on the original twentieth-century support. Paolo Terzi in Berruti et al. (2022).

Berruti et al. disassembled Boni's necklaces, in order to obtain a specimen of 520 beads, which were then individually examined. The perforations in these beads were found to be larger than the 'natural' holes caused by Cretaceous Worm-borings, and the beads themselves were, on average more uniform in size and more rounded than a selection of random Porosphaera globularis fossils. This implies strongly that the beads in the Moderna collection have been subjected to Human selection, although whether this was by Acheuleans or nineteenth century archaeologists is unclear.

Next Berruti et al. examined wear traces on the beads, finding that they showed wear around their perforations (as would be caused by a string, whether ancient of modern), and on the surfaces where the perforations were found (i.e. on the surfaces where the beads would rub-together while suspended on a string), but not on other surfaces of the beads. Furthermore, many of the beads had developed a patina, which was not seen on the surfaces adjacent to the holes. All of these have been recorded on Porosphaera beads used in other studies, and taken as evidence of the beads having been worn on a string of some description, and having rubbed against one-another while being worn.

However, Berruti et al. consider that while these traces could have been made by the actions of fashion-conscious Acheuleans, it is also possible that they could have been caused by the actions of nineteenth century antiquarians, either intentionally, to increase the value of their finds, or inadvertently, while mounting the beads onto strings for display purposes.

Since this matter cannot be resolved by looking at wear on the beads caused by them rubbing against one-another on a string, or the friction of the string itself, Berruti et al. consider an alternative source of information, namely to what extent would the beads by modified by rubbing against the skin of their wearers? (Clothing has never been found in association with Acheulean archaeological sites, and these people are therefore assumed not to have worn clothing). If the beads had never been worn by Acheuleans, but rather collected and strung by antiquarians for the first time, then any markings left by such rubbing against skin should be absent.

To this end Berruti et al. obtained five non-perforated specimens of Porosphaera globularis (which, lacking perforations, could never have been worn as beads), and tested these by rubbing them against Pig skin (considered similar enough to Human skin to be used in a variety of trials) for a total of ten minutes each; three of the beads were rubbed against clean skin and two against dirty skin.

All of the beads showed signs of abrasion and rounding after ten minutes, suggesting that they would be unlikely to survive long-term wear as items of jewellery work against the skin. The beads rubbed against dirty skin developed distinctive striations within the ten minutes, a phenomenon absent in the Moderna beads.

(a) Photomicrographs of the specimen K126 from Hannover before and after the experimentation (rubbing for 10 min on dirty pig skin); (b) Photomicrographs of the specimen L844 from Logstor before and after the experimentation (rubbing for 10 min on pig skin); in the lower part of the image, two photomicrographs of the surfaces of two different specimens of the Modena collections. The surfaces of the samples K126 and L844 before the experimentation are similar to the surfaces of the samples from the Museum collection; after the experimentation, the surfaces are strongly smoothed. Berruti et al. (2022).

Close examination of the Moderna beads enabled them to be divided into three groups, based upon their geology. The first of these show signs of having been rolled on the seafloor before being buried, producing a unique set of scratches and markings. The second group have been partially or wholly remineralized after being buried. The third set show no signs of either mechanical abrasion or remineralization. 

Specimens of the Modena collection. Specimens with microstructure very well preserved, the pattern of the cells forming the sponge skeleton is clearly readable (1)–(2); specimens with surfaces showing marked rounding, smoothing and erosion surfaces, caused by their rolling in water environments (3)–(4); specimens with almost uniform surface concretions, mainly yellowish (goethite, limonite) or reddish (haematite), due to the stay of the fossils into soils or karst wells with a clayish matrix rich in iron minerals (5)–(6); specimens with marked dissolution and recrystallization phenomena having an irregular distribution and due to rainwater circulation (vadose meteoric environment) (7)–(8). Indeed, there are clear phenomena of calcite mineralization, macrocrystalline as well, located only on lower fossil surface, the pending one. Berruti et al. (2022).

Berruti et al. looked for signs of intentional modification of the wholes through the beads, from which it might be possible to determine the nature of the tool being used, and therefore whether the person carrying out this action lived in the Palaeolithic or the nineteenth century. Several of the beads show signs of mechanical action around the hole, though it cannot safely be said whether this was a result of drilling by bead-maker, or abrasion by the string. In two cases the hole through the bead was hourglass shaped, which was most likely caused by drilling from each end, but is was not possible to tell what tool was used, not when this action occurred.

Specimens of the Modena collection. Specimens with preserved marl residuals in the through-hole (1)–(4); specimens with two opposite conical holes that converge in the shape of an hourglass towards the centre of the hole (5)–(10). Looking in detail at the through-hole surface, concentric striae can be identified (9)–(10); they affect the internal calcite wall of the sponge and they seemingly confirm the use of a bow drill. Berruti et al. (2022).

In the late nineteenth century the concept of symbolic thought, and its importance as a step in the development of achieving the cognitive abilities of modern Humans, was barely (if at all) understood. Even today, there are those who believe that this is a unique trait in anatomically modern Humans, and that any evidence for this in Europe prior to the arrival of anatomically modern Humans, about 40 000 years ago, must be erroneous. Many scholars in the field, however, support the idea that this, like other traits, must have evolved gradually, and therefore it is not unreasonable to expect to find evidence for some sort of symbolic thought in earlier groups.

The apparent use of personal ornamentation by Neanderthals has been seen as a clear piece of evidence in support of this idea, and the presence of beads in the classical Acheulean deposits as fairly strong evidence of the creative abilities of Neanderthals. However, the Saint Acheul beds are significantly older than any other deposits thought to have yielded material associated with personal ornamentation (made by Neanderthals, anatomically modern Humans, or anybody else), which should automatically raise questions about the reliability of these items.

Based upon this analysis, Berruti et al. conclude that the Acheulean  Porosphaera beads are entirely natural in their origin; possibly with a little bit of help by over-enthusiastic nineteenth century antiquarians, but definitely not produced by early Acheuleans.

Berruti et al. do not, however, extrapolate from this data to assume that all evidence of symbolic thought attributed to Neanderthals are false. There is a considerable body of evidence which suggests that Neandethals were capable of artistic representation, albeit later in their history than the Saint Acheul deposits. Even if this evidence is all erroneous, and our current ideas about Neanderthals are completely wrong, this will only be overturned by looking at the validity of each individual piece of evidence, with no single source of data being able to tell the whole story.

See also...


Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.


Sunday, 26 August 2018

Deciphering the imput of Neanderthal and Denisovan genetic material into modern, non-African, Human populations.

Early Modern Humans migrating from Africa are known to have encountered and interbred with two Archaic Human populations, Neanderthals and Denisovans, with almost all non-African Humans carrying some DNA from these groups and most Africans carrying little if any. Previous studies have suggested that modern Eurasians have inherited about 2% of their DNA from Neanderthal ancestors, while Melanesians have about 5% Denisovan DNA.

In a paper published in the journal Cell on 22 March 2018, Sharon Browning of the Department of Biostatistics at the University of Washington, Brian Browning of the Division of Medical Genetics at the University of Washington, Ying Zhou, also of the Department of Biostatistics at the University of Washington, Serena Tucci of the Department of Ecology and Evolutionary Biology at Princeton University, and Joshua Akey of the Department of Ecology and Evolutionary Biology and the Lewis-Sigler Institute for Integrative Genomics at Princeton University, publish the results of a new study in which genomes from non-African populations from the 1000 Genomes Project were compared to the genomes of two Archaic Humans from the Altai Mountains of southern Siberia, one Denisovan and one Neanderthal, in order to better understand the genetic contribution of these two groups to non-African Modern Human groups.

All Humans, including Archaic populations such as Neanderthals and Denisovans, share almost all of their DNA. In this context 'Neanderthal DNA' or 'Devisovan DNA' refers to variable alleles found in the ancient population, but not in modern African populations not thought to share any genetic heritage since the ancestors of these groups left Africa in the Middle Pleistocene.  An allele is one of two or more different genes that can occur at a gene locus, for example different alleles for blue or brown eyes may be found at the gene locus for eye colour in Humans

Reconstruction of a Neanderthal Woman. Morten Jacobsen.

In line with previous studies, Browning et al. found that East Asian populations had a higher proportion of Neanderthal DNA than European populations, while the proportion of Neanderthal DNA in South Asians and Europeans was roughly similar, while the Papuan population had a significant proportion of Denisovan DNA. Modern Europeans were also shown to have a significantly higher proportion of Neanderthal DNA than modern West Africans (who have almost no Neanderthal DNA), while Americans have lower levels of Neanderthal DNA than Europeans (though this may be due to recent mixing with other population groups. Denisovan DNA was found at a higher level in East and South Asians than Europeans, with some European groups, such as Finns, having a higher proportion of Denisovan DNA than others. Native American populations also had some Denisovan DNA, though less than in South and East Asians.

Curiously modern East Asian populations seemed to carry Denisovan DNA from two sources, one closely related to the Altai Denisovan, and one more distantly related, whereas all Denisovan DNA in other populations, including Papuans, appeared to carry only DNA from the distantly related population. This suggests that East Asians went through an additional phase of interbreeding with Denisovans after their split from Papuans and South Asians, while Papuans may have had a second phase of interbreeding with the distantly related Denisovan population after their split from East and South Asians, or simply have derived from a subsection of that early population that had interbred with Denisovans more extensively.

Reconstruction of a Denisovan Man. John Baravo.

East Asians were shown to have an average of 30% more Neanderthal DNA than Europeans, though there was no suggestion that this came from more than one source. Browning et al. suggest that the most likely explanation for this is interbreeding between the ancestors of modern Europeans and other Modern Human populations with no admixture of Neanderthal DNA after their split from East Asians.

See also...

https://sciencythoughts.blogspot.com/2018/07/iberias-oldest-cave-art-can-be.htmlhttps://sciencythoughts.blogspot.com/2016/03/identifying-archaic-human-dna-in-gene.html
https://sciencythoughts.blogspot.com/2016/07/evidence-of-cannibalism-in-neanderthal.htmlhttps://sciencythoughts.blogspot.com/2016/03/identifying-archaic-human-dna-in-gene.html
https://sciencythoughts.blogspot.com/2015/12/genetic-data-from-two-new-denisovan.htmlhttps://sciencythoughts.blogspot.com/2015/09/neanderthal-dna-from-37-000-42-000.html
Follow Sciency Thoughts on Facebook.

Wednesday, 25 July 2018

Iberia's oldest cave art can be confidently assigned to Neanderthal artists.

Neanderthals were an archaic Human group that first appeared in Europe between 430 000 and 250 000 years ago. They were for a long time seen as more primitive than modern Humans, with a lower capacity for technology, little art or symbolism, and probably a much less sophisticated grasp of language, though this view has changed in recent decades, as they have been shown to have used more sophisticated tools than previously understood, as well as dyes for body art and even musical instruments, though cave painting has never been confidently added to this list of achievements.

In a paper published in the journal Science on 23 February 2018, a group of scientists led by Dirk Hoffmann of the Department of Human Evolution at the Max Planck Institute for Evolutionary Anthropology, describe the results of a study of cave art in Spain, which used uranium-thorium dating of flowstone deposits overlaying parts of the artwork to provide minimum dates for the paintings, which suggests that they are to old to be attributed to Modern Humans.

Flowstone is formed by the deposition of calcium carbonate onto surfaces by evaporating water; typically water that has flowed through limestone deposits then run out onto a surface such as a cave wall or cliff face before evaporating. The most obvious examples of this are stalagmites and stalactites, though many caves have an interior surfaces covered by flowstone. Where these flowstone deposits occur in caves with paintings they will often overlay the artwork, which means that if the flowstone can be dated, then a minimum age for the art can be established (as the art cannot be younger than the flowstone that overlays it).

Red scalariform sign, panel 78 in hall XI of La Pasiega gallery C. This panel features the La Trampa pictorial group. (Inset) Crust sampled and analysed for a minimum age, which constrains the age of the red line. Hoffmann et al. (2018).

Uranium-thorium dating works because uranium decays to thorium at a known rate, so that the ratio  of the two elements in minerals that naturally incorporate uranium but not thorium can be used to establish a date for the minerals. Neither uranium nor thorium are typically found in carbonate deposits, but uranium can be absorbed into these minerals as they form, whereas thorium cannot.

Hoffmann et al. sampled flowstone overlaying paintings in three caves, the La Pasiega Cave in the Monte Castillo Cave Art Complex World Heritage Site in Cantabria in the north of the country, the Maltravieso Cave in Extremadura in the west of the country, and Doña Trinidad Cave in Andalucia, in the south of the country.

Hand stencil GS3b in Maltravieso Cave. (Top) Original photo. The inset shows where the overlying carbonate was sampled. (Bottom) Same picture after application of the DStretch software (correlation LRE 15%, auto contrast) to enhance colour contrast. Hoffman et al. (2018).

The La Pasiega Cave is known to have been occupied for the much of the past 100 000 years, which it was occupied by first Neanderthals, who were present in the region until about 39 000 years ago, and then by Modern Humans, who first appeared in the region about 45 000 years ago. This means that any art younger than 39 000 years old must have been made by Modern Humans, while any art older than 45 000 years old must have been made by Neanderthals, with a period of about 6000 years in the middle where art could have been produced by either group.

The site contains a variety of paintings, predominantly in red and black, and including groups of animals, linear signs, claviform signs, dots, and possible anthropomorphs. Hoffmann et al. obtained samples of limestone from a flowstone deposit overlaying a ladder-like red symbol. This contained three distinct layers of material, with the innermost layer yielding an age of 64 800 years, roughly 20 000 years too old to have been produced by Modern Humans.

Speleothem curtain 8 in section II-A-3 in Ardales Cave with red pigment. (Left) Series of curtains with red paint on top, partially covered with later speleothem growth.The white rectangle outlines the area shown at right. (Right) Detail of curtain 8.The black square indicates where carbonate, overlying the red paint, was sampled. Hoffman et al. (2018).

The Maltravieso Cave is thought to have been occupied intermittently from about 160 000 years ago onwards, which again implies that it was occupied sequentially by first Neanderthals and then Modern Humans. This cave contains about sixty hand stencils, as well as geometric shapes and Human figures. Hoffmann et al. obtained a series of samples from carbonate deposits overlaying a red hand stencil, with the oldest yielding a minimum age of 66 700 years, again too old for the painting to have been produced by Modern Humans.

The Doña Trinidad Cave has not previously been dated, but has produced artifacts associated with the Middle and Late Palaeolithic, technologies associated with both Modern Humans and Neanderthals. The cave has numerous paintings, including hand stencils, geometric shapes and animal figures. Hoffmann et al. obtained samples from a flowstone curtain overlaying an area of cave wall that had been painted red, yielding ages of between 32 100 and 63 700 years, again implying that painting on the cave wall began long before modern Humans arrived in Iberia.

See also...

https://sciencythoughts.blogspot.com/2017/11/determining-origin-of-yabroud.htmlhttps://sciencythoughts.blogspot.com/2016/07/evidence-of-cannibalism-in-neanderthal.html
https://sciencythoughts.blogspot.com/2016/04/mitochondrial-genomes-of-pleistocene.htmlhttps://sciencythoughts.blogspot.com/2016/03/middle-palaeolithic-stone-tools-from.html
https://sciencythoughts.blogspot.com/2014/10/acheulian-and-levallois-technologies.htmlhttps://sciencythoughts.blogspot.com/2014/10/human-remains-from-middle-pleistocene.html
Follow Sciency Thoughts on Facebook.

Saturday, 21 January 2017

Understanding the ecological niche of the Neanderthals.

The Neanderthals were an early Human group living in Europe during the Late Pleistocene, from about 250 000 to about 40 000 years ago. They are considered by some palaeoanthropologists to have been a separate species of Humans, closely enough related to Modern Humans to have occasionally interbred with us, while others see them as a distinct group of Modern Humans adapted to living in Pleistocene environments that have now disappeared. The traditional view of Neanderthals is of a cold-adapted group, able to survive in harsh, Ice Age environments that Modern Humans could not tolerate, but unable to compete with Modern Humans in the milder climate of the Holocene. However an expanding number of Neanderthal finds and work upon these has painted a different picture, with the Neanderthals reaching their maximum range of expansion during the Last Interglacial Climatic Optimum, 125-119 000 years ago, when temperatures were on average 2°C warmer than today across Europe, and the last Neanderthals having lived around the Mediterranean Basin close to the Last Glacial Maximum, 40 000 years ago, at a time when Modern Humans, with more advanced textile manufacturing capabilities, were already moving into parts of Central Europe.

In a paper published in the Journal of Biogeography on 9 August 2016, Blas Benito and Jens-Christian Svenning of the Section for Ecoinformatics & Biodiversity at Aarhus University, Trine Kellberg-Nielsen and Felix Riede of the Department of Archaeology, also at Aarhus University, Graciela Gil-Romera of the Quaternary Palaeoenvironments and Global Change Department at Campus Aula Dei, Thomas Mailund of the Bioinformatics Research Centre at Aarhus University, Peter Kjaergaard of the Natural History Museum of Denmark at the University of Copenhagen, and Brody Sandel, also of the Section for Ecoinformatics & Biodiversity at Aarhus University, describe the results of study of the distribution of Neanderthals in Europe and the Middle East during the Last Interglacial Climatic Optimum, made with the aim of understanding the optimum ecological niche of the group.

Neanderthals have traditionally been thought of as a cold-adapted Human group, but this may not be the case. Walking with Cavemen/BBC.

Benito et al. mapped the known distribution of Neanderthal sites in Europe and the Middle East against factors likely to have effected their distribution, notably maximum temperature of the warmest month, minimum temperature of the coldest month, annual precipitation, precipitation during the warmest quarter, topological variability and average slope. Neanderthal populations from Central Asia and Siberia were not included in this study as insufficient information on these was available.

Some previous studies have suggested that parts of Central Europe were covered by dense forests during the Last Interglacial Climatic Optimum, which would have excluded large game upon which Neanderthals were dependent, and therefore the Neanderthals themselves, from these areas. However more recent studies have suggested that these areas were covered not by a single homogenous dense forest, but by a more patchwork environment with forested and open areas, which would not have excluded big game, implying that if Neanderthals were absent from these areas it would have been for other reasons. Benito et al. observe that the addition of detailed mapping of vegetation in Europe during the Last Interglacial Climatic Optimum would have been useful, but that such information is not available at a sufficiently detailed level at the current time.

It has also been suggested that the biggest limiting factor for Neanderthals in Northern Europe would be a short growing season, which would have limited the available food for prey animals both large and small, thereby limiting the amount of food available to Neanderthals. At the other extreme Neanderthals could have been excluded from some more southerly areas by a warm dry climate, with low summer rainfall again limiting plant growth and available food for herbivorous animals, again limiting the Neanderthals by reducing their hunting opportunities. This latter theory has been undermined somewhat by the discovery of a large number of Neanderthal sites around the Mediterranean Basin, leading to suggestions that Neanderthals may have been able to cope with an absence of game animals in these regions by substituting seafood such as shelfish gathered on the shore.

Neanderthals were found to be able to tolerate a high temperature range, with a maximum average warmest month temperature of 38.4°C and an average minimum coldest month temperature of -19.3°C. Reasonably high rainfall levels also seemed to be important, with Neanderthals favouring areas with about 900 mm of rain per year and high summer rains. Neanderthals also favoured areas with high topological variability (on average 73.8%) and an average slope between 0.5 and 6.8°. In layman’s terms this means they needed a reasonably varied terrain, enabling foraging in a variety of habitats, and avoided both flatlands and mountainous regions. The absence of Neanderthals from mountain ranges such as the Alps and Pyrenees has been noted before, and it has been suggested that this may be due to the loss of archaeological remains by glacial scouring. However a number of recent finds of Pleistocene Cave Bears from sites in the Alps has suggested that such remains can survive here at least in caves, and Neanderthals are known to have taken advantage of such natural shelters just as Bears do.

Neanderthal sites in the European and Irano-Turanian Region used to calibrate the models and habitat suitability during the Last Interglacial Climatic Optimum. Site codes: (1) Lehringen; (2) Veltheim Steinm€uhle; (3) Neumark Nord; (4) Burgtonna; (5) Waziers; (6) Jaskinia Nietoperzowa; (7) Caours; (8) Gouberville; (9) Velykyj Glybochok; (10) Horka Ondrej; (11) Yezupil; (12) Subalyuk Cave; (13) Krapina; (14) Betalov Podmol; (15) Kabazi II; (16) Grotte Vauffrey; (17) Payre; (18) Abri des Pécheurs; (19) Oyambre; (20) El Castillo; (21) Lezetxiki; (22) Crvena Stijena; (23) Saccopastore; (24) Estragales; (25) Grotta del Cavallo; (26) Grotta Riparo del Poggio; (27) Gánovce; (28) Bolomor Cave; (29) La Carihuela; (30) Del Angel Cave; (31) Karain Cave; (32) Es Skhul; (33) Tabun. Benito et al. (2016).

The single highest factor affecting the distribution of Neanderthals turned out to be annual rainfall, followed by minimum winter temperature (undermining the idea that Neanderthals were a cold-adapted group). However at local level slope was the most important factor followed by summer rainfall and coldest winter temperature again.

This model indicates that the optimum environment for Neanderthals was found in Southern Europe and the Mediterranean Basin, in central and southern France, Italian Peninsula, the Mediterranean islands, along the Atlantic coast of the Iberian Peninsula, the southern coast of the Black Sea and the Levantine coasts of the Mediterranean Sea. A less optimal environment was found in inland areas of Southern Europe and coastal areas further north, such as the continental areas of the Iberian Peninsula, British Isles, Dinaric Alps, Balkan Mountains, continental areas of Anatolia and the southern coasts of the Baltic Sea. Others areas, such as high-altitude regions of the Alps and Pyrenees, across the Scandinavian Shield, and the current Arabian Desert, were highly unsuitable for Neanderthal occupation.

See also...
 
http://sciencythoughts.blogspot.co.uk/2016/07/evidence-of-cannibalism-in-neanderthal.htmlhttp://sciencythoughts.blogspot.co.uk/2016/03/identifying-archaic-human-dna-in-gene.html

http://sciencythoughts.blogspot.co.uk/2015/12/genetic-data-from-two-new-denisovan.htmlhttp://sciencythoughts.blogspot.co.uk/2015/09/neanderthal-dna-from-37-000-42-000.html
http://sciencythoughts.blogspot.co.uk/2014/10/human-remains-from-middle-pleistocene.htmlhttp://sciencythoughts.blogspot.co.uk/2012/03/ritual-use-of-raptor-claws-by.html
Follow Sciency Thoughts on Facebook.

Saturday, 23 July 2016

Evidence of cannibalism in a Neanderthal population from the Late Pleistocene of Belgium.

In the century and a half since the discovery of the first Neanderthal remains traces of the group have been found across much of Europe and Western Asia. During this time there has been a great deal of speculation about the cognitive abilities of Neanderthals, particularly since the discovery of examples of ritual behaviour otherwise known only in Modern Humans, such as burying their dead, making jewelry and even using cosmetics. One behavioural trait occasionally reported in Neanderthals, is cannibalism (eating members of their own species), interpreted as having taken place at sites where Neanderthals show signs of having been modified in ways that suggest butchery. However while this behaviour has been suggested for Neanderthals on several occasions, the evidence is very limited, comprising largely of isolated finds from different localities, making it difficult to interpret as a consistent and planned activity, and in many cases difficult to assert that the butchering was carried out by Neanderthals themselves, and not early Modern Humans.

In a paper published in the journal Scientific Reports on 6 July 2016, a team of scientists led by Hélène Rougier of the Department of Anthropology at California State University, Northridge describe a series of Neanderthal remains from the Late Pleistocene Goyet Cave System in Belgium.

The Goyet Cave System was first excavated in 1868, with further  excavations in the early twentieth century and 1990s. Archaeological material comes from a number of layers in the Troisième Caverne (Third Cave), which has produced artifacts assigned to the Mousterian (a culture considered to exclusively Neanderthal), the Lincombian-Ranisian-Jerzmanowician (which may have been made by late Neanderthals or early Modern Humans), the Aurignacian, the Gravettian and the Magdalenian (Modern Human cultures from the Late Pleistocene and Early Holocene). Early excavations at the site were not carried out to modern standards, but it is thought that the Mousterian comes from several layers and indicates several separate periods of occupation.

As well as artifacts Goyet has yielded 283 bones and teeth identified as Human, including 96 bones and three teeth considered to be of Neanderthal origin, as well as a large volume of bones and teeth of non-Human origin. Rouger et al. carried out carbon dating on 10 of these Neanderthal specimens, yielding dates of 40-45 000 years before the present, relatively young by Neanderthal standards, but to old to be of Modern Human origin. A DNA analysis was also carried out of fifteen sets of the remains, the results of which suggests that the individuals were closely related to other late Pleistocene Neanderthals, including those from the Neander Valley in Germany, El Sidrón in Spain and Vindija in Croatia.

Neandertal remains from the Troisième caverne of Goyet (Belgium). * Designates the specimens that have been directly dated. Scale bar is 3 cm. Rouger et al. (2016).

All of the Neanderthal remains were highly fragmentary (no complete bones were present), with the majority coming from either long limb bones or the cranium. Of the 96 bone fragments, 47 could be refitted to other fragments, suggesting they represent a fairly low number of individuals. Roughly half of the Neanderthal bones showed signs of butchering with stone tools, including marks consistent with defleshing (cutting meat from the skeleton) and dismemberment (cutting the skeleton into smaller, more manageable pieces). Four of the bones, a femur and three tibias, show signs of having been used to retouch stone tools.

Retouching marks (b1,b2) and cutmarks (c1,c2) present on the Goyet Neandertal bones (example of femur III). (a) femur III in anterior view; (b1,c1) close-up photos; (b2,c2) images obtained using a minidome. Rouger et al. (2016).

Since these skeletons date from considerably before the occupation of northern Europe by Modern Humans, the possibility of butchery by Modern Humans can be discounted, providing clear evidence for the practise of cannibalism amongst a Late Pleistocene Neanderthal population in northern Europe for the first time. The bones appear to have been cut while the bodies were still fresh, suggesting that the people making the cuts would have known that they were dismembering other people rather than animals, but whether this was a ritualised activity, or an activity carried out for strictly pragmatic reasons cannot be asserted upon the available evidence.

Four other sites within 250 km of Goyet have yielded Neanderthal remains, none of which provide any evidence of funeral behaviour. Walou Cave and Trou de l’Abîme in Belgium have produced only loose teeth while Feldhofer in Germany has produced a series of Neanderthal remains associated with Keilmesser technologies; an older Neanderthal technology not found at Goyet, which suggests an age of over 70 000 years. Interestingly one of the Feldhofer skeletons has marks interpreted as cut marks, though this skeleton has the long bones of its limbs intact, suggesting that butchery was not the motive for these cuts. The final site, Spy in Belgium, has produced items of the Lincombian-Ranisian-Jerzmanowician technology, along with two adult skeletons. However the more intact of these shows signs of having been buried in a contracted position, and the remains appear to have been buried rapidly, suggesting that they may have died and been burried as a result of some natural event, without any input from either other Neanderthals or early Modern Humans.

See also...

http://sciencythoughts.blogspot.co.uk/2015/09/neanderthal-dna-from-37-000-42-000.htmlNeanderthal DNA from a 37 000-42 000 modern Human jaw from Romania.     Neanderthals first appeared in Europe around 300 000 years ago and were replaced by anatomically modern Humans between 45 000 and 35 000 years ago. Genetic studies if modern Human populations show that almost all non-Africans have traces


Early and Middle Pleistocene Human remains are extremely rare in northern Europe, having to date...
Ritual or symbolic behavior is generally taken as a sign of cognitive levels comparable to those of modern humans by palaeoanthropologists studying ancient...
Follow Sciency Thoughts on Facebook.

Saturday, 19 March 2016

Identifying Archaic Human DNA in gene sequences from modern Melanesians.

Modern DNA recovery techniques have allowed scientists to recover genetic sequences from a number of Neanderthal individuals (members of a fairly well known Archaic Human population found in Europe and West Asia before about 40 000 years ago) as well as some Denisovans (members of a poorly understood Archaic Human population found in Central Asia before about 50 000 years ago). This has led to the discovery of genetic material derived from these ancient populations within many modern Human groups, and, more recently, attempts to determine what genes preserved from Archaic Human groups might contribute to modern Humans. Such studies have found evidence of Neanderthal DNA in all non-African modern populations, while Denisovan DNA has been found only in Melanesian populations.

In a paper published in the journal Science on 17 March 2016, a team of scientists led by Benjamin Vernot of the Department of Genome Sciences at the University of Washington present the results of a study of the genomes of 1523 modern Humans from around the globe, including 35 Melanesians from Papua New Guinea and the Bismarck Archipelago, and attempt to analyse the preserved DNA sequences in these individuals.

Melanesian genomic variation in a global context. (A) Locations of the 159 geographically diverse populations studied. Information on the Melanesian individuals sequenced (blue triangles) is shown in the inset. Vernot et al. (2016).

All Humans, including Archaic populations such as Neanderthals and Denisovans, share almost all of their DNA. In this context 'Neanderthal DNA' or 'Devisovan DNA' refers to variable alleles found in the ancient population, but not in modern African populations not thought to share any genetic heritage since the ancestors of these groups left Africa in the Middle Pleistocene.  An allele is one of two or more different genes that can occur at a gene locus, for example different alleles for blue or brown eyes may be found at the gene locus for eye colour in Humans

The highest proportion of Neanderthal DNA was found in modern East Asians, with Europeans having a slightly lower level and South Asians a slightly lower level still. The proportion of Neanderthal found in Melanesians was much lower (roughly half) than that found in any of these groups, but still much larger than the highest found in any African group (people from the Western Division of The Gambia).

Only Melanesians were found to have significant levels of Denisovan DNA (trace amounts were found in samples from East and South Asians), who had slightly higher levels of Denisovan DNA than they did Neanderthal DNA - though the combined level of Denisovan and Neanderthal DNA found in Melanesians was slightly higher than that found in East Asians.

The areas of DNA from Archaic populations were not random, but rather similar sections of Archaic DNA appear to have been retained in different populations. This suggests that some Archaic DNA alleles were strongly selected against in the ancestors of modern humans, while others appear to have been more useful. In particular Vernot et al. note that a section of Archaic DNA alleles in an area of chromosome 7 associated with language skills has been lost in all modern Humans. Conversely a number of Archaic alleles associated with the metabolism have been retained in different modern Human populations, including genes associated with glucose metabolism and lipid processing. A number of genes associated with the immune system have also been conserved.

See also...

http://sciencythoughts.blogspot.co.uk/2015/12/genetic-data-from-two-new-denisovan.htmlGenetic data from two new Denisovan individuals.                                                                 The Denisonvans were an ancient people who are known from only a single archaeological site, a cave...
http://sciencythoughts.blogspot.co.uk/2015/09/neanderthal-dna-from-37-000-42-000.htmlNeanderthal DNA from a 37 000-42 000 modern Human jaw from Romania.     Neanderthals first appeared in Europe around 300 000 years ago and were replaced by anatomically modern Humans between 45 000 and 35 000 years ago. Genetic studies if modern Human populations show that almost all non-Africans have traces of Neanderthal...
http://sciencythoughts.blogspot.co.uk/2014/10/human-remains-from-middle-pleistocene.htmlHuman remains from the Middle Pleistocene of Normandy.                                                                Early and Middle Pleistocene Human remains are extremely rare in northern Europe, having to date...
Follow Sciency Thoughts on Facebook.
 

Friday, 4 December 2015

Genetic data from two new Denisovan individuals.


The Denisonvans were an ancient people who are known from only a single archaeological site, a cave in the Altai Mountains of southern Siberia. The group were identified as being genetically distinct after scientists studied genetic data from the fingerbone of a child found in 2008 and thought to have lived at least 50 000 years ago.  Mitochondrial DNA from this individual suggests that the most recent female direct ancestor that this individual shared with Neanderthals and Modern Humans that lived about a million years ago. This was possible because mitochondrial DNA is found in the mitochondria, organelles outside the cell nucleus, it is passed directly from mother to child without being sexually recombined each generation, enabling precise estimations of when individuals shared common ancestors, at least through the female line (it is also possible to trace direct ancestry through the male line, using DNA from the Y chromosome, which is passed directly from father to son without sexual recombination). However analysis of the main nuclear DNA of the individual (DNA which is found in the nucleus of the cell and which is recombined with each generation), suggests that he or she shared a more recent common ancestor with Neanderthals (though clearly from a genetically distinct and separate population), and came from a population that had supplied about 5% of the DNA found in modern Melanesian populations and about 0.2% of the DNA found in modern East Asian and Native American populations.

In 2010 a foot bone was recovered from the same site, thought to be from an individual that lived in the area at approximately the same time (i.e. to within a few thousand years). However genetic material recovered from this specimen revealed it to be of Neanderthal rather than Denisovan origin.

In a paper published in the Proceedings of the National Academy of Sciences of the United States of America on 16 November 2015, a team of scientists led by Susanna Sawyer and Gabriel Renaud of the Department of Evolutionary Genetics at the Max Planck Institute for Evolutionary Anthropology describe the results of a study of two molars found in the Denisova Cave in 2000 and 2010.

The molars are distinctly larger and flatter than anything seen in Modern Humans or Neanderthals, more similar to those seen in Pliocene Hominids. Only two comparable teeth have been found at Late Pleistocene sites elsewhere, one from Romania and one from Uzbekistan. Both are heavily worn, and were most likely third molars.

Occlusal surfaces of the Denisova 4 and Denisova 8 molars and third molars of a Neandertal and a present-day European. Sawyer & Renaud (2015).

Radiocarbon dating of the layers from which the teeth were recovered suggests that they were deposited more than 50 000 years ago and about 48 600 years ago. A molecular clock approach (which measures the rate of mutation on non-sequencing DNA), suggests that the oldest individual may have lived as long as 60 000 years before the youngest. This suggests that Denisovans were in the area and using the cave for a considerable period of time, possibly intermittently with the cave being inhabited by Neanderthals at other times.

Genetic comparison placed the teeth in a group along with the fingerbone, suggesting that the Denisovans do form a separate population, distinct from either Neanderthals or Modern Humans. However the study showed more genetic diversity among the three Denisovan individuals (who were all buried in the same cave) than among all known Neanderthals sequenced (who come from a large area of Europe and West Asia), though this diversity was still considerably lower than found in modern Europeans.

The study again found the Denisovans shared more genetic material with Neanderthals than Modern Humans, but that this was probably the result of interbreeding, with the ancestors of the Denisovans having diverged from the common ancestor of Neanderthals and Modern Humans long before these two groups split, and all Modern Humans having shared a common ancestor more recently than the split with Neanderthals.

See also...

http://sciencythoughts.blogspot.co.uk/2015/09/neanderthal-dna-from-37-000-42-000.htmlNeanderthal DNA from a 37 000-42 000 modern Human jaw from Romania.     Neanderthals first appeared in Europe around 300 000 years ago and were replaced by anatomically modern Humans between 45 000 and 35 000 years ago. Genetic studies if modern Human populations show that almost all non-Africans have traces of Neanderthal...
http://sciencythoughts.blogspot.co.uk/2015/05/rainforest-resources-in-diet-of-late.htmlRainforest resources in the diet of Late Pleistocene Humans from Sri Lanka.              Early modern Humans expanded from Africa around the globe in the Late Pleistocene, from about 125 000 years ago onwards. In doing so they adapted to a wide variety of environments, though some habitats...
http://sciencythoughts.blogspot.co.uk/2015/01/hominin-teeth-from-middle-pleistocene.htmlHominin teeth from the Middle Pleistocene of Anhui Province, China.                                     In the 1970s and 1980s a collection of Hominin bones and teeth were unearthed in the Longtan Cave at Hexian in Anhui Province in eastern China. The bones of these remains have been extensively studied, and assigned to the species Homo erectus, though...

Follow Sciency Thoughts on Facebook.