Tag Archives: Anatomically modern human

Neanderthal development

Despite the lingering public image that Neanderthals were not as bright as fully modern humans some had significantly larger brains than we do, albeit with most of the difference being in the rear part of the brain region. So they may have had different powers, such as enhanced vision and awareness of position (proprioception). Because there are few cranial fossils of immature Neanderthals and, for them, little evidence of ages, not much is known about how they developed from birth. A common assumption has been that because their brain was larger post-natal development much have been faster than in modern humans. Set against our slow post-natal development and the faster pace in chimpanzees this assumption has been used in support of limited Neanderthal cognitive abilities.

The El Sidron Neanderthal boy, including a reconstruction of his skull and brain cast. (credit: Antonio Rosas, Museo Nacional de Ciencias Naturales, Madrid, Spain)

The El Sidron cave in Asturias region of northern Spain has yielded fossil remains of a dozen Neanderthals dated at between 49 and 37 ka, the time when anatomically modern humans were also present in Europe. They are among the best studied examples of this human group. Three were of boys, the best preserved of whom is estimated to have died at 7.7 years old from analysis of his dental development (Rosas, A. and 10 others 2017. The growth pattern of Neandertals, reconstructed from a juvenile skeleton from El Sidrón (Spain). Science, v. 357, p. 1282-1287; doi:10.1126/science.aan6463) Analysis of signs of the maturation stage that he had reached, including that of his brain, show no fundamental difference from modern human juveniles in his overall pace of growth. Other workers have found that a similarly aged Homo erectus boy from Kenya had indeed developed more quickly than modern human juveniles.

It’s not much to go on, but the El Sidron boy supports the view that Neanderthals were not much different from us.

You can find more information on migration of modern humans here.

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Early modern humans in Sumatra before the Toba eruption

In late July 2017 news emerged that modern humans first reached Australia at least 65 thousand years ago. Confirming that the date of departure from Africa to end up in SE Asia and Australasia was  considerable earlier than previously believed, deposits in Sumatra that contain remains of early Home sapiens have yielded even older ages (Westaway, K.E. and 22 others 2017. An early modern human presence in Sumatra 73,000–63,000 years ago. Nature v. 548 online; doi:10.1038/nature23452). This resulted from a re-examination of material from the Padang Caves first excavated more than a century ago by Eugène Dubois, famous for his discovery in Java of the first H. erectus remains. A richly fossiliferous breccia in the Lida Ajer cave yielded a fauna characteristic of a rainforest biome and included two teeth that Dubois considered to be human. Several later palaeontologists confirmed his identification as have hominin specialists in the present Australian-Indonesian-American-British-Dutch-German team. The fossil assemblage has long suggested great antiquity for the site, but only now has it been dated precisely. The dating employed three methods: optically stimulated luminescence dating of quartz grains from the breccia (85±25 to 62±5  ka); uranium-series dating of speleothem including fragments of hollow ‘soda-straw’ stalactites(84±1 to 71±7 ka); uranium-series dating of gibbon and orangutan teeth found together with the human teeth (86±13 to 76±7 ka). Statistical analysis of the age data suggests 73 to 63 ka for the fauna, with a maximum age for deposition of the breccia of 84±1 ka.

Satellite image of Lake Toba, the site of a VE...

Satellite image of Lake Toba in NW Sumatra (at centre), the site of the largest volcanic eruption during the history of human evolution ~71,600 years ago (credit: Wikipedia)

Stone tools which may have been carried by anatomically modern humans into the area have previously been used to suggest a minimum date of the arrival of migrants, though they may have been carried by ­H. erectus. Remarkably, such tools have been found beneath a thick bed of volcanic ash found throughout southern Asia and in Indian Ocean sediment cores. This has been dated at 71.6 ka and represents the explosive collapse of the caldera now containing Lake Toba in NW Sumatra that was the largest volcanic event in the entire history of the genus Homo. The new age data from Lida Ajer suggests that modern humans were present in its vicinty before the eruption, a view also supported by ‘molecular-clock’ dating of the range of mitochondrial DNA carried by living SE Asian people (79 to 75 ka). So, despite the stupendous magnitude of the Toba eruption is seems likely that some of the migrants survived.  Together with the dating of the earliest Australians the Sumatran evidence is at odds with the view, widely held by palaeoanthropologists, that the ‘Out of Africa’ exodus began by crossing the Straits of Bab el Mandab between 74 and 58 ka when global sea-level fell markedly during marine oxygen-isotope Stage 4 (MIS4). A problem with that hypothesis has been that climatic and ecological conditions in southern Asia during MIS4 were unfavourable. But is seems that modern humans were already there and capable of adapting to both the climate shift and to the devastation undoubtedly caused by Toba.

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.