Friday, May 15, 2020

Denisova Cave - First Evidence of the Denisovan People

Denisova Cave is a rockshelter with important Middle Paleolithic and Upper Paleolithic occupations. Located in the northwestern Altai Mountains some 6 km from the village of Chernyi Anui, the site shows human occupation from the Middle Paleolithic to the Late Middle Paleolithic, beginning ~200,000 years ago. Most importantly, the cave is where the first evidence was discovered of Denisovans, a newly identified species of human being. Key Takeaways: Denisova Cave Denisova Cave is a rockshelter in the Altai Mountains of Siberia.First location where new hominid species Denisovan was identified, reported in 2011Human occupations include Neanderthals, Denisovans, and one individual of Neanderthal and Denisovan parentageCultural remains are similar to that found at Mousterian (Neanderthal) Upper Paleolithic sitesOccupations date between 200,000 and 50,000 years ago The cave, formed from Silurian sandstone, is ~28 meters above the right bank of the Anui River near its headwaters. It consists of several short galleries extending out from a central chamber, with a total cave area of some 270 sq. m. The central chamber measures 9x11 meters, with a high arched ceiling. Pleistocene Occupations at Denisova Cave Excavations in the central chamber at Denisova have revealed 13 Pleistocene occupations between 30,000 and ~125,000 years bp. The chronological dates are by and large radiothermalluminescence dates (RTL) taken on sediments, with the exception of Strata 9 and 11, which have a handful of radiocarbon dates on charcoal. The RTL dates on the lowest are considered unlikely, probably only in the range of 125,000 years ago. Stratum 9, Upper Paleolithic (UP), Mousterian and Levallois, ~46,000 (OIS-2)Stratum 11, Initial Upper Paleolithic, Altai Mousterian, ~29,200-48,650 BP (OIS-3)Strata 20-12, Later Middle Paleolithic Levallois, ~69,000-155,000 BPStrata 21 and 22, Initial Middle Paleolithic Levallois, Mousterian, ~171,000-182,000 BP (OIS-5) Climate data derived from palynology (pollen) and faunal taxa (animal bone) suggests that the oldest occupations were located in birch and pine forests, with some large treeless areas in higher elevations. The following periods fluctuated considerably, but the coldest temperatures occurred just before the Last Glacial Maximum, ~30,000 years ago, when a steppe environment was established. Hominins Hominid remains recovered from the cave include four Denisovans, two Neanderthals, and one individual, Denisova 11, represented by a fragment of a long bone, that genetic investigations indicate was the child of a Neanderthal mother and a Denisovan father. The individual was at least 13 years old at death: and her genetic makeup indicates that her father, too, was the result of sexual congress between a Neanderthal and a Denisovan. The earliest Denisovan in the cave lived between 122.7–194.4 thousand years ago (kya); another lived between 105.6 and 136.4 kya; and two lived between 51.6 and 76.2 kya. Neanderthals lived between 90.0 and 147.3 kya; and the Denisovan/Neanderthal child lived between 79.3 and 118.1 kya. The most recent date is not that different from the nearby Ust Ishim site, an Initial Upper Paleolithic site dated between 45–48 kya, leaving the possibility that Ust Ishim may have been a Denisovan occupation. Denisova Cave Upper Paleolithic Although the site is for the most part stratigraphically quite intact, unfortunately, a major discontinuity separates the two UP levels 9 and 11, and the contact between them is significantly disturbed, making it difficult to securely separate the dates of the artifacts in them. Denisova is the type site for what Russian archaeologists have called the Denisova variant of Altai Mousterian, belonging to the Initial Upper Paleolithic period. Stone tools in this technology exhibit use of the parallel reduction strategy for cores, large numbers of laminar blanks and tools fashioned on large blades. Radial and parallel cores, limited numbers of true blades and a diverse series of ​racloirs are also identified in the stone tool assemblages. Several remarkable art objects have been recovered within the Altai Mousterian layers of the cave, including decorative objects of bone, mammoth tusk, animal teeth, fossilized ostrich egg shell and mollusk shell. Two fragments of a stone bracelet made of drilled  worked and polished dark green chloritolite was discovered in these UP levels at Denisova. A set of bone tools including small needles with drilled eyes, awls and pendants, and a collection of cylindrical bone beads has also been found in the Upper Paleolithic deposits. Denisova contains the earliest evidence of eyed needle manufacture in Siberia. Denisova and Archaeology Denisova Cave was discovered over a century ago, but its Pleistocene deposits were not recognized until 1977. Since then, extensive excavations by the Russian Academy of Sciences at Denisova and nearby sites of Ust-Karakol, Kara-Bom, Anuy 2 and Okladnikov have recorded considerable evidence about the Siberian Middle and Upper Paleolithic. Selected Sources Douka, Katerina, et al. Age Estimates for Hominin Fossils and the Onset of the Upper Palaeolithic at Denisova Cave. Nature 565.7741 (2019): 640–44. Print.Krause, Johannes , et al. The Complete Mitochondrial DNA Genome of an Unknown Hominin from Southern Siberia. Nature 464.7290 (2010): 894–97. Print.Martinà ³n-Torres, Marà ­a, Robin Dennell, and Josà © Marà ­a Bermà ºdez de Castro. The Denisova Hominin Need Not Be an out of Africa Story. Journal of Human Evolution 60.2 (2011): 251–55. Print.Mednikova, M. B. A Proximal Pedal Phalanx of a Paleolithic Hominin from Denisova Cave, Altai. Archaeology, Ethnology and Anthropology of Eurasia 39.1 (2011): 129–38. Print.Reich, David, et al. Genetic History of an Archaic Hominin Group from Denisova Cave in Siberia. Nature 468 (2010): 1053–60. Print.Slon, Viviane, et al. The Genome of the Offspring of a Neanderthal Mother and a Denisovan Father. Nature 561.7721 (2018): 113–16. Print.Slon, Viviane, et al. A Fourth Denisovan Individual. Science Advances 3.7 (2017): e1700186. Print.

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