First dating study of the new species 'Homo naledi’
Yesterday 9th of May 2017, the journal eLife published the results of a multidisciplinary dating work revealing for the first time that Homo naledi lived between 230,000 and 330,000 years ago in South Africa. Based on the combination of a wide range of methods such as Luminescence, Palaeomagnetism, Electronic Spin Resonance (ESR) and Uranium-Thorium Series, this work enables for the first time to obtain a reliable date for this new species discovered and published by the paleoanthropologist Lee R. Berger and his team in 2015. This new scientific study led by Prof. Paul Dirks from James Cook University involved many researchers from several institutions in Australia, USA, South Africa and Spain, including the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) in Burgos. Since the announcement of its discovery in September 2015, several hypotheses have been formulated on the age of H. naledi, based mainly on the archaic morphology of the fossil remains. One of the hypotheses with more weight proposed a very old age, up to 2 million years. However, the new dating undoubtedly points towards a much more recent chronology. The central point of the work is the direct dating of several human teeth with the ESR method, since it is one of the very few, if not the only one, methods that can be used for fossil remains older than 50,000 years, the maximum time range covered by the Radiocarbon dating method. Part of this dating work was carried out by Dr Mathieu Duval, a former member of CENIEH and now at Griffith University (Brisbane, Australia), within the framework of the European research project Marie Curie IOF HR_ESR (Project ID: 626474), and in collaboration with Prof. Rainer Grün, member of the Australian Research Centre for Human Evolution (ARCHE) at Griffith University. Aspects of this dating study were also covered by an Australian Research Council Future Fellowship (FT150100215) granted to M. Duval. In order to obtain a reliable age result without destroying the human teeth, the authors had had to use a special analytical procedure that consists in measuring enamel fragments by ESR in combination with high resolution Laser Ablation ICP-MS U-series analyses, which was one of the research issues specifically investigated within the framework of the HR_ESR research project. The obtained data allow locating H. naledi in a position much more advanced than initially expected in the human evolutionary tree, whereas it seems to be a primitive species within the genus Homo (and in spite of sharing derived features with archaic and modern humans). By providing ages that fall in the late Middle Pleistocene, this new dating study shows that H. naledi lived at the same time, and in the same place, as modern humans. These new results combined with those recently obtained for the 'Hobbits' in Flores or the Denisovans in Russia, demonstrate that the human lineage is much more complex than thought only a few years ago. More information @ https://elifesciences.org/content/6/e24231 Source: based on media reports.
Keywords
Human evolution, ESR dating, Homo naledi, Quaternary Geochronology
Countries
Spain
