Species of ancient humans and the extinct relatives of our ancestors are typically described from a limited number of fossils. More than 1500 fossils representing at least 15 individuals of this species were unearthed from the Rising Star cave system in South Africa between 20.
Found deep underground in the Dinaledi Chamber, the H.
The remains are exceptionally well preserved and represent the largest collection of fossils from a single primitive hominin species ever discovered in Africa. naledi fossils occur without a direct association with non-hominin macrofossil remains, and are found deep inside the difficult to access U. The Dinaledi Chamber is characterised by a sedimentary environment that is geochemically and sedimentologically distinct from the rest of the Rising Star Cave (Dirks et al., 2015), and the fossiliferous deposit it contains is profoundly different from other known hominin-bearing cave assemblages in the Co H (e.g., Reynolds and Kibii, 2011; Dirks et al., 2010; Pickering et al., 2011a; Dirks and Berger, 2013; Bruxelles et al., 2014).
The fossils occur as a dense bone accumulation in mostly unconsolidated muddy sediment that largely originated from within the cave through weathering of the dolomite host rock (Dirks et al., 2015). In this paper we present results of uranium-thorium (U-Th) disequilibrium, electron spin resonance (ESR), radiocarbon, and optically stimulated luminescence (OSL) dating in combination with palaeomagnetic analyses, to provide ages for the fossils and surrounding deposits in the Dinaledi Chamber, and build upon the geological context described in Dirks et al. Dates acquired via U-Th and ESR techniques were obtained using a double blind approach for each technique to ensure robust, reproducible results, with each laboratory using their own analytical and computational approach.
Approaches taken by each laboratory that contributed to this paper are described in detail in the methodology section. naledi and early Homo) and associated mammals, reptiles, and birds (e.g., Vrba, 1975, 1995; Brain, 1993; Tobias, 2000; Berger et al., 2010, 2015).
We consider the maximum age scenario to more closely reflect conditions in the cave, and therefore, the true age of the fossils.This result has been confirmed independently by dating three H.naledi teeth with combined U-series and electron spin resonance (US-ESR) dating.By combining the US-ESR maximum age estimate obtained from the teeth, with the U-Th age for the oldest flowstone overlying Homo naledi fossils, we have constrained the depositional age of Homo naledi to a period between 236 ka and 335 ka.These age results demonstrate that a morphologically primitive hominin, Homo naledi, survived into the later parts of the Pleistocene in Africa, and indicate a much younger age for the Homo naledi fossils than have previously been hypothesized based on their morphology.