Human and cervid osseous materials used for barbed point manufacture in Mesolithic Doggerland

Barbed bone points originally deposited in Doggerland are regularly collected from the shores of the Netherlands. Their typology and direct 14C dating suggest they are of Mesolithic age. However, the species of which the barbed points were made cannot be identified based on morphological criteria. The bones used to produce the barbed points have been intensively modified during manufacture, use, and post-depositional processes. Here, we taxonomically assess ten barbed points found on the Dutch shore using mass spectrometry and collagen peptide mass fingerprinting alongside newly acquired 14C ages and δ13C and δ15N measurements. Our results demonstrate a sufficient preservation of unmodified collagen for mass spectrometry-based taxonomic identifications of bone and antler artefacts which have been preserved in marine environments since the beginning of the Holocene. We show that Homo sapiens bones as well as Cervus elaphus bones and antlers were transformed into barbed points. The 14C dating of nine barbed points yielded uncalibrated ages between 9.5 and 7.3 ka 14C BP. The δ13C and δ15N values of the seven cervid bone points fall within the range of herbivores, recovered from the North Sea, whereas the two human bone points indicate a freshwater and/or terrestrial fauna diet. The wide-scale application of ZooMS is a critical next step towards revealing the selection of species for osseous-tool manufacture in the context of Mesolithic Doggerland, but also further afield. The selection of Cervus elaphus and human bone for manufacturing barbed points in Mesolithic Doggerland is unlikely to have been opportunistic and instead seems to be strategic in nature. Further, the occurrence of Homo sapiens and Cervus elaphus bones in our random and limited dataset suggests that the selection of these species for barbed point production was non-random and subject to specific criteria. By highlighting the transformation of human bones into barbed points – possibly used as weapons – our study provides additional evidence for the complex manipulation of human remains during the Mesolithic, now also evidenced in Doggerland

Revised age and stratigraphy of the classic Homo erectus-bearing succession at Trinil (Java, Indonesia)

Obtaining accurate age control for fossils found on Java (Indonesia) has been and remains challenging due to geochronologic and stratigraphic uncertainties. In the 1890s, Dubois excavated numerous faunal fossils—including the first remains of Homo erectus—in sediments exposed along the Solo River at Trinil. Since then, various, and often contradictory age estimates have been proposed for the Trinil site and its fossils. However, the age of the fossil-bearing layers and the fossil assemblage remains inconclusive. This study constructs a chronostratigraphic framework for the Trinil site by documenting new stratigraphic sections and test pits, and by applying 40Ar/39Ar, paleomagnetic, and luminescence (pIRIR290) dating methods. Our study identifies two distinct, highly fossiliferous channel fills at the Trinil site. The stratigraphically lower Bone-Bearing Channel 1 (BBC-1) dates to 830–773 ka, while Bone-Bearing Channel 2 (BBC-2) is substantially younger with a maximum age of 450 ± 110 ka and an inferred minimum age of 430 ± 50 ka. Furthermore, significantly younger T2 terrace deposits are present at similar low elevations as BBC-1 and BBC-2. Our results demonstrate the presence of Early and Middle Pleistocene, and potentially even late Middle to Late Pleistocene fossiliferous sediments within the historical excavation area, suggesting that Dubois excavated fossils from at least three highly fossiliferous units with different ages. Moreover, evidence for reworking suggests that material found in the fossil-rich strata may originate from older deposits, introducing an additional source of temporal heterogeneity in the Trinil fossil assemblage. This challenges the current assumption that the Trinil H.K. fauna –which includes Homo erectus-is a homogeneous biostratigraphic unit. Furthermore, this scenario might explain why the Trinil skullcap collected by Dubois is tentatively grouped with Homo erectus fossils from Early Pleistocene sediments at Sangiran, while Trinil Femur I shares affinities with hominin fossils of Late Pleistocene age

Inbreeding, Allee effects and stochasticity might be sufficient to account for Neanderthal extinction

The replacement of Neanderthals by Anatomically Modern Humans has typically been attributed to environmental pressure or a superiority of modern humans with respect to competition for resources. Here we present two independent models that suggest that no such heatedly debated factors might be needed to account for the demise of Neanderthals. Starting from the observation that Neanderthal populations already were small before the arrival of modern humans, the models implement three factors that conservation biology identifies as critical for a small population’s persistence, namely inbreeding, Allee effects and stochasticity. Our results indicate that the disappearance of Neanderthals might have resided in the smallness of their population(s) alone: even if they had been identical to modern humans in their cognitive, social and cultural traits, and even in the absence of inter-specific competition, Neanderthals faced a considerable risk of extinction. Furthermore, we suggest that if modern humans contributed to the demise of Neanderthals, that contribution might have had nothing to do with resource competition, but rather with how the incoming populations geographically restructured the resident populations, in a way that reinforced Allee effects, and the effects of inbreeding and stochasticity

Inbreeding, Allee effects and stochasticity might be sufficient to account for Neanderthal extinction

\u3cp\u3eThe replacement of Neanderthals by Anatomically Modern Humans has typically been attributed to environmental pressure or a superiority of modern humans with respect to competition for resources. Here we present two independent models that suggest that no such heatedly debated factors might be needed to account for the demise of Neanderthals. Starting from the observation that Neanderthal populations already were small before the arrival of modern humans, the models implement three factors that conservation biology identifies as critical for a small population’s persistence, namely inbreeding, Allee effects and stochasticity. Our results indicate that the disappearance of Neanderthals might have resided in the smallness of their population(s) alone: even if they had been identical to modern humans in their cognitive, social and cultural traits, and even in the absence of inter-specific competition, Neanderthals faced a considerable risk of extinction. Furthermore, we suggest that if modern humans contributed to the demise of Neanderthals, that contribution might have had nothing to do with resource competition, but rather with how the incoming populations geographically restructured the resident populations, in a way that reinforced Allee effects, and the effects of inbreeding and stochasticity.\u3c/p\u3

Improving the chronological framework for Laugerie-Haute Ouest (Dordogne, France)

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