Hominins performed a variety of carcass processing activities at two sites in the Olduvai Gorge, Tanzania
In this paper, pounded objects from excavations at HWK EE and EF-HR are presented, which are studied from macro and microscopic perspectives. Analysis of HWK EE revealed one of the largest collections of percussive objects from Olduvai Gorge, while excavations at EF-HR have allowed a team of archaeologists ffom University College London to recover a much wider collection of percussive tools than previously recorded. Differences are observed between the two localities. At the Acheulean site of EF-HR, percussive tools were predominantly used in the production of flakes and large cutting tools (LCTs). At the Oldowan site of HWK EE, the tool repertoire probably related to a wider range of activities, including bone breaking and bipolar knapping. Comparison of these two assemblages, potentially produced by different hominin species, helps provide a wider picture of pounding activities during the Oldowan-Acheulean transition at Olduvai Gorge.
Publication date: 21 November 2017
Migratory activity is a critical factor in shaping processes of biological and cultural change through time. We introduce a method to estimate changes in underlying migratory activity that can be applied to genetic, morphological, or cultural data and is well-suited to samples that are sparsely distributed in space and through time. By applying this method to ancient genome data, we infer a number of changes in human mobility in Western Eurasia, including higher mobility in pre- than post-Last Glacial Maximum hunter–gatherers, and oscillations in Holocene mobility with peaks centering on the Neolithic transition and the beginnings of the Bronze Age and the Late Iron Age. A team of scientists from University College London, including Liisa Loog, Mirna Kovacevic and Mark G. Thomas led to this research.
Publication date: 21 November 2017
Previous dating of the Vi-207 and Vi-208 Neanderthal remains from Vindija Cave (Croatia) led to the suggestion that Neanderthals survived there as recently as 28,000–29,000 B.P. Subsequent dating yielded older dates, interpreted as ages of at least ∼32,500 B.P. We have redated these same specimens using an approach based on the extraction of the amino acid hydroxyproline, using preparative high-performance liquid chromatography (Prep-HPLC). This method is more efficient in eliminating modern contamination in the bone collagen. The revised dates are older than 40,000 B.P., suggesting the Vindija Neanderthals did not live more recently than others across Europe, and probably predate the arrival of anatomically modern humans in Eastern Europe. We applied zooarchaeology by mass spectrometry (ZooMS) to find additional hominin remains. We identified one bone that is Neanderthal, based on its mitochondrial DNA, and dated it directly to 46,200 ± 1,500 B.P. We also attempted to date six early Upper Paleolithic bone points from stratigraphic units G1, Fd/d+G1 and Fd/d, Fd. One bone artifact gave a date of 29,500 ± 400 B.P., while the remainder yielded no collagen. We additionally dated animal bone samples from units G1 and G1–G3. These dates suggest a co-occurrence of early Upper Paleolithic osseous artifacts, particularly split-based points, alongside the remains of Neanderthals is a result of postdepositional mixing, rather than an association between the two groups, although more work is required to show this definitively.
Publication date: 24 September 2017
Ontogenetic studies help us understand the processes of evolutionary change but no one single system defines the ontogeny of an individual. Previous studies of Neanderthals have focused more on the pace than the pattern of growth. Thirteen genetically related Neanderthals have been recovered from the 49 ky site of El Sidrón, Asturias, Spain, including a new juvenile partial skeleton for which there is associated dental, cranial and postcranial material. This individual provides the first opportunity to establish chronological age using dental histology with which to compare growth across the skeleton. A team of scientists based in Madrid (led by CSIC's Antonio Rosas and Luis Ríos) and at UCL (CBD's Christopher Dean) and QMUL (Institute of Dentistry's Helen Liversidge) have together explored the development of this specimen. Maturation of almost all cranio-dental and postcranial elements falls within the expected range of modern humans of this age. However, at around 7.7 years of age, the most striking difference in growth between Neanderthals and modern humans occurs in the vertebral column. The atlas and the mid-thoracic vertebral bodies and neural arches remain unfused and at a stage more typical of a modern 5-6 year old child and so appearing to take longer to establish the larger more capacious adult morphology of the Neanderthal chest. Furthermore, a number of endocranial features suggest that at the time of death brain growth was not yet completed. The implication of these findings is that Neanderthal brain growth and somatic growth must have incorporated changes in both rate and timing that differ slightly from modern humans today in order to achieve their adult size.
Publication date: 22 September 2017
This paper investigates the formation history of the early Acheulean site of EF-HR (Olduvai Gorge, Tanzania). The study focuses on the main site (T2-Main Trench) and adjacent trenches (T12 and T9), which constitute the bulk of the archaeological assemblage recently excavated in the EF-HR area (de la Torre et al., submitted). Site formation processes are investigated through taphonomic proxies and spatial analysis, and consider artifact features, orientation patterns, and topographic data retrieved during archaeological excavation. This enables an assessment of the impact of natural agents on the assemblage and a discussion of the relevance of water disturbance in shaping the structure of the EF-HR archaeological record. The results indicate that fluvial action over the assemblage was significant, although it is likely that EF-HR still preserves areas marginally affected by water sorting and rearrangement. In summary, by applying a novel approach that combines a systematic analysis of artifact attributes with GIS spatial analysis of archaeological remains and topographic features, our study aims to provide a fresh look at the interaction of human and natural agents in the formation of Early Stone Age assemblages at Olduvai Gorge.
Publication date: 18 August 2017
Recent fossil finds have highlighted extensive morphological diversity within our genus, Homo, and the co-existence of a number of species. However, little is known about the evolutionary processes responsible for producing this diversity. Understanding the action of these processes can provide insight into how and why our lineage evolved and diversified. Here, cranial and mandibular variation are examined and diversification from the earliest emergence of our genus at 2.8 Ma until the Late Pleistocene (0.126–0.0117 Ma), using statistical tests developed from quantitative genetics theory to evaluate whether stochastic (genetic drift) versus non-stochastic (selection) processes were responsible for the observed variation. Results show that random processes can account for species diversification for most traits, including neurocranial diversification, and across all time periods. Where selection was found to shape diversification, we show that: 1) adaptation was important in the earliest migration of Homo out of Africa; 2) selection played a role in shaping mandibular and maxillary diversity among Homo groups, possibly due to dietary differences; and 3) Homo rudolfensis is adaptively different from other early Homo taxa, including the earliest known Homo specimen. These results show that genetic drift, and, likely, small population sizes were important factors shaping the evolution of Homo and many of its novel traits, but that selection played an essential role in driving adaptation to new contexts.
Publication date: 30 July 2017
Computer modelling suggests that cannibalism could have been a factor in the extinction of Homo neanderthalensis
After more than 100,000 years of evolutionary success in Western Eurasia, Neanderthals rapidly went extinct between 40,000 and 30,000 years ago, almost coinciding with the spread of Anatomically Modern Homo sapiens (AMHS) in Europe. Several scenarios relate their extinction to competition with AMHS, climatic changes during the last glacial period or a combination of both. Here we propose a much simpler scenario, in which the cannibalistic behaviour of Neanderthals may have played a major role in their eventual extinction. We show that this trait was selected as a common behaviour at moments of environmental or population stress. However, as soon as Neanderthals had to compete with another species that consumed the same resources (AMHS in this case) cannibalism had a negative impact, leading, in the end, to their extinction. To test this hypothesis, an agent-based model computer simulation was used. The model is simple, with only traits, behaviours and landscape features defined and with no attempt to re-create the exact landscape in which Neanderthals lived or their cultural characteristics. The basic agent of our system is a group of individuals that form a community. The most important state variable of the model is the location of the group, coupled with a defined home range and two additional factors: cannibalism and the chance of fission. The result of the simulation shows that cannibalistic behaviour is always selected when resources are scarce and clustered. However, when a non-cannibalistic species (late Pleistocene AMHS) is introduced into the same environment, the cannibalistic species retreats and the new species grows until it has reached the carrying capacity of the system. The cannibalistic populations that still survive are displaced from the richest areas, and live on the borders with arid zones, a situation which is remarkably similar to what we know about the end of the Neanderthals.
Publication date: 23 July 2017
Understanding demographic and evolutionary processes shaping human life history diversity depends on precise age estimations. Inferring age is a challenge in small-scale societies, and especially in those societies that do not follow a calendar year. This method opens possibilities in demographic and life history studies allowing cross-sectional data to be incorporated in cross-cultural comparisons and a better understanding of the adaptive importance of human life history variation. This research was conducted by a team of anthropologists and geneticists at the UCL Department of Anthropology and the UCL Genetics Institute
Publication date: 13 July 2017
Further evidence suggests that the EDJ can discriminate to the highest accuracy between different species of hominin
This study explores the morphological differences between the enamel–dentine junction (EDJ) of maxillary and mandibular molars of Neanderthals (n = 150) and recent modern humans (n = 106), and between an earlier Neanderthal sample (consisting of Pre-Eemian and Eemian Neanderthals dating to before 115 ka) and a later Neanderthal sample (consisting of Post-Eemian Neanderthals dating to after 115 ka). The EDJ was visualised by segmenting microtomographic scans of each molar. A geometric morphometric methodology compared the positioning of the dentine horns, the shape of the marginal ridge between the dentine horns, and the shape of the cervix. The palaeoanthropologists also examined the manifestation of non-metric traits at the EDJ including the crista obliqua, cusp 5, and post-paracone tubercle. Furthermore, the team report on additional morphological features including centrally placed dentine horn tips and twinned dentine horns. The results indicate that EDJ morphology can discriminate with a high degree of reliability between Neanderthals and recent modern humans at every molar position, and discriminate between the earlier and the later Neanderthal samples at every molar position, except for the M3 in shape space. The cervix in isolation can also discriminate between Neanderthals and recent modern humans, except at the M3 in form space, and is effective at discriminating between the earlier and the later Neanderthal samples, except at the M2/M2 in form space. In addition to demonstrating the taxonomic valence of the EDJ, the analysis reveals unique manifestations of dental traits in Neanderthals and expanded levels of trait variation that have implications for trait definitions and scoring.
Publication date: 8 July 2017
The understanding of Neanderthal societies, both with regard to their funerary behaviors and their subsistence activities, is hotly debated. Old excavations and a lack of taphonomic context are often factors that limit our ability to address these questions. To better appreciate the exact nature of what is potentially the oldest burial in Western Europe, Regourdou (Montignac-sur-Vézère, Dordogne), and to better understand the taphonomy of this site excavated more than 50 years ago, it is reported in this contribution a study of the most abundant animals throughout its stratigraphy: the European rabbit (Oryctolagus cuniculus). In addition to questions surrounding the potential bioturbation of the site's stratigraphy, analysis of the Regourdou rabbits could provide new information on Neandertal subsistence behavior. The mortality profile, skeletal-part representation, breakage patterns, surface modification, and comparison with modern reference collections supports the hypothesis that the Regourdou rabbit remains were primarily accumulated due to natural (attritional) mortality. Radiocarbon dates performed directly on the rabbit remains give ages ranging within the second half of Marine Isotope Stage 3, notably younger than the regional Mousterian period.The rabbits dug their burrows within Regourdou's sedimentological filling, likely inhabiting the site after it was filled. The impact of rabbit activity now brings into question both the reliability of the archaeostratigraphy of the site and the paleoenvironmental reconstructions previously proposed for it, and suggests rabbits may have played a role in the distribution of the Neandertal skeletal remains.
Publication date: 8 July 2017
Laser ablation U-series dating results on a human cranial bone fragment from Apidima, on the western cost of the Mani Peninsula, Southern Greece, indicate a minimum age of 160,000 years. The dated cranial fragment belongs to Apidima 2, which preserves the facial skeleton and a large part of the braincase, lacking the occipital bone. The morphology of the preserved regions of the cranium, and especially that of the facial skeleton, indicates that the fossil belongs to the Neanderthal clade. The dating of the fossil at a minimum age of 160,000 years shows that most of the Neanderthal traits were already present in the MIS 6 and perhaps earlier. This makes Apidima 2 the earliest known fossil with a clear Neanderthal facial morphology. Together with the nearby younger Neanderthal specimens from Lakonis and Kalamakia, the Apidima crania are of crucial importance for the evolution of Neanderthals in the area during the Middle to Late Pleistocene. It can be expected that systematic direct dating of the other human fossils from this area will elucidate our understanding of Neanderthal evolution and demise.
Publication date: 17 June 2017
In the last years different methodologies have been developed to reconstruct worn teeth. In this article, a team of palaeoanthropologists, including those of the Department of Anthropology University College London propose a new 2-D methodology to reconstruct the worn enamel of lower molars. Our main goals are to reconstruct molars with a high level of accuracy when measuring relevant histological variables and to validate the methodology calculating the errors associated with the measurements. The new methodology based on polynomial regressions can be confidently applied to the reconstruction of cuspal enamel of lower molars, as it improves the accuracy of the measurements and reduces the interobserver error. The present study shows that it is important to validate all methodologies in order to know the associated errors. This new methodology can be easily exportable to other modern human populations, the human fossil record and forensic sciences.
Publication date: 31 May 2017
A variety of mechanical processes can result in antemortem dental chipping. In this study, chipping data in the teeth of Homo naledi are compared with those of other pertinent dental samples to give insight into their etiology.
Publication date: 30 May 2017
Malapa Hominin (MH) 1, an immature individual whose second permanent molars had recently reached occlusion at the time of death, is the holotype of Australopithecus sediba, a 2-myr-old South African taxon that has been hypothesized to link phylogenetically australopith-grade hominins to the Homo clade. Given the existence of 2.8 myr-old fossils of Homo in eastern Africa, this hypothesis implies a ghost lineage spanning at least 800 kyr. An alternative hypothesis posits a unique relationship between Au. sediba and Australopithecus africanus, which predates the Malapa hominins in southern Africa and whose phylogenetic relationships remain ambiguous. The craniofacial morphology of MH 1 looms large in the framing of the two hypotheses. These alternatives were evaluated in two ways. First, it was investigated whether the craniofacial morphology of MH 1 was ontogenetically stable at death. Based on data from a late-growth series of chimpanzee, gorilla, and modern human crania, we found that key aspects of MH 1's resemblance to Homo can be accounted for by its immaturity. Second, MH 1 was studied with an eye to identifying craniofacial synapomorphies shared with Au. africanus. In this case, MH 1 shows unambiguous affinities in its zygomaticomaxillary and supraorbital morphology to crania from Sterkfontein Member 4, which we found to exhibit unusual derived morphology compared to Homo and other australopiths. It is argued that MH 1 provides clear evidence that A. sediba was uniquely related to Au. africanus and that the hypothesis of an extensive ghost lineage connecting Au. sediba to the root of the Homo clade is unwarranted.
Publication date: 20 May 2017
New discoveries and dating of fossil remains from the Rising Star cave system, Cradle of Humankind, South Africa, have strong implications for our understanding of Pleistocene human evolution in Africa. Direct dating of Homo naledi fossils from the Dinaledi Chamber (Berger et al., 2015) shows that they were deposited between about 236 ka and 335 ka (Dirks et al., 2017), placing H. naledi in the later Middle Pleistocene. Hawks and colleagues (Hawks et al., 2017) report the discovery of a second chamber within the Rising Star system (Dirks et al., 2015) that contains H. naledi remains. Previously, only large-brained modern humans or their close relatives had been demonstrated to exist at this late time in Africa, but the fossil evidence for any hominins in subequatorial Africa was very sparse. It is now evident that a diversity of hominin lineages existed in this region, with some divergent lineages contributing DNA to living humans and at least H. naledi representing a survivor from the earliest stages of diversification within Homo. The existence of a diverse array of hominins in subequatorial comports with our present knowledge of diversity across other savanna-adapted species, as well as with palaeoclimate and paleoenvironmental data. H. naledi casts the fossil and archaeological records into a new light, as we cannot exclude that this lineage was responsible for the production of Acheulean or Middle Stone Age tool industries.
Publication date: 14 May 2017