A 400,000-year-old Acheulean assemblage associated with the Aroeira-3 human cranium (Gruta da Aroeira, Almonda karst system, Portugal)
Bifaces dominate the Acheulean stone tools recovered during the archaeological excavation of layer X of Gruta da Aroeira, dated to 389–436 ka. Faunal remains and a human cranium were found in association with this lithic assemblage. The raw materials used are mostly quartz and quartzite cobbles available in the vicinity of the site. Technological and systematic analysis shows that there are no Levallois elements and suggests that on-site knapping consisted of the reduction of centripetal cores. Flake cleavers are absent. Use-wear analysis indicates the processing of hard materials, mainly wood. Gruta da Aroeira represents one of the few Middle Pleistocene sites that provide securely dated diagnostic human remains and associated Acheulean lithics, thus representing a major step forward in our understanding of the variability of westernmost Europe's Acheulean and of the human populations that made it.
Publication date: 22 September 2018
Archaeological recovery of chimpanzee Panda oleosa nut cracking tools at the Panda 100 (P100) and Noulo sites in the Taï Forest, Côte d'Ivoire, showed that this behavior is over 4000 years old, making it the oldest known evidence of non-human tool use. In 2002, the first report on the lithic material from P100 was directly compared to early hominin stone tools, highlighting their similarities and proposing the name ‘Pandan’ for the chimpanzee material. Here we present an expanded and comprehensive technological, microscopic, and refit analysis of the late twentieth century lithic assemblage from P100. Our re-analysis provides new data and perspectives on the applicability of chimpanzee nut cracking tools to our understanding of the percussive behaviors of early hominins. We identify several new refit sets, including the longest (>17 m) hammerstone transport seen in the chimpanzee archaeological record. We provide detailed evidence of the fragmentation sequences of Panda nut hammerstones, and characterize the percussive damage on fragmented material from P100. Finally, we emphasize that the chimpanzee lithic archaeological record is dynamic, with the preservation of actual hammerstones being rare, and the preservation of small broken pieces more common. P100 – the first archaeological chimpanzee nut cracking lithic assemblage – provides a valuable comparative sample by which to identify past chimpanzee behavior elsewhere, as well as similar hominin percussive behavior in the Early Stone Age.
Publication date: 22 September 2018
The oldest recognized artifacts at the Swartkrans cave hominid-bearing site in South Africa have long been known to occur in the Lower Bank of Member 1, now dated with the cosmogenic nuclide burial method to ca. 1.8–2.19 Ma. However, the affinities of this industry have been debated due to small sample size. In this paper we present newly excavated material from the Lower Bank retrieved since 2005 in the Swartkrans Paleoanthropological Research Project. The sample is now large enough to confirm its affinity with the Oldowan industrial complex. The assemblage is highly expedient and core reduction strategies are largely casual. Although freehand flaking is present, the bipolar technique is most significant, even in non-quartz raw materials. The Swartkrans assemblage shows some significant contrasts with the Sterkfontein Oldowan, ca. 2.18 Ma, which can be explained by its closer proximity to raw material sources, its somewhat different geographic context, and its more expedient nature. The Swartkrans Oldowan now provides us with the first good indication of Oldowan variability in southern Africa, where only two sizeable assemblages have thus far been discovered. Comparisons are made with other sites across Africa that help to place this variability within our overall understanding of the Oldowan industrial complex.
Publication date: 20 August 2018
The view that Homo sapiens evolved from a single region/population within Africa has been given primacy in studies of human evolution.
Publication date: 13 July 2018
The terminology used to describe Palaeolithic industries has an important impact upon our interpretation of past behaviour. In South Asia, the term Late Palaeolithic is employed to refer to Late Pleistocene microlithic industries, distinguishing them chronologically from Holocene Mesolithic industries, and technologically from preceding Middle Palaeolithic technologies. Historically, however, an intermediate technological stage between Middle Palaeolithic and microlithic industries has been recognised and called ‘Upper’ Palaeolithic. Examining whether these ‘Upper’ Palaeolithic industries fit contemporary definitions of Middle or Late Palaeolithic technologies, distinct diversity within one of these technologies or a transitional phase between the two is therefore necessary to reintegrate these ‘Upper’ Palaeolithic sites into current debate. This is a particularly timely issue as the connection between some Late Palaeolithic artefact types, particularly backed microliths, and the earliest modern human populations in South Asia no longer appears tenable, and thus a rush to identify the earliest appearance of microliths must give way to more detailed examinations of behavioural variability. This paper re-examines lithic assemblages from Buddha Pushkar, western India, originally reported as an ‘Upper’ Palaeolithic industry. An attribute study of metric and categorical variables recorded on stone tools is used to examine how flaking technology, raw material use and reduction intensity vary within and between these assemblages. The results indicate raw material choices had a marked impact on stone tool technologies, nested within a pattern of technological diversity in western India during the terminal Pleistocene that complement models of regional trajectories in the evolution of Late Palaeolithic technologies.
Publication date: 8 July 2018
Euprimates of the Eocene that were likely ancestral to modern lemurs and possibly ancestral to anthropoids
Publication date: 29 June 2018
Based on the results of the current study, and given the large amount of variation observed within modern humans, concluding based on metatarsal robusticity patterns alone that a fossil hominin's foot kinematics and associated pedal loading regime was, or was not, like a modern human has limited value. Rather, it is more appropriate to be cautious and to identify whether the observed metatarsal robusticity pattern allows us to infer if the fossil hominin was more “African ape-like” with a 1 > 2/3 > 4/5 pattern or if it was more “human-like” with a 1 > 5/4 > 3/2 pattern, and the extent to which there may be overlap between these two patterns. If similarity to one group's pattern over the other is found, then it would provide strong evidence about whether the fossil was habitually bipedal or not. In the case of OH 8, despite very rare overlap in relative ranking patterns between humans and African apes, it is clear that it is more like humans than African apes. Thus, by examining cross-sectional properties across the metatarsals in the foot, a consensus bipedal signal emerges. This is especially valuable when other biomechanically informative regions such as the metatarsal heads (e.g., Latimer and Lovejoy, 1990; Duncan et al., 1994; Fernández et al., 2015 ; Fernández et al., 2016) are absent in a fossil, as they are in OH 8.
Publication date: 28 May 2018
Objectives: A nearly complete hominin fossil cranium from Dali in Shaanxi Province, China was excavated in 1978. We update and expand on previous research by providing a multivariate analysis of the specimen relative to a large sample of Middle and Late Pleistocene hominins.
Publication date: 28 April 2018
The ecology of Neanderthals is a pressing question in the study of hominin evolution. Diet appears to have played a prominent role in their adaptation to Eurasia. Based on isotope and zooarchaeological studies, Neanderthal diet has been reconstructed as heavily meat-based and generally similar across different environments. This image persists, despite recent studies suggesting more plant use and more variation. However, we have only a fragmentary picture of their dietary ecology, and how it may have varied among habitats, because we lack broad and environmentally representative information about their use of plants and other foods. To address the problem, we examined the plant microremains in Neanderthal dental calculus from five archaeological sites representing a variety of environments from the northern Balkans, and the western, central and eastern Mediterranean. The recovered microremains revealed the consumption of a variety of non-animal foods, including starchy plants. Using a modeling approach, we explored the relationships among microremains and environment, while controlling for chronology. In the process, we compared the effectiveness of various diversity metrics and their shortcomings for studying microbotanical remains, which are often morphologically redundant for identification. We developed Minimum Botanical Units as a new way of estimating how many plant types or parts are present in a microbotanical sample. In contrast to some previous work, we found no evidence that plant use is confined to the southern-most areas of Neanderthal distribution. Although interpreting the ecogeographic variation is limited by the incomplete preservation of dietary microremains, it is clear that plant exploitation was a widespread and deeply rooted Neanderthal subsistence strategy, even if they were predominately game hunters. Given the limited dietary variation across Neanderthal range in time and space in both plant and animal food exploitation, we argue that vegetal consumption was a feature of a generally static dietary niche.
Publication date: 23 April 2018
Archaeological excavations at EF-HR and HWK EE allow reassessment of Bed II stratigraphy within the Junction Area and eastern Olduvai Gorge. Application of Sequence Stratigraphic methods provides a time-stratigraphic framework enabling correlation of sedimentary units across facies boundaries, applicable even in those areas where conventional timelines, such as tephrostratigraphic markers, are absent, eroded, or reworked. Sequence Stratigraphically, Bed II subdivides into five major Sequences 1 to 5, all floored by major disconformities that incise deeply into the underlying succession, proving that simple "layer cake" stratigraphy is inappropriate. Previous establishment of the Lemuta Member has invalidated the use of Tuff IIA as the boundary between Lower and Middle Bed II, now redefined at the disconformity between Sequences 2 and 3, a lithostratigraphic contact underlying the succession containing the Lower, Middle, and Upper Augitic Sandstones. HWK EE site records Oldowan technology in the Lower Augitic Sandstone at the base of Sequence 3, within Middle Bed II. We suggest placement of recently reported Acheulean levels at FLK W within the Middle Augitic Sandstone, thus emphasizing that handaxes are yet to be found in earlier stratigraphic units of the Olduvai sequence. This would place a boundary between the Oldowan and Acheulean technologies at Olduvai in the Tuff IIB zone or earliest Middle Augitic Sandstone. A major disconformity between Sequences 3 and 4 at and near EF-HR cuts through the level of Tuff IIC, placing the main Acheulean EF-HR assemblage at the base of Sequence 4, within Upper rather than Middle Bed II. Sequence stratigraphic methods also yield a more highly resolved Bed II stratigraphic framework. Backwall and sidewall surveying of archaeological trenches at EF-HR and HWK EE permits definition of “Lake-parasequences” nested within the major Sequences that record downcutting of disconformities associated with lake regression, then sedimentation associated with lake transgression, capped finally by another erosional disconformity or hiatal paraconformity caused by the next lake withdrawal. On a relative time-scale rather than a vertical metre scale, the resulting Wheeler diagram framework provides a basis for recognizing time-equivalent depositional episodes and the position of time gaps at various scales. Relative timing of archaeological assemblage levels can then be differentiated at a millennial scale within this framework.
Publication date: 23 April 2018
Understanding the timing and character of the expansion of Homo sapiens out of Africa is critical for inferring the colonization and admixture processes that underpin global population history. It has been argued that dispersal out of Africa had an early phase, particularly ~130–90 thousand years ago (ka), that reached only the East Mediterranean Levant, and a later phase, ~60–50 ka, that extended across the diverse environments of Eurasia to Sahul. However, recent findings from East Asia and Sahul challenge this model. Here we show that H. sapiens was in the Arabian Peninsula before 85 ka. We describe the Al Wusta-1 (AW-1) intermediate phalanx from the site of Al Wusta in the Nefud desert, Saudi Arabia. AW-1 is the oldest directly dated fossil of our species outside Africa and the Levant. The palaeoenvironmental context of Al Wusta demonstrates that H. sapiens using Middle Palaeolithic stone tools dispersed into Arabia during a phase of increased precipitation driven by orbital forcing, in association with a primarily African fauna. A Bayesian model incorporating independent chronometric age estimates indicates a chronology for Al Wusta of ~95–86 ka, which we correlate with a humid episode in the later part of Marine Isotope Stage 5 known from various regional records. Al Wusta shows that early dispersals were more spatially and temporally extensive than previously thought. Early H. sapiens dispersals out of Africa were not limited to winter rainfall-fed Levantine Mediterranean woodlands immediately adjacent to Africa, but extended deep into the semi-arid grasslands of Arabia, facilitated by periods of enhanced monsoonal rainfall.
Publication date: 9 April 2018
Hammerstone use during marrow extraction and flake production shown to be key variables in anatomical and functional evolution
It is widely agreed that biomechanical stresses imposed by stone tool behaviours influenced the evolution of the human hand. Though archaeological evidence suggests that early hominins participated in a variety of tool behaviours, it is unlikely that all behaviours equally influenced modern human hand anatomy. It is more probable that a behaviour's likelihood of exerting a selective pressure was a weighted function of the magnitude of stresses associated with that behaviour, the benefits received from it, and the amount of time spent performing it. Based on this premise, we focused on the first part of that equation and evaluated magnitudes of stresses associated with stone tool behaviours thought to have been commonly practiced by early hominins, to determine which placed the greatest loads on the digits. Manual pressure data were gathered from 39 human subjects using a Novel Pliance® manual pressure system while they participated in multiple Plio-Pleistocene tool behaviours: nut-cracking, marrow acquisition with a hammerstone, flake production with a hammerstone, and handaxe and flake use. Manual pressure distributions varied significantly according to behaviour, though there was a tendency for regions of the hand subject to the lowest pressures (e.g., proximal phalanges) to be affected less by behaviour type. Hammerstone use during marrow acquisition and flake production consistently placed the greatest loads on the digits collectively, on each digit and on each phalanx. Our results suggest that, based solely on the magnitudes of stresses, hammerstone use during marrow acquisition and flake production are the most likely of the assessed behaviours to have influenced the anatomical and functional evolution of the human hand.
Publication date: 8 April 2018
Reanalysis of Late Pleistocene teeth from Kalamakia, Greece sheds light on Homo neanderthalensis & Homo sapiens evolution
This study investigates two Neanderthal lower fourth premolars from Kalamakia, Greece, in order to better explore and document the morphology of the Kalamakia assemblage. The material consisted of micro-CT scans of the Kalamakia premolars (KAL6 and KAL9), and a comparative sample of 51 specimens, including 10 Neanderthals, one early Homo sapiens, and 40 recent Homo sapiens. The premolars were analyzed applying geometric morphometric methods on crown outlines as well as collecting measurements on internal dental structures. Data were subjected to principal components and other standard statistical analyses. A between-group principal components analysis of the outline shape coordinates separated our Neanderthal sample from the modern human one with little overlap. KAL9 showed the most extreme Neanderthal shape while KAL6 fell within the NEA shape range. Additional measurements of internal structures, especially the lateral dentine and pulp chamber volume, strengthened these results.
Publication date: 5 April 2018
The Cro-Magnon 1 skeleton corresponds to a 28 000 BCE Homo sapiens male individual that was discovered in 1868 in a rock shelter in Les Eyzies, France. Since its discovery, various diagnoses have been proposed with regards to a round polycyclic osteolytic lesion on the right frontal bone, measuring 37 mm x 27 mm (appendix): post-mortem alteration due to the soil, rickets, actinomycosis, and Langerhans cell histiocytosis.
Publication date: 30 March 2018
H. naledi likely occupied a distinct ecological niche from the South African hominins that predate it.
Though late Middle Pleistocene in age, Homo naledi is characterized by a mosaic of Australopithecus-like (e.g., curved fingers, small brains) and Homo-like (e.g., elongated lower limbs) traits, which may suggest it occupied a unique ecological niche. Ecological reconstructions inform on niche occupation, and are particularly successful when using dental material. Tooth shape (via dental topography) and size were quantified for four groups of South African Plio-Pleistocene hominins (specimens of Australopithecus africanus, Paranthropus robustus, H. naledi, and Homo sp.) on relatively unworn M2s to investigate possible ecological differentiation in H. naledi relative to taxa with similar known geographical ranges. H. naledi has smaller, but higher-crowned and more wear resistant teeth than Australopithecus and Paranthropus. These results are found in both lightly and moderately worn teeth. There are no differences in tooth sharpness or complexity. Combined with the high level of dental chipping in H. naledi, this suggests that, relative to Australopithecus and Paranthropus, H. naledi consumed foods with similar fracture mechanics properties but more abrasive particles (e.g., dust, grit), which could be due to a dietary and/or environmental shift(s). The same factors that differentiate H. naledi from Australopithecus and Paranthropus may also differentiate it from Homo sp., which geologically predates it, in the same way. Compared to the great apes, all hominins have sharper teeth, indicating they consumed foods requiring higher shear forces during mastication. Despite some anatomical similarities, H. naledi likely occupied a distinct ecological niche from the South African hominins that predate it.
Publication date: 23 March 2018