Tribes of Yore
Baboons (Papio anubis) living in larger social groups have bigger brains
Adrien Meguerditchian et al.
Evolution and Human Behavior, January 2021, Pages 30-34
The evolutionary origin of Primates' exceptionally large brains is still highly debated. Two competing explanations have received much support: the ecological hypothesis and the social brain hypothesis (SBH). We tested the SBH in (n = 82) baboons (Papio anubis) belonging to the same research centre but housed in groups with size ranging from 2 to 63 individuals. We found that baboons living in larger social groups had larger brains. This effect was driven mainly by white matter volume and to a lesser extent by grey matter volume but not by the cerebrospinal fluid. In comparison, the size of the enclosure, an ecological variable, had no such effect. In contrast to the current re-emphasis on potential ecological drivers of primate brain evolution, the present study provides renewed support for the social brain hypothesis and suggests that the social brain plastically responds to group size. Many factors may well influence brain size, yet accumulating evidence suggests that the complexity of social life might be an important determinant of brain size in primates.
Debasement of silver throughout the Late Bronze – Iron Age transition in the Southern Levant: Analytical and cultural implications
Tzilla Eshel et al.
Journal of Archaeological Science, January 2021
The study of silver, which was an important mean of currency in the Southern Levant during the Bronze and Iron Age periods (~1950–586 BCE), revealed an unusual phenomenon. Silver hoards from a specific, yet rather long timespan, ~1200–950 BCE, contained mostly silver alloyed with copper. This alloying phenomenon is considered here for the first time, also with respect to previous attempts to provenance the silver using lead isotopes. Eight hoards were studied, from which 86 items were subjected to chemical and isotopic analysis. This is, by far, the largest dataset of sampled silver from this timespan in the Near East. Results show the alloys, despite their silvery sheen, contained high percentages of Cu, reaching up to 80% of the alloy. The Ag–Cu alloys retained a silvery tint using two methods, either by using an enriched silver surface to conceal a copper core, or by adding arsenic and antimony to the alloy. For the question of provenance, we applied a mixing model which simulates the contribution of up to three end members to the isotopic composition of the studied samples. The model demonstrates that for most samples, the more likely combination is that they are alloys of silver from Aegean-Anatolian ores, Pb-poor copper, and Pb-rich copper from local copper mines in the Arabah valley (Timna and Faynan). Another, previously suggested possibility, namely that a significant part of the silver originated from the West Mediterranean, cannot be validated analytically. Contextualizing these results, we suggest that the Bronze Age collapse around the Mediterranean led to the termination of silver supply from the Aegean to the Levant in the beginning of the 12th century BCE, causing a shortage of silver. The local administrations initiated sophisticated devaluation methods to compensate for the lack of silver – a suspected forgery. It is further suggested that following the Egyptian withdrawal from Canaan around the mid-12th century BCE, Cu–Ag alloying continued, with the use of copper from Faynan instead of Timna. The revival of long-distance silver trade is evident only in the Iron Age IIA (starting ~950 BCE), when silver was no longer alloyed with copper, and was imported from Anatolia and the West Mediterranean.
Genomic Steppe ancestry in skeletons from the Neolithic Single Grave Culture in Denmark
Anne Friis-Holm Egfjord et al.
PLoS ONE, January 2021
The Gjerrild burial provides the largest and best-preserved assemblage of human skeletal material presently known from the Single Grave Culture (SGC) in Denmark. For generations it has been debated among archaeologists if the appearance of this archaeological complex represents a continuation of the previous Neolithic communities, or was facilitated by incoming migrants. We sampled and analysed five skeletons from the Gjerrild cist, buried over a period of c. 300 years, 2600/2500–2200 cal BCE. Despite poor DNA preservation, we managed to sequence the genome (>1X) of one individual and the partial genomes (0.007X and 0.02X) of another two individuals. Our genetic data document a female (Gjerrild 1) and two males (Gjerrild 5 + 8), harbouring typical Neolithic K2a and HV0 mtDNA haplogroups, but also a rare basal variant of the R1b1 Y-chromosomal haplogroup. Genome-wide analyses demonstrate that these people had a significant Yamnaya-derived (i.e. steppe) ancestry component and a close genetic resemblance to the Corded Ware (and related) groups that were present in large parts of Northern and Central Europe at the time. Assuming that the Gjerrild skeletons are genetically representative of the population of the SGC in broader terms, the transition from the local Neolithic Funnel Beaker Culture (TRB) to SGC is not characterized by demographic continuity. Rather, the emergence of SGC in Denmark was part of the Late Neolithic and Early Bronze Age population expansion that swept across the European continent in the 3rd millennium BCE, resulting in various degrees of genetic replacement and admixture processes with previous Neolithic populations.
Earliest Olduvai hominins exploited unstable environments ~ 2 million years ago
Julio Mercader et al.
Nature Communications, January 2021
Rapid environmental change is a catalyst for human evolution, driving dietary innovations, habitat diversification, and dispersal. However, there is a dearth of information to assess hominin adaptions to changing physiography during key evolutionary stages such as the early Pleistocene. Here we report a multiproxy dataset from Ewass Oldupa, in the Western Plio-Pleistocene rift basin of Olduvai Gorge (now Oldupai), Tanzania, to address this lacuna and offer an ecological perspective on human adaptability two million years ago. Oldupai’s earliest hominins sequentially inhabited the floodplains of sinuous channels, then river-influenced contexts, which now comprises the oldest palaeolake setting documented regionally. Early Oldowan tools reveal a homogenous technology to utilise diverse, rapidly changing environments that ranged from fern meadows to woodland mosaics, naturally burned landscapes, to lakeside woodland/palm groves as well as hyper-xeric steppes. Hominins periodically used emerging landscapes and disturbance biomes multiple times over 235,000 years, thus predating by more than 180,000 years the earliest known hominins and Oldowan industries from the Eastern side of the basin.
Microbotanical evidence for the spread of cereal use during the Mesolithic-Neolithic transition in the Southeastern Europe (Danube Gorges): Data from dental calculus analysis
Jelena Jovanović et al.
Journal of Archaeological Science, January 2021
Research increasingly suggests that natural and social environments shaped the Neolithic expansion of the farming niche into Europe. The Danube Gorges, on account of its position between the Mediterranean and more temperate regions and the presence of archaeological sites with continuous Mesolithic and Neolithic layers of occupation associated with vast burial grounds is ideal for studying the modality of Neolithization. Previous dietary stable isotope (carbon, nitrogen, and sulphur) studies in the Central Balkan area indicate that many Neolithic humans remained reliant on foraged aquatic resources in the Gorges. Until now, there is no unambiguous evidence of cereal consumption in this region. The possibility that the rich aquatic resources of the Danube river habitats within Central Balkans influenced diet and thus delayed uptake of Neolithic cultigens is unanswered. The extensive skeletal record from sites in the Danube Gorges (Central Balkans) with its long temporal sequence, provides the opportunity to reconstruct plant use during Mesolithic and the Neolithic. To assess when cereals and possibly cultivated plants spread to the region, we analysed the microbotanical remains (starch grains and phytoliths) entrapped in the dental calculus of 81 individuals dating from 9100 to 5500 cal BC, recovered from five sites in the Danube Gorges. This study marks the largest study of dental calculus from this period so far conducted. Added to this, we present new radiocarbon dates (n = 17), bone collagen stable isotope data (δ13C and δ15N; n = 5) and data on caries frequency. This dietary study identifies that the growing of crops commenced in the Early Neolithic circa 6000 cal BC and was brought by farming migrants of north-western Anatolian ancestry into the Danube Gorges. Despite bringing a Neolithic agro-pastoral subsistence practices and cultural novelties in the Gorges, these migrants and their descendants adopted some of the local dietary and cultural traditions, suggesting a mosaic pattern of Neolithization. The resulting data provides a better understanding of the tempo and spread of cereal agriculture practices and the role of cereals in the diet of Danube Gorges inhabitants.
Continuity of the Middle Stone Age into the Holocene
Eleanor Scerri et al.
Scientific Reports, January 2021
The African Middle Stone Age (MSA, typically considered to span ca. 300–30 thousand years ago [ka]), represents our species’ first and longest lasting cultural phase. Although the MSA to Later Stone Age (LSA) transition is known to have had a degree of spatial and temporal variability, recent studies have implied that in some regions, the MSA persisted well beyond 30 ka. Here we report two new sites in Senegal that date the end of the MSA to around 11 ka, the youngest yet documented MSA in Africa. This shows that this cultural phase persisted into the Holocene. These results highlight significant spatial and temporal cultural variability in the African Late Pleistocene, consistent with genomic and palaeoanthropological hypotheses that significant, long-standing inter-group cultural differences shaped the later stages of human evolution in Africa.