PaleoAnthropology

Occupation Duration and Identification of Technological Traditions: Insights from the Late Middle Paleolithic Site of Nahal Dimona 24 in the Negev Desert, Israel

Maya Oron, Naomi Porat, Erella Hovers — Wed, 22 Jan 2025 00:00:00 +0100

Nahal Dimona 24 is a Middle Paleolithic rock shelter, the first Middle Paleolithic sheltered site identified and excavated in the arid Negev region, southern Israel. The site exhibits at least one well preserved in situ archaeological horizon that was dated by Optically stimulated luminescence (OSL) to MIS 3-4 (Late Middle Paleolithic). The lithic assemblage from Nahal Dimona 24 in dominated by the centripetal Levallois knapping mode, sharing technological characteristics with earlier Middle Paleolithic sites from the southern Levant such as Qafzeh Cave and Nesher Ramla Quarry. At the same time, Nahal Dimona 24 differs from other late Middle Paleolithic sites mainly in the paucity of unidirectional convergent Levallois strategy and triangular end-products. Within the southern Levant Middle Paleolithic, dominance of centripetal Levallois knapping mode has frequently been associated with MIS 5 chronology and is seen by some as a cultural marker of human demic diffusion into the Levant during this time span. Based on the lithic assemblage and OSL ages from Nahal Dimona 24, we suggest that within the technological variability of the Middle Paleolithic in the Levant, the dominance of a specific lithic production mode is not a sufficient cultural or chronological marker. We further propose that since long stratified sequences may be a result of many visits by different human groups, short-term occupations like Nahal Dimona 24 might shed new light on the use of the different modes of Levallois preparation in the late Middle Paleolithic since they may better reflect the use of specific technological traditions related to Levallois preparation.

Growing Pains: Opportunities to Adjust Phenotypic Trajectories in Childhood and Adolescence Complicate Studies of Developmental Plasticity in Late Homo

Cait McPherson — Mon, 17 Oct 2022 00:00:00 +0200

Developmental plasticity, the ability to regulate aspects of development in response to environmental cues, is hypothesized to evolve in response to environmental heterogeneity and may facilitate dispersal, novel habitat occupation, and niche construction. Although the adaptive value of developmental plasticity is a topic of debate in biological anthropology, alternative phenotypes associated with developmental stress observed in living human populations may have been fitness enhancing in the novel and marginal environments encountered by our ancestors. For these reasons, there has been increased interest in studying developmental plasticity in skeletal biology, with the goal of assessing how plastic developmental processes have contributed to the patterning of phenotypic variation, disease susceptibility, and mortality risk in both modern humans and fossil hominin populations. What we currently know about hominin evolution suggests that, after the emergence of Homo erectus, climate change and repeated episodes of dispersal may have promoted the accumulation and maintenance of plastic traits in hominin populations. At the same time, our lineage developed life history traits thought to significantly increase risks associated with predictive plasticity (e.g., extended development, longer lifespans), alongside novel life history stages (e.g., childhood, adolescence) that created additional opportunities for environmental signals to inform development. It is therefore essential that we consider how derived features of hominin life history patterns shape opportunities for phenotypic-environmental interactions at the level of systems and tissues. In studies of developmental plasticity involving skeletal and fossil samples, this approach will facilitate more robust analyses of the relationship between environmental signals and corresponding phenotypic effects, and the identification of potential sources of bias related to “swamping”, compensatory plasticity, and equifinality.

Microtomographic Archive of Hominin Fossils from the Swartkrans Formation, South Africa (1948-1967)

Wed, 22 Jan 2025 00:00:00 +0100

Since initial excavations in 1948, the site of Swartkrans, located in the ‘Cradle of Humankind,’ South Africa has yielded hundreds of fossil hominin specimens belonging to species of Paranthropus, Homo, and possibly Australopithecus. Here we provide an updated catalogue of material excavated between 1948-1967 from Swartkrans (SK prefix) with additional information about associations between specimens and preserved anatomy. In particular, we employ microtomography to comprehensively catalogue the preserved dental remains, including unerupted teeth. Information about the internal preservation provided here and via human-fossil-record.org will facilitate research applications for access to the original CT volumes from the relevant curatorial institution.

Does Early Homo Dental Variation Follow a Neutral Pattern of Divergence?

Luca Del Giacco, Lauren Schroeder — Wed, 22 Jan 2025 00:00:00 +0100

The fragmentary early Homo fossil record represents a temporally expansive and complex lineage that is morphologically and geographically diverse. This large amount of variation, which also captures the transition period from Australopithecus to Homo, has been the focus of a number of studies that have attempted to tease apart taxonomic relationships among specimens, however, results have been ambiguous. More recently, several craniomandibular studies have focused instead on reconstructing the evolutionary processes that produced this diversity, showing that much of it is consistent with non-adaptive evolutionary processes, providing an added level of complexity to how our lineage evolved and diversified. Here, we add to this body of work by applying methods developed from evolutionary quantitative genetics to assess whether genetic drift or natural selection was responsible for the observed diversification in early Homo dental remains. Utilizing previously published standard dental measurements of Homo fossil specimens dated between 2.8 and 1.5 million years (Ma), we found that mandibular dental variation does not deviate from a model of genetic drift across regions (southern Africa, southeast Africa, east Africa, northeast Africa, Dmanisi), or across time periods (2.8–2.3 Ma, 2.29–1.8 Ma, 1.79–1.5 Ma). In contrast, the null hypothesis of genetic drift was rejected for maxillary dental remains, specifically between some of the earliest Homo specimens and later Homo, and comparisons involving the Dmanisi hominins. The latter illustrates that adaptation, probably dietary, was an important factor in the earliest migrations of Homo out of Africa, and the former indicates an interesting pattern of selection between time periods in early Homo, possibly representative of different species. Finally, the contrasting pattern seen between mandibular and maxillary remains is consistent with studies indicating that morphological integration is stronger in mandibular dentition, and thus a potential constraint on the effect of diversifying selection.

No Geoarchaeological Evidence for Deliberate Burial by Homo naledi

Kimberly Foecke, Alain Queffelec, Robyn Pickering — Wed, 22 Jan 2025 00:00:00 +0100

In mid-2023, a preprint was uploaded by some of the team working at the Rising Star Cave System in South Africa on new finds regarding the hominin Homo naledi. The authors reported what they claim is evidence for deliberate burials by this small-brained species and conducted extensive media engagement presenting this claim to the public, including a Netflix documentary that further amplified the claims made in the paper. Subsequently, unanimously negative publicly available peer-reviews were released that stated that the evidence presented is incomplete and inadequate to support the claims made. The authors are yet to fully address the peer-reviews. Here we present a detailed critical assessment and re-analysis of the geochemical and sedimentological data published by the authors as a cornerstone for their assertion. We find that the theory and experimental design are not supported by the realities of the sedimentary environment and violate all prerequisites for conducting a study in the manner selected. The authors do not meet minimum reporting standards for their geochemical methods, a problem stretching back to 2015 through the published material from this research team. Based on available information, we surmise that there are likely missteps in data acquisition and quantification leading to inaccurate final data values. We found deep structural issues with data analysis, visualization, and interpretation in addition to mis-characterization and mis-use of statistical methods in assessing data. We show that even if the data provided accurately represent the composition of the samples, when analyzed appropriately the same data does not support the interpretations, conclusions, and claims made by the authors. There is insufficient sampling and structured variation in the datasets to allow detection of any difference between the proposed burial features and the surrounding sediment – indeed, all sample groups fully overlap in composition. The preprint represents an example of where data have been fitted to a presupposed narrative. In the interest of providing broader utility to the archaeological and paleoanthropological community, we offer here an overview of best practices in geochemical data collection and handling for conducting such a study. In conclusion, we argue that from a geoarchaeological standpoint there is no evidence of deliberate burial of H. naledi remains.

Flakes, Feelings, and Finesse: Experiential Studies of Skill Acquisition in Novice Knappers

Wed, 22 Jan 2025 00:00:00 +0100

Here, we present preliminary results from research investigating the influence of different pedagogical methods on skill acquisition amongst novice knappers, with implications for interpreting the Paleolithic and devising pedagogical methods in classrooms. We addressed questions related to knowledge acquisition amongst novice knappers in issues such as raw material selection and technological strategies comprising bipolar knapping, flaking cobbles, and handaxe façonnage. Experiments were set in a highly social and experiential framework and focused on investigating skill acquisition based on observation, mimicry, and direct or indirect intervention of an expert knapper. Variables included self-assessed emotional states of novice knappers before and after each experiment and analysis of selected attributes of the lithics (n=1835 artifacts in 10 experiments). We generated indices for variables related to skill acquisition that are significant for interpreting individual tools, assemblages, and evolutionary trends. Results suggest variability in skill acquisition in different technological processes through time and the effects of differing teaching methods. Large databases of lithic assemblages generated from novice knapping would facilitate global comparative studies investigating learning processes in lithic knapping, thereby enhancing an understanding of the archeological record.