The study of archaeological or palaeontological bone material often requires a preliminary cleaning treatment to remove the sedimentary matrix adhering to the specimen surface. The characteristics of this matrix and its interaction with the bone material determine the methods to be applied. However, the impact of this interaction on the effectiveness of cleaning treatments has received little attention. This study aims to characterise bone cortical preservation, the surrounding sedimentary matrix and their interaction at the contact interface, to understand how these factors influence the cleaning process and outcome. Specimens from three sites, each with carbonated concretions requiring similar cleaning methods, were included in the study. Despite the use of comparable techniques, different levels of impact were observed after cleaning. A combination of qualitative and quantitative methods was used to characterise the three factors: optical and electron microscopy, micro-computed tomography, X-ray diffraction and Fourier-transform infrared spectroscopy. The results show that variability in the degree of interaction between the concretion and the bone can influence the cleaning process, even when the specimens initially appear to have similar characteristics. These findings provide valuable insights for optimising cleaning treatments and understanding their impact on subsequent analyses, with significant implications for zooarchaeological and taphonomic research.

Seasonal variations in climatic variables, and the resulting changes in vegetation, are strong factors governing ecosystem dynamics in modern and ancient times. Stable isotope ratios recorded in tooth enamel document isotopic variations in the environment at the time of enamel formation and thus reveal the intensity and duration of seasonal dietary and climatic variations. However, the long and multi-phased process of enamel mineralization causes a dampening of the original input signal. An inverse model previously developed for ever-growing canines of Hippopotamus amphibius proposes to recover the original input signal and assumes constant enamel growth rate, appositional angle, and maturation length. The present study aims to test these assumptions. To do so, we integrated data from histological thin sections, microtomodensitometric analyses, and stable isotope analyses on teeth of extant H. amphibius specimens (3 upper canines, 1 lower canine, 1 third molar) to quantify the geometric and temporal patterns of enamel mineralization. To estimate enamel extension rates (EER, in µm/increment), we counted the number of increments representing the position of appositional front for each segment of 5 mm along the enamel-dentine junction in thin sections made along the growth axis of each tooth. We used microtomodensitometry to determine the pattern of enamel maturation using grey values profiles of X-ray radiographies as a proxy for enamel mineralization degree. Serial sampling along one upper canine of an individual from Chad, coming from an environment with one rainy season per year, allowed us to document the intra-tooth d13C and d18O variations over 6 years and thus provided an independent temporal control on histological variations. The histological study showed that the enamel apposition phase is strongly irregular over time within the canines, with no clear temporal trend. EERs vary strongly among teeth and within each tooth (50-200 µm/increment, 100-350 µm/increment, and 80-200 µm/increment for the 3 upper canines; 150-550 µm/increment for the lower canine; 70-130 µm/increment for the third molar). The median EER value from the upper canine of the juvenile individual (ca. 180 µm/increment) is significantly higher than median EER values from the upper canines of two adult individuals (ca. 110 µm/increment). Similar variations are also observed in apposition angles (3°-8°, 2.5°-4.5°, 3°-7° for the 3 upper canines; 2°-8° for the lower canine; 6°-18° for the third molar). The enamel mineralization parameters vary with age and tooth type (canine vs. molar). Based on strongly correlated seasonal variations in d13C and d18O, we also confirm cyclic dietary variations with higher proportions of C4 plants consumed during the dry seasons. Using the range of enamel mineralization parameters observed within one single hippo canine, we conducted sensitivity tests on the inverse modeling method, producing different modeled input signals that suggest a wider range of uncertainty. In conclusion, the documented intra-canine variability of EER, as well as other histological parameters (apposition angle, maturation length), reveals challenges when applying the current inverse model to wild populations. Future work would benefit from a systematic histological investigation into the sources of variation of enamel growth and mineralization patterns.

This pilot study focusses on improving the methodological approach of histotaphonomy by integrating image analysis software for assessing bone diagenesis in both bone histological sections and microcomputed tomography (mu-CT) scans of the same bone slice. Femurs and ribs from six individuals buried at the churchyard of St. Anne in Koekelberg (Belgium, 1833-1916) were analyzed with mu-CT and histology (light microscopy and scanning electron microscopy). Bone diagenesis was scored visually by the assessor, as well as quantitatively by image analysis. The results suggest that image analysis is an effective quantitative scoring method, eliminating subjectivity bias, specifically regarding the precision in percentage calculation of preserved areas which aids in assigning the right category of the Oxford Histological Index. However, algorithm limitations can affect the accuracy and reliability of the results, hence specialized expertise is advised. The taphonomic results show that bacterial degradation was similar within and between rib and femur of the same individual but varied between individuals depending on burial treatment (wooden versus zinc-lined coffins). Other inter-skeletal differences were caused by biological parameters such as the amount of primary lamellar bone. This study demonstrates the accuracy of quantitative scoring by advancements in technology such as image analysis, creating a basis for the incorporation of machine learning algorithms in future histotaphonomy studies. It also stresses the importance of using both histology and mu-CT as complementary methods.

Lithic weapon points occasionally found in Middle Palaeolithic Neanderthal sites are large and do not differ in size, shape or type from those used in other activities such as butchering or plant gathering. The presence in a same assemblage of various types of projectile armatures, some of which are microlithic and designed for this purpose, has only been documented in Modern Humans sites. Recent studies indicate that light projectile points, which would become a key element in Upper Palaeolithic lithic industries, were already present in its formative stages. However, they remain marginal in debates regarding the Middle to Upper Paleolithic transition. We present the initial findings of a traceological search for weapon heads in the oldest layers of the Obi-Rakhmat rock shelter in Uzbekistan, dating back around 80 ka. The lithic industry of this settlement is forming part of the Levantine Early Middle Paleolithic continuity but with several innovative traits. This site, located in the western foothills of the Tian Shan Mountains, northeastern Uzbekistan, has yielded throughout 10 meters of Pleistocene deposits covering 40,000 years a lithic industry characterized by the systematic production of blades (regular thick narrow blades from unipolar and bipolar sub-prismatic and narrow-faced cores, thin and wide blades from flat-faced Levallois-like cores) along with shorter pieces from convergent or centripetal Levallois cores, and bladelets from burin-cores and other small cores. Three types of projectile armature are identified over a selection of 20: retouched points, bladelets and more particularly unretouched triangular micropoints which had previously gone unoticed due to their fragmentary state. According to the fundamental principles of hunting weapon design these micropoints are too narrow for having been fitted to anything other than arrow-like shafts. They resemble the armatures described in a pioneer settlement by Sapiens in the Rhône Valley, France, 25,000 years later.

Histology is a conventional but destructive technique for investigating bone diagenesis. Micro-tomography is a non-destructive technique that can also be used to investigate diagenetic alterations. The aim of this study is to evaluate the benefits and limitations of these two methods by analysing bone diagenesis to determine if micro-tomography (non-destructive) can be more beneficial than histology (destructive), and if scoring can be quantified in both methods. Therefore, bone samples from six individuals from the churchyard of St. Anne (1833-1916) in Koekelberg (Belgium) were analysed. Each thin section and scan was qualitatively scored with the Oxford Histological Index and quantitatively assessed through image analysis. The results show that micro-tomography allows assessment of degradation of the scanned bones without destruction. This is impossible with histology where analysis is restricted to a small cross-section. On the other hand, histology brings more detail to the bone microstructure thanks to its finer resolution. Overall, this study demonstrates that both methods provide different but complementary information about bone diagenesis and stresses the importance of using quantifying methods to analyse diagenetic alterations.

de l'ancien cimetière de Koekelberg (Belgique, XIX e siècle) Confrontation of the histological and micro-tomographic approaches for the study of bone diagenesis: application to the anthropobiological remains of the old cemetery of Koekelberg (Belgium, 19 th century)

Leprosy can lead to blood depletion in Zn, Ca, Mg, and Fe and blood enrichment in Cu. In late medieval Europe, minerals were used to treat leprosy. Here, physiological responses to leprosy and possible evidence of treatment are investigated in enamel, dentine, and cementum of leprosy sufferers from medieval Denmark (n = 12) and early 20th century Romania (n = 2). Using SXRF and LA-ICP-TOFMS, 12 elements were mapped in 15 tooth thin sections, and the statistical covariation of paired elements was computed to assess their biological relevance. The results show marked covariations in the Zn, Ca, and Mg distributions, which are compatible with clinical studies but cannot be directly attributed to leprosy. Minerals used historically as a treatment for leprosy show no detectable intake (As, Hg) or a diffuse distribution (Pb) related to daily ingestion. Intense Pb enrichments indicate acute incorporations of Pb, potentially through the administration of Pb-enriched medication or the mobilization of Pb from bone stores to the bloodstream during intense physiological stress related to leprosy. However, comparisons with a healthy control group are needed to ascertain these interpretations. The positive correlations and the patterns observed between Pb and essential elements may indicate underlying pathophysiological conditions, demonstrating the potential of SXRF and LA-ICP-TOFMS for paleopathological investigations.

The activities’ spatial organization of Neanderthal’s territory is often explored by studying stone tool production and use, and its economy, but not their hunting behavior. Consequently, the hypothesis that Neanderthals lacked planning potential or complex land-use strategies during the Mousterian, such as collaborative hunting and food storage, has been questioned. A cementochronology analysis of reindeer in Quina and Discoidal Denticulate in four neanderthal sites in southwestern France suggests a repeated use of specific sites at a precise time of the year for similar hunting purposes scheduled according to a year-round pattern. The development of landmark sites during the late Middle Paleolithic used every year, at the same moment, indicates that the predation system began to structure the activity’s organization within the territory in time and space and that the preys’ behavior directly impacted the social organization of the hunting groups.

For human dental cementum research, sample preparation protocol is now widely tested, validated, and standardized, thanks to the low variability in teeth morphology. For non-human mammals, posterior teeth are typically preferred. However, the taxa diversity implies a significant variation in morphology or specific characteristics for certain species (equids, suids), leading to multiple unstandardized protocols. This work aims to improve protocols for producing a thin section by optimizing the parameters, minimizing the risk of errors, and offering an easily reproducible quality of thin-sections. The result of 26 experiments and 124 analyses during stages of consolidation (embedding), cutting, gluing, and finishing (grinding) allowed the co-authors' combined experience from multiple laboratories to propose standardized humans and ungulates (large teeth) protocols for the systematic analysis of dental research collections.

AbstractHigher education in evolutionary anthropology involves providing students with in‐depth knowledge of biological and cultural heritage sites and collections that are frequently inaccessible. Indeed, most sites, fossils, and archaeological remains can be visited or manipulated only rarely and solely by specialists with extensive experience. Owing to the development of 3D and medical imaging techniques, this fragile heritage is now more widely accessible, and in a dynamic way. However, exclusive adoption of virtual teaching and learning has a negative impact on student engagement and, naturally, on exchanges with instructors, and thus cannot be used without some reservations. In the ITAP (Immersion dans les Terrains de l’Anthropologie biologique et de la Préhistoire) project of the higher education STEP (Soutien à la Transformation et à l’Expérimentation Pédagogiques) transformation program at the University of Bordeaux, we combine student‐active teaching with Master's students fully immersed in ongoing fieldwork, laboratory study, and dissemination of research results in order to develop more individually shaped learning curricula and to foster both professional and new interdisciplinary skills. Here, we present examples of experiments conducted in the ITAP project using both authentic and virtual collections of archaeological, experimental, and reference materials that help to break down the barriers between research activities and higher education, as well as providing a more general appraisal of the appropriate use of virtual tools in higher education by combining them with real‐life situations.

Seasonal variations directly impacted the social and economic activities of past human populations. Cementochronology is one of the methods available to address seasonality questions. It relies on the cyclic deposition rate of dental cementum observed microscopically on petrographic thin‐sections of animal teeth from archaeological contexts. However, no protocol exists to select a Region of Interest (ROI) or to identify the last cementum increment. This chapter proposes consensual biological and optical criteria for the selection of optimal ROIs and their analysis. Interobserver tests were performed to assess the criteria, as well as age and season of death, on thirty thin‐sections of modern documented reindeer teeth. Results demonstrate the accuracy, and replicability of this protocol, and emphasize the influence of training and experience for the proper implementation of cementochronology.

Intra-tooth stable isotope variations have been used to interpret seasonality and aridity in paleoenvironmental reconstructions of paleontological and archeological sites. However, most infra-tooth datasets only permit qualitative interpretations of seasonality, because the measured signal is attenuated due to the duration of enamel mineralization process and sampling geometry. The common warthog (Phacochoerus africanus) is an ideal organism to investigate stable isotope variation in enamel. Their canines grow continuously through the life of the individual and are therefore excellent candidates for mathematical modeling of seasonal signals and of signal attenuation; further, their isotope profiles (a series of isotope measurements) can be compared to isotope profiles of third molars (M3) to provide insights into environmental reconstructions. We first obtained paired infra-tooth enamel samples from ever-growing canines and hypsodont M3s of two extant common warthog specimens from Laikipia, Kenya. Second, from a different set of specimens, we collected data on enamel growth patterns and geometry using histological thin sections and transmitted light microscopy, and enamel miner- alization parameters using micro-CT scans in each tooth type. Third, we reconstructed the timeline of un- attenuated seasonal delta O-1(8) signal from canine enamel using growth rate estimates and the inverse model of Passey et al. (2005). Our results demonstrate that canines, which capture similar to 1.5 years of time, exhibit near-constant growth rates and simple enamel maturation geometry, whereas M3s, which also represent similar to 1.5 years of time, exhibit linearly decreasing growth rates and more complex maturation patterns. We compare the timelines of unattenuated seasonal delta O-1(8) signal and measured M3 profiles and find an average signal reduction of similar to 50% in the M3s, providing interpretations of the duration of seasonal cycles that are consistent 75% of the time. We conclude that warthog canines are well suited for the inverse model approach, and we established the model parameters for the forward and inverse methods. Timeline reconstructions based on M3 histology are promising for investigating the pattern of rainfall seasonality in the past. Finally, we found an unexpected carbon isotopic spacing of similar to 2 parts per thousand between canine and M3 enamel, which suggests caution in interpreting delta C-1(3) results from suid canine or molar enamel alone.

We propose for the first time the use of the combination of two high-resolution techniques, dental wear (meso- and microwear) and dental cementum analyses, to gain a better understanding of Neanderthal subsistence strategies and occupational patterns. Dental wear analysis provides information not only on ungulate palaeodiet and palaeoenvironments but also on hunting time and seasons. Dental cementum analysis allows the accurate determination of the age and season at death of a prey. Our study has focused on the Cantabrian region and has applied both methods to investigate the Mousterian faunal assemblages in Covalejos Cave. Identification of the ungulate palaeodiet reveals information on the environmental conditions of the studied region. Moreover, it may facilitate observation on the evolution of both palaeodiet and palaeoenvironment throughout the site sequence. Results show a general stability in the palaeoenvironmental conditions and in the ungulate palaeodiet throughout the Mousterian sequence; this finding may be attributed to the role of the area as a climate refuge, and slight differences in levels 8, 7 and 4 suggest long- or short-term but repeated Neanderthal occupations at different seasons in the annual cycle.