The article submitted by Guillaume Porraz et al. [1] shed light on the evolutionary changes recorded during the Pre-Still Bay Lynn stratigraphic unit (SU) from Diepkloof (Southern Africa). It promotes a multi-proxy and integrative approach based on a set of innovative behaviors, such as the engraving of geometric forms, silcrete heat- treatment, the use of adhesive, bladelet and bifacial tools production. This approach is not so common in Middle Stone Age (MSA) studies and makes a lot of sense for discussing the mechanisms that have fostered later innovations during the Still Bay and Howiesons Poort periods. The various innovations that emerge synchronously in this layer contrast with earlier innovations which appear as isolated phenomena in the MSA archaeological record. The strong inventiveness documented in Lynn SU is reported to a phase of experimentation for testing new ideas, new behaviors that would have played a crucial role for the emergence of the Still Bay in a context of socio-economic transformation.

The data presented in this article broadens the scope of two previous articles [2-3] based on a more representative record, collected on an area of 3,5 m² opposed to 2 m² previously, and on the first presentation and description of an engraved bone with a rhomboid pattern. Macro- and microscopic analyses together with the analysis of the distribution of the engraved lines argue convincingly for an intentional engraving. This article constitutes a key contribution to the question of HOW emerged modern cultures in Southern Africa, while calling for further research related to sites’ function, environment and local resources to address the ever-debated question of WHY the MSA groups from Southern Africa developed such unprecedented inventiveness. It makes no doubt that this article deserves recommendation by PCI Archaeology.

[1] Porraz, G., Schmidt, P., Bereiziat, G., Brugal, J.Ph., Dayet, L., Igreja, M., Miller, C.E., Viola, C., Tribolo, C., Val, A., Verna, C., Texier, P.J. 2020. Experimentation preceding innovation in a MIS5 Pre-Still Bay layer from Diepkloof Rock Shelter (South Africa): emerging technologies and symbols. 10.32942/osf.io/ch53r

[2] Porraz, G., Texier, P.J., Archer, W., Piboule, M., Rigaud, J.P, Tribolo, C. 2013. Technological successions in the Middle Stone Age sequence of Diepkloof Rock Shelter, Western Cape, South Africa. Journal of Archaeological Science 40, 3376–3400. 10.1016/j.jas.2013.02.012

[3] Porraz, G., Texier, J.P. Miller, C.E., 2014. Le complexe bifacial Still Bay et ses modalités d’émergence à l’abri Diepkloof (Middle Stone Age, Afrique du Sud). In: XXVIIème Congrès Préhistorique de France, Transitions, Ruptures et Continuité en Préhistoire. Mémoires de la Société Préhistorique Française, 155–175.

The community of archaeologists, bioanthropologist and paleontologists relying on tools use-wear and dental microwear has grown in the recent years, mainly driven by the spread of confocal microscopes in the laboratories. If the diversity of microscopes is quite high, the main software used for 3D surface texture data analysis are mostly different versions of the same Mountains Map core. In addition to this software, since the beginning of 3D surface texture analysis in dental microwear, surface sensitive fractal analysis (SSFA) initially developed for industrial research (Brown & Savary, 1991) have been performed in our disciplines with the Sfrax/Toothfrax software for two decades (Ungar et al., 2003). This software being discontinued, these calculations have been integrated to the new versions of Mountains Map, with multi-core computing, full integration in the software and an update of the calculation itself.

New research based on these standard parameters of surface texture analysis will be, from now on, mainly calculated with this new add-on of Mountains Map, and will be directly compared with the important literature based on the previous software. The question addressed by Calandra et al. (2022), gathering several prominent researchers in this domain including the Mountains Map developer F. Blateyron, is key for the future research: can we directly compare SSFA results from both software?

Thanks to a Bayesian approach to this question, and comparing results calculated with both software on three different datasets (two on dental microwear, one on lithic raw materials), the authors show that the two software gives statistically different results for all surface texture parameters tested in the paper. Nevertheless, applying the new calculation to the datasets, they also show that the results published in original studies with these datasets would have been similar. Authors also claim that in the future, researchers will need to re-calculate the fractal parameters of previously published 3D surfaces and cannot simply integrate ancient and new data together.

We also want to emphasize the openness of the work published here. All datasets have been published online and will be probably very useful for future methodological works. Authors also published their code for statistical comparison of datasets, and proposed a fully reproducible article that allowed the reviewers to check the content of the paper, which can also make this article of high interest for student training.

This article is therefore a very important methodological work for the community, as noted by all three reviewers. It will certainly support the current transition between the two software packages and it is necessary that all surface texture specialists take these results and the recommendation of authors into account: calculate again data from ancient measurements, and share the 3D surface measurements on open access repositories to secure their access in the future.

References

Brown CA, and Savary G (1991) Describing ground surface texture using contact profilometry and fractal analysis. Wear, 141, 211–226. https://doi.org/10.1016/0043-1648(91)90269-Z

Calandra I, Bob K, Merceron G, Blateyron F, Hildebrandt A, Schulz-Kornas E, Souron A, and Winkler DE (2022) Surface texture analysis in Toothfrax and MountainsMap® SSFA module: Different software packages, different results? Zenodo, 7219877, ver. 4 peer-reviewed and recommended by Peer Community in Archaeology. https://doi.org/10.5281/zenodo.7219877

Ungar PS, Brown CA, Bergstrom TS, and Walker A (2003) Quantification of dental microwear by tandem scanning confocal microscopy and scale-sensitive fractal analyses. Scanning: The Journal of Scanning Microscopies, 25, 185–193. https://doi.org/10.1002/sca.4950250405

The paper entitled “Probabilistic Modelling using Monte Carlo Simulation for Incorporating Uncertainty in Least Cost Path Results: a Roman Road Case Study” [1] submitted by J. Lewis presents an innovative approach to applying Least Cost Path (LCP) analysis to incorporate uncertainty of the Digital Elevation Model used as the topographic surface on which the path is calculated.

The proposition of using Monte Carlo simulations to produce numerous LCP, each with a slightly different DEM included in the error range of the model, allows one to strengthen the method by proposing a probabilistic LCP rather than a single and arbitrary one which does not take into account the uncertainty of the topographic reconstruction. This new method is integrated in the R package leastcostpath [2].

The author tests the method using a Roman road built along a ridge in Cumbria, England. The integration of the uncertainty of the DEM, thanks to Monte Carlo simulations, shows that two paths could have the same probability to be the real LCP. One of them is indeed the path that the Roman road took. In particular, it is one of two possibilities of LCP in the south to north direction.

This new probabilistic method therefore strengthens the reconstruction of past pathways, while also allowing new hypotheses to be tested, and, in this case study, to suggest that the northern part of the Roman road’s location was selected to help the northward movements.

[1] Lewis, J., 2020. Probabilistic Modelling using Monte Carlo Simulation for Incorporating Uncertainty in Least Cost Path Results: a Roman Road Case Study. SocArXiv, mxas2, ver 17 peer-reviewed and recommended by PCI Archaeology, 10.31235/osf.io/mxas2.

[2] Lewis, J., 2020. leastcostpath: Modelling Pathways and Movement Potential Within a Landscape. R package. Version 1.7.4.

Quartz adornments (beads, pendants, etc.) are frequent artifacts found in the Caribbean, particularly from Early Ceramic Age contexts (~500 BC-AD 700). As a form of specialization, these are sometimes seen as indicative of greater social complexity and craftsmanship during this time. Indeed, ethnographic analogy has purported that such stone adornments require enormous inputs of time and labor, as well as some technological sophistication with tools hard-enough to create the holes (e.g., metal or diamonds). However, given these limitations, one would expect unfinished beads to be a common artifact in the archaeological record. Yet, whereas unworked/raw materials are often found, beads with partial/unfinished perforations are not.
 
Could the perforations of stone beads be made using more accessible materials? Some ethnographic sources from Central America suggest certain plant materials could work. Thus, Raymond et al. (2022) endeavored to test the manufacturing process of stone beads by experimenting with several underrated (yet readily available) materials from the Caribbean: various species of wood, bone, thorns, and chert. As it turns out, thorns from an endemic cactus (Melocactus intortus) worked best and were actually harder than many of the other materials attempted. Even the chert drills were too large and fragile to be effective (neither are they found archaeologically). Using debitage powder from the rock itself, some water, and a basic bow drill mounted with a cactus thorn, the team successfully created perforations on unworked samples of quartz that were similar to those found archaeologically. This was corroborated by analyzing the results at different levels of magnification, including X-ray microtomography and SEM, and then comparing that to similar studies on ancient beads.
 
The results of this study offer useful parameters for the feasibility of bead craftsmanship in the ancient Caribbean. For one, all of the materials used are fairly common in the region, including quartz (although the source of amethyst in the Caribbean is believed to be Guyana (Cody 1990)). Additionally, the practice does not require much skill, as the authors (neophyte craftspeople) were able to replicate the holes. Presumably, a child could do this (an intriguing prospect). The study therefore offers practical data for the once mysterious production of precolumbian personal adornments. Indeed, the article indirectly offers arguments for the presence of bead crafting specialists in other areas of the world as well, where production of ornaments entails similar time investments and complexity. For example, similar quartz materials, like carnelian or agate, shaped into long barrels or cylindrical beads forming beautiful parures, are common to pre-metallic contexts of agro-pastoral societies of Europe and North Africa in the VI and V millennium BC.
 
That said, the huge time commitment (over 200 hours per bead), although far less than the years (or lifetimes) some researchers had previously estimated, socially translates into a distraction from subsistence activities, which may indicate the presence of individuals devoted (at least part-time) to producing non-utilitarian adornments (see also Kenoyer et al. 1991 on this topic). 
 
Focusing on the specific aspect of finding the most appropriate substitute to metal piercing devices and the related aspects of the overall chaîne opératoire, the document invites further research, for example on the bead locking system during the piercing phase, in the management of the force exerted during the process, and in the number of failures (and on their potential uses).
 

References:
Raymond, M., Fouéré, P., Ledevin, R., Lefrais, Y., and Queffelec, A. (2022) Technological analysis and experimental reproduction of the techniques of perforation of quartz beads from the Ceramic period in the Antilles. SocArXiv, a5tgp, ver. 4 peer-reviewed and recommended by Peer Community in Archaeology. https://osf.io/preprints/socarxiv/a5tgp

Cody, A.K. (1990) Prehistoric patterns of exchange in the Lesser Antilles: materials, models, and preliminary observations. PhD thesis, San Diego State University.

Kenoyer, J.M., Vidale, M. and Bhan, K.K. (1991) Contemporary stone bead-making in Khambhat, India: Patterns of craft specialization and organization of production as reflected in the archaeological record. World Archaeology 23 (1), 44-63. https://doi.org/10.1080/00438243.1991.9980158

The paper “For our world without sound. The opportunistic debitage in the Italian context: a methodological evaluation of the lithic assemblages of Pirro Nord, Cà Belvedere di Montepoggiolo, Ciota Ciara cave and Riparo Tagliente” [1] submitted by M. Carpentieri and M. Arzarello is a welcome addition to a growing number of studies focusing on flaking methods showing little to no core preparation, e.g., [2–4]. These flaking methods are often overlooked or seen as ‘simple’, which, in a Middle Palaeolithic context, sometimes leads to a dichotomy of Levallois vs. non-Levallois debitage (e.g., see discussion in [2]).

The authors address this topic by first providing a definition for ‘opportunistic debitage’, derived from the definition of the ‘Alternating Surfaces Debitage System’ (SSDA, [5]). At the core of the definition is the adaptation to the characteristics (e.g., natural convexities and quality) of the raw material. This is one main challenge in studying this type of debitage in a consistent way, as the opportunistic debitage leads to a wide range of core and flake morphologies, which have sometimes been interpreted as resulting from different technical behaviours, but which the authors argue are part of a same ‘methodological substratum’ [1].

This article aims to further characterise the ‘opportunistic debitage’. The study relies on four archaeological assemblages from Italy, ranging from the Lower to the Upper Pleistocene, in which the opportunistic debitage has been recognised. Based on the characteristics associated with the occurrence of the opportunistic debitage in these assemblages, an experimental replication of the opportunistic debitage using the same raw materials found at these sites was conducted, with the aim to gain new insights into the method. Results show that experimental flakes and cores are comparable to the ones identified as resulting from the opportunistic debitage in the archaeological assemblage, and further highlight the high versatility of the opportunistic method.

One outcome of the experimental replication is that a higher flake productivity is noted in the opportunistic centripetal debitage, along with the occurrence of 'predetermined-like' products (such as déjeté points). This brings the authors to formulate the hypothesis that the opportunistic debitage may have had a role in the process that will eventually lead to the development of Levallois and Discoid technologies. How this articulates with for example current discussions on the origins of Levallois technologies (e.g., [6–8]) is an interesting research avenue. This study also touches upon the question of how the implementation of one knapping method may be influenced by the broader technological knowledge of the knapper(s) (e.g., in a context where Levallois methods were common vs a context where they were not). It makes the case for a renewed attention in lithic studies for flaking methods usually considered as less behaviourally significant.

[1] Carpentieri M, Arzarello M. 2020. For our world without sound. The opportunistic debitage in the Italian context: a methodological evaluation of the lithic assemblages of Pirro Nord, Cà Belvedere di Montepoggiolo, Ciota Ciara cave and Riparo Tagliente. OSF Preprints, doi:10.31219/osf.io/2ptjb

[2] Bourguignon L, Delagnes A, Meignen L. 2005. Systèmes de production lithique, gestion des outillages et territoires au Paléolithique moyen : où se trouve la complexité ? Editions APDCA, Antibes, pp. 75–86. Available: https://halshs.archives-ouvertes.fr/halshs-00447352

[3] Arzarello M, De Weyer L, Peretto C. 2016. The first European peopling and the Italian case: Peculiarities and “opportunism.” Quaternary International, 393: 41–50. doi:10.1016/j.quaint.2015.11.005

[4] Vaquero M, Romagnoli F. 2018. Searching for Lazy People: the Significance of Expedient Behavior in the Interpretation of Paleolithic Assemblages. J Archaeol Method Theory, 25: 334–367. doi:10.1007/s10816-017-9339-x

[5] Forestier H. 1993. Le Clactonien : mise en application d’une nouvelle méthode de débitage s’inscrivant dans la variabilité des systèmes de production lithique du Paléolithique ancien. Paléo, 5: 53–82. doi:10.3406/pal.1993.1104

[6] Moncel M-H, Ashton N, Arzarello M, Fontana F, Lamotte A, Scott B, et al. 2020. Early Levallois core technology between Marine Isotope Stage 12 and 9 in Western Europe. Journal of Human Evolution, 139: 102735. doi:10.1016/j.jhevol.2019.102735

[7] White M, Ashton N, Scott B. 2010. The emergence, diversity and significance of the Mode 3 (prepared core) technologies. Elsevier. In: Ashton N, Lewis SG, Stringer CB, editors. The ancient human occupation of Britain. Elsevier. Amsterdam, pp. 53–66.

[8] White M, Ashton N. 2003. Lower Palaeolithic Core Technology and the Origins of the Levallois Method in North‐Western Europe. Current Anthropology, 44: 598–609. doi:10.1086/377653