Tektites, a naturally occurring glass produced by major cosmic impacts and ejected at long distances, are known from five impacts worldwide [1]. The presence of this impact-generated glass, which can be dated in the same way as a volcanic rock, has been used to date archaeological sites in several regions of the world. This paper by Marwick and colleagues [2] reviews and adds new data on the use and misuse of this specific material as a chronological marker in Australia, East and Southeast Asia, where an impact dated to 0.78 Ma created and widely distributed tektites. This material, found in archaeological excavations in China, Laos, Thaïland, Australia, Borneo, and Vietnam, has been used to date layers containing lithic artifacts, sometimes creating a strong debate about the antiquity of the occupation and lithic production in certain regions.

The review of existing data shows that geomorphological data and stratigraphic integrity can be questioned at many sites that have yielded tektites. The new data provided by this paper for five archaeological sites located in Vietnam confirm that many deposits containing tektites are indeed lag deposits and that these artifacts, thus in secondary position, cannot be considered to date the layer. This study also emphasizes the general lack of other dating methods that would allow comparison with the tektite age. In the Vietnamese archaeological sites presented here, discrepancies between methods, and the presence of historical artifacts, confirm that the layers do not share similar age with the cosmic impact that created the tektites.

Based on this review and these new results, and following previous propositions [3], Marwick and colleagues conclude that, if tektites can be used as chronological markers, one has to prove that they are in situ. They propose that geomorphological assessment of the archaeological layer as primary deposit must first be attained, in addition to several parameters of the tektites themselves (shape, size distribution, chemical composition). Large error can be made by using only tektites to date an archaeological layer, and this material should not be used solely due to risks of high overestimation of the age of the archaeological production. 

[1] Rochette, P., Beck, P., Bizzarro, M., Braucher, R., Cornec, J., Debaille, V., Devouard, B., Gattacceca, J., Jourdan, F., Moustard, F., Moynier, F., Nomade, S., Reynard, B. (2021). Impact glasses from Belize represent tektites from the Pleistocene Pantasma impact crater in Nicaragua. Communications Earth & Environment, 2(1), 1–8, https://doi.org/10.1038/s43247-021-00155-1

[2] Marwick, B., Son, P. T., Brewer, R., Wang, L.-Y. (2022). Tektite geoarchaeology in mainland Southeast Asia. SocArXiv, 93fpa, ver. 6 peer-reviewed and recommended by PCI Archaeology, https://doi.org/10.31235/osf.io/93fpa.

[3] Tada, T., Tada, R., Chansom, P., Songtham, W., Carling, P. A., Tajika, E. (2020). In Situ Occurrence of Muong Nong-Type Australasian Tektite Fragments from the Quaternary Deposits near Huai Om, Northeastern Thailand. Progress in Earth and Planetary Science 7(1), 1–15, https://doi.org/10.1186/s40645-020-00378-4

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

Anneke H. van Heteren based on reviews by Stefan Schlager and 1 anonymous reviewer

Phenomics is the analysis of high-dimensional phenotypic data [1]. Phenomics research strategies are capable of linking genetic variation to phenotypic variation [2], but a genetic component is not absolutely necessary. The paper “Archaeophenomics of ancient domestic plants and animals using geometric morphometrics: a review” by Evin and colleagues [3] examines the use of geometric morphometrics in bioarchaeology and coins the term archaeophenomics. Archaeophenomics can be described as the large-scale phenotyping of ancient remains, and both addresses taxonomic identification, as well as infers spatio-temporal agrobiodiversity dynamics. It is a relatively new field in bioarchaeology with the first paper using this approach stemming from 2004. This study by Evin et al. [3] presents an excellent review and unquestionably demonstrates the potential of archaeophenomics.

The authors provide an exhaustive review specifically of bioarchaeological studies in international journals using geometric morphometrics to study archaeological remains of domestic species. Although geometric morphometrics lends itself well for archaeophenomics, readers should keep in mind that this is not the only method and other approaches might equally fall under archaeophenomics as long as high-dimensional phenotypic archaeological data are involved.

Distinguishing archaeophenomics from phenomics is important because of a critical difference. Archaeological remains are often altered by taphonomical processes. As such data may not be as complete as when working with modern specimens. Although this poses difficulties, morphometric analyses can usually still be performed as long as the structures presenting the relevant geometrical features are present. Even fragmented remains can be studied with a restricted version of the original landmarking/measurement protocol.

Evin et al. [3] define archaeophenomics as “phenomics of the past”. This is only partly correct. It can be deduced from their review that they really mean phenomics of our (human) past. This leaves a gap for phenomics of the non-human past, for which I suggest the term palaeophenomics. 

[1] Jin, L. (2021). Welcome to the Phenomics Journal. Phenomics, 1, 1–2. https://doi.org/10.1007/s43657-020-00009-4.
[2] Bilder, R.M., Sabb, F.W., Cannon, T.D., London, E.D., Jentsch, J.D., Stott Parker, D., Poldrack, R.A., Evans, C., Freimer, N.B. (2009). Phenomics: the systematic study of phenotypes on a genome-wide scale. Neuroscience, 164(1), 30-42. https://doi.org/10.1016/j.neuroscience.2009.01.027
[3] Evin, A., Bouby, L., Bonhomme, V., Jeanty, A., Jeanjean, M., Terral., J.-F. (2022). Archaeophenomics of ancient domestic plants and animals using geometric morphometrics: a review. Peer-reviewed and recommended by PCI Archaeology. https://doi.org/10.31219/osf.io/skeu5

Data authenticity and approaches to data authentication are crucial issues in ancient protein research. The advent of modern mass spectrometry has enabled the detection of traces of ancient biomolecules contained in fossils, including protein sequences. However, detecting proteins in ancient samples does not equate to demonstrating their endogenous nature: instead, if the mechanisms that drive protein preservation and degradation are understood, then the extent of protein diagenesis can be used for evaluating preservational quality, which in turn may be related to the authenticity of the protein data. 

The post-mortem deamidation of asparaginyl and glutamyl residues is a key degradation reaction, which can be assessed effectively on the basis of mass spectrometry data, and which has accrued a long history of research, both in terms of describing the mechanisms governing the reactions and with regard to the best strategies for assessing and quantifying the extent of glutamine (Gln) and asparagine (Asn) deamidation in ancient samples (Pal Chowdhury et al., 2019; Ramsøe et al., 2021, 2020; Schroeter and Cleland, 2016; Simpson et al., 2016; Solazzo et al., 2014; Welker et al., 2016; Wilson et al., 2012). 

In their paper, Nair and colleagues (2022) build on this wealth of knowledge and present a tool for quantifying the extent of Gln deamidation in parchment. Parchment is a collagen-based material which can yield extraordinary insights into manuscript manufacturing practices in the past, as well as on the daily lives of the people who assembled and used them (“biocodicology”) (Fiddyment et al., 2021, 2019, 2015; Teasdale et al., 2017). Importantly, the extent of deamidation can be directly related to the quality of the parchment produced: rapid direct deamidation of Gln is induced by the liming process, therefore high extents of deamidation are linked to prolonged exposure to the high pH conditions which are typical of liming, thus implying lower-quality parchment.

Nair et al.’s approach focuses on collagen peptides which are typically detected during MALDI-TOF mass spectrometry analyses of parchment and build a simple three-step workflow able to yield an overall index of deamidation for a sample (the parchment glutamine index - PQI) 一 taking into account that different Gln residues degrade at different rates according to their micro-chemical environment. The first step involves pre-processing the MALDI spectra, since Nair et al. are specifically interested in maximising information which can be obtained by low-quality data. The second step builds on well-established methods for quantifying Q → E from MALDI-TOF data by modelling the convoluted isotope distributions (Wilson et al., 2012). Once relative rates of deamidation in selected peptides within a given sample are calculated, the third step uses a mixed effects model to combine the individual deamidation estimates and to obtain an overall estimate of the deamidation for a parchment sample (PQI). 

The PQI can be used effectively for assessing parchment quality, as the authors show for the dataset from Orval Abbey. However, PQI could also have wider applications to the study of processed collagen, which is widely used in the food and pharmaceutical industries. In general, the study by Nair et al. is a welcome addition to a growing body of research on protein diagenesis, which will ultimately improve models for the assessment of the authenticity of biomolecular data in archaeology. 

References

Chowdhury, P.M., Wogelius, R., Manning, P.L., Metz, L., Slimak, L., and Buckley, M. 2019. Collagen deamidation in archaeological bone as an assessment for relative decay rates. Archaeometry 61:1382–1398. https://doi.org/10.1111/arcm.12492

Fiddyment, S., Goodison, N.J., Brenner, E., Signorello, S., Price, K., and Collins, M.J.. 2021. Girding the loins? Direct evidence of the use of a medieval parchment birthing girdle from biomolecular analysis. bioRxiv. https://doi.org/10.1098/rsos.202055

Fiddyment,S., Holsinger, B., Ruzzier, C., Devine, A., Binois, A., Albarella, U., Fischer, R., Nichols, E., Curtis, A., Cheese, E., Teasdale, M.D., Checkley-Scott, C., Milner, S.J., Rudy, K.M., Johnson, E.J., Vnouček, J., Garrison, M., McGrory, S., Bradley, D.G., and Collins, M.J. 2015. Animal origin of 13th-century uterine vellum revealed using noninvasive peptide fingerprinting. Proc Natl Acad Sci U S A 112:15066–15071. https://doi.org/10.1073/pnas.1512264112

Fiddyment, S., Teasdale, M.D., Vnouček, J., Lévêque, É., Binois, A., and Collins, M.J. 2019. So you want to do biocodicology? A field guide to the biological analysis of parchment. Heritage Science 7:35. https://doi.org/10.1186/s40494-019-0278-6

Nair, B., Rodríguez Palomo, I., Markussen, B., Wiuf, C., Fiddyment, S., and Collins, M. Parchment Glutamine Index (PQI): A novel method to estimate glutamine deamidation levels in parchment collagen obtained from low-quality MALDI-TOF data. BiorRxiv, 2022.03.13.483627, ver. 6 peer-reviewed and recommended by Peer community in Archaeology. https://doi.org/10.1101/2022.03.13.483627 

Ramsøe, A., Crispin, M., Mackie, M., McGrath, K., Fischer, R., Demarchi, B., Collins, M.J., Hendy, J., and Speller, C. 2021. Assessing the degradation of ancient milk proteins through site-specific deamidation patterns. Sci Rep 11:7795. https://doi.org/10.1038/s41598-021-87125-x

Ramsøe, A., van Heekeren, V., Ponce, P., Fischer, R., Barnes, I., Speller, C., and Collins, M.J. 2020. DeamiDATE 1.0: Site-specific deamidation as a tool to assess authenticity of members of ancient proteomes. J Archaeol Sci 115:105080. https://doi.org/10.1016/j.jas.2020.105080

Schroeter, E.R., and Cleland, T.P. 2016. Glutamine deamidation: an indicator of antiquity, or preservational quality? Rapid Commun Mass Spectrom 30:251–255. https://doi.org/10.1002/rcm.7445

Simpson, J.P., Penkman, K.E.H., and Demarchi, B. 2016. The effects of demineralisation and sampling point variability on the measurement of glutamine deamidation in type I collagen extracted from bone. J Archaeol Sci 69: 29-38. https://doi.org/10.1016/j.jas.2016.02.002

Solazzo, C., Wilson, J., Dyer, J.M., Clerens, S., Plowman, J.E., von Holstein, I., Walton Rogers, P., Peacock, E.E., and Collins, M.J. 2014. Modeling deamidation in sheep α-keratin peptides and application to archeological wool textiles. Anal Chem 86:567–575. https://doi.org/10.1021/ac4026362

Teasdale, M.D., Fiddyment, S., Vnouček, J., Mattiangeli, V., Speller, C., Binois, A., Carver, M., Dand, C., Newfield, T.P., Webb, C.C., Bradley, D.G., and Collins M.J. 2017. The York Gospels: a 1000-year biological palimpsest. R Soc Open Sci 4:170988. https://doi.org/10.1098/rsos.170988

Welker, F., Soressi, M.A., Roussel, M., van Riemsdijk, I., Hublin, J.-J., and Collins, M.J. 2016. Variations in glutamine deamidation for a Châtelperronian bone assemblage as measured by peptide mass fingerprinting of collagen. STAR: Science & Technology of Archaeological Research 3:15–27. https://doi.org/10.1080/20548923.2016.1258825

Wilson, J., van Doorn, N.L., and Collins, M.J. 2012. Assessing the extent of bone degradation using glutamine deamidation in collagen. Anal Chem 84:9041–9048. https://doi.org/10.1021/ac301333t

The paper 'A database of lapidary artifacts in the Caribbean for the Ceramic Age' by Queffelec et al. [1] presents a description of a dataset of nearly 5000 lapidary artefacts from over 100 sites. The data are dominated by beads and pendants, which are mostly made from Diorite, Turquoise, Carnelian, Amethyst, and Serpentine. The raw material data is especially valuable as many of these are not locally available on the island. This holds great potential for exchange network analysis. The data may be especially useful for investigating one of the fundamental questions of this region: whether the Cedrosan and Huecan are separate, little related developments, with different origins, or variants or a single tradition [2].

In addition to metric and technological details about the artefacts, the data include a variety of locational details, including coordinates, distance to coast, and altitude. This enables many opportunities for future spatial analysis and geostatistical modelling to understand human behaviours relating to ornament production, use, and discard. I recommend the authors make a minor revision to Table 1 (spatial coverage of the dataset) to make the column with the citations conform to the same citation style used in the rest of the text.

I warmly commend the authors for making transparency and reproducibility a priority when preparing their manuscript. Their use of the R Markdown format for writing reproducible, dynamic documents [3] is highly impressive. This is an excellent example for others in the international archaeological science community to follow. The paper is especially useful for researchers who are new to R and R Markdown because of the elegant and accessible way the authors document their research here.

[1] Queffelec, A., Fouéré, P. and Caverne, J.-B. 2021. A database of lapidary artifacts in the Caribbean for the Ceramic Age. SocArXiv, 7dq3b, ver. 4 Peer-reviewed and recommended by PCI Archaeology. https://doi.org/10.31235/osf.io/7dq3b

[2] Reed, J. A. and Petersen, J. B. 2001. A comparison of Huecan and Cedrosan Saladoid ceramics at the Trants site, Montserrat. In Proceedings of the XVIIIth International Congress for Caribbean Archaeology (pp. 253-267).

[3] Marwick, B. 2017. Computational Reproducibility in Archaeological Research: Basic Principles and a Case Study of Their Implementation. Journal of Archaeological Method and Theory 24, 424–450. https://doi.org/10.1007/s10816-015-9272-9