Neanderthal Stone Tool Secrets Revealed by 3D Scans at Italian Rock Shelter

Deep inside a limestone rock shelter in southern Italy, a team of researchers has pieced together one of the most detailed portraits yet of how Neanderthal communities lived, worked, and passed on their craft across thousands of years. At Riparo l’Oscurusciuto, a site perched above the Ginosa ravine in Apulia, excavations have uncovered a six-metre-thick stack of archaeological deposits spanning roughly 55,000 to 40,000 years ago, a window that captures the final chapters of the Middle Palaeolithic and the dramatic cultural transformations that followed. A new study published in Archaeological and Anthropological Sciences combines traditional stone tool analysis with cutting-edge three-dimensional scanning to ask a deceptively simple question: did the people who returned to this shelter generation after generation belong to the same cultural lineage, or did new groups with different traditions arrive and replace them?

The answer, according to the research team led by Francesco Valletta of the University of Haifa together with colleagues from the University of Siena, the University of Bologna, and other institutions, points strongly toward continuity. By examining stone tools from three stratigraphic units, SU 11 near the bottom of the excavated sequence, SU 4 in the middle, and SU 2 near the top, the researchers found that the same set of technological solutions was used throughout. The knappers who worked flint at the shelter relied predominantly on the Levallois method, a sophisticated prepared-core technique in which the stone’s surface is shaped so that a single, carefully planned flake or point can be struck off. At Oscurusciuto, the dominant variant was unidirectional convergent Levallois, aimed at producing elongated points, with a secondary strategy devoted to extracting flakes and blades from simple single-platform cores.

What makes this conclusion remarkable is the method behind it. Traditional lithic analysis sorts artifacts into discrete qualitative categories, points, blades, scrapers, cores, and describes them with attributes such as platform type or scar orientation. These approaches are powerful but subjective, and different analysts using different definitions can produce results that are difficult to compare directly. The new study introduces a hybrid protocol that fuses human expertise with automated 3D measurement. Digital models of each artifact, captured with structured-light scanners, are first processed by software that automatically segments the surface into individual flake scars based on curvature. The analyst then identifies which scars correspond to blank removals and striking platforms, after which the software computes precise quantitative measures that were previously impossible to standardise.

Among these measures are three Euler angles, yaw, pitch, and roll, that describe the orientation of each flake scar in three-dimensional space, together with the core platform angle, the inclination between the striking platform and the reduction surface. In Levallois reduction, platform angles cluster near 90 degrees and flakes are removed parallel to the main surface, producing pitch values close to zero. Deviations from these expectations reveal different reduction strategies: convergent patterns, centripetal exploitation, or the semi-tournant method in which the reduction surface wraps around the sides of the core. Because angles are periodic values that repeat every 360 degrees, the researchers analysed them with circular statistics, and they used a density-based clustering algorithm called DBSCAN to sort reduction sequences into technologically homogeneous groups without predetermining how many groups should exist.

The clustering revealed five distinct reduction modalities across the 188 analysable core sequences from the three layers. Crucially, the defining features of each modality remained statistically stable through time. Within each cluster, there was no significant variation between the stratigraphic units in platform angles, pitch, or the dispersion of scar orientations. The analysis of blanks told the same story: interior and exterior platform angles and ventral face profiles showed no clear-cut change across the sequence. Even micro-points, small convergent blanks shorter than 30 millimetres that had been interpreted as an innovation appearing only in the uppermost layer, turned out to be present in all three units, with no significant technological differences between them. What did change was the size of the finished products and the relative frequency of different reduction strategies, shifts the researchers attribute not to a new population but to flexible adjustments within a stable tradition.

This distinction between a manufacturing tradition and its organisation lies at the heart of the study’s interpretation. The researchers argue that deeply embedded motor skills and methodological choices, the so-called technological fingerprints of a community of practice, are difficult to transmit between groups because they are largely invisible in the finished product and technologically rigid. Their persistence across layers therefore suggests that the shelter was occupied, over a span of some fifteen millennia, by groups sharing the same learning traditions and possibly the same cultural identity. Changes in blank dimensions, in the proportions of naturally backed knives, and in the incidence of particular core strategies, by contrast, reflect the interaction between mobility, resource availability, group composition, and the economic activities conducted at the site, in other words, the flexible organisation of technology rather than its replacement.

The environmental backdrop makes this flexibility all the more striking. The sequence records the deposition of volcanic ash from the Mount Epomeo Green Tuff eruption around 56,500 years ago, an event that interrupted use of the shelter’s interior space, as well as a later expansion of grassland environments during the climatically volatile Marine Isotope Stage 3. Yet neither the tephra fall nor the shifting vegetation disrupted the local manufacturing tradition. Apulia, with its sheltered ravines and reliable water sources, may have functioned as a refugium where thermophile plants and animals persisted through cold spells, allowing Neanderthal groups to anchor their landscape use to places where resources remained predictable. Returning repeatedly to the same shelter, they drew on a conservatively transmitted repertoire of knapping solutions while adjusting the details of production to meet changing circumstances.

At the same time, the very conservatism of the technology carries a sobering implication. The absence of significant innovation or external influence along the sequence suggests that these communities were relatively isolated, with little input of new ideas or people from neighbouring regions. The researchers propose that Late Mousterian Italy was a mosaic of small, geographically fragmented populations, each maintaining its own local identity and technological drift. Such isolation carries risks: small effective population sizes limit the number of cultural traits that can be transmitted between generations, and isolated groups lack the extensive social networks that buffer other hunter-gatherers against poor years, accidents, and environmental deterioration. Local extinctions become more likely, and the cumulative loss of such communities could ultimately have contributed to the demise of the Mousterian technocomplex across the peninsula, without any single catastrophic trigger.

The study also demonstrates the growing power of digital methods in archaeology. All 3D models, scar segmentations, and analytical procedures have been released in a public Zenodo repository, allowing other researchers to verify and replicate the results, a level of transparency that traditional hand measurement cannot match. The authors emphasise that the interpretive role of the human analyst remains central: the software identifies scars, but only an experienced technologist can decide which of them belong to a reduction sequence. It is precisely this hybrid character, automated precision combined with expert judgement, that the team hopes will allow comparable datasets to be built for other Late Middle Palaeolithic assemblages across Italy and the wider Mediterranean, sharpening the picture of how people and ideas moved, or failed to move, during the pivotal millennia when Neanderthal Europe gave way to the world of modern humans.

Subject of Research: Late Mousterian lithic technological continuity and flexibility at Riparo l'Oscurusciuto, Italy, analysed through typo-technological and 3D-based methods

Article Title: Flexible Late Mousterian lithic technological organisation at Riparo l’Oscurusciuto (Italy): A typo-technological and 3D-based approach

Article References: Valletta, F., Oron, M., Rossini, M., Marciani, G., Caricola, I., Abrunhosa, A., Spagnolo, V., Ronchitelli, A., Berna, F., Benazzi, S., Boschin, F., & Barzilai, O. (2026). Flexible Late Mousterian lithic technological organisation at Riparo l’Oscurusciuto (Italy): A typo-technological and 3D-based approach. Archaeological and Anthropological Sciences, 18(10), Article 200. https://doi.org/10.1007/s12520-026-02558-7

Image Credits: AI Generated

DOI: 10.1007/s12520-026-02558-7

Keywords: Neanderthals, Late Mousterian, lithic technology, Levallois, 3D scanning, Riparo l'Oscurusciuto, Middle Palaeolithic, Italy, cultural transmission, stone tools, technological organisation, Archaeological and Anthropological Sciences