Roberto Ontañón

Previous efforts to link Palaeolithic cultural records to specific populations through DNA analysis have focused on materials from archaeological floor deposits such as bones, sediments, and artefacts. In this study, we explore whether rock art, a spatially distinct expression of human activity, can also preserve DNA traces from its creators. We analyse DNA preservation in pigment samples collected in and around 24 rock art panels from 11 caves across Spain and Portugal, including simple marks (from nine sites), hand stencils (Maltravieso Cave, Extremadura, Spain), and figurative paintings (Cave of Altamira, Cantabria, Spain). We recover traces of ancient human mitochondrial and nuclear DNA, unaccompanied by faunal DNA, from a pigmented calcite crust at Escoural Cave (Portugal), as well as from an unpigmented cave wall sample from the same site. The absence of faunal DNA in both samples suggests direct DNA deposition through human contact. In contrast, three additional unpigmented samples, from Escoural and Covarón Cave (Asturias, Spain), yielded mixtures of human and faunal DNA, suggesting indirect deposition. Although our results do not conclusively link ancient human DNA preservation to the generation of cave art, we show that traces of human DNA can persist on cave walls for thousands of years.

Sustainable public access to rock art caves requires an evaluation of how visitor presence alters cave microclimates. This study analyzed the response of Santián Cave (Cantabria, northern Spain) to controlled experimental visits conducted during the seasonal phase of reduced cave ventilation and elevated background CO₂. Visitor impact showed a strong spatial contrast: Sector I exhibited only minor thermal anomalies (0.01–0.02 °C), whereas the inner decorated sector recorded mean increases of 0.11 °C in Conjunto I and 0.28 °C in Conjunto II, with a maximum of 0.37 °C. CO₂ showed the clearest cumulative behavior, with daily increases of 268–368 ppm in Conjunto I and 327–376 ppm in Conjunto II, incomplete overnight recovery, and delayed propagation into connected sectors. Suspended particles also increased with visit intensity, from values below 300 particles L⁻¹ for spaced groups of five visitors to a maximum of 686 particles L⁻¹ and recovery times of 13.6 h for consecutive groups of 6–8 visitors. The results show that the most stable cave areas are highly sensitive to visits, cumulative effects become significant without adequate recovery time, and CO₂ serves as the best short-term indicator for access management. The proposed thresholds should be considered preliminary and seasonally dependent.

Horses have inhabited Iberia (present-day Spain and Portugal) since the Middle Pleistocene, shaping a complex history in the region. Iberia has been proposed as a potential domestication centre and is renowned for producing world-class bloodlines. Here, we generate genome-wide sequence data from 87 ancient horse specimens (median coverage = 0.97X) from Iberia and the broader Mediterranean to reconstruct their genetic history over the last ~26,000 years. Here, we report that wild horses of the divergent IBE lineage inhabited Iberia from the Late Pleistocene, while domesticated DOM2 horses, native from the Pontic-Caspian steppes, already arrived ~1850 BCE. Admixture dating suggests breeding practices involving continued wild restocking until at least ~350 BCE, with IBE disappearing shortly after. Patterns of genetic affinity highlight the far-reaching influence of Iberian bloodlines across Europe and north Africa during the Iron Age and Antiquity, with continued impact extending thereafter, particularly during the colonization of the Americas.

This article presents an innovative workflow for the acquisition and storage of archaeological data. The system is based on open-source software to enhance method replication and media accessibility. QGIS software is used as the central platform, connected to a spatial database developed in PostgreSQL and managed with the SQL and Python programming languages. The aim is to achieve an efficient, flexible, and reproducible digital method for data collection and management that can be applied to surface archaeological surveys. During the implementation and development of the method, we have recorded over 4,600 archaeological remains in two different structures with traces of Upper Paleolithic activity in the Lower Gallery of La Garma (Cantabria, Spain). After 18 months of continuous work, the results obtained demonstrate the usefulness and versatility of this procedure, which can be adapted to each context and to the specific needs of each researcher. Our goal is not simply to systematize archaeological documentation, as traditionally proposed, but to establish a simple and robust method for data collection and preservation, accessible to any user. Its fully open-source approach aims to promote a model that is nurtured by the use and contributions of the research community.

The Cantabrian region, located in north Spain, is home to many caves with parietal art, some of them included on the UNESCO World Heritage list, such as El Castillo and Covalanas. These two caves are currently open to tourism and boast an exceptional archaeological heritage that includes magnificent examples of Palaeolithic cave art. Through a multiyear research project (2020–2022) sponsored by the Government of Cantabria, a precise characterisation of the environmental dynamics of each cave under different meteorological contexts was carried out, as well as an evaluation of the evolution of the impacts of anthropic origin on the underground microclimate under different degrees of influx of visitors on an interannual scale. We aimed to unravel the effects of daily visitor flow on cave environmental stability and offer well-defined recommendations to harmonise conservation priorities with public accessibility based on sustainable tourism management. Once the microclimatic control parameters for the conservation of the paintings, engravings, and supporting rock, such as temperature and CO₂ concentration in the air, were assessed under different seasonal meteorological conditions, a standardised graphic method was implemented based on the frequency distribution of the variations in each parameter, grouped according to the different increasing ranges of daily visits. With this method, it is possible to evaluate, probabilistically and in percentage terms, the microclimatic destabilisation of the cave generated by each group of visitors, taking as a reference the daily variation ranges of each control parameter under natural conditions, i.e., during the days or periods of time in which each cave remained closed to tourist visits. The recommended values of maximum visitor capacity for each cave, in terms of average monthly daily visitor numbers, have been set at 60 and 15 visitors/day for El Castillo and Covalanas caves, respectively. Based on these results, the cave managers are carrying out, from May 2024, a progressive adaptation in the tourist management of these caves until they are fully adapted to the environmental sustainability parameters defined in this study.

In the studies on Prehistoric Graphic Expression, there are recurrent discussions about the tracings generated by different observers of the same motif. Methodological issues concerning the role of archaeological imaging are often implied within those debates. Do the tracings belong to the observational data exposition chapter, or are they part of the interpretative conclusions? How can the current technological scenario help solve these problems? In 2017, we conducted new documentation of the Peña Tu rock shelter, a well-known site with an intriguing post-palaeolithic graphic collection documented on several occasions throughout the twentieth century. Our objective was to provide quantifiable and, if possible, objective documentation of the painted and engraved remnants on the shelter’s surface. To achieve this, we employed two data capture strategies. One strategy focused on analysing the vestiges of paintings using a hyperspectral sensor, while the other centred on the geometric definition of engravings and the rock support, utilising photogrammetric techniques and laser scanning. These approaches presented various parallax challenges. Despite these challenges, our results were highly satisfactory. We resolved uncertainties regarding the formal features of specific designs that had been subject to debate for a long time. Additionally, we discovered previously unpublished areas with traces of paintings. Lastly, we developed a map highlighting recent alterations and deteriorations, providing a valuable tool for assessing the site’s preservation status. In conclusion, by employing advanced technology and comprehensive documentation methods, we significantly contributed to understanding and preserving the prehistoric graphic expressions at the Peña Tu rock shelter.

In the studies on Prehistoric Graphic Expression, there are recurrent discussions about the tracings generated by different observers of the same motif. Methodological issues concerning the role of archaeological imaging are often implied within those debates. Do the tracings belong to the observational data exposition chapter, or are they part of the interpretative conclusions? How can the current technological scenario help solve these problems? In 2017, we conducted new documentation of the Peña Tu rock shelter, a well-known site with an intriguing post-palaeolithic graphic collection documented on several occasions throughout the 20th century. Our objective was to provide quantifiable and, if possible, objective documentation of the painted and engraved remnants on the shelter's surface. To achieve this, we employed two data capture strategies. One strategy focused on analyzing the vestiges of paintings using a hyperspectral sensor, while the other centred on the geometric definition of engravings and the rock support, utilizing photogrammetric techniques and laser scanning. These approaches presented various parallax challenges. Despite these challenges, our results were highly satisfactory. We resolved uncertainties regarding the formal features of specific designs that had been subject to debate for a long time. Additionally, we discovered previously unpublished areas with traces of paintings. Lastly, we developed a map highlighting recent alterations and deteriorations, providing a valuable tool for assessing the site's preservation status. In conclusion, by employing advanced technology and comprehensive documentation methods, we significantly contributed to understanding and preserving the prehistoric graphic expressions at the Peña Tu rock shelter.

Cantabrian cave art is familiar from photographs reproduced in textbooks, but these two-dimensional images do not capture the irregularities of the rock surfaces on which animals and other designs were painted or engraved. Here, the authors use stereoscopic photography to review the parietal art of La Pasiega cave. By documenting the uneven surfaces of the cave's walls alongside painted and engraved marks, they identify new animal figures and reinterpret others, previously thought to be partial representations, as complete. The results show the positioning of animal figures to make use of concave/convex surfaces and rock edges to define the outlines of animals, reinforcing the need to record and interpret cave art three-dimensionally.