New Neandertal remains from Sirogne Cave (Lot, France): implications for human evolution and behavior prior to the last interglacial

Abstract

International audienceWhile neighboring regions have yielded numerous Neandertal remains, few discoveries have been reported from the limestone plateaus of the Quercy region in France [1]. However, the accidental discovery in 2006 of a Neandertal-like hemimandible and a deciduous tooth by a speleologist in Sirogne Cave — located within a Jurassic karst system in the northern part of the Alzou Canyon near Rocamadour (Lot, France) — prompted six excavation seasons between 2013 and 2018. These aimed to better understand the chronology, modes of Neandertal occupation, and biological evolution of the populations using the site.The excavations clarified the context of the 2006 discovery and revealed a partially disturbed stratigraphy, affected by recent human interventions. Nevertheless, several preserved layers, covered by stalagmitic floors along the western wall of the cave, were identified. Most notably, nearly 100 human fossils were unearthed from the cave, representing at least 10 individuals: Three children (aged 3–8 years), two adolescents, three young adults, and two older adults. The remains include two hemimandibles (one immature, one adult), over 80 isolated teeth, and infracranial elements. Although most come from sediments affected by post-depositional processes, all exhibit unambiguous Neandertal features. Several infracranial bones show cutmarks indicative of dismemberment and disarticulation, suggesting complex mortuary behaviors. The reworked layers also contained faunal remains from over 20 taxa, reflecting a broad but clearly Pleistocene spectrum resulting from both natural and anthropogenic accumulations. More than 2,000 lithic artefacts in quartz, flint, and limestone were also recovered, pointing to at least two Paleolithic techno-complexes: one attributed to the Middle Paleolithic and another to the end of the Last Glacial Maximum. Moreover, Sirogne may correspond to the “Crozo del Dua” cave excavated in the early 20th century by André Niederlander, which yielded five isolated Neandertal teeth and a lithic assemblage [1-3]. Our reanalysis of his faunal collectionled to the identification of two additional Neandertal remains — a phalanx and a lower permanent canine — morphologically consistent with the Sirogne material. Combined geological, taphonomic, biochronological, and absolute dating of the stalagmitic floors and associated sediments place the Neandertal fossils within Marine Isotope Stage (MIS) 6, most probably at the end of the Middle Pleistocene (ca. 150,000–130,000 years ago), which represents a critical, yet poorly documented, phase in Neandertal evolutionary history [4].Morphometric analyses of the teeth and mandibles suggest that the Sirogne individuals are more closely aligned with early Neandertals (pre-MIS 5) than with later groups. They exhibit classic Neandertal features and share affinities with Middle Pleistocene fossils based on external dental dimensions, enamel-dentine junction (EDJ) shape, and non-metric dental traits. Additionally, the low inter-individual variation in EDJ morphology indicates significant biological homogeneity within the Sirogne group. This homogeneity appears even greater than that observed at the Krapina MIS 5e site (Croatia), possibly reflecting regional isolation during MIS 6. Altogether, this exceptional assemblage offers rare and crucial insights into 18 population dynamics and evolutionary processes during a key period in Neandertal history. The evidence supports a model of strong group structuring and complex demographic patterns in Europe prior to 120,000 years ago [4]. Further analyses are currently underway, including attempts at ancient DNA extraction, calcium isotope studies for dietary reconstruction, and SR-microCT imaging of dental microstructures to explore growth patterns and developmental stress. A new three-year excavation project will further refine the chronocultural context and clarify the processes underlying the accumulation of human remains at the site