Stone artifacts from layer 11 of Bacho Kiro Cave (excavation 1971–1975) stored at the National Museum of History, Sofia (Bulgaria)

The 1971–1975 excavations at Bacho Kiro Cave (Bulgaria) uncovered a rich stratigraphic sequence spanning the Middle to Upper Paleolithic transitional period, with Layer 11 representing one of the earliest Upper Paleolithic occupations in Europe. A subset of this collection—lithic artifacts and animal tooth pendants—is currently stored at the National Museum of History in Sofia. Although these artifacts were selected for their completeness, they nonetheless provide valuable complementary data to the recently excavated Initial Upper Paleolithic (IUP) assemblages from the same site. Here we present an integrated analysis of this collection combining raw material provenance, techno-typological classification, and use-wear analysis. Raw material analysis reveals two principal flint sources: Lower Cretaceous flint from the Ludogorie region up to 190 km northeast, and Upper Cretaceous flint from the Nikopol–Asenovo area on the Danube’s right bank up to 130 km north. The lithic collection is dominated by endscrapers, pointed blades, and retouched blades. Its techno-typological features reveal a duality: Middle Paleolithic traits—including Levallois-like reduction, facetted platforms, and retouched pointed blades (some of which are stylistically close to Mousterian points)—coexist with Upper Paleolithic innovations, such as systematic blade production, endscrapers, and a diverse range of tool types, several of which show intensive reworking. Use-wear analysis indicates that most artifacts preserve diagnostic traces of woodworking, hide scraping, and working hard animal materials, with extensive edge damage suggesting long-term tool use. The high fragmentation rate and transformation of outworn tools into scaled pieces attest to a curated technological organization linked to the logistical constraints of distant raw material procurement. This study confirms the integrity of Layer 11 and its correlation with recently excavated layers, demonstrating that this collection accurately reflects the distinctive economic and technological behavior of IUP Homo sapiens groups at Bacho Kiro Cave. These early European populations are caracterized by a combination of long-distance raw material transport, intensive tool curation, and diverse domestic activities, illuminating the adaptive strategies that underpinned their dispersal into Eurasia.