Initial Upper Palaeolithic humans in Europe had recent Neanderthal ancestry.

Modern humans appeared in Europe by at least 45,000 years ago1-5, but the extent of their interactions with Neanderthals, who disappeared by about 40,000 years ago6, and their relationship to the broader expansion of modern humans outside Africa are poorly understood. Here we present genome-wide data from three individuals dated to between 45,930 and 42,580 years ago from Bacho Kiro Cave, Bulgaria1,2. They are the earliest Late Pleistocene modern humans known to have been recovered in Europe so far, and were found in association with an Initial Upper Palaeolithic artefact assemblage. Unlike two previously studied individuals of similar ages from Romania7 and Siberia8 who did not contribute detectably to later populations, these individuals are more closely related to present-day and ancient populations in East Asia and the Americas than to later west Eurasian populations. This indicates that they belonged to a modern human migration into Europe that was not previously known from the genetic record, and provides evidence that there was at least some continuity between the earliest modern humans in Europe and later people in Eurasia. Moreover, we find that all three individuals had Neanderthal ancestors a few generations back in their family history, confirming that the first European modern humans mixed with Neanderthals and suggesting that such mixing could have been common.

Initial Upper Palaeolithic Homo sapiens from Bacho Kiro Cave, Bulgaria.

The Middle to Upper Palaeolithic transition in Europe witnessed the replacement and partial absorption of local Neanderthal populations by Homo sapiens populations of African origin1. However, this process probably varied across regions and its details remain largely unknown. In particular, the duration of chronological overlap between the two groups is much debated, as are the implications of this overlap for the nature of the biological and cultural interactions between Neanderthals and H. sapiens. Here we report the discovery and direct dating of human remains found in association with Initial Upper Palaeolithic artefacts2, from excavations at Bacho Kiro Cave (Bulgaria). Morphological analysis of a tooth and mitochondrial DNA from several hominin bone fragments, identified through proteomic screening, assign these finds to H. sapiens and link the expansion of Initial Upper Palaeolithic technologies with the spread of H. sapiens into the mid-latitudes of Eurasia before 45 thousand years ago3. The excavations yielded a wealth of bone artefacts, including pendants manufactured from cave bear teeth that are reminiscent of those later produced by the last Neanderthals of western Europe4-6. These finds are consistent with models based on the arrival of multiple waves of H. sapiens into Europe coming into contact with declining Neanderthal populations7,8.

Initial Upper Paleolithic bone technology and personal ornaments at Bacho Kiro Cave (Bulgaria).

The expansion of Homo sapiens and our interaction with local environments, including the replacement or absorption of local populations, is a key component in understanding the evolution of our species. Of special interest are artifacts made from hard animal tissues from layers at Bacho Kiro Cave (Bulgaria) that have been attributed to the Initial Upper Paleolithic. The Initial Upper Paleolithic is characterized by Levallois-like blade technologies that can co-occur with bone tools and ornaments and likely represents the dispersal of H. sapiens into several regions throughout Eurasia starting by 45 ka or possibly earlier. Osseous artifacts from the Initial Upper Paleolithic are important components of this record and have the potential to contribute to our understanding of group interactions and population movements. Here, we present a zooarchaeological, technological, and functional analysis of the diverse and sizable osseous artifact collection from Bacho Kiro Cave. Animal raw material sources are consistent with taxa found within the faunal assemblage including cervids, large bovids, and cave bears. A variety of bone tool morphologies, both formal and informal, indicate a diverse technological approach for conducting various on-site activities, many of which were focused on the processing of animal skins, likely for cold weather clothing. Technological flexibility is also evident in the manufacture of personal ornaments, which were made primarily from carnivore teeth, especially cave bear, though herbivore teeth and small beads are also represented. The osseous artifacts from Bacho Kiro Cave provide a series of insights into the bone technology and indirectly on the social aspects of these humans in southeast Europe, and when placed within the broader Initial Upper Paleolithic context, both regional and shared behaviors are evidently indicating widespread innovation and complexity. This is especially significant given the location and chronology of the site in the context of H. sapiens dispersals.

Subsistence behavior during the Initial Upper Paleolithic in Europe: Site use, dietary practice, and carnivore exploitation at Bacho Kiro Cave (Bulgaria).

The behavioral dynamics underlying the expansion of Homo sapiens into Europe remains a crucial topic in human evolution. Owing to poor bone preservation, past studies have strongly focused on the Initial Upper Paleolithic (IUP) stone tool record. Recent excavations and extensive radiocarbon dating at Bacho Kiro Cave (Bulgaria) pushed back the arrival of IUP H. sapiens into Europe to ca. 45,000 years ago. This site has exceptional bone preservation, and we present the study of 7431 faunal remains from across two IUP layers (I and J) and one Middle Paleolithic layer (K). We identified a shift in site use and occupation intensity through time, marked by increased find density and human modifications in Layer I. Alongside a decrease in carnivore presence and seasonality data demonstrating human presence in all seasons, this indicates a more frequent or prolonged occupation of the site by IUP groups. Contrarily, the dietary focus across the IUP and Middle Paleolithic layers is similar, centered on the exploitation of species from a range of habitats including Bos/Bison, Cervidae, Equidae, and Caprinae. While body parts of large herbivores were selectively transported into the site, the bear remains suggest that these animals died in the cave itself. A distinct aspect of the IUP occupation is an increase in carnivore remains with human modifications, including these cave bears but also smaller taxa (e.g., Canis lupus, Vulpes vulpes). This can be correlated with their exploitation for pendants, and potentially for skins and furs. At a broader scale, we identified similarities in subsistence behavior across IUP sites in Europe and western Asia. It appears that the first IUP occupations were less intense with find densities and human modifications increasing in succeeding IUP layers. Moreover, the exploitation of small game appears to be limited across IUP sites, while carnivore exploitation seems a recurrent strategy.

Evidence of Neanderthals in the Balkans: The infant radius from Kozarnika Cave (Bulgaria).

Excavations conducted by a Bulgarian-French team at Kozarnika Cave (Balkans, Bulgaria) during several seasons yielded a long Paleolithic archaeological sequence and led to the discovery of important faunal, lithic, and human samples. This paper aims to describe the unpublished radius shaft of an infant who died approximately before the sixth month postnatal that was recovered from layer 10b, which contained East Balkan Levallois Mousterian with bifacial leaf points. The layer was dated between 130 and 200 ka (large mammals biochronology) and between 128 ± 13 ka and 183 ± 14 ka (OSL), i.e. OIS6. Here we show that, given the scarcity of Middle Pleistocene infant remains in general, and Middle Paleolithic human remains from this part of Eastern Europe in particular, the study of the Kozarnika specimen is of special interest. We discuss its place in the Middle Pleistocene European hominine record and substantiate the hypothesis of early Neanderthal presence in the eastern Balkans.

Curated character of the Initial Upper Palaeolithic lithic artefact assemblages in Bacho Kiro Cave (Bulgaria).

The dispersal of Homo sapiens across Eurasia during MIS 3 in the Late Pleistocene is marked by technological shifts and other behavioral changes, known in the archaeological record under the term of Initial Upper Paleolithic (IUP). Bacho Kiro Cave in north Bulgaria, re-excavated by us from 2015 to 2021, is one of the reference sites for this phenomenon. The newly excavated lithic assemblages dated by radiocarbon between 45,040 and 43,280 cal BP and attributed to Homo sapiens encompass more than two thousand lithic artifacts. The lithics, primarily from Layer N1-I, exist amid diverse fauna remains, human fossils, pierced animal teeth pendants, and sediment with high organic content. This article focuses on the technological aspects of the IUP lithics, covering raw material origin and use-life, blank production, on-site knapping activities, re-flaking of lithic implements, and the state of retouched lithic components. We apply petrography for the identification of silicites and other used stones. We employ chaîne opératoire and reduction sequence approaches to profile the lithics techno-typologically and explore the lithic economy, particularly blade production methods, knapping techniques, and artifact curation. Raw material analysis reveals Lower Cretaceous flints from Ludogorie and Upper Cretaceous flints from the Danube region, up to 190 km and 130 km, respectively, from Bacho Kiro Cave, indicating long-distance mobility and finished products transport. Imported lithic implements, were a result of unidirectional and bidirectional non-Levallois laminar technology, likely of volumetric concept. Systematic on-anvil techniques (bipolar knapping) and tool segmentation indicate re-flaking and reshaping of lithic implements, reflecting on-site curation and multifaceted lithic economy. A limited comparison with other IUP sites reveals certain shared features and also regional variations. Bacho Kiro Cave significantly contributes to understanding the technological and behavioral evolution of early Homo sapiens in western Eurasia.

A 14C chronology for the Middle to Upper Palaeolithic transition at Bacho Kiro Cave, Bulgaria.

The stratigraphy at Bacho Kiro Cave, Bulgaria, spans the Middle to Upper Palaeolithic transition, including an Initial Upper Palaeolithic (IUP) assemblage argued to represent the earliest arrival of Upper Palaeolithic Homo sapiens in Europe. We applied the latest techniques in 14C dating to an extensive dataset of newly excavated animal and human bones to produce a robust, high-precision radiocarbon chronology for the site. At the base of the stratigraphy, the Middle Palaeolithic (MP) occupation dates to >51,000 yr BP. A chronological gap of over 3,000 years separates the MP occupation from the occupation of the cave by H. sapiens, which extends to 34,000 cal BP. The extensive IUP assemblage, now associated with directly dated H. sapiens fossils at this site, securely dates to 45,820-43,650 cal BP (95.4% probability), probably beginning from 46,940 cal BP (95.4% probability). The results provide chronological context for the early occupation of Europe by Upper Palaeolithic H. sapiens.