Modelling the end of the Acheulean at global and continental levels suggests widespread persistence into the Middle Palaeolithic

ARTICLE https://doi.org/10.1057/s41599-021-00735-8 OPEN Modelling the end of the Acheulean at global and continental levels suggests widespread persistence into the Middle Palaeolithic 1234567890():,; Alastair J. M. Key 1 ✉, Ivan Jarić2,3 & David L. Roberts4 The Acheulean is the longest cultural tradition ever practised by humans, lasting for over 1.5 million years. Yet, its end has never been accurately dated; only broad 300–150 thousand years ago (Kya) estimates exist. Here we use optimal linear estimation modelling to infer the extinction dates of the Acheulean at global and continental levels. In Africa and the Near East the Acheulean is demonstrated to end between 175 and 166 Kya. In Europe it is inferred to end between 141 and 130 Kya. The Acheulean’s extinction in Asia occurs later (57–53 Kya), while global models vary depending on how archaeological sites are selected (107–29 Kya). These models demonstrate the Acheulean to have remained a distinct cultural tradition long after the inception of Middle Palaeolithic technologies in multiple continental regions. The complexity of this scenario mirrors the increasingly dynamic nature of the Middle Pleistocene hominin fossil record, suggesting contemporaneous hominin populations to have practised distinct stone-tool traditions. 1 School of Anthropology and Conservation, University of Kent, Canterbury, Kent CT2 7NR, UK. 2 Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, České Budějovice, Czech Republic. 3 Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic. 4 Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, University of Kent, Canterbury, Kent CT2 7NR, UK. ✉email: HUMANITIES AND SOCIAL SCIENCES COMMUNICATIONS | (2021)8:55 | https://doi.org/10.1057/s41599-021-00735-8 1 ARTICLE A HUMANITIES AND SOCIAL SCIENCES COMMUNICATIONS | https://doi.org/10.1057/s41599-021-00735-8 Introduction cheulean stone tools were produced for more than 1.5 million years. Such an extended period of production is well established, with an age bracket of ~1.75 to 0.15 million years ago (Mya) widely cited as ‘the Acheulean period’ (Gowlett, 2015; de la Torre, 2016; Shea, 2017; Galway-Witham et al., 2019). Discoveries at Konso (Ethiopia), Olduvai Gorge (Tanzania), and West Turkana (Kenya) provide convincing evidence of the Acheulean’s origin in east Africa around 1.75 Mya (Lepre et al., 2011; Beyene et al., 2013; Diez-Martín et al., 2015). Multiple other sites support such an early occurrence in this region (de la Torre and Mora, 2014; de la Torre, 2016; Gallotti and Mussi, 2018), and no other countries claim evidence to the contrary (e.g. Dennell, 2018; Moncel and Ashton, 2018). The location and timing of the onset of the Acheulean therefore appears well supported. In comparison, the end of the Acheulean is a relative unknown. No sites are widely recognised as displaying evidence of the ‘last Acheulean populations’, and no single region (nor continent) is convincingly argued to display the last stronghold of this technology. Instead, the Acheulean is broadly considered to have been replaced across the Old World between 0.3 and 0.15 Mya, but there is considerable debate on precisely when and where these transitions occurred, and how they varied between different regions (McBrearty and Tryon, 2006; Norton et al., 2009; Fontana et al., 2013; Akhilesh et al., 2018; Méndez-Quintas et al., 2020). Clarity on when and where the Acheulean ended is hampered by a lack of sites younger than 300 thousand years ago (Kya), limited radiometric dating, the publication of minimum-only dates, geographic imbalances in where artefacts are discovered, and debate concerning ‘transitional’ assemblages. The Korean peninsula, for example, has a series of sites displaying handaxelike implements dating to <100 Kya (Bae, 2017; Lee, 2017). However, because of their recent age (i.e. under 150 Kya) and a lack of understanding concerning the Acheulean of northeast Asia, we do not know whether these occurrences represent technological convergence, a very late, localised continuation of the Acheulean, or part of a broader maintenance of the tradition across east Asia (Bae, 2017; Lee, 2017). Similar arguments can be made concerning other late Acheulean sites in India, the Arabian Peninsula, Western Europe, and sub-saharan Africa (e.g. Michel et al., 2009; Haslam et al., 2011; Scerri et al., 2018; MéndezQuintas et al., 2019), although temporal and geographic discrepancies with traditional notions of the late Acheulean are often reduced. Brumm and Rainey (2011) highlight such issues well in their description of bifacial core tools from Northern Australia. In any other region of the Old World these tools could easily have been described as Acheulean handaxes “based on typology alone” (Brumm and Rainey, 2011, p. 57), and yet when found in an Australian context with no Acheulean hominin associations, technological convergence is by far the more plausible explanation. Yet, understanding when and where the Acheulean ended is important. The technologies characterising the Acheulean, handaxes and cleavers, are unavoidably associated with Homo erectus, H. heidelbergensis, and other Middle Pleistocene hominin species (Corvinus, 2004; Dennell, 2009; Lycett, 2009; Haslam et al., 2011; Herries, 2011; de la Torre and Mora, 2014; Bae, 2017; GalwayWitham et al., 2019; Moncel et al., 2020a). In turn, where one is found, the other is often inferred, and an absence of Acheulean artefacts has recurrently (but not always [e.g. Sanchez-Yustos et al., 2018]) been linked to an absence of these species. Moreover, Acheulean tools have been fundamental to debates on the ‘muddle in the middle’ (Isaac, 1972; Gowlett, 1997; MalinskyBuller, 2016), and are unavoidably linked to our understanding of hominin cognition, sociality, language, anatomy, and behaviour 2 during this period (e.g. Hopkinson, 2007; Stout, 2011; Uomini and Meyer, 2013; Gowlett, 2015; Key and Lycett, 2018; Wynn and Gowlett, 2018; Pappu and Akhilesh, 2019). The replacement of Acheulean tools by the Middle Stone Age (MSA) and Middle Palaeolithic (MP) also represents a significant behavioural shift, marking the arrival of more complex Levallois and blade technologies often associated with early H. sapiens and Neanderthals (H. neanderthalensis) (Foley and Lahr, 1997; Henshilwood and d’Errico, 2005; McBrearty and Tryon, 2006; Villa, 2009; Fontana et al., 2013; Shipton, 2016; Deino et al., 2018; Galway-Witham et al., 2019; Scerri et al., 2019). Levallois and blade production techniques arrive with regionally dependent variation, and yet no matter when and where they first appear, changes to the cognition, anatomy, diet, and behaviour of hominins are inferred (e.g. Villa, 2009; Shipton, 2016; Picin, 2017; Akhilesh et al., 2018; Pappu and Akhilesh, 2019; Mathias et al., 2020; Moncel et al., 2020a; Meignen and Ba (...truncated)