Sonia Harmand

3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya

Human evolutionary scholars have long supposed that the earliest stone tools were made by the genus Homo and that this technological development was directly linked to climate change and the spread of savannah grasslands. New fieldwork in West Turkana, Kenya, has identified evidence of much earlier hominin technological behaviour. We report the discovery of Lomekwi 3, a 3.3-million-year-old archaeological site where in situ stone artefacts occur in spatiotemporal association with Pliocene hominin fossils in a wooded palaeoenvironment. The Lomekwi 3 knappers, with a developing understanding of stone’s fracture properties, combined core reduction with battering activities. Given the implications of the Lomekwi 3 assemblage for models aiming to converge environmental change, hominin evolution and technological origins, we propose for it the name ‘Lomekwian’, which predates the Oldowan by 700,000 years and marks a new beginning to the known archaeological record.

An earlier origin for the Acheulian

The Acheulian is one of the first defined prehistoric techno-complexes and is characterized by shaped bifacial stone tools. It probably originated in Africa, spreading to Europe and Asia perhaps as early as ∼1 million years (Myr) ago. The origin of the Acheulian is thought to have closely coincided with major changes in human brain evolution, allowing for further technological developments. Nonetheless, the emergence of the Acheulian remains unclear because well-dated sites older than 1.4 Myr ago are scarce. Here we report on the lithic assemblage and geological context for the Kokiselei 4 archaeological site from the Nachukui formation (West Turkana, Kenya) that bears characteristic early Acheulian tools and pushes the first appearance datum for this stone-age technology back to 1.76 Myr ago. Moreover, co-occurrence of Oldowan and Acheulian artefacts at the Kokiselei site complex indicates that the two technologies are not mutually exclusive time-successive components of an evolving cultural lineage, and suggests that the Acheulian was either imported from another location yet to be identified or originated from Oldowan hominins at this vicinity. In either case, the Acheulian did not accompany the first human dispersal from Africa despite being available at the time. This may indicate that multiple groups of hominins distinguished by separate stone-tool-making behaviours and dispersal strategies coexisted in Africa at 1.76 Myr ago.

Pedogenic carbonate stable isotopic evidence for wooded habitat preference of early Pleistocene tool makers in the Turkana Basin.

The origin and evolution of early Pleistocene hominin lithic technologies in Africa occurred within the context of savanna grassland ecosystems. The Nachukui Formation of the Turkana Basin in northern Kenya, containing Oldowan and Acheulean tool assemblages and fossil evidence for early members of Homo and Paranthropus, provides an extensive spatial and temporal paleosol record of early Pleistocene savanna flora. Here we present new carbon isotopic (δ(13)CVPDB) values of pedogenic carbonates (68 nodules, 193 analyses) from the Nachukui Formation in order to characterize past vegetation structure and change through time. We compared three members (Kalochoro, Kaitio, and Natoo) at five locations spanning 2.4-1.4Ma and sampled in proximity to hominin archaeological and paleontological sites. Our results indicate diverse habitats showing a mosaic pattern of vegetation cover at each location yet demonstrate grassland expansion through time influenced by paleogeography. Kalochoro floodplains occurred adjacent to large river systems, and paleosols show evidence of C3 woodlands averaging 46-50% woody cover. Kaitio habitats were located along smaller rivers and lake margins. Paleosols yielded evidence for reduced portions of woody vegetation averaging 34-37% woody cover. Natoo environments had the highest percentage of grasslands averaging 21% woody cover near a diminishing Lake Turkana precursor. We also compared paleosol δ(13)CVPDB values of lithic archaeological sites with paleosol δ(13)CVPDB values of all environments available to hominins at 2.4-1.4Ma in the Nachukui and Koobi Fora Formations. Grassy environments became more widespread during this interval; woody canopy cover mean percentages steadily decreased by 12%. However, significantly more wooded savanna habitats were present in the vicinity of lithic archaeological sites and did not mirror the basin-wide trend of grassland spread. Hominin lithic archaeological sites consistently demonstrated woody cover circa 40% throughout our study interval and were 4-12% more woody than coeval basin environs. We propose that Turkana Basin early tool makers may have preferred a more wooded portion of the savanna ecosystem to reduce heat stress and to gain differential access to potable water, raw materials, animal carcasses, and edible plants.

A Pleistocene palaeovegetation record from plant wax biomarkers from the Nachukui Formation, West Turkana, Kenya

Reconstructing vegetation at hominin fossil sites provides us critical information about hominin palaeoenvironments and the potential role of climate in their evolution. Here we reconstruct vegetation from carbon isotopes of plant wax biomarkers in sediments of the Nachukui Formation in the Turkana Basin. Plant wax biomarkers were extracted from samples from a wide range of lithologies that include fluvial–lacustrine sediments and palaeosols, and therefore provide a record of vegetation from diverse depositional environments. Carbon isotope ratios from biomarkers indicate a highly dynamic vegetation structure (ca 5–100% C4 vegetation) from 2.3 to 1.7 Ma, with an overall shift towards more C4 vegetation on the landscape after about 2.1 Ma. The biomarker isotope data indicate ca 25–30% more C4 vegetation on the landscape than carbon isotope data of pedogenic carbonates from the same sequence. Our data show that the environments of early Paranthropus and Homo in this part of the Turkana Basin were primarily mixed C3–C4 to C4-dominated ecosystems. The proportion of C4-based foods in the diet of Paranthropus increases through time, broadly paralleling the increase in C4 vegetation on the landscape, whereas the diet of Homo remains unchanged. Biomarker isotope data associated with the Kokiselei archaeological site complex, which includes the site where the oldest Acheulean stone tools to date were recovered, indicate 61–97% C4 vegetation on the landscape. This article is part of the themed issue ‘Major transitions in human evolution’.

An interdisciplinary approach to percussive technology – international conference, Institute of Archaeology, University College London, September 18th-19th, 2014.

I n the last decade, percussive technology has been widely discussed due to its importance in understanding Early Stone Age hominin behavior. From the archaeological perspective, a number of sites have yielded artifacts that may have been involved in percussive activities. To understand these tools, archaeologists often use as an analogy stone tools utilized by wild chimpanzees as well as modern primate behavioral patterns. In this regard, the so called ‘primate archaeology’ has developed a discipline in which archaeological and primatological methods are combined in order to better understand diachronic hominin and nonhuman primate tool use. To foster a discussion and collaborative approaches to future research on percussive technology, the Institute of Archaeology (University College London) hosted an international and interdisciplinary conference between the 18 and 19 of September 2014. It focused on various aspects of percussive technology, from primatological studies to archaeological and ethnographical investigations. This conference, sponsored by the Leverhulme Trust International Network Program and organized by Ignacio de la Torre (UCL), brought together a group of highly experienced primatologists and archaeologists, all experts in the study of percussive technology.

New views on old stones: France-Stanford Conference on Early Stone Tools and Cognitive Evolution

E nhanced cognitive capacity is the hallmark of our species. Building and testing models about how this capacity developed is of central importance in understanding early human evolution. Stone tools are presently the best source of information regarding the cognitive capacity of early hominids, and the approaches used to study stone tools have a potentially large impact on proposed models of early human cognition. The ‘‘France-Stanford Conference on Early Stone Tools and Cognitive Evolution,’’ organized by Sonia Harmand and held May 3–4th, 2010, at Stanford University assembled several of the world’s experts on early stone tools to present their work and share their experiences in the analysis of early stone tool assemblages (Fig. 1). They also discussed, in workshop style, how the different approaches developed to study early stone tools produce different models of early human cognitive capacity, the implications for paleoanthropological inference, and the possibility of combining aspects of different approaches for the mutual benefit of all. The conference was financed by the France-Stanford Center for Interdisciplinary Studies, a partnership between StanfordUniversity and the FrenchMinistry of Foreign Affairs, and by the Stanford Human Origins Program, and was held in Stanford University’s Department of Anthropology. The conference was open to the Bay Area academic community and the public at large. Klein (Stanford) opened the conference by enumerating three broad key issues in early human evolution that he hoped research on Oldowan stone tools can eventually address: whether there is a difference between Oldowan assemblages in Africa and early lithic assemblages in Europe that some have called Oldowan; which species (singular or plural) made Oldowan stone tools; and what the implications of the tools are with regard to how Oldowan people made a living. de la Torre (UCL), who discussed the history of research on early stone tools, compared and contrasted the typological approach (developed by Bordes), the processual approach (developed by Isaac), and the technological approach (initiated by Leroi-Gourhan). He described how a technological reanalysis of the Olduvai assemblages, on which Mary Leakey based her typological definitions of the Oldowan culture, has revealed a wider range of behaviors, particularly bashing activities, than were previously included. He also presented fresh ideas on how flaking schemas changed through time in the tradition previously called the ‘‘Developed Oldowan.’’ Texier (CNRS, Bordeaux) noted that some researchers have used the term ‘‘culture’’ to describe chimpanzee use of wood and rocks to access or process foods, pointing out that culture in this sense differs from ‘‘culture’’ as we apply it to ancient stone tools. In his view, it is the use of natural materials to transform objects into unnatural forms, and particularly the use of stones to modify other stones, that is the defining criterion of hominization, implying that the knappers had a desired end product in mind. Pelegrin (CNRS, Nanterre, presentation in absentia), considered the notions of ‘‘intention’’ and ‘‘predetermination,’’ which are widely used by lithic specialists, but which he believes are a source of confusion between French and Anglo-Saxon archeologists. To better understand hominin cognition from early stone tools, he suggested that archeologists need to communicate better with cognitive psychologists and primatologists using common analytical terminology. Then, after noting cognitive and methodological considerations, he examined different aspects or degrees of predetermination, from the production of elementary flakes to the complete geometrical predetermination of Levallois flaking and some blade reductionmethods. Hovers (Hebrew University) began by asking whether paleoanthropologists are using a shared definition of cognition, how we identify cognition in the Oldowan, and what Oldowan lithics can tell us or, more importantly, cannot tell us about cognition. She then described how research on Oldowan assemblages can directly access aspects of cognition, especially