A 1.4-Million-Year-Old Bone Handaxe from Konso, Ethiopia, Shows Advanced Tool Technology in the Early Acheulean
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A 1.4-million-year-old bone handaxe from Konso, Ethiopia, shows advanced tool technology in the early Acheulean Katsuhiro Sanoa, Yonas Beyeneb,c, Shigehiro Katohd, Daisuke Koyabue, Hideki Endof, Tomohiko Sasakig, Berhane Asfawh, and Gen Suwaf,1 aCenter for Northeast Asian Studies, Tohoku University, Aoba-ku, Sendai 980-8576, Japan; bAssociation for Conservation of Culture Hawassa, Addis Ababa, Ethiopia; cFrench Center for Ethiopian Studies, Addis Ababa, Ethiopia; dDivision of Natural History, Hyogo Museum of Nature and Human Activities, Yayoigaoka, Sanda 669-1546, Japan; eJockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon 999077, Hong Kong; fThe University Museum, The University of Tokyo, Tokyo 113-0033, Japan; gKyoto University Museum, Kyoto University, Kyoto 606-8501, Japan; and hRift Valley Research Service, Addis Ababa, Ethiopia Contributed by Gen Suwa, June 1, 2020 (sent for review April 6, 2020); reviewed by John A. J. Gowlett and Nicholas Toth) In the past decade, the early Acheulean before 1 Mya has been a A prepared core technology, including roughly executed cen- focus of active research. Acheulean lithic assemblages have been tripetal core preparation, was practiced in producing early shown to extend back to ∼1.75 Mya, and considerable advances in Acheulean large cutting tools (LCTs) at Peninj at 1.5 to 1.1 Mya core reduction technologies are seen by 1.5 to 1.4 Mya. Here (30), Melka Kunture at ∼1.5 to 0.85 Mya (31), EF-HR of Olduvai we report a bifacially flaked bone fragment (maximum dimension Gorge at ∼1.4 Mya (32), and Konso at ∼1.4 to 1.25 Mya (14, 15). ∼13 cm) of a hippopotamus femur from the ∼1.4 Mya sediments In addition, a striking feature of the Konso ∼1.4 to 1.25 Mya as- of the Konso Formation in southern Ethiopia. The large number of semblages is the occurrence of the Kombewa method (15) nearly flake scars and their distribution pattern, together with the high half a million y earlier than previously known (31). This is a frequency of cone fractures, indicate anthropogenic flaking into specialized technique that produces flakes with two ventral faces, handaxe-like form. Use-wear analyses show quasi-continuous alter- inferring predetermination of blank shape. The lithic technology nate microflake scars, wear polish, edge rounding, and striae seen in the Konso ∼1.4 to 1.25 Mya assemblages also show ad- ∼ ANTHROPOLOGY patches along an 5-cm-long edge toward the handaxe tip. The vanced workmanship in tip thinning, reduced edge sinuosity, and striae run predominantly oblique to the edge, with some perpen- increased cross-section and planform symmetry. However, there dicular, on both the cortical and inner faces. The combined evidence is is high interassemblage variability at Konso (14, 15) and among consistent with the use of this bone artifact in longitudinal motions, the other East African early Acheulean sites of this time period such as in cutting and/or sawing. This bone handaxe is the oldest (3, 13, 30–33). known extensively flaked example from the Early Pleistocene. De- At Konso, the ∼0.85 Mya Acheulean assemblages show fur- spite scarcity of well-shaped bone tools, its presence at Konso ther technological innovation. A substantial reduction of LCT shows that sophisticated flaking was practiced by ∼1.4 Mya, thickness was routinely attained by detaching thinner blanks (or not only on a range of lithic materials, but also occasionally on by using thin cobbles) and by shallower invasive flaking of the bone, thus expanding the documented technological repertoire of African Early Pleistocene Homo. blank surfaces. These additional levels of advanced flaking technology enabled achievement of the 3D symmetry of the Acheulean technology | bone handaxe | use-wear | core preparation | LCTs (14, 15). Other assemblages in the 0.8 to 1.0 Mya time Early Pleistocene period known to exhibit LCTs with advanced planform and Significance he Acheulean is the most widespread Paleolithic technolog- Tical tradition in the Old World, characterized by handaxes, cleavers, and sometimes picks, as well as a range of other smaller We report a rare example of a 1.4-million-y-old large bone frag- artifacts (1–9). An additional important hallmark of the Acheulean ment shaped into handaxe-like form. This bone tool derives from the Konso Formation in southern Ethiopia, where abundant early lithic technology is use of large flake blanks accompanied by hier- – Acheulean stone artifacts show considerable technological pro- archical and spatial structuring of tool production (2, 7, 8, 10 13). gression between ∼1.75 and <1.0 Mya. Technological analysis of Large flake blanks were not used in the preceding Oldowan and are the bone tool indicates intensive anthropogenic shaping. Edge ∼ first seen in the 1.75 to 1.6 Mya East African Acheulean as- damage, polish, and striae patterns are consistent with use in semblages at Konso in Ethiopia (14, 15), west of Lake Turkana in longitudinal motions, such as in butchering. The discovery of this Kenya (16, 17), Olduvai Gorge in Tanzania (18–20), and Gona in bone handaxe shows that advanced flaking technology, practiced Ethiopia (7, 21). Many researchers consider the recurrent, if not at Konso on a variety of lithic materials, was also applied to bone, preconceived, form of the Acheulean stone tools to be related to thus expanding the known technological repertoire of African advanced cognition of the makers relative to earlier Homo (7, 10, Early Pleistocene Homo. 12, 22–26). The Acheulean is also known as a long-term lithic tradition (duration of >1.5 million y) and shows considerable Author contributions: K.S., Y.B., S.K., B.A., and G.S. designed research; K.S., Y.B., S.K., D.K., H.E., T.S., B.A., and G.S. performed research; K.S., Y.B., S.K., B.A., and G.S. analyzed data; conservatism until diversification in the late Acheulean (4, 6, 27). and K.S., Y.B., S.K., B.A., and G.S. wrote the paper. This has in turn been interpreted to stem from the comparatively Reviewers: J.A.J.G., University of Liverpool; and N.T., Stone Age Institute. restricted capacities of the manufacturers in hierarchical per- The authors declare no competing interest. ception (12), working memory (28), and/or cognitive fluidity for Published under the PNAS license. technological invention (29) relative to later Homo. However, 1To whom correspondence may be addressed. Email: [email protected]. technomorphological investigations of East African early Acheulean This article contains supporting information online at https://www.pnas.org/lookup/suppl/ assemblages indicate considerable temporal advances between ∼1.75 doi:10.1073/pnas.2006370117/-/DCSupplemental. and 0.8 Mya in multiple technological aspects, as summarized below. www.pnas.org/cgi/doi/10.1073/pnas.2006370117 PNAS Latest Articles | 1of8 Downloaded by guest on September 29, 2021 biconvex cross-sectional symmetry are from Melka Kunture in much later in these regions. This may be because they were Ethiopia (31), several sites in Kenya (Olorgesailie Members 6/7, produced only rarely, as was the case at Olduvai Gorge Beds II Kilombe, Kariandusi, and possibly Isenya) (2, 34–37), and Bed to IV (3, 38). Except at Castel di Guido in Italy (64), only single IV of the Olduvai Gorge (37, 38). From tuff correlation with or two bone handaxes have been reported from these sites, Olorgesallie Member 4, Isenya has recently been considered to mostly made from elephant bones. Due to the scarcity of bone be as old as 0.97 My (39). However, this was based on major handaxes as well to as the remarkable preference for elephant element compositions of a single tuff and this is not conclusive. bones, ritual or symbolic purposes rather than functional pur- Biochronological assessments (40) suggest that Isenya is broadly poses have been suggested, especially in Europe (61). coeval with site HEB of Olduvai Bed IV at >0.8 Mya, an age that As with Olduvai Gorge Bed II, at Konso, only one bone remains an alternative possibility. The scarce hominin fossil re- specimen exhibited a clear handaxe-like form, whereas a con- cord of this time period (31, 41–47) needs to be substantially siderable number of bones were modified (65). Therefore, it is improved to unravel how the emergence of enhanced LCT important to exclude the possibility that taphonomic processes technology related to the poorly understood transition of late produced the handaxe-like long bone fragment at Konso. Based Homo erectus to Homo rhodensiensis/heidelbergensis sensu lato. on a technological flake scar analysis, we examined whether or From the ∼1.4 Mya time horizon of the Konso Formation (SI not the bifacially flaked long bone exhibits attributes of anthropic Appendix, Fig. S1 provides a chronostratigraphic summary), modification. Moreover, a use-wear analysis was undertaken to there is an additional outstanding biface made on bone (14). A determine whether the piece shows evidence characteristic of use. mammalian long bone fragment collected at locality KGA13 Finally, we evaluated the significance of the bone handaxe in the shows bifacial flake scars with extensive overlap of removals, context of technological advances seen in the Acheulean lithic resulting in a pointed handaxe-like form. The use of bone tools assemblages. by early hominins has long been a subject of debate as to whether they were intentionally used and/or modified or were mimics The Konso Research Area made by a variety of taphonomic agencies (48–51). The flaked The Konso (or Konso-Gardula) research area is located at the large mammal bones from Olduvai Gorge Beds I and II (∼1.9 to southwestern extremity of the Main Ethiopian Rift, south of 1.3 Mya) (52, 53), reported by Mary Leakey in 1971 (3), indeed Lake Chamo, ∼180 km northeast of the fossiliferous Plio- seem to have been intentionally modified (54, 55).