Elsevier Editorial System(tm) for Journal of Human Evolution Manuscript Draft Manuscript Number: HUMEV-T-16-00456R1 Title: Pounding tools in HWK EE and EF-HR (Olduvai Gorge, Tanzania): percussive activities in the Oldowan - Acheulean transition Article Type: SI: Oldowan-Acheulean Keywords: Battered tools; Early Homo; Subsistence strategies; Early Stone Age; use-wear analysis Corresponding Author: Dr. Adrian Arroyo, Ph.D. Corresponding Author's Institution: University College London First Author: Adrian Arroyo, Ph.D. Order of Authors: Adrian Arroyo, Ph.D.; Ignacio de la Torre, Professor Abstract: In this paper, we present pounded objects from excavations at HWK EE and EF-HR, which are studied from macro and microscopic perspectives. Analysis of HWK EE revealed one of the largest collections of percussive objects from Olduvai Gorge, while excavations at EF-HR have allowed us to recover a much wider collection of percussive tools than previously recorded. Differences are observed between the two localities: at the Acheulean site of EF-HR, percussive tools were predominantly used in the production of flakes and large cutting tools (LCTs). At the Oldowan site of HWK EE, the tool repertoire probably related to a wider range of activities, including bone breaking and bipolar knapping. Comparison of these two assemblages, potentially produced by different hominin species, helps provide a wider picture of pounding activities during the Oldowan - Acheulean transition at Olduvai Gorge. *Revised Manuscript Unmarked Click here to view linked References 1 Pounding tools in HWK EE and EF-HR (Olduvai Gorge, Tanzania): percussive 2 activities in the Oldowan - Acheulean transition 3 4 Adrián Arroyo1, Ignacio de la Torre1 5 6 1 Institute of Archaeology, University College London. 31-34 Gordon Square, London, WC1H 0PY, UK 7 8 * Corresponding author: [email protected] (A. Arroyo) 9 10 Abstract 11 In this paper, we present pounded objects from excavations at HWK EE and EF-HR, which 12 are studied from macro and microscopic perspectives. Analysis of HWK EE revealed one of 13 the largest collections of percussive objects from Olduvai Gorge, while excavations at EF-HR 14 have allowed us to recover a much wider collection of percussive tools than previously 15 recorded. Differences are observed between the two localities: at the Acheulean site of EF- 16 HR, percussive tools were predominantly used in the production of flakes and large cutting 17 tools (LCTs). At the Oldowan site of HWK EE, the tool repertoire probably related to a wider 18 range of activities, including bone breaking and bipolar knapping. Comparison of these two 19 assemblages, potentially produced by different hominin species, helps provide a wider picture 20 of pounding activities during the Oldowan - Acheulean transition at Olduvai Gorge. 21 22 Keywords 23 Battered tools; Early Homo; Subsistence strategies; Early Stone Age; use-wear analysis. 24 25 26 1 27 1. Introduction 28 Interest in determining the function of percussive tools began early in African Stone 29 Age studies, as illustrated by debate on the use of so-called ‘bolas’ and spheroids (Gobert, 30 1910; Leakey, 1931; 1950; Clark, 1955; Leakey, 1971; Schick and Toth, 1994; Willoughby, 31 1985). Since then, researchers have included pounding tools in their technological analyses of 32 Early Stone Age assemblages documented across the East African Rift valley (e.g. Leakey, 33 1971; Isaac, 1997; Piperno et al., 2004; Chavaillon, 2004; Delagnes and Roche, 2005; Mora 34 and de la Torre, 2005). More recent research has developed techniques to differentiate marks 35 caused by natural agents from use-wear traces produced during percussive activities (Caruana 36 et al., 2014). This has been accompanied by the development of more quantitative approaches 37 to the study of wear traces on pounding tools (de la Torre et al., 2013; Caruana et al., 2014; 38 Benito-Calvo et al., 2015). 39 Functional analysis through microscopic studies has been extensively used to assess 40 activities on Palaeolithic sites. Despite the limited number of use-wear analyses conducted 41 specifically on Early Stone Age (ESA) assemblages to study the function of flakes (e.g. 42 Keeley and Toth, 1981; Sussman, 1987), new investigations have shown that hominins 43 manufactured and used stone tools to consumed not only meat but also a variety of plants 44 (Lemorini et al., 2014; Melamed et al., 2016), emphasizing the diversity of hominin diet. It 45 has been hypothesized that during the ESA hominins used percussive tools to process nuts 46 (Goren-Inbar et al., 2002; 2014; 2015), as well as plants and meat (e.g. Willoughby, 1985; de 47 la Torre et al., 2013). Taphonomic studies have shown that hominins broke bones to access 48 marrow (Bunn, 1981; Blumenschine and Selvaggio, 1988; Pobiner, 2007; Pobiner et al., 49 2008; Ferraro et al., 2013). Others have noted the benefits of pounding food in the absence of 50 fire (Carmody and Wrangham, 2009), and the importance of consuming nuts, fruits and 51 tubers as a source of nutrients (Peters, 1987). Primatological studies show that nuts, 2 52 processed through pounding activities, represent an important source of food for West 53 African chimpanzees (Yamakoshi, 1998), and ethnographic studies indicate the importance of 54 percussive activities among hunter-gatherers (Murray et al., 2001). 55 In her seminal publication on Olduvai Gorge Mary Leakey (1971) described a series 56 of objects under the category of ‘utilised material’, which grouped tools bearing percussive 57 traces such as anvils and hammerstones. Subsequent re-analysis of Olduvai lithic 58 assemblages emphasized the importance of these objects during Bed I and II times (Mora and 59 de la Torre, 2005). Others have examined the function of pounding tools from Olduvai Gorge 60 through experimental programmes (e.g. de la Torre et al., 2013; Sánchez-Yustos et al., 2015), 61 began to apply microscopic analyses to the study of archaeological pounding tools (Arroyo 62 and de la Torre, 2016), and compared them with chimpanzee nut cracking stone tools (Arroyo 63 et al., 2016). The next step in percussive tool research is to expand these new protocols on 64 experimental objects, and use such framework to undertake functional analysis of 65 archaeological assemblages. 66 In this paper, we present a comprehensive study of percussive objects excavated by 67 the Olduvai Geochronology Archaeology Project (OGAP) in the HWK EE and EF-HR 68 localities. HWK EE, a late Oldowan site, was originally excavated by Mary Leakey after she 69 had prepared her 1971 monograph, and the assemblage remained unpublished (Pante and de 70 la Torre, submitted). Renewed excavations at this locality by OGAP have produced a detailed 71 record of the stratigraphic sequence, in the transition from Lower to Middle Bed II (around 72 1.7 Ma), and revealed one of the largest Oldowan collection of stone tools and fossil 73 assemblages (de la Torre et al., submitted ‘a’). 74 The Acheulean site of EF-HR was discovered in 1931, and is a well-known locality 75 on the north side of the Gorge, about 1.2 km from the Third Fault (Leakey, 1971). The age of 76 EF-HR was previously estimated at 1.6-1.5 Ma (Manega, 1993), although recent work by 3 77 OGAP has refined its stratigraphic position, and located this site above Tuff IIC and therefore 78 within Upper Bed II (de la Torre et al, submitted ‘b’; McHenry, submitted). 79 In this study, we present a systematic technological and microscopic analysis of a 80 large sample of percussive tools from HWK EE and EF-HR, and compare them with results 81 from other Beds I and II pounding tools (Arroyo and de la Torre, 2016), as well as 82 experimental tools made from Olduvai quartzite (de la Torre et al., 2013; Arroyo et al., 2016). 83 Overall, our aim is to discuss differences on the type of pounding tools across the 84 Oldowan-Acheulean transition at Olduvai Gorge, thus contributing to a better understanding 85 of variations in technological and functional patterns. 86 This study is the first systematic functional analysis of complete assemblages of 87 percussive tools from late Oldowan and Acheulean sites. In addition to shed new light on 88 hominin tool use and subsistence strategies, and complement the technological analysis of the 89 lithic assemblages (de la Torre and Mora, submitted ‘a’ and ‘b’), our use-wear contribution 90 aims to serve as a reference for the identification of pounding tools in other African ESA 91 sites, and set the foundations for a better understanding of their function. 92 93 2. Materials and methods 94 2.1 The percussive assemblages from HWK EE and EF-HR 95 The HWK EE percussive collection presented here (T1-Main Trench and satellite 96 trenches [T27, T28 and T29]) consists of 349 pounded objects (representing 1.93% of the 97 stone tool assemblage [n= 18,107] collected from the four trenches) (de la Torre et al., 98 submitted ‘a’). As such, HWK EE has one of the largest concentrations of percussive tools in 99 Bed I and Bed II localities (Table 1). Complete objects form 59.3% (n= 207) of the studied 100 assemblage, 35.2% (n= 123) are fractured percussive tools, and 5.4% (n= 19) are 101 hammerstone flakes/ fragments. Most percussive objects (n= 293 [84%]) were recovered 4 102 from the T1-Main Trench, 3.7% (n= 13) from Trench 27, 6% (n= 21) from Trench 28, and 103 6.3% (n= 22) from Trench 29 (see details in de la Torre et al., submitted ‘a’). 104 105 Insert Table 1 106 107 Percussive tools from HWK EE are most abundant in archaeological layers within the 108 Lower Augitic Sandstone (LAS) (n= 283 [81.1%]) and the Lemuta member (LEM) (n= 58 109 [16.6%]).