Late and lithic variability in Southeastern Ethiopia: implications for the understanding of the Middle and Late of the Horn of

Alice Leplongeon1,2*, David Pleurdeau2 and Erella Hovers3

* Corresponding author: [email protected]

1 McDonald Institute for Archaeological Research, Downing Street, CB2 3ER Cambridge, UK

2 Département de Préhistoire, UMR 7194 CNRS, Muséum national d'Histoire naturelle, Sorbonne

Universités, 1 rue René Panhard, 75013 Paris,

3 Institute of Archaeology, The Hebrew University of Jerusalem, Mt Scopus, Jerusalem 91905,

Israel

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Abstracts

The Late Pleistocene is a key period to understand the shift from the Middle (MSA) to the Late

Stone Age (LSA) in Africa. More generally, it is also a crucial time for elucidation of changes in the technological behaviours of populations in Africa after the main Out of Africa event of modern ca. 60-50 thousand years ago. However, the archaeological record for this period is relatively poor, particularly for the . Here we present a detailed analysis of the lithic assemblages from Goda Buticha (GB), a in southeastern Ethiopia, which has yielded a long stratigraphic sequence including Late Pleistocene and Holocene levels. This study (1) contributes to a better knowledge of the late MSA in the Horn of Africa; (2) documents a late Holocene LSA level

(GB – Complex I); (3) highlights the presence of MSA characteristics associated with LSA features in the Holocene (GB – Layer IIc). This adds to the emerging record of great lithic technological variability during the Late Pleistocene and Holocene in this region.

Le Pléistocène récent est une période clé pour comprendre le changement du Middle (MSA) vers le

Late Stone Age (LSA) en Afrique. Plus généralement, c’est une période-clé pour comprendre les changements dans les comportements techniques des populations humaines en Afrique, après l'épisode principal Out of Africa des Hommes modernes, ca 60-50 ka. Cependant, les données archéologiques pour cette période sont relativement rares, particulièrement pour la Corne de l'Afrique. Nous présentons ici une analyse détaillée des assemblages lithiques de la grotte de Goda

Buticha (GB), située près de Dire-Dawa, en Ethiopie, et qui a livré une longue séquence stratigraphique incluant des niveaux datés du Pléistocène récent et de l'Holocène. Cette étude (1) contribue à une meilleure connaissance du MSA récent de la Corne de l'Afrique ; (2) décrit un niveau LSA de l'Holocène récent (GB – complexe I) ; (3) souligne la présence de caractéristiques

MSA associées à des traits LSA très tard dans l'Holocène (GB – couche IIc). Ces nouvelles données attestent de la grande variabilité technique au Pléistocène récent et à l'Holocène dans cette région.

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1. Introduction

Understanding the mechanisms behind the “transition(s)” between major techno-cultural complexes has been the focus of recent archaeological research. There are two facets to such efforts. One is theoretical, and focuses on clarifying what is meant by the term “transition” (e.g. Hovers & Kuhn

2006; Camps & Chauhan 2009). The other is practical, attempting to apply the criteria derived from theoretical considerations to the archaeological record (e.g. “transitional industries” of the Late

Pleistocene in Europe and Africa, Early Upper Palaeolithic or early (LSA) industries/cultures (see Tostevin 2000, 2003; Hovers & Kuhn 2006; Kuhn 2013; Tostevin 2013).

In this context, the shift from the (MSA) to the Late Stone Age (LSA) in Africa has been the topic of major discussion because of its numerous specificities, including the fact that the same hominin species, Homo sapiens, is regarded as the maker of most of the MSA and of the

LSA material cultures (e.g. Basell 2008). Moreover, this shift seems to have taken place asynchronously across geographic regions. Some of the sites document very early LSA (>50 ka BP)

(e.g. in (Villa et al. 2012), Mumba rockshelter in (Prendergast et al. 2007; Diez-Martin et al. 2009; Gliganic et al. 2012), Enkapune Ya Muto in (Ambrose

1998), while other localities present relatively late MSA (e.g. Rose Cottage Cave in South Africa

(~28 ka uncal BP (Clark 1997; Wadley 1997)); sites within the Wasiriya Beds on Rusinga Island

(>30-45 ka, eastern Lake Victoria Basin, (Tryon et al. 2010)); B1s3 in the Ziway-Shala Basin in

Ethiopia (~33-34 ka cal BP; (Ménard et al. 2014)) (see fig. 1). Such instances demonstrate the great variability of the material cultures and lithic industries dated to the Late Pleistocene and indicate a complex pattern for the shift from the MSA to the LSA.

This state of affairs has led some researchers to avoid the terms Middle and Late Stone Age in their descriptions of the assemblages (e.g. at Mochena Borago (Brandt et al. 2012)). The difficulty to relate lithic assemblages dated to Marine Isotopic Stages (MIS) 4-3 to the general schema of the

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MSA and LSA highlights the need for detailed studies on local and regional scales in order to best understand cultural change. This is especially important for the end of the Pleistocene where a growing body of genetic studies document complex patterns of dispersals within, out of, and back into Africa (e.g. Campbell & Tishkoff 2010; Hodgson et al. 2014).

In the Horn of Africa particularly few sites document the period of MIS 4 and MIS 3, and even fewer are securely dated. This paper focuses on a cave site located in southeastern Ethiopia, Goda

Buticha, which yielded a long stratigraphic sequence dated from 62ka to 1ka by means of radiocarbon and optically-stimulated luminescence (OSL) methods (Tribolo et al. 2017; Pleurdeau et al. 2014). This sequence documents a depositional hiatus and chronological gap from ca. 24ka to

8ka. The evidence from Goda Buticha is consistent with stratigraphic records from many other sites in the Horn of Africa, in which archaeological deposits dated to MIS2 are missing. This gap may correspond to either a cessation of human occupation in the region or results from research bias

(e.g. Bon et al. 2013; Ménard et al. 2014; Pleurdeau et al. 2014; Ménard & Bon 2015).

With such a long chronological gap in the sequence of Goda Buticha, one might expect an abrupt change in material culture characteristics at the site before and after the hiatus in deposition. Yet, preliminary results of the analysis conducted on part of the assemblage indicated that this was not the case at Goda Buticha (Pleurdeau et al. 2014). This paper confirms and analyses in detail the unexpected typo-technological similarities between the assemblages from Goda Buticha, placing this sequence in the context of local scale variability of Late Pleistocene and Holocene lithic variability in the Horn of Africa.

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2. Late Pleistocene and Holocene record of the Horn of Africa

Lithic assemblages from the Late MSA in the Horn of Africa (see fig. 2) are few and characterized by high variability. In addition to the “classical” characteristics of the MSA (Goodwin & Van Riet

Lowe 1929; Goodwin 1946), which include flake production by means of Levallois flaking systems and high percentages of retouched points amongst the types, many late MSA assemblages from the Horn of Africa show high percentages of elongated blank production or of pointed blank production (K’one, locality 5 extension, (Kurashina 1978); Aduma, locality A5 and later, (Yellen et al. 2005); Porc-Epic, (Pleurdeau 2005a, 2005b); Deka Wede 1, (Bon et al. 2013; Ménard et al.

2014).

Lithic assemblages attributed to the LSA in the Horn of Africa are characterized by “general” LSA technological features (e.g. Goodwin 1946; Phillipson 1982), such as prismatic or bladelet production, as the dominant tool type, and absence of characteristic MSA Levallois production or retouched points. The earliest LSA of the region is late compared to its adjacent area in East Africa: at FeJx4 around Lake Besaka, three radiocarbon dates obtained from Layer 2 on fragments of ostrich eggshells gave dates between 19-22ka (Brandt 1982 pp. 60–61), while the LSA sequence at Ziway-Shalla only starts during the terminal Pleistocene (Bon et al. 2013; Ménard et al.

2014). The LSA encompasses a great variability in both and typology and is sometimes considered as a “catch-all” category (Bon & Fauvelle-Aymar 2014).

Within the Late Pleistocene and Holocene archaeological record of the Horn of Africa a number of sites contain assemblages with features of both the MSA and the LSA, and therefore have not been attributed to either one of these cultural taxonomies (see fig. 2). Such instances include the Late

Pleistocene levels at Mochena Borago with rare Levallois cores, flake and blade(let) production and retouched dominated by scrapers, retouched points and backed pieces (Brandt et al. 2012); at

Midhishi 2 in , Unit CSUb, dated around 18ka, has yielded an assemblage with both

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Levallois and blade production, backed pieces and retouched points (Gresham 1984); the lower units of Shelter 7 of Laas Geel (), considered to be of a Terminal Pleistocene age despite conflicting dates, have yielded material with both Levallois and production, retouched points and microliths. These assemblages have been attributed to a revisited “Hargeisan”

(Gutherz et al. 2014). Similarly, the first study of the Goda Buticha material highlighted the presence of both MSA and LSA features throughout the sequence (Pleurdeau et al. 2014).

Overall, the tempo and pattern of technological changes during the Late Pleistocene in the Horn of

Africa remain unclear, leaving open questions about the persistence, reintroduction, or convergent, independent appearance of MSA features in lithic assemblages throughout the end of the

Pleistocene and the Holocene despite the widely-recognized gap corresponding to MIS2 in many of the sites. Analyses of technological changes throughout this crucial period, focusing on elongated blank (blade / bladelet) production, Levallois production, as well as the manufacture of retouched points and microliths, may help in a more nuanced understanding of the processes leading to the observed record. The analysis of Goda Buticha, with its long and well-dated Late Pleistocene and

Holocene sequence and rich lithic assemblages, contributes to these issues.

The main objective of this paper is therefore to conduct an in-depth study of the lithic assemblages from Goda Buticha in order to further investigate diachronic technological change (or persistence) at the site and how these characteristics fit with the local and regional archaeological record and more generally with the current definitions of the MSA and the LSA.

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3. Material and methods

3.1. Goda Buticha

Goda Buticha (GB), located around 30 kms from Dire-Dawa, in southeastern Ethiopia, was discovered1 in 2007 by the South East Ethiopia Cave Survey Project (SEECSP) (Assefa et al. 2014).

The SEECSP noted the presence of as well as a high density of lithic material on the floor of one of the chambers. Two field season at the site took place in 2008 and 2011. The long (>2 m) stratigraphic sequence was divided on the basis of sedimentological observations into two main complexes (II and I, from bottom to top) and three main layers (Layers IId-IIf, Layer IIc and

Complex I). The sequence is dated from the end of MIS4/MIS3 to MIS1, with a major depositional and chronological gap corresponding to MIS 2 (Tribolo et al. 2017; Pleurdeau et al. 2014) (see fig.

3). This site represents one of the rare well-dated long stratigraphic sequences in the Horn of Africa.

Sedimentological analyses (Tribolo et al. 2017) confirmed initial field observations that did not identify any major disturbances or mixing of sediments.

The sequence of Goda Buticha yielded human remains, ostrich eggshell beads, macro- and micro- faunal remains, and abundant lithic artefacts (Tribolo et al. 2017; Assefa et al. 2014; Leplongeon

2014; Pleurdeau et al. 2014). The material analyzed in this paper derives from the two excavated squares and including the as yet unpublished lithic material excavated in 2011. The lithic assemblages discussed in the current paper originated from Layers IId-IIf (ca. 63-25ka), Layer IIc

(ca 8-6 ka) and in Complex I (ca 2-1 ka). Lithic artefacts show peaks of density corresponding to these layers (see fig. 3 and table 1). Material derived from the boundaries of the layers (i.e. IIc/IId or I/IIa-IIb) was not considered in the analysis.

1 Dr Amélie Chekroun, Historian, conducted research on the Capuchin archaeologist François Bernardin Azaïs and his travels to Ethiopia (1922-1936) (Chekroun, 2011). She showed one of us (AL) unpublished photographs from his expedition in the Dire-Dawa region, currently stored in the Capuchin Archives of the Collegio San Lorenzo Da Brandizi in Roma and we were able to recognize Goda Buticha, then named Hadjo.

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3.2. Methods : chaîne opératoire and attribute analyses

In order to best highlight changes or continuities in the techno-typological characteristics of the assemblages and place them in a comparative context, the assemblages were subjected to an in- depth analysis of four main lithic categories corresponding to key-elements that define the MSA or the LSA in the Horn of Africa (see section 2, fig. 2 and suppl. data): the Levallois production, the production of elongated blanks, the manufacture of retouched points and the microliths. The latter has been fully presented in a previous paper (Leplongeon 2014) and will not be developed here.

Elongated blank is a generic term used here for blanks that are more than twice as long as they are wide. Elongated blanks are divided into blades (large elongated blanks) and bladelets (small elongated blanks). Here we use an assemblage-specific method to separate blades from bladelets by observing the distribution of the length of all elongated products. In case of a bimodal distribution, the group with the larger dimensions are considered blades and the other bladelets. Although subject to sample-size bias, this method alleviates the need to rely on a fixed, arbitrary value for defining blades and bladelets. The elongated blanks and associated cores are analyzed in a second step in order to characterize the different behind their production.

In this paper, the lithic assemblages of Goda Buticha are first generally described, including the frequency and modalities of the Levallois production, in order to have a general view of the composition of the assemblages. This will also ensure that the assemblages studied are comparable with previous studies of the material from these sites (2008 material of GB (Pleurdeau et al. 2014)).

An in-depth description of the characteristics of the elongated blank production(s) and of the retouched tools focusing on the retouched points (and with a summary of the data on microliths) will then be presented. Relying on these data, comparative analyses between the levels of Goda

Buticha will be conducted.

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All selected artefacts were analyzed relying on the chaîne opératoire concept. This approach, borrowed from ethnologists, was first applied to prehistoric artefacts by Andre Leroi-Gourhan

(Leroi-Gourhan 1964) and later developed by other prehistorians (e.g. Geneste 1985; Pelegrin et al.

1988; Karlin et al. 1991; Soressi & Geneste 2011). It allows a reconstruction of the reduction strategies and their analysis in terms of “knowledge” and “know-how”, which can then be interpreted to distinguish between groups with different technical practices. This qualitative approach is combined with an attribute analysis. The same attributes are described for each lithic artefact (e.g. Hovers 2009 p. 18). This allows the quantification of technological characteristics.

Non-parametric statistical tests were deemed favorable for this study (the chi-squared test with simulate p-value, the fisher test, the kruskal-wallis test followed by a Wilcoxon pair-wise test) because they allow treatment of samples that are not normally distributed.

4. Lithic assemblages from Goda Buticha

4.1. Goda Buticha: previous studies

Pleurdeau et al. (2014) describe the trends in throughout the sequence based on the material from the 2008 season. Raw materials are dominated by (51%), obsidian (30%), basalt (9%) and quartzite (6%). Flake production predominates (55%). Levallois cores are numerous and show both centripetal preparation for the removal of a preferential flake and the unipolar recurrent method. Other cores show several flaking surfaces. Levallois products, including mainly flakes but also a few blades (n=2) and points (n=5) are present, associated with debordant flakes. Volumetric blade production also occurs. Blades account for 16% of ; single platform cores (prismatic / pyramidal) are also present (7% of cores). A few crested blades and overshot products attest to the presence of a “true” blade production. Retouched tools account for

14% of the 2008 assemblage (excluding debris) and consist of retouched points (21%), backed pieces (15%), side-scrapers (35%) and various retouched pieces. There are no abrupt typo- technological changes throughout the sequence (Pleurdeau et al. 2014 p. 126). The frequency of

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obsidian increases from the bottom to the top of the sequence, as does the frequency of backed microliths. Overall, the sequence shows the association of typical “LSA” elements such as the backed pieces with typical “MSA” elements such as the Levallois flaking and retouched points.

Overall, the lithic material retrieved from both the 2008 and 2011 excavations present similar characteristics (see table 1).

A local origin is postulated for the chert, basalt and quartzite used at Goda Buticha. Of note is the relative high frequency of artefacts made on obsidian at Goda Buticha. In the near-by site of Porc-

Epic cave, some 35km north east of GB, where obsidian represents about 6% of the assemblage

(e.g. Pleurdeau 2005b), a distant origin is suggested. No obsidian source is known in the vicinity of the site although (Clark & Williamson 1984 p. 49) mention that “a source of poor obsidian is known about 40 km to the east of Dire Dawa but this would not have been suitable for artifacts

(W.H. Morton, pers. Comm.)”. Geochemical analysis of obsidian artefacts from Porc-Epic Cave, show the use of sources located 140kms or even 300kms away but also identify a number of unknown sources (Negash & Shackley 2006; Vogel et al. 2006; Negash et al. 2011). Thus we cannot rule out the possibility that obsidian source(s) may have been closer to GB.

4.2. Goda Buticha IId/IIf, 63-25ka

4.2.1. General characteristics

OSL and AMS radiocarbon age estimates place layers IId-IIf between 63±7 ka and 24.8±2.6 ka

(Tribolo et al. 2017; Pleurdeau et al. 2014). These layers yielded in total 3068 lithic artefacts, representing an average density of around 1500 artefacts per m3. A peak in density is observed between spit 90-80cm to spit 40-30cm above datum (with ages between 45 and 25 ka (Tribolo et al.,

2017, see fig. 3). There are no major changes in the frequencies of main categories of stone artefacts (see table 1). Given its homogeneity, the lithic assemblage from the lower part of the lower complex (including layers IId, IIe and IIf) was analyzed as one assemblage.

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The assemblage is oriented towards flake production, which represents two-third of the artefacts

(excluding chips and chunks). Cores are also mainly oriented towards flake production (57%,

N=24/40). Point production is minor (less than 1% of the blanks). None of the cores are for point production. Levallois products and elongated blanks are frequent.

The Levallois production is well represented, with 14 cores (one third of all cores) attributed to the

Levallois concept (see table 2). All the cores but two are for flake production, including centripetal preparation for the removal of a preferential flake (N=4), unipolar recurrent flaking (N=5) and centripetal recurrent flaking (n=3). In addition, 73 Levallois blanks (representing ca. 5% of the debitage items) were recovered, as well as 8 retouched Levallois blanks (9% of all retouched tools), consisting of four unifacial points, two retouched flakes and one notched piece).

Nearly a third of the Levallois blanks (32%) are made on basalt, compared to all the debitage (9%).

The frequency of Levallois cores made on basalt is much lower (ca. 7%; table 2). This may suggest an off-site Levallois production on basalt. Levallois blanks are mainly flakes (N=48), and the use of the Levallois flaking system for elongated blank production is minor (N=5 Levallois blades, N=2

Levallois cores for recurrent blade production). The majority of the products have a plain or faceted striking platform and show centripetal (N=27), or bidirectional (N=14) scar patterns, consistent with the observations on the cores.

Figure 4 presents a synthetic view of the technological characteristics of the lithic artefacts from

Complex I.

4.2.2. Production of elongated products

Elongated blanks

Layers IId-IIf yielded 279 elongated blanks. Chert is the dominant raw material (52%), followed by obsidian (21%), basalt and quartzite (12% each). These raw material frequencies are similar to those observed in all the debitage, indicating that there was no particular raw material selection for producing the elongated blank in IId-IIf (see table 3). Dimensions of complete elongated blanks

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(Ntot=130) are given in table 4 and fig. 5. There are no statistically significant raw material-related differences in artefact dimensions (see table 4).

Although very small elongated products are present (length below 25mm), the distributions of length and width are unimodal and suggest a single production system of both the large and small items. The elongation index is relatively low as well as the thickness index.

Only seven cores show elongated removal scars, including four in obsidian. Two of them are

Levallois (one unipolar recurrent, the other one bidirectional recurrent). Another two are related to a non-Levallois planimetric conception of debitage (one with a unipolar debitage, the other one with a bidirectional debitage). Two cores show a volumetric conception of debitage and one an intermediate one (see fig. 6)2. Striking platforms are mainly faceted (N=3,) or plain (N=3), with one dihedral striking platform.

The elongated products themselves present plain platforms (56% of determinable platforms), a rather high frequency of linear and punctiform platforms (17%), dihedral (13%) and faceted (9%) platforms (see table 5). The high percentage of salient to very salient bulbs (66%) associated with rather large platforms (mean=3.24mm, sd=2.2) suggests the use of hard hammer percussion. Core trimming elements related to blade production are consistent with production based on a planimetric conception of debitage with flakes bearing elongated removal scars (N=7) and non-Levallois planimetric debordant products (N=7). One overshot item and one ridge blade indicate the use of a volumetric conception of debitage (see fig. 6 h.).

The direction of debitage as shown by the removal scars on the elongated products is mainly unipolar (61%), while unipolar and orthogonal (12%), bidirectional (9%) or centripetal (14%) scar patterns occur in low frequencies. Elongated products are relatively thin, with flat to slightly curved longitudinal profile (51%), flat lateral profiles (75%) and with parallel edges (39%) or show at least one distal convergent segment (30%).

2 Planimetric conception is opposed to volumetric conception of debitage (sensu Van Peer et al., 2010, p. 41-42). Semi-rotating cores are the most common cores for a volumetric conception (or laminar debitage (Delagnes and Meignen, 2006).

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The data from the cores, technical pieces and elongated products (see figs 6 and 7) indicate that part of the knapping at IId-IIf was oriented towards the production of relatively small elongated products, with the occasional use of the Levallois recurrent method or of the prismatic blade production. The production of elongated products seems to have involved little preparation of the cores’ striking platforms or of the debitage surfaces. The latter appear to be quite flat, as indicated by the longitudinal and lateral profiles of the blanks as well as some debordant products.

Retouched elongated products

Twenty-eight percent of the retouched tools (N=29/102) are made on elongated blanks, six of which are small (below 30mm of length). This percentage is higher than the frequency of elongated blanks among the debitage (18%), which may reflect a selection of this type of blanks for the retouch. The majority of retouched items on elongated blanks are retouched blades. There are also scrapers, composite tools, unifacial or bifacial tools and a on a bladelet (see table 6). The selection of obsidian for retouched elongated blanks is clear (62% of items in this category).

4.2.3. Retouched points

Production of pointed flakes

There are no cores with point removal scars in the IId/IIf lithic assemblages, and the assemblage contains only 25 pointed flakes (<2%, see table 1). Five of them are Levallois points (see above and table 2). However, in the absence of cores, the use of Levallois flaking systems for the production of pointed blanks remains hypothetical.

Retouched points

Thirty retouched points (including ten fragments) were counted in the IId/IIf assemblage (29% of all retouched tools; table 7 and fig. 7). The extent of the retouch often prevents the determination of the type of blank for many points, which can be determined for only nine retouched points. Six are made on pointed flakes, including one Levallois point, and three are made on flakes.

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Thirteen of the retouched points are made on chert (43%), seven (23%) on obsidian and nine (30%) on basalt. These values are comparable with raw material distribution in the total assemblage, suggesting that there was no selection for specific raw material for retouched points.

The points are retouched mainly unifacially (N=20). Two points are parti-bifacial and eight are bifacial points. The retouch is invasive to covering, especially for bifacial points (table 7 and fig. 7

(f-p)). Most of the retouched points show regularly convergent edges, the edges starting to converge from the first half of the length (as opposed to converging occurring only in the distal part).

The retouched points are relatively small (mean length =37.8mm, sd =6.7) and narrow (mean laminarity index = 1.8, sd=0.4) (table 8). There are no statistically significant differences in point dimensions according to either raw material or type.

4.2.4. Microliths

Only two pieces in IId/IIf, one backed microlith and one retouched bladelet, can be considered as microliths (Leplongeon 2014). In addition, it may be noted that a relatively low number of small elongated products were retouched, despite their high frequency among the unretouched blanks (see above).

4.3. Goda Buticha IIc, 8-6ka

4.3.1. General characteristics

Layer IIc, dated between 4422±47 cal BC and 5426±40 cal BC (Tribolo et al. 2017, fig. 3), yielded

2276 lithic artefacts, representing an average density of around 1625 artefacts per m3. The peak of density is at 140-120cm above datum (table 1 and fig. 3). The assemblage is oriented towards flake production; more than half of the artefacts (excluding chips and chunks, see table 1) are flakes.

Cores are also mainly oriented towards flake production, at least in their last stages of reduction

(58%, N=35/60). Point production is minor while elongated blanks are frequent (29% of debitage).

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While the planimetric conception of debitage dominates among the flake cores, only three (5% of all cores) can be attributed to the Levallois flaking system, including two with a centripetal preparation for the removal of a preferential flake and one with a bipolar recurrent flaking. In addition, 33 Levallois blanks have been recovered (3% of the debitage), including eight possible

Levallois blades. Only two of these blanks are retouched. Levallois blanks show mainly centripetal or bipolar scar pattern (see table 2).

Figure 8 presents a synthetic view of the technological characteristics of the lithic artefacts from IIc.

4.3.2. Production of elongated blanks

Elongated blanks

Layer IIc yielded 355 elongated products. They are made mainly on chert (64%), followed by obsidian (27%) and basalt (5%). One-hundred and ninety elongated products are complete (see dimensions in table 4). The items are relatively small (with a mean length ca. 30mm), with low values of the laminarity and thickness indices. The length distribution of complete elongated products (figure 5), suggests that blades (N=214) are distinguished from bladelets (N=141) at the length threshold of 26mm.

Elongated products made on obsidian tend to be smaller than those made on other raw materials (p- values of a Kruskal-Wallis test and the following pairwise Wilcoxon test <0.05: figure 5). Since bladelets are made on obsidian more often (38%) than on chert (20%), the bimodal distribution may be a reflection of the preference of using small obsidian nodules. This may also a more intensive reduction of obsidian compared to other raw materials or reflect the smaller size of the nodules.

Fourteen cores in Layer IIc show elongated removal scars (figure 9 b-f). Although the sample is too small to characterize their size distributions, eight of the cores are smaller than 30mm and qualified as bladelet cores. Seven cores are made on chert, while five cores are made on obsidian. None of these cores are Levallois. Four of them are planimetric in conception, with a “direct” (i.e. opportunistic) debitage without any preparation of the debitage surface. Seven are volumetric

(semi-rotating) cores, including six of the bladelet cores. Most of cores show plain striking

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platforms (N=10/18 surfaces), followed by dihedral (N=5/18), cortical (N=2/18) and faceted

(N=1/18) striking platform. Thirty-six core trimming elements associated with elongated blank production were found in Layer IIc. Ridge blades (N=4) and overshot products (N=7) attest to the use of technologically formal blade production, at least for some of the elongated blanks.

Eight elongated blanks are of Levallois type but in the absence of Levallois blade cores, these products may represent equifinality rather than unequivocal evidence for the use of the Levallois flaking system. A planimetric conception of debitage is indicated by “debordant” products (N=15), as well as flakes with elongated removal scars (N=9).

Consistent with core platform characteristics, the blades and bladelets from Layer IIc present mainly plain platforms (43%) followed by faceted (17%) and linear / punctiform platforms (11%)

(see figures 14 and 15). Bulbs are mostly salient, even when associated with narrow (linear or punctiform) platforms (table 5), suggesting the use of a hard hammer percussion. Given the high frequency of linear/punctiform platforms, the use of soft hammers cannot be excluded.

Most of the elongated blanks do not show any cortical surfaces. The direction of debitage as shown by the removal scars is mainly unipolar (55%), but differ between blades and bladelets. The unipolar scar pattern characterizes more than 70% of the bladelets compared to 45% for the blades.

The blades present a higher frequency of the “unipolar and lateral” scar pattern (22%) compared to the bladelets (10%) and of the “bidirectional” scar pattern (12% vs. 4% for blades and bladelets, respectively).

The thickness index shows that blades are relatively thick (36%), while bladelets are thin to relatively thick. Their longitudinal profile is flat to curved, and lateral profile mainly flat. Blades and bladelets show similar characteristics for their contours, with 41% showing parallel edges and around 25% with convergent edges.

Retouched elongated products

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Sixty two percent of the 111 retouched tools of the Layer IIc assemblage are made on elongated blanks, 42 on blades and 28 on bladelets (table 6). This high frequency indicates that elongated blanks (blades and bladelets), which only amount to 29% of the debitage were preferentially selected for retouch. Most of the retouched elongated blanks are on obsidian (52% of retouched blades and 61% of retouched bladelets. This indicates a preferential selection of obsidian for the retouched tools (Fisher Test <0.05).

4.3.3. Retouched points

Production of pointed flakes

A single very small core bearing one pointed flake removal scar was found in the IIc assemblage, along with 15 pointed flakes (including 4 fragments), of which two are of Levallois type.

Retouched points

Layer IIc has yielded 23 retouched points (tables 6 and 7), out of which 18 are unifacial points

(including 16 unifacial bilateral points). Two additional ones are parti-bifacial points and another 3 are bifacial points. Most of the retouched points present covering retouch (52%), leading to a high frequency of undetermined blanks. Seventy percent of the retouched points (N=16/23) are made on obsidian (figure 10), which indicates a strong preference for this raw material.

Only ten points present identifiable platform types: six are faceted, three dihedral and one cortical.

This would indicate the use of blanks from prepared cores.

The retouched points from IIc are relatively small (mean length is 37.8mm±13.8) and elongated

(mean length to width ratio is 1.9±0.4) (table 8). Although retouched points on obsidian tend to beare smaller, the difference is not statistically significant (p-value of the Kruskal-Wallis test >.05), which is probably due to the small sample. Most of the retouched points have regularly convergent edges with a rounded proximal part.

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4.3.4. Microliths

Layer IIc has yielded 31 microliths (28% of all retouched tools). They are composed of 10 retouched bladelets and 21 backed microliths, including four geometric microliths. Detailed treatment of these items is presented by Leplongeon (2014).

4.4. Goda Buticha I, <4 ka

4.4.1. General characteristics

Complex I is dated by 14C and OSL from 4.07 ± 55 Cal BP to 0.7 ±0.1 ka and may reach even later dates, given that the topmost layers remain undated (Tribolo et al. 2017). The assemblage consists of 550 artefacts. The calculated density of ca. 550 artefacts per m3.(table 1, figure 3) is a third of the values obtained for the layers in Complex II.

The assemblage is oriented towards flake production (56% of the debitage), with elongated blank accounting for 22% of the debitage. Among the 15 cores from Complex I, nine present flake removal scars and six present elongated flake removal scars. Planimetric conception of debitage dominates among the cores. Two Levallois cores were shaped by bipolar recurrent flaking, for elongated blank production and for flake production (table 2). Seven additional cores present blank reduction from the widest surface, from one or two striking platforms. There is a single pyramidal core for bladelet production.

The assemblage contains no points and only two Levallois flakes. Elongated blanks are relatively frequent (21%), although less than in the lower layers. In contrast to the lower layers, obsidian is the main raw material used in the assemblage (accounting for 56% and 75% of the assemblage

(excluding and including chips, respectively) (table 3). Levallois production is of minor importance, with only two possible cores and two flakes.

Figure 11 presents a synthetic view of the technological characteristics of the lithic artefacts from

Complex I.

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4.4.2. Production of elongated blanks

Elongated blanks

Only 44 elongated products were counted in Complex I, of which 33 are complete (table 2). Most of the elongated items are small (N=28 less than 30mm long). The majority (ca. 85%) are made on obsidian, indicating a preferential selection of this raw material for blade(let) production.

Six cores in Complex I present elongated removal scars, five of them are microlithic (< 30mm long). All of the cores are on obsidian. One is pyramidal while the others seem to be related to a planimetric or intermediate conception of debitage, with little preparation of the flaking surface (see fig. 12). Six core trimming elements are related to blade(let) production. Of these two are flakes with elongated removal scars, three are non-Levallois debordant products and one is an overshot flake.

Most of the elongated products show plain (33%) or faceted (28%) platforms, this is consistent with the data from the cores' striking platforms where both of these types are present. Bulbs of percussion are mostly salient to very salient for blades, as well as for bladelets, suggesting the use of hard hammer percussion. The majority of the elongated blanks show a unipolar direction of debitage (N=23/40). Blades and bladelets are relatively thick, with curved longitudinal profiles and flat lateral profiles (N=26/40), although twisted profiles occur (N=13/40). Most of the artefacts show parallel edges.

Retouched elongated products

Half of the retouched tools from Complex I are made on elongated blanks (N=15/30). Of these, four retouched blades, three are backed blades, two are retouched bladelets and six are backed bladelets.

Thirteen retouched blade(let)s are in obsidian while two are made from chert.

The retouched bladelets fall within the size category of “microliths”. There is a preference for retouch on elongated blades. It also very likely that they were selected for the manufacture of microliths, although the type of retouch applied prevents the determination of the type of blank.

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4.4.3. Retouched points

There is no evidence for point production or retouch in Complex I.

4.4.4. Microliths

Microliths form the main group of retouched tools in Complex I (N=17/30, 57%, fig. 11). They are composed of 15 backed microliths, including 12 geometric microliths (crescent shape), and two retouched bladelets. They have been described in detail elsewhere (Leplongeon 2014).

5. Discussion

5.1. Technological trends in the sequence of Goda Buticha

Table 9 summarizes and compares the main characteristics of the three assemblages. Statistical tests were performed in order to test the independence of the variables. Their interpretation mainly relies on the observation of the residuals in the case of chi-squared test.

The comparative analysis between the different levels at Goda Buticha highlight several differences and similarities throughout the sequence.

Main similarities between all levels from Goda Buticha are: (1) the preferential selection of obsidian for retouched tools, (2) all assemblages are flake dominated with the use of Levallois flaking systems and they present relatively high frequencies of elongated blank production (18-29% of debitage), (3) elongated blanks in all levels have similar dimensions (~28-33mm long), unidirectional scar pattern dominates as well as plain platforms and a relative variability in their morphology (parallel edges as well as rounded and convergent edges).

In addition, there are similarities between GB IId-IIf and GB IIc in the presence and types of retouched points, and between GB IIc and GB I in the production of bladelets and presence of microliths.

Main changes are also observed between the levels. The first one is a change in raw material procurement strategy as seen (1) in the increase in the use of obsidian, particularly between GB IIc

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and GB I, and in a lesser extent between GB IId-IIf and IIc; and (2) in the preferential selection of obsidian for certain blank production (i.e. elongated blanks and particularly bladelets in IIc and I) or certain types of tools (selection of obsidian for the manufacture of retouched points in IIc while this is not the case in IId-IIf). The frequency of Levallois flaking systems, used mainly for flake production, decreases from Layers IId-IIf to Complex I, while elongated blank production increases. In particular Layer IIc has a significantly higher percentage of elongated blank production, an emphasis on semi-rotating or prismatic blade(let) production compared to the other assemblages. Elongated blanks also tend to show higher frequencies of bidirectional scar pattern, particularly among the blades. In addition, there is a general increase of bladelet frequencies from

IId-IIf to IIc and to I, where they are the main focus of production. Technological characteristics of blades and bladelets suggest two separate reduction sequences in IIc, while this is not the case in

IId-IIf. Analyses have also shown that elongated blanks form a large part of the retouched tools in

IIc and I compared to IId-IIf.

Other changes are the absence of retouched points in GB I and the increased use of obsidian for the production retouched points in IIc (70% against 23% in GB IId-IIf). Microliths are nearly absent in

GB IId-IIf, while they are frequent in Layer IIc and constitute the main category of tools in

Complex I. While composed of mainly retouched bladelets and non-geometric backed microliths in

GB IIc, they show mainly geometric shapes in Complex I (Leplongeon 2014). Other typological features include the presence of characteristic elongated backed points only in GB IIc, while obsidian unifacial or bifacial ovate tools are found both in GB IId-IIf and GB IIc.

.

5.2. The Late MSA in southeastern Ethiopia

The lithic assemblage from Goda Buticha IId-IIf contains typical MSA features, such as emphasis on flake production with the rather frequent use of the Levallois flaking systems. Retouched points dominate the category of retouched items. Microliths, a typological landmark of the LSA, are nearly absent (N=2). Other characteristics of the lithic assemblage from Goda Buticha IId-IIf, which may

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be included in the MSA variability, are the high frequency of elongated blank production, which stands in contrast with the rare evidence for pointed blank production, as well as a great diversity in the types of retouched points.

Only few other Late Pleistocene sites in the Horn of Africa can be compared with Goda Buticha.

Although comparisons with other sites are not straightforward, given the different contexts in which they occur, the characteristics of the lithic assemblages of such sites are briefly reviewed here. At

Aduma A5 (Yellen et al. 2005), the assemblage is mainly flake-based. A high frequency of both elongated products and retouched points is noted. At Omo Kibish (BNS Member, Shea et al. 2007), the small assemblage (<1000 pieces, excluding debris and non proximal flake fragments) is oriented towards the production of flakes from “formal” cores (i.e. Levallois cores and asymmetrical discoids) and few retouched tools (n=30, among which are eight retouched points) are present. Late

Pleistocene assemblages at Mochena Borago (Brandt et al. 2012) are characterized by mainly flake production from non-Levallois flaking systems. Backed tools are present, along with retouched points. The bipolar technique appears in the later Pleistocene layer, thus presenting very different characteristics from Late Pleistocene levels at Porc-Epic and Goda Buticha. At K'one – locality 5 extension (Kurashina 1978), the assemblage is mostly oriented towards the production of flakes and pointed blank relying on the Nubian method. Midhishi 2, in Somalia (Gresham 1984) has yielded an

MSA assemblage (CSUb) characterized by flake, blade and pointed blank production, mainly by the use of Levallois flaking systems. A late MSA has been described in the Ziway-Shala Basin

(B1s3, Ménard et al. 2014) and is characterized by blade production using bidirectional recurrent

Levallois flaking methods.

Porc-Epic cave is the closest site to Goda buticha. The site yielded a long stratigraphic sequence with very rich lithic remains. Unfortunately, dating is still problematic, although the MSA at the site is considered to fall within the later part of the Upper Pleistocene (Pleurdeau 2004, 2005a, 2005b;

Assefa et al. 2008; Rosso et al. 2016). The MSA lithic assemblages are characterised by relatively

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high frequencies of elongated blanks, relying on both planimetric and volumetric conceptions along with a more “classical” Levallois flake production (lineal and recurrent centripetal methods) and a minor component of pointed blank production. This contrasts with the presence of numerous retouched points with a great diversity of types (Perlès 1974). Generally speaking, the Porc-Epic assemblage therefore presents the same characteristics as GB IId-IIf (Pleurdeau 2004, 2005b;

Leplongeon 2014). However, the raw material composition of both assemblages, with a much less emphasis on obsidian at Porc-Epic (around 7%, Pleurdeau 2004, 2005b) suggests different procurement sources and possibly different mobility patterns. Although present in small numbers, microliths do occur within GB IId-IIf, along with the production of smaller blanks, while these characteristics are absent in Porc-Epic (Leplongeon 2014). These features, combined with the lack of secure dating at Porc-Epic, do not allow to conclude that these assemblages are part of a same technical tradition.

5.3. An atypical lithic assemblage dated to the mid-Holocene

The lithic assemblage from GB IIc, dated to 6-8 ka, distinguishes itself from both GB IId-IIf and

GB I by several features. It is characterized by a high frequency of both blades and bladelets, produced using various methods, including planimetric but also a high frequency of methods of volumetric, semi-rotating conception (as inferred from the cores). These elongated blanks are frequently selected for retouch, which confirms that they were one of the main aims of lithic production in this layer. Obsidian is particularly valued in this layer. While present in similar quantities to the lower levels (GB IId-IIf), it is almost systematically selected for retouch (including for example 70% of the retouched points). Other blank production sequences include flake production, sometimes by means of the use of Levallois flaking systems. Retouched tools are composed mainly of MSA-like retouched points and of microliths. The latter are either retouched bladelets or non-geometric backed microliths. Unifacial or bifacial ovate tools in obsidian are also present and are similar to those found in GB IId-IIf, and elongated backed points.

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The lithic assemblage from mid-Holocene GB IIc thus presents unexpected similarities with MSA assemblages. The technical similarities are (1) the presence of Levallois cores and products, (2) the presence of retouched points of the same types known from the earlier assemblages (both GB IId-IIf and Porc-Epic), except for the marked selection of obsidian in GB IIc, and (3) the production of elongated blanks with comparable methods of debitage, although the volumetric production is more frequent. This is associated with more “classical” LSA features such as a volumetric production of blades and bladelets, and the presence of backed microliths. This mixture of characteristics cannot be attributed to post-depositional disturbances (see Pleurdeau et al. 2014; Tribolo et al. 2017).

This association of features is unusual, although not entirely unique, for a Holocene assemblage

(e.g. Phillipson 1977; Gutherz et al. 2014). It is comparable to the lithic assemblage from

Stratigraphic Layers (SU) 709-711 of Shelter 7 of Laas Geel, in Somaliland (Gutherz et al. 2014).

This assemblage shows bladelet and blade production associated with the presence of Levallois cores and products. Retouched tools are composed of retouched Levallois blanks, microliths, including elongated backed bladelets as well as unifacial points. Gutherz et al. (2014) propose the reintroduction of Clark's (1954) Hargeisan to describe this assemblage. However the dates from this site are problematic (with one sample dated to 13 cal ka BP and another one around 40 ka BP,

Gutherz et al. 2014). Although this lithic assemblage seems to be earlier that the one from GB IIc, it too presents an association of MSA-like features with LSA-like characteristics. At the current state of our knowledge, the use of the terminology “Middle Stone Age” or “Later Stone Age” is not satisfactory for these types of assemblages and the use of smaller layers (at the “industry” and regional level) may be more relevant.

The temporal gap between GB IId-IIf and GB IIc broadly corresponds to MIS 2, sometimes referred as the “Big Dry”. Despite scarce data for this period, palaeoenvironmental record from

Southwestern Ethiopia suggests a period of dry conditions between 35-19ka (Foerster et al. 2012,

2015). Currently, there is no site in the Horn of Africa documenting a MIS2 occupation. The most

24

parsimonious explanation for this phenomenon would be that human occupation was not possible, at least on the local scale of southeastern Ethiopia, during MIS 2 (Pleurdeau et al. 2014; Tribolo et al. 2017).

How then to interpret the reminiscent MSA features in GB IIc? Do they correspond to technological convergence, linked with the adaptation to similar environmental conditions? An alternative hypothesis of technological continuity would imply the presence of complex population dynamics between areas which had become too arid (such as southeastern Ethiopia), and refugia. For example, a model similar to the one suggested by Foerster and colleagues for southwestern Ethiopia and Norther Kenya (Foerster et al. 2015), could be proposed by which populations dispersed from southeastern Ethiopia to adjacent regions where the climate was milder, and technological exchange and continuity of technological practices could occur. When it became possible for humans to re- inhabit southeastern Ethiopia, groups could have moved to the region, potentially bearing a mixture of old (e.g., Levallois production and the use of retouched points) and new (e.g., a significant increase in the production of bladelets and microliths) features integrated into their technological behavior.

The analysis of other types of material can contribute to this debate. Of note are the ostrich eggshell

(OES) beads. OES fragments occur throughout the sequence. However, their number increased with elevation above datum. Layer IIc was the only layer in Goda Buticha to have yielded ostrich eggshell beads (N=5) in different stages of manufacture (Pleurdeau et al. 2014), similar to the ones found earlier in sites such as Enkapune Ya Muto in Kenya (Ambrose 1998) or Mumba rockshelter in Tanzania (Mehlman 1989). Interestingly, MSA beads in southeastern Ethiopia are rare, and when reported (e.g. Porc-Epic, Assefa et al. 2008), they are made of very different materials (naturally perforated gastropod shells). The presence of the ostrich eggshell beads may highlight a significant behavioural change in IIc, compared to IId-IIf, and one that may attest to ‘imported’ cultural norms.

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5.4. A Later Stone Age lithic assemblage dated to the late Holocene

The lithic assemblage from GB I is dated to 1.9-0.7 ka and corresponds to the last human occupation documented in the cave, after a relatively short gap that post-dates Layer IIc, lasting between 6.9±0.7 ka and 3.3±0.4 ka (Tribolo et al. 2017). Although the sediments are characterized by thick ashes from anthropogenic , the density of material is very low.

The lithic assemblage shows very distinct characteristics compared to the lower layers, starting from a shift in the use of obsidian as the dominant raw material. Except for two Levallois cores and products, the lithic assemblage does not show any of the MSA characteristics present in the lower assemblages. The assemblage can be defined as microlithic with blank production mainly oriented towards obtaining small flakes and bladelets. Retouched tools are composed mainly of microliths, of which geometric microliths are dominant.

The nearby rockshelter of Laga Oda, located around 10 km southeast of Goda Buticha, contains a

1.5m deep stratigraphic sequence that has yielded only LSA material, attributed to the Somaliland

Wilton Industrial Complex (Clark 1954; Kurashina 1978, chap. 4). Five radiocarbon dates are available for the sequence, ranging from 15590+/-460BP at the bottom to 325+/-70BP at the top of the sequence (Kurashina 1978 p. 449). The material has highest densities at a depth of 40-50cm below datum, (bracketed by radiocarbon dates of 595± 70BP at 30-40cm and 3510±105BP at 50-

80cm). LSA lithic assemblages show the use of primarily chert and quartz, which are locally available, only 4% of the assemblage is made on obsidian. The assemblages are microlithic, with high frequencies of crescents and backed flakes among the retouched tools. The general composition of the assemblages (Kurashina 1978) seems similar to what is observed in GB

Complex I, although the low density in the latter makes comparisons difficult. Unfortunately most of the material from Laga Oda is unavailable for study. Kurashina (Kurashina 1978 p. 14) writes that the “the material from K'one and Laga Oda was shipped back to Berkeley for detailed attribute analysis for a one year period between the 1975 and 1977 field seasons. All shaped tools and measured debitage from these two sites were air freighted to the National Museum at the end of

26

analysis and the remainder was shipped back via Djibouti.”. This ship has apparently never arrived as only a small amount of the material from Laga Oda and K'one is present in the National Museum of Ethiopia in Addis Ababa.

Domesticates appear in the Horn of Africa at a relatively late date (ca 4000 BP, Gutherz et al.

1996; Lesur-Gebremariam 2009; Lesur et al. 2014), due to either unfavourable topography or to infectious diseases that slowed down its spread. No domesticated animal remains were identified in

Complex I, in contrast to the nearby site of Laga Oda, where remains of domestic Bos were found in a level dated to 1500 BC (Clark & Williams 1978). In this respect, GB resembles Mochena-

Borago, in southwestern Ethiopia, where domesticates are absent even from the latest levels dated to 485-55 cal. BC (Lesur et al. 2007). also appears very late in the region (Lesur et al. 2007;

Hildebrand et al. 2010). Thus, the presence of five pottery shreds in Complex I argues for a significant change in subsistence strategies.

6. Conclusion

This paper presents a detailed study of the lithic assemblages from Goda Buticha, a cave site in

Southeastern Ethiopia with a long stratigraphic sequence dated to the Late Pleistocene and to the

Holocene. Particularly, it brings new data on the Late MSA in this area, as well as a previously undescribed set of features, associating both MSA-like and LSA-like artefacts and technology for a

Holocene assemblage (Layer IIc). This regional record therefore documents a clear change in technical behaviour seen only in the late Holocene (Complex I). It also raises a major research question related to the presence of MSA-like characteristics so late in the Holocene: does it correspond to persistence, reinvention or reintroduction?

We suggest that currently these different hypotheses cannot yet be tested rigorously. A major gap, broadly corresponding to MIS 2, is present in the regional sequence (Pleurdeau et al. 2014; Tribolo et al. 2017). Currently, no human occupation in the Horn of Africa is securely dated to MIS2. This gap may be due to a research bias or it may represent a real hiatus in human occupation at this time,

27

which would be consistent with the reconstructed regional palaeoenvironmental studies in

Southeastern Ethiopia (e.g. Foerster et al. 2012, 2015). This raises questions as to potential refugia to which populations from this region may have dispersed. Future research relying on a larger set of data may help testing the hypotheses of the persistence or reintroduction of certain technical traits

(versus the hypothesis of convergence).

Supplementary data for this paper including the list of attributes used in the analysis and the raw data for elongated blanks, cores and retouched tools, is available here: https://doi.org/10.17863/CAM.6736

Acknowledgements

We thank the Ethiopian Authority for Research and Conservation of Cultural Heritages (ARCCH) for permission to survey in the area, to excavate in Goda Buticha and to study the material of both

Goda Buticha and Porc-Epic at the National Museum of Ethiopia. The excavation was supported by grants to Zelalem Assefa for the South East Ethiopia Cave Survey Project from the National

Geographic Society (grants #8110-06 and 8510-08) and to ZA and DP from the Wenner-Gren

Foundation (Grant # ICRG-102). We thank the Tourism and Culture Offices of the Eastern

Harerghe, Western Harerghe, the Dire Dawa Administration, and Harari National Regional State for fieldwork administrative support. AL's PhD research was supported by the Department of

Prehistory of the National Museum of Natural History in Paris, France, as well as by the UMR

CNRS 7194. We are grateful to the French Center for Ethiopian Studies for providing logistical support and for funding part of the post-excavation analyses, as well as to the Association des

Femmes Françaises diplômées des Universités and the Société des Amis du Museum for grants to

AL. This research has received funding from the European Union's Horizon 2020 research and

28

innovation programme under the Marie Skolowska-Curie grant agreement No 655459 as well as from the French Agence Nationale pour la Recherche Project #ANR-14-CE31-0023-03.

We would like to acknowledge the efforts of Tilahun G/Selassie, Workalemahu Bekele, Hadis,

DeJene Dendana Gulti as well as the local people living near the site for their assistance with the excavation. We are also very thankful to Cécile Chapon, Simon Puaud, Marion Hernandez and

Chantal Tribolo, for their current support for sedimentological and OSL dating analyses, and to

Sébastien Nomade for providing some radiocarbon analysis facilities.

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33 FLAKES ELONG. CONV. CORES RET. CHUNKS CHIPS TOTAL 210-200 5 0 0 0 0 0 1 6 200-190 6 2 0 1 1 0 3 13 190-180 26 11 0 1 9 0 123 170 COMPLEX I 180-170 62 35 2 13 17 1 182 312 170-160 17 6 0 3 3 0 41 70 116 54 2 18 30 1 350 571 52.5% 24.4% 0.9% 8.1% 13.6% 0.5%

Layers 160-150 19 2 0 1 6 0 14 42 IIa/IIb 0.61% 160-150 0 1 3 1 0 0 0 5 150-140 88 35 1 6 11 9 76 226 140-130 195 92 3 20 30 19 238 597 130-120 162 92 3 17 35 15 278 602 Layer IIc 120-110 113 61 1 7 18 9 123 332 110-100 101 74 4 9 17 7 165 377 659 355 15 60 111 59 880 2139 52.3% 28.2% 1.2% 4.8% 8.8% 4.7%

Layers 100-090 113 34 2 2 23 5 165 344 IIc/IId

100-090 7 29 0 2 8 0 0 46 090-080 105 39 8 6 24 2 125 309 085-075 93 27 2 6 9 0 145 282 080-070 118 27 4 1 6 4 193 353 075-065 61 17 2 3 13 1 61 158 070-060 96 24 2 1 7 1 220 351 065-055 8 6 0 0 0 1 3 18 060-050 134 26 5 9 18 4 262 458 Layers IId-IIe-IIf 050-040 158 34 5 6 11 3 324 541 040-030 60 16 1 3 1 4 151 236 030-020 56 24 3 2 3 3 73 164 020-010 14 5 0 0 0 1 9 29 010-000 22 5 0 1 0 1 41 70 000– 0 0 0 0 1 0 0 1 010 932 279 32 40 101 25 1607 3016 66.1% 19.8% 2.3% 2.8% 7.2% 1.8%

TOTAL 1839 724 51 121 271 90 3016 6112

Table 1. Goda Buticha. General composition of the material from 2008 and 2011 excavations (Squares A1 and B1) elong. = elongated blanks, conv. = convergent blanks, ret. = retouched

IIdIIf IIc I

Chert Basalt Obsi- Other Total Chert Basalt Obsi- Other Total Chert Obsi- Total dian dian dian

flakes 15 13 10 16 54 15 2 2 3 22 1 1 elongated 5 4 0 5 14 2 3 1 1 7 points 0 4 1 0 5 1 1 2 1 1 Total 20 21 11 21 73 18 5 3 5 31 1 1 2 Levallois blanks Levallois

flakes 1 1 1 3 1 1 elongated 1 1 2 1 1 points 2 1 3

Retouched Retouched Total 3 2 2 1 8 1 1 2 Levallois blanks Levallois centripetal 3 1 4 1 1 2 lineal

centripetal 3 3 recurrent unidirectional 2 3 5 recurrent bidirectional 1 1 2 1 1 2 2 Levallois cores Levallois recurrent Total 9 1 4 14 2 1 3 2 2

Table 2. Goda Buticha. General overview of the Levallois production.

Total Total GB Flakes Elongated Retouched Cores Chips without with chips chips 47 39 30 14 290 130 420 I 35.10% 84.80% 88.20% 93.30% 89.50% 55.80% 75.40% 54 96 69 21 325 240 565 IIc 7.30% 27.00% 62.20% 33.90% 33.30% 18.70% 25.00% 96 58 51 13 307 218 525 IId-IIf 10.30% 20.79% 53.13% 32.50% 19.10% 15.53% 17.44%

Table 3. Goda Buticha. Percentage of artefacts made on obsidian, per category

GB - IIdIIf GB - IIc GB - I Length n mean (sd) n mean (sd) n mean (sd) Chert 68 34.3 (14.9) 110 30** (9.3) 3 range: 21.5-52.5 Obsidian 27 27.3 (8.4) 58 23.9** (7.5) 29 26.4 (6.3) Other 23 53.1 (21.2) 19 44.2** (20.8) / Total 118 33.4 (14.4) 187 29.6 (11.9) Width n mean (sd) n mean (sd) n mean (sd) Chert 68 13.7 (6.2) 110 11.9** (4.2) 3 range: 9.9-19.5 Obsidian 27 10.1 (4.4) 58 8.9** (3.5) 29 10.1 (2.9) Other 23 15.1 (5.8) 19 16.4** (5.7) / Total 118 13.1 (6) 187 11.4 (4.7) Thickness n mean (sd) n mean (sd) n mean (sd) Chert 68 4.9 (3.1) 110 4.5** (2.4) 3 range: 3.6-13.5 Obsidian 27 3.4 (1.6) 58 2.8*/** (1.5)* 29 3.8* (1.7)* Other 23 4.9 (2.4) 19 5.7** (2.5) / Total 118 4.5 (2.8) 187 4.1 (2.4) Ratio length/width n mean (sd) n mean (sd) n mean (sd) Chert 68 2.6 (0.5) 110 2.6 (0.6) 3 range: 2.2-2.7 Obsidian 27 3 (1.2) 58 2.9 (1.1) 29 2.7 (0.6) Other 23 2.5 (0.6) 19 2.6 (0.6) / Total 118 2.7 (0.7) 187 2.7 (0.8) Ratio width/thickness n mean (sd) n mean (sd) n mean (sd) Chert 68 3.3 (1.2) 110 3 (1.1) 3 range: 1.3-2.8 Obsidian 27 3.2 (1) 58 3.7 (1.7) 29 3.2 (1.5) Other 23 3.6 (1.7) 19 3.1 (0.8) / Total 118 3.3 (1.3) 187 3.3 (1.3)

* p-value Kruskal-Wallis <.05 (comparisons of thickness of obsidian elongated blanks between layers, post-hoc Wilcoxon test with p-value <.05 only between GB I and GB Iic

**comparisons of dimensions of elongated products within the levels according to their raw material. Obsidian elongated blanks significantly smaller than chert elongated blanks, themselves significantly smaller than blanks on other raw materials (p-value <.01, except for thickness between chert and other (p-value <.05))

Table 4. Goda Buticha. Dimensions of elongated blanks.

Platform type cortical dihedral faceted lin / punct plain Total I 1 10 5 12 28 3.6% 35.7% 17.9% 42.9% Not salient 7.1% 3.6% 3 Slightly 3.6% 7.1% 7.1% 5 Salient 3.6% 28.6% 3.6% 28.6% 18 Very Salient 3.6% 1 Other 3.6% 1 IIc 6 18 43 29 111 207 2.9% 8.7% 20.8% 14.0% 53.6% Not salient 1.4% 1.0% 2.4% 10

Slightly 0.5% 2.4% 1.4% 7.7% 25

type Salient 1.9% 6.8% 15.9% 11.1% 37.7% 152 Very Salient 0.5% 1.9% 1.0% 7 Bulb Bulb Other 0.5% 0.5% 0.5% 4.8% 13 IId-IIf 8 21 15 28 93 165 4.8% 12.7% 9.1% 17.0% 56.4% Not salient 0.6% 0.6% 6.7% 13 Slightly 0.6% 0.6% 2.4% 4.2% 10.3% 30 Salient 3.0% 9.7% 6.1% 9.7% 29.7% 96 Very Salient 1.2% 1.2% 0.6% 0.6% 4.2% 13 Other 0.6% 1.8% 5.5% 13

Table 5. Goda Buticha. Types of platform and bulb for proximal fragments and complete elongated blanks.

Complex I Layer IIc Layers IId-IIf TYPE type of blank N % N % N % RET. FLAKE flake 2 7% 5 4% 21 21% RET. BLADE blade 3 10% 18 16% 15 15% flake 1 1 4 ENDSCRAPER blade 3 total 1 3% 4 4% 4 4% flake 5 9 incl. Dentic. 2 incl. Double 1 1 incl. Bif. 1 SIDE blade 5 6 incl. Dentic. incl. Double 3 indet 1 total 11 10% 15 15% flake 2 3 blade 1 RET. POINT pointed 4 6 indet 16 21 total 23 20% 30 29% flake (backed) 4 1 bladelet 8 30 2 incl. Ret. 2 11 1 MICROLITHS incl. Backed 6 19 1 indet (backed) 5 total 17 57% 31 27% 2 2% blade 4 7 LARGE BACKED indet 1 1 PIECES total 5 17% 8 7% 2 7% 1 1% UNIF/BIF TOOLS 7 6% 8 8% COMPOSITE flake 3 3% TOOL blade 4 4% 2 2% RESHARPENING FLAKE 3 3% 1 1% TOTAL 30 114 102

Table 6. Goda Buticha. Types of retouched tools.

GB – IIc GB – IId-IIf Type of Types of points N % N % retouch localised / / 1 3% Unifacial unilateral points peripheral 2 9% 3 10% invasive / / 2 7% localised 1 4% / / Unifacial bilateral peripheral 3 13% 3 10% points invasive 5 22% 6 20% covering 7 30% 5 17% peripheral / / / / Partly-bifacial points invasive / / / / covering 2 9% 2 7% localised / / / / peripheral / / / / Bifacial points invasive / / 1 3% covering 3 13% 7 23% Sub-total localised retouch 1 4% 1 3% Sub-total peripheral retouch 5 22% 6 20% Sub-total invasive retouch 5 22% 9 30% Sub-total covering retouch 12 52% 14 47% TOTAL 23 30

Table 7. Goda Buticha. Characteristics of retouched points

Length Width Thickness N function L/W W/T (L) (W) (T) IIdIIf mean 37.8 21.9 6.3 1.8 3.7 20 total sd 6.7 5.4 2.0 0.4 1.2 IIdIIf mean 35.5 18.9 5.8 2.0 3.3 4 obsidian sd 2.1 6.0 1.6 0.6 0.5 IIdIIf mean 38.7 22.1 6.3 1.8 3.8 12 chert sd 8.4 5.3 2.2 0.3 1.4 IIdIIf mean 37.7 24.7 6.9 1.6 3.9 4 basalt sd 3.0 5.1 1.7 0.4 1.4 mean 37.8 19.4 6.5 1.9 3.3 IIc total 15 sd 13.8 4.6 2.6 0.4 1.1 IIc mean 33.0 18.5 5.7 1.8 3.6 10 obsidian sd 10.3 4.4 2.3 0.3 1.2 mean 39.5 22.0 6.9 1.9 3.5 IIc chert 2 sd 0.4 5.0 3.5 0.4 1.1 mean 41.0 17.1 7.6 2.4 2.4 IIc basalt 2 sd 5.7 1.2 2.1 0.1 0.8 IIc mean 75.5 27.4 11.2 2.8 2.4 1 quartzite sd NA NA NA NA NA

Table 8. Goda Buticha. Main dimensions (in mm) of retouched points per layer and per raw material.

Goda Buticha IId- Goda Buticha Goda Buticha I Statistical tests IIf IIc

Frequency of Chi2 = 167.82, p 15% 19% 56% obsidian <.01 (1) Elongated blank production Chi2= 56.95,p frequency 18% 29% 22% <.01(1)

K-W Chi2= 5.17,p mean length ±SD 33.7mm ±14.7 30.1mm±12.5 28.3mm±9.1 > .05 (2)

Only for bladelets (raw selection of obsidian NO YES material constraint?) bladelet frequency - 40% 61%

blade frequency 100%? 60% 39%

scar pattern unipolar 61% 56% 58% Chi2= 8.08, p > .05 Unipolar & lateral 12% 17% 23% (1) bidirectional 9% 14% 13% centripetal 14% 6% 5% platform types plain 57% 43% 29% Chi2= 7.17, p > .05 (1) Faceted & dihedral 21% 25% 27% Linear & punctiform 16% 11% 15% edges parallel 41% 42% 51% rounded to Chi2= 4.77, 6% 5% 3% convergent p>.051(1) convergent 26% 27% 31% rounded 11% 9% 5% conception (cores &

CTE's) planimetric ++ ++ +

volumetric + +++ + selection of elongated blanks for retouched NO YES YES tools selection of obsidian for retouched YES YES n=13/15, yes elongated blanks Levallois production frequency 5-6% 3% NO?

lineal, unipolar recurrent & lineal and centripetal Bipolar methods bipolar recurrent recurrent for flakes recurrent? for flakes and blades (in a lesser extent) Goda Goda Buticha Goda Buticha Buticha Statistical tests IIc I IId-IIf Retouched points frequency 31% 21% - mean length 38mm 38mm / selection of obsidian NO YES / types

unifacial bilateral 47% 70% - Chi2= 3.54 p > .05 (1) bifacial 33% 21% - retouch type

peripheral 23% 26% -

invasive 30% 22% - Chi2= 0.46, p >.05 (1)

covering 47% 52% -

Microliths 27% 57.00% frequency N=2/101 (n=31/114) (n=17/30) types

retouched bladelets N=1 33% (N=10) 12% (N=2) backed microliths N=1 67% (N=21) 88% (N=15) Incl. Geometric N=4 N=12 microliths Backed points Presence / absence NO YES NO

Unifacial & bifacial tools Presence / absence YES YES NO

(1) Pearson's Chi-squared test with simulated p-value (based on 5000 Replicates). (2) Kruskal-Wallis rank sum test

Table 9. Main characteristics of the lithic assemblages from Goda Buticha.

Figure 1. Location of sites mentioned in the text. Created using Natural Earth Data in QGIS

Figure 2. Characteristics of lithic assemblages from main sites in the Horn of Africa dated to between 100ka and 8ka.

Figure 3. Goda Buticha. A. general view of the cave. B. Floor plan indicating the excavated areas from which the current sample derives. C. A schematic stratigraphic section showing the main units and dates D. Barchart: count of lithic material according to the main stratigraphic units. *OSL dates after Tribolo et al, 2017; ** radiocarbon dates, after Pleurdeau et al, 2014

Figure 4. Main characteristics of the lithic assemblage from layers IId-IIf, Goda Buticha

Figure 5. Graphs of length and width of complete elongated blanks from Layers IIdIIf, IIc and I of Goda Buticha: A: scatterplot of length and width according to raw material, B: histogram of lengths; C: Goda Buticha IIc. Histogram of lengths according to raw material.

Figure 6. Lithic artefacts from Goda Buticha IId-IIf. (a,c): blade cores, (b): Levallois core, (d): bladelet core, (e,f): Levallois blades, (g-m): technical pieces related to elongated blank production, including (h,l,m): technical pieces related to a volumetric conception of debitage, (n-r): elongated blanks.

Figure 7. Lithic artefacts from Goda Buticha IId-IIf. (a-e): elongated blanks, (f-p): retouched points, (q-s): small uni- or bifacial obsidian ovates, (t-u): microliths

Figure 8. Main characteristics of the lithic assemblage from layer IIc at Goda Buticha

Figure 9. Lithic artefacts from Layer IIc at Goda Buticha. (a) Levallois core, (b,c): blade cores, (d-f): bladelet cores, (g-n): technical pieces related to blade(let) production, (o-v): blades, (w): bladelet

Figure 10. Lithic artefacts from Layer IIc at Goda Buticha. (a-g): bladelets, (h-n): retouched points, (o-p): elongated backed points, (q-r): backed pieces, (s-u): microliths, (v-w): fragments of microliths or elongated backed points, (x-y): small unifacially retouched obsidian ovates.

Figure 11. Main characteristics of the lithic assemblage from Complex I at Goda Buticha

Figure 12. Lithic artefacts from Complex I at Goda Buticha. (a) Levallois-like core, (b-d) cores for elongated blanks, (e,f,j): technical pieces related to elongated blank production, (g- i) bladelets, (k-m) geometric microliths, (n) large backed piece Figure 1. Location of sites mentioned in the text. Created using Natural Earth Data in QGIS

Figure 2. Characteristics of lithic assemblages from main sites in the Horn of Africa dated to between 100ka and 8ka.

Figure 3. Goda Buticha. A. general view of the cave. B. Floor plan indicating the excavated areas from which the current sample derives. C. A schematic stratigraphic section showing the main units and dates C. Barchart: count of lithic material according to the main stratigraphic units. *OSL dates after Tribolo et al, in prep; ** radiocarbon dates, after Pleurdeau et al, 2014

Figure 4. Main characteristics of the lithic assemblage from layers IId-IIf, Goda Buticha

Figure 5. Plots of length and width of complete elongated blanks from Layers IIdIIf, IIc and I of Goda Buticha.

Figure 6. Lithic artefacts from Goda Buticha IId-IIf. (a,c): blade cores, (b): Levallois core, (d): bladelet core, (e,f): Levallois blades, (g-m): technical pieces related to elongated blank production, including (h,l,m): technical pieces related to a volumetric conception of debitage, (n-r): elongated blanks.

Figure 7. Lithic artefacts from Goda Buticha IId-IIf. (a-e): elongated blanks, (f-p): retouched points, (q-s): small uni- or bifacial obsidian ovates, (t-u): microliths

Figure 8. Main characteristics of the lithic assemblage from layer IIc at Goda Buticha

Figure 9. Lithic artefacts from Layer IIc at Goda Buticha. (a) Levallois core, (b,c): blade cores, (d-f): bladelet cores, (g-n): technical pieces related to blade(let) production, (o-v): blades, (w): bladelet

Figure 10. Lithic artefacts from Layer IIc at Goda Buticha. (a-g): bladelets, (h-n): retouched points, (o-p): elongated backed points, (q-r): backed pieces, (s-u): microliths, (v-w): fragments of microliths or elongated backed points, (x-y): small unifacially retouched obsidian ovates.

Figure 11. Main characteristics of the lithic assemblage from Complex I at Goda Buticha

Figure 12. Lithic artefacts from Complex I at Goda Buticha. (a) Levallois-like core, (b-d) cores for elongated blanks, (e,f,j): technical pieces related to elongated blank production, (g-i) bladelets, (k-m) geometric microliths, (n) large backed piece