Skeletal element representation for (A) small and (B) medium-sized bovids, Bed KS-1.

<p>Abundance data presented as percent minimum animal units (%MAU), calculated following the literature <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Lyman1" target="_blank">[43]</a>. KJS data derived from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174.s003" target="_blank">Table S3</a>. 100% MAU = 6 for small bovids, 9 for medium-sized bovids. Similar patterns of skeletal element representation are present in Beds KS-2 and KS-3.</p

Tooth-mark frequencies and long bone portion representation: results from modern experiments and excavations at KJS.

<p>Portions defined in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone-0062174-t002" target="_blank">Table 2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174.s001" target="_blank">Table S1</a>. ‘Shafts’ include both near-epiphyseal and mid-shaft specimens. Complete bones are not included in epiphysis-to-shaft calculations (number of complete bones = 2, 7, and 1; beds KS-1 through KS-3, respectively). Ellipses outline the range of results in experimental feeding scenarios involving: carnivores-only, hominins-only, or a sequence of hominins-then-carnivores (i.e., ‘hominin-first’). The dashed line is a published least-squares regression for hominin-first scenarios <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Blumenschine1" target="_blank">[22]</a>. Hominin-only scenarios have no tooth marks, hence the placement of the ellipse beneath the x-axis. KJS data from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone-0062174-t002" target="_blank">Table 2</a> are for summed body sizes. KJS epiphysis-to-shaft ratios: 0.26, 0.22, and 0.19 for beds KS-1 though KS-3 respectively. KJS tooth-mark data displayed as solid vertical bars, with bars representing the range of analysts’ results. Results from Kanjera are consistent with hominin-first contexts.</p

Location of Kanjera along the modern shoreline of Lake Victoria, East Africa.

<p>(A) Kanjera lies to the immediate northeast of Homa Mountain, a volcanic complex active from the middle Miocene to the Pleistocene. The Winam Gulf fills the western end of the Nyanza Rift, an E-W graben with origins in the early Miocene. (B) Beds KS-1 through KS-3 of the Kanjera Formation (Southern Member) sample floodplain and low-aspect channel contexts originally deposited between the mountain and the nearby shores of a shallow lake <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Plummer2" target="_blank">[49]</a>. Satellite imagery from USGS and NASA.</p

Faunal and lithic inventory.

<p>NISP (number of identified specimens) and MNI (minimum number of individuals) are defined and quantified following the literature <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Lyman1" target="_blank">[43]</a>. ‘Total NISP’ reflects the sum of specimens recovered with coordinate data and included in this study. Tens of thousands of non-identifiable bone and tooth fragments <2 cm are omitted from this study. Fossils from conglomeratic facies (CP levels) are poorly preserved <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Plummer2" target="_blank">[49]</a>, and are likewise excluded from this study: KS-2CP (n = 259), KS-3CP (n = 102). Macro-mammals are defined here as weighing >5 kg. Macro-mammal NISP values are total sums and, in parentheses, the sum of specimens identified beyond Linnean class. %NISP and %MNI include macro-mammals only. Faunal and lithic counts are from the literature <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Ferraro1" target="_blank">[17]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Braun4" target="_blank">[55]</a>.</p

Tooth-marked mid-shaft fragments: results from experimental assemblages and excavations at KJS.

<p>Figure follows a published model <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Lupo1" target="_blank">[26]</a>. Hominin-first assemblages refer to remains initially defleshed and demarrowed by hominins, then subsequently exposed to large-bodied carnivores (primarily hyenas). Carnivore-first assemblages refer to remains initially defleshed and/or demarrowed by large-bodied carnivores (primarily hyenas and/or lions). Data for body sizes 1–4 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Bunn1" target="_blank">[21]</a>. Modern data (with single standard deviations where available) derived from the literature <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Blumenschine2" target="_blank">[23]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Lupo1" target="_blank">[26]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Selvaggio1" target="_blank">[56]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Marean2" target="_blank">[58]</a>. KJS frequencies are from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone-0062174-t002" target="_blank">Table 2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174.s001" target="_blank">Table S1</a>. Multiple symbols for KJS indicate the results of multiple analysts. X’s indicate minimum and maximum estimates of damage (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174.s001" target="_blank">Table S1</a>).</p

Bone surface modifications.

<p>(A) KJS 7472, a small bovid metatarsal from KS-2 bearing cut marks; (B) KJS 7379, a medium-sized bovid humerus from KS3 bearing pair of hammerstone notches, the specimen is also cut-marked (not figured); (C) KJS 5447, a mammal limb bone shaft fragment from KS-2 with percussion pit and striae, the specimen is also cut-marked (not figured); (D) KJS 2565, a small bovid femur from KS-2 with numerous cut marks. Scale is 1 cm in panels (A-D); 1 mm in the panel (D) close-up. Specimen numbers are field designations, not KNM accession numbers.</p

Bone surface modification frequencies.

<p>Modifications detailed by long bone portion <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Blumenschine1" target="_blank">[22]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Capaldo1" target="_blank">[24]</a>, bed, and analyst. Epiphyseal fragments (EPI) bear at least some of the proximal or distal articular surface. Mid-shaft fragments (MSH) are diaphyseal specimens that lack cancellous bone on medullary surfaces. Bone modifications follow the literature [17 and references therein], and include tooth marks (TM: pits, scores, furrows), cut marks (CM), and percussion marks (PM: pits, striae). Bone modification frequencies are listed by analyst: Ferraro, Pobiner, and Oliver (in order from left to right). Samples are bovid and taxonomically-indeterminate long bone specimens (i.e., humerus, radius, metacarpal, femur, tibia, metatarsal, or ‘long bone shaft fragment’), ≥2 cm in length, from body sizes 1–3 (i.e., small and medium-sized) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Bunn1" target="_blank">[21]</a>, with ‘very good’ to ‘excellent’ bone surface preservation (i.e., surface conditions 4–5 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062174#pone.0062174-Ferraro1" target="_blank">[17]</a>) and without recent or geological fractures. Data for summed body sizes, including ‘size indet’.</p