faith et al in press

Paleoenvironmental context of the Middle Stone Age record

for human and faunal dis

J. Tyler Faith a, *, Christian A. TryScott Blumenthal e, Kendra L. Cha School of Social Science, University of Queensland, Brib Department of Anthropology, Harvard University, Peabc Terrestrial Paleoclimatology Research Group, Departmd Department of Anthropology, University of Connecticue Department of Anthropology, The Graduate Center, Citf Department of Biology, University of Utah, Salt Lake Cg Center for the Advanced Study of Hominid Paleobiolog

a semi-arid environment characterized by seasonal precipitation and the dominance of C4 grasslands,d fossil assemblageallopatric ungulatesservations. Analysisation in assemblageg phases of limitedearby Rusinga Islandites. This may reectpaleoenvironmental

. All rights reserved.

Fossil evidence from East Africa provides the earliest knownspecimens attributed toHomo sapiens, dating to ~195 ka (thousandsof years ago) (McDougall et al., 2005; Brown et al., 2012). Theseearly humans later diverged into multiple genetically (Campbell

erse (Creveceouret al., 2009; Gunz et al., 2009; Harvati et al., 2013; Tryon et al.,2015) populations during the Late Pleistocene (126e12 ka), likelyreecting complex phases of population dispersal and vicarianceacross Africa (Campbell and Tishkoff, 2010; Soares et al., 2012; Ritoet al., 2013). This biological diversity among early modern humansis accompanied by substantial behavioral diversity, with theMiddleStone Age (MSA) archaeological record of East Africa (~285e50 ka)characterized by exceptional variability and only rare cases ofgeographic or temporal patterning (Tryon and Faith, 2013).

* Corresponding author.

Contents lists availab

Journal of Hum

.e l

Journal of Human Evolution xxx (2015) 1e18E-mail address: [email protected] (J.T. Faith).likely associated with a substantial reduction in Lake Victoria. The well-preserveindicates that these conditions are associated with the convergence of historicallyfrom north and south of the equator, in agreement with predictions from genetic obof the East African MSA record reveals previously unrecognized northesouth varicomposition that is consistent with episodes of population fragmentation durindispersal potential. The grassland-associated MSA assemblages from Karungu and nare characterized by a combination of artifact types that is more typical of northern sthe dispersal of behavioral repertoiresdand perhaps human populationsdduring aphase dominated by grasslands.

2015 Elsevier Ltd

Introduction and Tishkoff, 2010) and morphologically divStable isotopes well as obsidian akes similar in geochemical composition to documented sources near Lake Naivasha(250 km east). A combination of sedimentological, paleontological, and stable isotopic evidence indicatesa r t i c l e i n f o

Article history:Received 29 April 2014Accepted 12 March 2015Available online xxx

Keywords:Modern human originsObsidian sourcinghttp://dx.doi.org/10.1016/j.jhevol.2015.03.0040047-2484/ 2015 Elsevier Ltd. All rights reserved.

Please cite this article in press as: Faith, J.T., eKenya, and its implications for human andj.jhevol.2015.03.004persals in East Africa

on b, Daniel J. Peppe c, Emily J. Beverly c, Nick Blegen d,ritz f, Steven G. Driese c, David Patterson g

sbane, QLD 4072, Australiaody Museum, 11 Divinity Ave, Cambridge, MA 02138, USAent of Geology, Baylor University, Waco, TX 76798, USAt, Storrs, CT 06269, USAy University of New York, New York, NY 10016, USAity, UT 84112, USAy, Department of Anthropology, The George Washington University, Washington, DC 20052, USA

a b s t r a c t

The opening and closing of the equatorial East African forest belt during the Quaternary is thought tohave inuenced the biogeographic histories of early modern humans and fauna, although precise detailsare scarce due to a lack of archaeological and paleontological records associated with paleoenvir-onmental data. With this in mind, we provide a description and paleoenvironmental reconstruction ofthe Late Pleistocene Middle Stone Age (MSA) artifact- and fossil-bearing sediments from Karungu,located along the shores of Lake Victoria in western Kenya. Artifacts recovered from surveys andcontrolled excavations are typologically MSA and include points, blades, and Levallois akes and cores, asfrom Karungu, Lake Victoria Basin, Kenya, and its implicationsjournal homepage: wwwt al., Paleoenvironmental contfaunal dispersals in East Ale at ScienceDirect

an Evolution

sevier .com/locate/ jhevolext of theMiddle Stone Age record from Karungu, Lake Victoria Basin,frica, Journal of Human Evolution (2015), http://dx.doi.org/10.1016/

Understanding the mechanisms underlying the diversity ofearly human populations and their dispersals within and out ofAfrica remains a fundamental challenge of human origins research.A commonly proposed mechanism is environmental change, whichmay have mediated population distributions and demographics(Scholz et al., 2007; Eriksson et al., 2012; Rito et al., 2013), theopening and closing of biogeographic barriers (Vaks et al., 2007;Cowling et al., 2008; Carto et al., 2009; Compton, 2011; Faithet al., in press), and behavioral adaptations to resource availability(Ambrose and Lorenz, 1990; McCall, 2007; Marean, 2010). Ofparticular relevance to East Africa, Cowling et al. (2008) proposethat the repeated opening and closing of the equatorial East Africanforest belt throughout the Quaternary, mediated by changes inrainfall and atmospheric CO2 concentrations, potentially played akey role in the dispersals of humans and fauna. Their model issupported by genetic evidence from contemporary fauna, with abroad range of widely distributed vertebrate species, includingwildebeest (Connochaetes taurinus), hartebeest (Alcelaphus busela-phus), waterbuck (Kobus ellipsiprymnus), giraffe (Giraffa camelo-pardalis), ostrich (Struthio camelus), and many others, showingpronounced differentiation between populations from north andsouth of the equator (Dehghani et al., 2008; Miller et al., 2011;

(3) the MSA archaeological record from Karungu, and (4) thepaleoenvironmental implications of the associated faunal assem-blage, including stable isotopic analysis of bovid and East Africanmole rat (Tachyoryctes splendens) tooth enamel. We use these data,together with an analysis of variation in the Late Pleistocene MSArecord of East Africa, to explore the potential role of an equatorialdispersal barrier in the biogeographic histories of early modernhumans and fauna.

The Lake Victoria Basin

Straddling the equator in East Africa, Lake Victoria is the largestAfrican lake by surface area (66,400 km2; Adams, 1996) and rep-resents a signicant barometer of Quaternary paleoenvironmentalchange. Because water input is determined primarily by rainfalldirectly over its surface, rather than inow from rivers and streams,Lake Victoria is highly sensitive to changes in precipitation(Broecker et al., 1998; Nicholson, 1998; Milly, 1999; Bootsma andHecky, 2003), with historic records from the last 200 years doc-umenting lake level uctuations of ~4 m in response to precipita-tion variability (Nicholson, 1998). The lake is also very shallow(maximum depth

The repeated expansion and contraction of Lake Victoria isknown to have had an important inuence on biotic communities.Evidence from pollen cores (Kendall, 1969), geochemical proxies forvegetation cover (Talbot and Laerdal, 2000; Talbot et al., 2006), andfossil mammals (Tryon et al., 2012, 2014) show that reductions inlake level were associated with a dominance of grasslands, incontrast to the evergreen bushland, thicket, and forest habitatshistorically present in the region (White, 1983; van Breugel et al.,2012). This expansion and contraction of grasslands and forestspotentially facilitated the dispersal of ora and fauna across theLake Victoria Basin, as indicated by the modern distribution ofspecies in the region (White, 1983; Kingdon, 1990; Wronski andHausdorf, 2008). Together, the evidence for dynamic vegetationchange and species dispersals suggests that the Lake Victoria Basinrepresents an ideal natural laboratory to explore the inuence ofenvironmental change on the dispersal histories of early modernhumans and associated fauna.

Background to Karungu

Karungu is located along the shores of Lake Victoria in southwestKenya (0.844S, 34.157E), 50 kmsouth of thewell-knownMiocene(e.g., Le Gros Clark and Leakey, 1950; Van Couvering, 1972; Leakey,1974; Andrews, 1981; Pickford, 1986; Teaford et al., 1988; Walkerand Teaford, 1988; Peppe et al., 2009; Michel et al., 2014) and Pleis-tocene (Pickford and Thomas, 1984; Tryon et al., 2010, 2012, 2014;Faith et al., 2011, in press) localities on Rusinga and Mfangano Is-land (Fig. 1) and 65 km southwest of the Miocene-to-Pleistocene

ranges from ~1000 to 1400 mm (Fullinger et al., 2004; Hijmans et al.,2005). The large mammal herbivores in the region historicallyincluded African buffalo (Syncerus caffer), bushbuck (Tragelaphusscriptus), duiker (Sylvicapra grimmia), Bohor reedbuck (Reduncaredunca), waterbuck (K. ellipsiprymnus), impala (Aepyceros mel-ampus), topi (Damaliscus lunatus), hartebeest (A. buselaphus), oribi(Ourebia ourebi), roan antelope (Hippotragus equinus), giraffe(G. camelopardalis), bushpig (Potamochoerus larvatus), black rhinoc-eros (Diceros bicornis), and elephant (Loxodonta africana) (Allsoppand Baldry, 1972; Kimanzi, 2011).

Karungu is among the earliest documented paleontological lo-calities in Kenya, with fossils rst discovered in the region in 1909(see Andrews,1981) and published two years later (Andrews,1911).Subsequent eldwork directed by Oswald focused on the richMiocene fossil sites (Andrews, 1914; Newton, 1914; Oswald, 1914)and incidentally documented the presence of lithic artifacts of aNeolithic character lying on the surface of Miocene deposits(Oswald, 1914:136). Since then, the Miocene deposits at Karunguhave been intermittently studied by L.S.B. Leakey, Andrews, Pick-ford, and McNulty and colleagues (Andrews, 1981; Pickford, 1984;Lehmann et al., 2014; McNulty et al., 2014).

During the 1930s, Archdeacon W.E. Owen conducted the rstexploration of the Quaternary sediments at Karungu (Owen, 1937,1938, 1939). In an unpublished manuscript, he notes the discoveryof in situ human remains fromup to six individuals froma site knownas Ngira (Figs.1 and 2), in addition to the presence of fossil fauna andartifacts referred to as Kenyan Aurignacian (Later Stone Age, LSA),Levallois (Middle Stone Age, MSA), and Acheulean (Owen, 1937).

ingph r

J.T. Faith et al. / Journal of Human Evolution xxx (2015) 1e18 3deposits on the Homa Peninsula (e.g., Oswald, 1914; Andrews, 1916;Pickford, 1984; Behrensmeyer et al., 1995; Ditcheld et al., 1999).Although much of the landscape around Karungu is now undercultivation, the historic vegetation included evergreen bushland andthicket in the immediate area, grading towoodlands andmore humidAfromontane rainforests further inland (White, 1983; van Breugelet al., 2012). Average annual rainfall at nearby Mbita (45 km north)

Figure 2. Front and back of photograph taken by W.E. Owen in 1935/1936 at Ngira showsoils. Source: National Museums of Kenya Archives. The text on the back of the photogra

fragments of skull seen were weathering out of the mound, just where they are lying. The phngers to see if any more fragments were contiguous. The mound top is indicated by suga

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004The human remains are associated with LSA artifacts and evidentlywith pottery; investigations of the geology by E.J. Wayland and ar-tifacts by M.C. Burkitt conrmed the in situ nature of these materialsand their Gamblian (=Holocene) age (Wayland,1938; Van Riet Lowe,1952:16). The fossils curated at theNationalMuseumofKenya (NMK)in Nairobi are weakly mineralized, further indicating a more recentage than the material described in this study. Many of the human

the location of human cranial fragments eroding from near the surface of black cottoneads as follows: Ng'ira, Karungu site. Tree is west of skull mound, eleven paces. The two

otograph shows clearly the place about them where I smoothed the soil away with myr cane stem.

ext of theMiddle Stone Age record from Karungu, Lake Victoria Basin,frica, Journal of Human Evolution (2015), http://dx.doi.org/10.1016/

remains collected by Owen have since been lost, some perhapsduring the bombing of the Royal College of Surgeons in Londonduring World War II, where Sir Arthur Keith and T.D. McCownstudied and described some of the remains (noted in Owen, 1937).Subsequent papers published by Owen (1938, 1939) also note thepresence of rolled Acheulean hand-axes, as well as Kombewa akesand cores from probable channel deposits at Ngira and Aringo.

Pickford's (1984) investigations at Karungu proved to be themost useful for guiding the present research. In his survey of pale-ontological sites from western Kenya, he mapped 12 localities withexposure of Pleistocene deposits (Fig. 1) that unconformably overliethe Miocene sequence. Pickford (1984) reported from these Pleis-tocene deposits the presence of MSA artifacts and fossil fauna,including an assortment of extant bovids, equids, and suids, whichled him to assign a probable Late Pleistocene age to the deposits.From 2011 to 2013, we conducted investigations of the depositsmapped by Pickford (1984). This included systematic pedestriansurveys, supplemented by controlled archaeological excavations andgeological trenching. We provide below the rst detailed descrip-tion of the geology, MSA archaeology, and paleontology of Karungu.

Methods

Field methods

Pedestrian surveys were conducted at all Pleistocene exposuresat Karungu from 2011 to 2013. Of the 12 Pleistocene localitiesmapped by Pickford (1984), we were able to collect artifacts andfossils from seven: Aoch Nyasaya, Aringo, Kachuku, Kisaaka, Ngira,Obware, and Onge (Fig. 1). The remaining localities are presently

under cultivation and no longer exposed (e.g., Owich) or are nowcommercial or residential centers that appear to have beendestroyed by recent construction (e.g., Sori).

The primary archaeological objective of the survey was toidentify the broad archaeological taxonomic units (e.g., ESA, MSA,LSA) present through the Karungu Pleistocene sequence. At all lo-calities, general collection of lithic artifacts documented during thesurvey was restricted only to those specimens that were diagnosticof these industries (n 63 specimens total). This collection wassupplemented by systematic collections of all lithic material bysurface crawls from six 24e25m2 gridded areas at Kisaaka, Obware,and Aringo (Fig. 3; Table 1). These grids were selected to maximizeartifact samples and were established at or near the base of activelyeroding proles containing one or more marker tephra deposits toprovide stratigraphic control (Fig. 4).

To characterize the in situ archaeological material, a test exca-vation was conducted at the Aringo 3 site in 2013 (Figs. 1 and 3),where a small geological trench uncovered numerous artifacts. Acontrolled test excavation of 5 m2 was set up adjacent to the trench,and excavated according to arbitrary 10-cm levels within discern-ible stratigraphic units. All sediment was sieved through 1/8-inchmesh and in situ artifacts were plotted in three-dimensions usinga total station linked to a laptop computer running EDM for Win-dows excavation software.

Following our previous collections on Rusinga and Mfanganoislands (Tryon et al., 2010, 2012), the collection of fauna empha-sized the recovery of taxonomically informative specimens,including all cranial and dental remains, bovid horn cores, rumi-nant astragali and metapodials, and all specimens belonging toprimates or carnivores. Microfaunal remains were recovered in

To

500m

RIN

go

No

bwa

ati

J.T. Faith et al. / Journal of Human Evolution xxx (2015) 1e184N KISAAKA

Modern alluvium

Exposure

Vegetation

Road

Lake Victoria

A

Arin

Main

ZTG

RCS

Figure 3. Location of the Aringo 3 excavation and systematic surface crawls at Kisaaka, O(RCS), Zebra Tooth Gully (ZTG), and Main.

Table 1Summary of artifacts recovered from survey, the Aringo 3 test excavation, and system

Site General survey Aringo 3 excavation Aringo north 1

Area (m2) N/A 5 25Complete akes 22 (1*, 2**) 54 (2*, 1**) 4Flake fragments 14 (2*, 1*) 44 (3*) 11Cores 17 (10*) 4 (2*) 1Retouched pieces 10 (1**) 0 0Handaxe 1b 0 0Angular waste 0 114 0Total 63 216 16Artifacts/m2 NA 43.2 0.64

a Values in parentheses are *Levallois or **blades.b A weathered and rolled specimen recovered from a modern alluvial deposit atop th

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004N

Karungu

GO

OBWARE

AOCH NYASAYA

500m 250m

3

rth 1

re, and Aringo (see also Table 1). Microfauna screened at Kisaaka Rodent Carbonate Site

c surface crawls at Aringo, Kisaaka, and Obware.a

Aringo north 2 Kisaaka-ZTG Kisaaka-Main Kisaaka-RCS Obware

25 25 25 25 246 8 6 3 5 (1**)27 18 (2**) 13 6 4 (1**)0 3 (1*) 0 0 5 (1*)0 0 2 (1**) 0 00 0 0 0 00 0 0 0 033 29 21 9 141.32 1.16 0.84 0.36 0.58e Miocene bedrock at Kisaaka.

ext of theMiddle Stone Age record fromKarungu, Lake Victoria Basin,frica, Journal of Human Evolution (2015), http://dx.doi.org/10.1016/

Figure 4. Stratigraphy of the Pleistocene deposits at Karungu. The type stratigraphic section for the Karungu deposits is at Kisaaka (far left). All other Karungu localities have beencorrelated to Kisaaka based on tephrostratigraphy (solid lines; SOM; see Blegen et al., submitted for publication for correlation of upper BTPT tephra) and lithostratigraphy (dashedlines). The widespread Nyamita Tuff has been used as a stratigraphic datum for correlation between sections. Locations of in situ artifacts, mammalian fossils, and the surfacecollection sites for micromammals and systematic surface crawls (Table 1) are indicated on each stratigraphic section. Fauna and diagnostic MSA artifacts were surface-collectedfrom all paleosols and conglomerates at all sites, spanning the Karungu Pleistocene sequence. The geographic locations of each locality are indicated in Fig. 1.

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental context of theMiddle Stone Age record from Karungu, Lake Victoria Basin,Kenya, and its implications for human and faunal dispersals in East Africa, Journal of Human Evolution (2015), http://dx.doi.org/10.1016/j.jhevol.2015.03.004

manabundance from the general surface collection at Kisaaka, withsmaller collections from Aoch Nyasaya, Aringo, and Obware.Microfaunal recoverywas enhanced at Kisaaka by screening surfacesediments from an approximately 10 m2 area through 1-mm meshat three sites: Zebra Tooth Gulley (ZTG), Rodent Carbonate Site(RCS), and Main (Fig. 3).

Obsidian geochemistry

Obsidian akes were documented in our excavation at Aringo 3(LVP2014-31) and collected from the surface at Kisaaka (LVP2014-32). The nearest documented obsidian sources are in the EasternRift Valley ~250 km to the east (Merrick and Brown, 1984; Brownet al., 2013). To identify the potential sources of these obsidian ar-tifacts, we characterized their geochemistry by wavelengthdispersive electron microprobe analysis conducted on a CamecaSX-50 in the Department of Geology and Geophysics at the Uni-versity of Utah. Analytical conditions follow the recent detailedsurvey of Kenyan obsidian sources provided by Brown et al. (2013).

Isotope analysis

To enhance our paleoecological interpretations of the fossilmammals, we conducted a stable isotope analysis of fossil bovid(n 20 specimens) and rodent tooth enamel (n 17 specimens).Modern bovids exhibit a wide range of habitat preferences and areparticularly useful for reconstructing paleoenvironments in EastAfrica (e.g., Gentry, 1970; Vrba, 1980; Scott, 1985; Cerling et al.,2003; Plummer et al., 2009), and we sampled teeth from thedominant tribes present in the assemblage (Alcelaphini, Antilopini,Bovini, and Reduncini). Due to their smaller home ranges, micro-mammals provide a more localized ecological signal than thewider-ranging bovids that relates to locally available microenvi-ronments (Kimura et al., 2013; Symes et al., 2013). Because carbonisotope values relate to the diet of mammalian herbivores, thesedata can be used to determine the presence of C4 grasses and theheterogeneity of available food resources at varying spatial scales(e.g., Cerling et al., 2003; Codron et al., in press).

Bovid teeth were selected from the surface collections, photo-graphed, and sampled along broken edges using a Dremel tool anddiamond drill bit, following the destructive sampling proceduresoutlined by the NMK. Enamel samples were prepared and analyzedat the University of Utah. Enamel powders were treated with 0.1 Mbuffered acetic acid for 30 min to remove labile carbonates (Lee-Thorp and van Der Merwe, 1987; Koch et al., 1997). Followingacid treatment, samples were rinsed three times with distilledwater and dried at 60 C overnight. Samples were weighed intosilver capsules and dried under vacuum at 200 C for two hoursprior to analysis. Samples were then digested in a common phos-phoric acid bath at 90 C for 15 min and analyzed for d13C on aFinnigan MAT 252 coupled to a Carboo dual-inlet carbonate de-vice. Stable isotope ratios are reported as d values relative to theinternational carbon isotope standard, Vienna Pee Dee Belemnite(VPDB), using the standard per mil () notation, whered13C (Rsample/Rstandard 1) 1000, and Rsample and Rstandard arethe 13C/12C ratios of the sample and standard, respectively. Stan-dard deviation of an internal carbonate standard (Carrara marble)was 0.1.

Microfaunal remains were selected from the surface collectionsand exported to the Department of Earth and Planetary Sciences atJohns Hopkins University, following NMK guidelines. Isotopic an-alyses of the microfauna were performed at Johns Hopkins Uni-versity, following approximately the same procedure describedabove for the bovids. All incisors were photographed prior to

J.T. Faith et al. / Journal of Hu6sampling with a Dremel Tool and diamond drill bit. Enamel powder

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004was treated for 15 min with 3% H2O2 and rinsed three times withdistilled water prior to the 15 min treatment with 0.1 M bufferedacetic acid. Following this treatment, samples were then rinsedthree times in distilled water and dried overnight at 60 C. Sampleswere loaded in silver capsules and then digested in a phosphoricacid bath at 90 C for 10 min and analyzed for d13C on a ThermoMAT 253 mass spectrometer. Standard deviation of three internalcarbonate standards was 0.32.

Dietary designations for bovids are based on estimated con-sumption of C4 plants (tropical grasses) and C3 plants (trees, shrubs,herbs), which is calculated using a hypothetical 100% C4 diet and anisotope enrichment ( 3*) between diet and herbivore tooth enamelof 14.1 (Cerling and Harris, 1999). Estimated carbon isotopecomposition of tooth enamel for a 100% C4 diet is based on theaverage isotopic value of modern C4 plants in eastern and centralAfrica (12.9, n 764; Cerling et al., 2011). Following Garret et al.(in press), changes in atmospheric CO2 between modern environ-ments and the Late Pleistocene (Tipple et al., 2010) were accountedfor by adding 1.6 to the modern average d13C of C4 plants.Althoughwe estimate the percentage of C4 vegetation consumptionby the rodents in our sample, we do not designate specic dietcategories (as with bovids) due to an incomplete understanding ofhow stable isotopes relate in a generalizable way to the con-sumption of different food resources among their extant relatives(Symes et al., 2013; Codron et al., in press).

Geological context

Although previous researchers have mapped the Pleistoceneexposures at Karungu (Owen, 1937; Pickford, 1984), there are noformal descriptions of the lithologies of these deposits or detailedstratigraphic measurements. The Pleistocene deposits are bestexposed at Kisaaka, Aringo, Onge, Aoch Nyasaya, and Obware.These form the basis of our geological description. At Kachuku andNgira, the Pleistocene deposits are poorly exposed and have un-dergone too much erosion for any geological interpretation.

The Pleistocene deposits of Karungu are discontinuouslyexposed over an area of ~40 km2 and aremost commonly preservedat elevations ~15e65 m above modern Lake Victoria (Fig. 1).Pleistocene sediment thickness at Karungu varies between sitesand ranges from 3.5 to 10.5 m. The deposits overlie a relativelycomplex eroded topography of Miocene bedrock (Oswald, 1914;Pickford, 1984). The entire sedimentary sequence is exposed atKisaaka and has been used to develop a composite stratigraphy ofthe Pleistocene deposits at Karungu (Fig. 4). Different sections ofthe Kisaaka composite stratigraphic sequence can be correlated tofossil- and artifact-bearing exposures at other sites in Karunguusing tephrostratigraphy (Blegen et al., submitted for publication;Supplementary Online Material [SOM]).

The Pleistocene sedimentary sequence at Karungu comprisesuvial deposits, paleosols, and variably reworked tephra (Fig. 4). Atthe base of the sequence is a conglomerate of varying thickness thatis overlain by three paleosols intercalated with tephra deposits.Field observations indicate that the basal paleosol is a paleo-Vertisol with pedogenic slickensides, gilgai topography, andwedge peds that formed as the soil expanded and contracted dur-ing wet and dry seasons (Beverly et al., in press). These vertic fea-tures indicate precipitation seasonality and a period of landscapestability of at least 0.5e2 kyr (Mermut et al., 1996; Buol et al., 2003;Southard et al., 2011). Where exposed, this basal paleo-Vertisol isrelatively similar in composition and character across the Karungulandscape. The upper two paleosols are identied as tuffaceouspaleo-Inceptisols, with angular blocky ped structures and illuviatedclay. These paleo-Inceptisols indicate a considerably shorter period

Evolution xxx (2015) 1e18of landscape stability than the basal paleo-Vertisol. An inux of


umantephra into the drainage basin, likely through a combination ofairfall events and uvial reworking of ash, affected the types of soilforming on the landscape (i.e., between the basal paleo-Vertisoland the upper two paleo-Inceptisols). Between the paleosols are aseries of tephra deposits that have been correlated to Aringo, Onge,Aoch Nyasaya, and Obware based on the geochemical signature ofthe volcanic glass, as well as to the Late Pleistocene exposures onRusinga and Mfangano Islands (Blegen et al., submitted forpublication; SOM).

In terms of sedimentology and lithology, the Pleistocene expo-sures at Karungu are similar and stratigraphically consistent withthe Pleistocene deposits at Rusinga and Mfangano Islands to thenorth (Tryon et al., 2010, 2012, 2014). The correlation of the series oftephra deposits at Karungu, Rusinga, and Mfangano, indicates thatall three regions are temporally equivalent (Blegen et al., submittedfor publication; SOM). While the deposits at Karungu, Rusinga, andMfangano are similar, there are some sedimentological differences.In particular, the deposits on Rusinga and Mfangano are more u-vially dominated and the paleosols are all poorly developed (Tryonet al., 2010, 2012, 2014), suggesting less stable depositional envi-ronments than those at Karungu. These differences are probablydue to the proximity of the Pleistocene deposits on Rusinga andMfangano to local topographic highs on the landscape (Tryon et al.,2014). Despite differences in pedogenic development, many of thepaleosols at Karungu, Rusinga, and Mfangano have vertic featuressuggesting similar climatic conditions (i.e., seasonal precipitation)across the region.

Direct age estimates for the Pleistocene deposits at Karungu areprovided by accelerator mass spectrometry (AMS) radiocarbondates on surface-collected ostrich eggshell fragments from Kisaakaand Aringo (below the Nyamita tuff in Fig. 4). The age estimates forKisaaka are 46,413 2595 14C yrs BP (AA95057) and46,100 2595 14C yrs BP (AA99936); the sample from Aringoyielded an innite age of >49,900 14C yrs BP (AA95785). As theseage estimates are at or very close to the limits of the AMS radio-carbon method, they are best considered minimum ages given theproblem of even trace amounts of recent contaminates yieldingspurious results. In addition, a freshwater stromatolite depositoverlying the Miocene bedrock at Aringo is associated with a U-series date of 455 45 ka, but this provides only an extrememaximum age for the overlying Pleistocene sediments discussedhere (Beverly et al., in press). These age estimates are consistentwith the tephra correlations to the Late Pleistocene sediments onRusinga and Mfangano. AMS radiocarbon age estimates on gas-tropods that burrowed into the Rusinga and Mfangano sedimentsafter deposition provide a minimum age estimate of ~45 ka.Maximum age estimates are provided by the composition of thetephras, which suggests that they derive from East African riftsystem volcanoes that began erupting early in the Late Pleistocene~100 ka (Tryon et al., 2010, 2012, Blegen et al., submitted forpublication), and U-series age estimates on a tufa deposit at thebase of the Pleistocene section at Nyamita on Rusinga Island (belowthe Nyamita Tuff in Fig. 4), which range from 94.0 3.3 ka to111.4 4.2 ka (Beverly et al., in press). Optically stimulated lumi-nescence (OSL) ages from channel deposits immediately above andbelow the Nyamita Tuff at Nyamita are 47 5 ka and 51 5 ka(Blegen et al., submitted for publication). Taken together, the cur-rent evidence suggests that the Pleistocene sequence at Karungudates from ~45 to 94 ka.

Pleistocene archaeology

Artifacts were collected from all localities spanning the Pleis-tocene sequence at Karungu (Fig. 4). The recovered artifact sample

J.T. Faith et al. / Journal of His summarized in Table 1. Artifact densities from surface crawls and

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004the Aringo 3 excavation range from 0.36 to 43.2 artifacts/m2,comparable to Late Pleistocene MSA assemblages from nearbyRusinga Island and other open-air sites made by foragers in general(see Garrett et al., in press). Although the sample size (n 401) istoo small to diagnose specic industrial afliation, the recoveredartifacts are consistent with a MSA attribution, particularly thepresence of points, blades, and preferential and recurrent Levalloisakes and cores (Fig. 5), which occur with discoidal, casual, andmultiplatform bipolar cores (denitions follow Isaac, 1977;Mehlman, 1989; Boeda, 1994, 1995) and rare retouched toolsincluding scrapers. The occurrence of such diagnostic MSA artifacts(Table 1) spans the entire Pleistocene sequence at Karungu, rangingfrom the base of the sequence in the Aringo 3 excavation to the topof the sequence at Obware and portions of Kisaaka (Fig. 4). A verylarge Levallois core (151 mm maximum dimension) from Aringoresembles those from Acheulean contexts in the Kapthurin for-mation, Kenya (Tryon et al., 2005), although the only diagnostic ESAimplement includes a single handaxe recovered from a modernalluvial deposit atop the Miocene bedrock at Kisaaka. Like many ofthe ESA artifacts collected by Owen (1938, 1939) and housed at theNMK, it is heavily rolled and weathered, unlike the MSA materialwe observed and collected from Karungu. These ESA artifacts likelyderive from older sediments since eroded away. Unlike Owen(1937), who noted Kenyan Aurignacian artifacts and potteryassociated with multiple presumably Holocene burials, we foundno clear evidence for LSA occupation at Ngira or elsewhere in thePleistocene exposures at Karungu (i.e., no backed pieces of anykind). The absence of LSA implements may be the result of Owen's(1937) extensive excavation of ~400 m2 compounded by recenterosion of the presumably Holocene deposits at Ngira (Fig. 2).

All MSA artifacts are made of a wide range of raw materials,including various lavas, quartz, quartzite, and chert, consistentwith the area's location at the interface between carbonatite-nephelinite volcanic complexes and outcrops of crystalline base-ment rock (Le Bas, 1977). The geochemical composition of theobsidian artifacts recovered from the Aringo 3 excavation(LVP2014-31) and from the surface at Kisaaka (LVP2014-32) arereported in Table 2. To illustrate the relationships of these speci-mens to the 77 Kenyan obsidian sources documented by Brownet al. (2013), Fig. 6 presents a Principal Components Analysis ofmajor elements and oxides. The rst three principal componentsaccount for the majority (>98%) of variation in obsidiangeochemistry (Principal Component (PC) 1 83.6%, PC2 13.1%,PC3 1.9%). Examination of PC1 vs PC2 and PC1 vs PC3 show theKarungu specimens to be very similar in composition to sourcesfrom the Ol Karia Group near Lake Naivasha (Broad Acres 1e2,Gorge Farm, Hell's Gate 1e2, Kibikoni 1e2, Ol Karia, Ololbutot 1e2)as well as Akira in southern Kenya (20 km south of Lake Naivasha),all of which are ~250 km east of Karungu.

Vertebrate fauna

The vertebrate remains from the Pleistocene deposits at Kar-ungu belong almost exclusively to large mammals and microfauna(Fig. 7), with only rare remains of tortoise and other small un-identied reptiles. We observed no bones, teeth, or scutesbelonging to crocodile, which is known throughout Lake Victoriaand associated river systems today (Spawls et al., 2002) and iscommonly found in the local Holocene (Robertshaw et al., 1983)and Miocene (Pickford, 1984; Lehmann et al., 2014) records.

Large mammals

Fossil remains of large mammals are well preserved and abun-

Evolution xxx (2015) 1e18 7dant at Karungu (Table 3). The dominance of alcelaphine antelopes


om

manand equids (70% of all large mammal specimens), including theextinct wildebeest (Rusingoryx atopocranion), the extinct blesbok(Damaliscus hypsodon), blue wildebeest (C. taurinus), hartebeest(A. buselaphus), plains zebra (Equus quagga), and Grevy's zebra

Figure 5. Select MSA artifacts from Karungu, including (A) Levallois ake fr

J.T. Faith et al. / Journal of Hu8(Equus grevyi), indicates the prevalence of open grassland vegeta-tion. Among the bovids, alcelaphines and antilopines account for76% of identied specimens, an abundance paralleled only incontemporary ecosystems characterized by arid to semi-aridgrassland environments (e.g., Vrba, 1980; Alemseged, 2003). Thedominant bovids, R. atopocranion and D. hypsodon, are character-ized by exceptional hypsodonty (Faith et al., 2011, 2012), a probableadaptation to consuming grasses in dry and gritty environments(Marean, 1992; Damuth and Janis, 2011). Drier conditions thanpresent are further supported by the recovery of arid-adaptedGrevy's zebra and oryx (Oryx beisa; Kingdon, 1982; Faith et al.,2013), although the presence of blue wildebeest suggests at leastseasonal availability of moist grasses (Skinner and Chimimba,2005). Rare fossils of bushbuck (T. scriptus) and black rhinoceros(D. bicornis) suggest a small component of closed habitats (e.g.,shrubland), while the presence of hippopotamus (Hippopotamusamphibius) indicates some free-standing water.

The Karungu faunal assemblage includes a large number ofextinct taxa compared to Late Pleistocene faunal assemblages fromelsewhere in Africa (Faith, 2014). In addition to R. atopocranion andD. hypsodon, extinct bovids include the long-horn buffalo (Syncerusantiquus), giant wildebeest (Megalotragus sp.), and a large-bodiedand very hypsodont impala (Aepyceros sp. nov.; Faith et al., 2014),all of which are characterized by specialized grassland adaptations(e.g., large body size or extreme hypsodonty; Faith, 2014). Inaddition to these extinct taxa, several of the extant ungulate speciesat Karungu occur well outside (~250e500 km) their historicgeographic ranges (Fig. 8), including Grevy's zebra, white rhinoc-eros (Ceratotherium simum), oryx, and southern reedbuck (Reduncaarundinum). These species are historically known from regionsnorth, south, and east of Lake Victoria (Fig. 8).

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004Microfauna

Preservation of microfauna at Karungu is exceptional (Fig. 7), incontrast to many open-air Pleistocene sites in East Africa. A large

Aringo, (B), Levallois core from Aringo, and (C) bifacial point from Obware.

Evolution xxx (2015) 1e18rodent sample (NISP 78) was recovered from Kisaaka, with only afew specimens recovered elsewhere (Table 3). Two taxa are pre-sent: East African mole rat (T. splendens) and vlei rat (Otomys sp.).The dominance of these relatively large rodent taxa is likely areection of size-based sampling bias. The East African mole ratoccurs in a diverse range of habitats, ranging from tropical moistforest and open woodland to grassland. Extant representatives ofTachyoryctes are typically found in regions with rainfall in excess of500 mm/yr, avoiding arid savannas and preferring well-drainedsoils suitable for digging complex and extensive burrows(Kingdon,1982; Nowak,1999). The presence of Otomys is consistentwith the grassland environment implied by the large mammals. Inmodern systems, species of Otomys prefer moist grasslands, and inthe dry season are frequently found in marshy areas around theedges of rivers or swamps (Smithers, 1971).

Isotope paleoecology

d13C values of 20 tooth enamel samples from at least sevenbovid species and 17 samples from East African mole rat are pre-sented in Table 4 and Fig. 9. Dietary categories for bovid taxafollow Cerling et al. (2003) and include the designations hyper-grazer (>95% C4), grazer (70e95% C4), or mixed feeder (>30% C4and >30% C3). These designations reect the degree of C4 grassconsumption in lowland tropical environments in many parts ofEast Africa; C4 grasses are only outcompeted by C3 grasses undercertain climatological and environmental conditions, such asincreased atmospheric pCO2, high elevation (typically >2000 m inEast Africa), changes in rainfall seasonality, and decreased reprevalence and grazing pressure (Tieszen et al., 1979; Sage andMonson, 1999).


Table

2Geo

chem

ical

compositionof

obsidianfragmen

tsfrom

theAringo

3excavation

(LVP2

014-31

)an

dfrom

thesurfaceat

Kisaaka

(LVP2

014-32

)(m

eansofve

measuremen

ts).

Field#

Major

elem

ents

(wt%)

SiO2

TiO2

ZrO2

Al 2O3

Fe2O3

MnO

MgO

CaO

Na 2O

K2O

FCl

LVP2

014-31

73.910.46

0.16

0.05

0.26

0.04

10.640.08

3.56

0.06

0.05

0.02

0.02

0.1

0.16

0.03

5.21

0.11

4.67

0.03

0.89

0.03

0.36

0.01

LVP2

014-32

72.930.21

0.16

0.02

0.32

0.04

10.350.05

3.82

0.05

0.05

0.01

0.02

0.1

0.13

0.05

5.39

0.16

4.65

0.13

0.91

0.06

0.39

0.02

J.T. Faith et al. / Journal of Human

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004Isotope data from the Karungu bovids and rodents indicate dietsdominated by C4 biomass. We caution that carbon isotope valuesfrom fossil tooth enamel cannot distinguish between the domi-nance of C4 grasses on the landscape from dietary preference for C4grasses among a mixed C3/C4 ground vegetation layer with C4grasses and C3 forbs, herbs, and shrubs. Additionally, minor isotopicvariation among C4 plants is associated with different photosyn-thetic sub-pathways, with mesic-adapted C4 grasses slightly moreenriched in d13C than xeric-adapted C4 grasses (Cerling et al., 2003).Therefore, in addition to the potential forminor addition of C3 foodsto the diet, the consumption of varying types of C4 grasses mayexplain some degree of variation seen within grazing taxa. Overall,these data agree well with isotope measurements of bovids frommodern East African environments (Cerling et al., 2003), as well aswith the contemporaneous fauna from nearby Rusinga and Mfan-gano Islands (Garrett et al., in press), and indicate that both largeand small herbivores were associated with a landscape in which C4grasses were abundant.

Paleoenvironmental summary

The Late Pleistocene sediments of Karungu provide a rare op-portunity to reconstruct the environmental context of landscapesoccupied by MSA humans in East Africa. The paleosols at Karungu(Fig. 4) indicate highly seasonal precipitation with prolonged pe-riods of dry conditions that allowed the soils to become desiccated;the development of the basal paleosol indicates that these condi-tions persisted for at least hundreds to a few thousand years(Mermut et al., 1996; Buol et al., 2003; Southard et al., 2011). As isalso the case for the Late Pleistocene sites at nearby Rusinga andMfangano Islands (Tryon et al., 2010, 2012, 2014), the mammalianfauna of Karungu indicate a paleoenvironment dominated bygrassland vegetation, distinct from the evergreen bushlands,woodlands, and forests found in the region today. The stable carbonisotopic signature of rodents and bovids clearly indicate that thesewere C4 grasslands, at both local scales (

manJ.T. Faith et al. / Journal of Hu10et al., 2012; Beverly et al., in press), whereas crocodiles rely heavilyon aquatic prey (Corbet, 1960) and may have required larger watersources to support viable populations. Further evidence for drierconditions is provided by the presence of oryx and Grevy's zebra,which are adapted to arid to semi-arid environments and implylower precipitation than at present (Marean, 1992; Faith et al.,2013). Last, the dominance of extinct bovid species characterizedby exceptional hypsodonty, a probable adaptation to feeding inopen and dry environments (Damuth and Janis, 2011), includingD. hypsodon and R. atopocranion, is also consistent with reducedprecipitation (Eronen et al., 2010).

The decrease in precipitation compared to the present impliedby the Karungu evidence is likely to translate to a decline in the sizeand level of Lake Victoria, which is highly sensitive to local pre-cipitation (Broecker et al., 1998; Milly, 1999). This is consistent withthe implications of the fossil ungulates from contemporaneousdeposits on nearby Mfangano Island (Tryon et al., 2014; Blegenet al., submitted for publication). Today Mfangano Island

Figure 6. Principal components analysis (left PC1 vs. PC2; right PC1 vs. PC3) of major elemdocumented sources in Kenya (average values for each source calculated from Brown et al.HG2 Hell's Gate 2; K1 Kibikoni 1; K2 Kibikoni 2; OK Ol Karia; O1 Ololbutot 1;

Figure 7. Left: Buccal (top) and occlusal (bottom) views of a right mandible of Oryx cf. besplendens).

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004Evolution xxx (2015) 1e18encompasses a mere 64 km2 of landmass, much of which isdominated by the steep topography of Mount Kwitutu, and islocated 10 km from the Kenyan mainland and separated by achannel 25 m in depth. As is the case of Karungu, its Late Pleisto-cene fossil assemblage is dominated by gregarious grassland un-gulates (Tryon et al., 2012), some of which (e.g., wildebeest) areknown to migrate long distances in response to seasonal resourceavailability. It is unlikely that migratory species would establishinsular populations where such migrations are not possible, sug-gesting a likely connection to the mainland. This is further sup-ported by the small size of Mfangano Island, which is insufcient tosupport viable populations of large gregarious game (Tryon et al.,2014). These lines of evidence imply a connection to the main-land, which requires a 25 m reduction in lake level (Tryon et al.,2014). Hydrological models (Broecker et al., 1998; Milly, 1999)suggest that the decrease in rainfall input needed to effect suchchange would have set in motion a series of feedback mechanismstranslating to a dramatically reduceddif not desiccateddLake

ents and oxides for the obsidian akes recovered from Karungu (Table 2) and the 77, 2013). AK Akira; BA1 Broad Acres 1; BA2 Broad Acres 2; HG1 Hell's Gate 1;O2 Ololbutot 2; O Olenguroni; M Mundui.

isa. Right: An articulated cranium and mandible of East African molerat (Tachyoryctes


Ao

umanTable 3Specimen counts (NISP) for the mammalian fauna recovered from Karungu.

Family Taxon Common name

Spalacidae Tachyoryctes splendens East African mole ratMuridae Otomys sp. Vlei ratLeporidae Lepus sp. Cape hare

Leporidae indet. Indet. leporidHyaenidae Crocuta crocuta Spotted hyenaFelidae cf. Caracal/Leptailurus Caracal or Serval

Panthera leo LionPanthera pardus Leopard

Elephantidae cf. Loxodonta africana African ElephantRhinocerotidae Ceratotherium simum White rhinoceros

Diceros bicornis Black rhinocerosEquidae Equus quagga Plains zebra

Equus grevyi Grevy's zebraEquus sp.

Suidae Phacochoerus sp. WarthogHippopotamidae Hippopotamus amphibius HippoBovidae Taurotragus oryx Eland

Tragelaphus scriptus BushbuckTragelaphini indet. Eland or kuduOryx cf. beisa OryxHippotragini indet.Redunca arundinum Southern reedbuckRedunca arundinum/Kobus kob Southern reedbuck or kobRedunca cf. redunca ReedbuckAlcelaphus buselaphus HartebeestConnochaetes taurinus WildebeestDamaliscus hypsodonb Extinct blesbok

J.T. Faith et al. / Journal of HVictoria (Tryon et al., 2014). While further chronological control isneeded for the Mfangano Island fauna and for the age and durationof Pleistocene desiccations of Lake Victoria, it is intriguing thatStager and Johnson (2008) estimate a Late Pleistocene age of ~80 ka(based on an extrapolation of sedimentation rates) for one of thedesiccation surfaces documented in seismic surveys.

Late Pleistocene dispersals

Consistent with predictions from vegetation models (Cowlinget al., 2008) and phylogeography (Lorenzen et al., 2012), theprobable reduction of Lake Victoria and dominance of semi-arid C4grasslands is associated with the convergence of historically allo-patric grassland ungulates at Karungu (Fig. 8), a pattern also seenon nearby Rusinga Island (Tryon et al., 2010, 2012; Faith et al., 2013,in press). The combination of genetic, fossil, and paleoenvir-onmental evidence is consistent with the hypothesis that vegeta-tion change mediated the expansion and fragmentation of speciesranges across equatorial East Africa during the Pleistocene. How-ever, whether or not these changes inuenced the dispersal historyof Late Pleistocene humans remains uncertain. Genetic evidencedemonstrates that northesouth human dispersals occurred acrossEast Africa during the Late Pleistocene (Rito et al., 2013), but it isunclear whether these dispersals were inuenced by the openingand closing of an equatorial dispersal barrier, as appears to be thecase for the ungulates (Lorenzen et al., 2012; Fig. 8). Although fewMSA sites are associated with detailed paleoenvironmental records,

Megalotragus sp.b Giant wildebeestRusingoryx atopocranionb Extinct wildebeestAlcelaphini indet.Gazella granti Grant's gazelleGazella thomsoni Thomson's gazelleAntilopini indet.Aepyceros sp. nov.b Extinct impalaSyncerus antiquusb Long-horn buffaloSyncerus caffer African buffaloSyncerus sp.Ourebia ourebi Oribi

SNISP

b Extinct.

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004ch Nyasaya Aringo Kachuku Kisaaka Ngira Obware Onge Total

0 1 0 68 0 0 0 692 0 0 10 0 2 0 140 0 0 3 0 0 0 30 0 0 2 0 0 0 20 1 0 0 0 0 0 10 0 0 1 0 0 0 10 0 1 1 0 1 0 30 0 1 0 0 0 0 10 0 0 0 0 0 1 12 3 0 2 0 0 0 70 0 0 1 0 0 0 18 5 2 32 0 0 7 541 10 0 10 0 0 3 247 12 2 18 0 1 12 523 6 0 9 0 4 2 240 1 0 3 0 0 5 91 0 0 3 0 0 0 40 2 0 2 0 0 0 40 0 0 2 0 0 0 21 0 1 8 1 1 0 120 0 0 1 0 0 0 10 0 0 1 0 0 0 10 1 0 3 0 0 0 41 0 0 0 0 0 0 11 7 0 17 0 0 1 261 6 0 18 0 0 2 276 13 0 12 0 0 8 39

Evolution xxx (2015) 1e18 11the occasional phases of vicariance caused by such a barrier (i.e.,fragmentation of populations north and south of the equator) couldcontribute to the gradual accumulation of novel behavioral reper-toires (Eerkens and Lipo, 2005). These should be reected archae-ologically by distinct technological signatures north and south ofthe barrier, reecting behavioral divergence during phases oflimited dispersal.

To test the hypothesis of an equatorial dispersal barrier, weexamine variability in artifact assemblage composition across EastAfrican Late Pleistocene MSA sites. These are reported in Table 5,which summarizes variation in broad artifact classes across 30 as-semblages from 15 of the better reported sites in the region. Theseinclude those assemblages designated Late MSA by Tryon and Faith(2013), supplemented by additional records from Shelter 7 at LaasGeel in Somalia (Gutherz et al., 2014), Goda Buticha in Ethiopia(Pleurdeau et al., 2014), and Magubike in Tanzania (Willoughby,2012). We exclude Middle Pleistocene MSA sites from considerationgiven the evidence for some temporal shifts in assemblage compo-sition between these and younger sites (Tryon and Faith, 2013). Theartifact categories used here are broad (e.g., bipolar core, blade) tominimize problems introduced by variable artifact typologies usedamong different researchers (e.g., Vermeersch, 2001). To quantify thevariability in assemblage composition, we conduct Principal Co-ordinates Analysis (PCoA) on a similarity matrix obtained using theDice coefcient for presence/absence data (Fig. 10) in the Paleonto-logical Statistics Package (Hammer et al., 2001). For a given pair ofassemblages, theDice coefcient is calculated2j/(ab),where j is the

1 4 0 3 0 0 1 95 12 0 49 0 0 3 691 9 0 28 0 2 5 450 1 0 0 0 0 0 12 2 0 7 0 5 1 170 0 0 2 0 0 0 21 0 0 0 0 0 0 15 1 0 5 0 0 0 112 5 1 16 0 0 2 260 1 0 0 0 0 0 10 1 0 3 0 0 1 5

51 104 8 340 1 16 54 574


number of artifact classes that co-occur at assemblages A and B, a isthe number of artifact classes at site A, and b is the number of artifactclasses at site B. The PCoA arranges assemblages in multi-dimensional space such that similar assemblages cluster togetherand dissimilar assemblages are grouped apart. For the purposes ofthis analysis, artifact classes indicated with a question mark (uncer-tain presence) in Table 5 are considered absent.

The PCoA reveals strong latitudinal patterning in assemblagecomposition when Axis 1 (23.1% of the variance) is plotted againstAxis 3 (10.1% of the variance; Fig. 10). With a few exceptions, whichinclude Karungu, Rusinga, and Prolonged Drift, those sites locatedat or south of the equator cluster apart from those sites locatedfurther north (>5 latitude). This is conrmed by signicant dif-ferences in average Axis 1 (t 2.197, p 0.036) and Axis 3 scores(t 3.390, p 0.002) between the northern and southern sites.Fisher's exact tests comparing the frequencies of assemblages withor without a given artifact type between northern and southernsites indicates that these differences are driven in part by the morefrequent presence of bipolar cores (p 0.026) and anvils(p 0.003) and the rarity of Levallois points or point cores(p 0.011) and large bifaces (p 0.012) in the southernassemblages.

Our analysis indicates northesouth geographic patterning in thecomposition of East African Late Pleistocene MSA artifact assem-blages. While this is consistent with the hypothesis of an equatorialdispersal barrier, other possible explanatory mechanisms includeenvironmental gradients, site type (open-air versus cave), and

L. Victoria

0 200

km

0 30010R. arundinum

C. simum

E. grevyi

Figure 8. The geographic ranges of white rhinoceros (Ceratotherium simum), Grevy'szebra (Equus grevyi), and southern reedbuck (Redunca arundinum; IUCN, 2013;Rookmaaker and Antoine, 2013).

Table 4Stable isotope composition (d13C VPDB and d18O VPDB) of tooth enamel from Karungu bovids and rodents.a

Field no Tribe Taxon d13C (VPDB) %C4 d18O (VPDB)

KAR13-76 Alcelaphini cf. Alcelaphus buselaphus 2.1 96 0.2KAR13-76 Alcelaphini cf. Alcelaphus buselaphus 1.9 95 1.3KAR13-81 Alcelaphini cf. Rusingoryx atopocranion 0.7 87 1.2KAR13-32 Alcelaphini cf. Rusingoryx atopocranion 1.1 90 0.8KAR13-42 Alcelaphini cf. Rusingoryx atopocranionKAR13-176 Alcelaphini Damaliscus hypsodonKAR13-137 Alcelaphini Damaliscus hypsodonKAR13-175 Alcelaphini Damaliscus hypsodonKAR13-172 Alcelaphini Damaliscus hypsodonKAR13-173 Alcelaphini Alcelaphini indet.KAR13-47 Alcelaphini Alcelaphini indet.KAR13-68 Antilopini Gazella thomsoniKAR13-136 Bovini Syncerus antiquusKAR13-168 Bovini Syncerus antiquusKAR13-159 Bovini Syncerus cafferKAR13-64 Bovini Syncerus cafferKAR13-161 Bovini Syncerus cafferKAR13-185 Neotragini Ourebia ourebiKAR13-186 Neotragini Ourebia ourebiKAR13-184 Reduncini Redunca cf. reduncaKR13-13 Tachyoryctes splendensKR13-14 Tachyoryctes splendensKR13-17 Tachyoryctes splendensKR13-18 Tachyoryctes splendensKR13-19 Tachyoryctes splendensKR13-31 Tachyoryctes splendensKR13-36 Tachyoryctes splendensKR13-37 Tachyoryctes splendensKR13-38 Tachyoryctes splendensKR13-41 Tachyoryctes splendensKR13-43 Tachyoryctes splendensKR13-52 Tachyoryctes splendensKR13-75 Tachyoryctes splendensKR13-82-1 Tachyoryctes splendensKR13-82-2 Tachyoryctes splendensKR13-82-3 Tachyoryctes splendensKR13-84 Tachyoryctes splendens

a Percent contribution of C4 resources to the diet is estimated using an isotope enrichmrespectively.

J.T. Faith et al. / Journal of Human Evolution xxx (2015) 1e1812

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.0040.5 79 0.92.7 100 0.12.7 100 0.72.2 97 0.72.5 99 0.12.4 98 1.81.7 94 2.6

0.9 77 1.12.0 96 1.80.1 83 1.1

0.2 81 1.63.2 100 0.3

0.7 78 1.81.8 94 1.42.6 100 0.42.3 98 0.2

0.6 96 0.72.2 85 2.72.5 83 0.70.2 99 0.20.4 98 1.40.1 100 0.2

1.4 90 0.82.9 80 1.42.2 85 1.20.6 96 0.72.3 84 1.13.8 74 0.90.7 95 1.22.6 83 0.00.3 98 1.20.1 99 1.11.3 91 0.5ent ( 3*) between diet and tooth enamel of 14.1 and 11.0 for bovids and rodents,


C4 fee

d linTachy

umanC3/mixed

Alcelaphini indet. (2)cf. Alcelaphus (2)

Damaliscus hyspsodon (4)cf. Rusingoryx (3)

Gazella thomsoni (1)Syncerus spp.(5)

Ourebia ourebi (2)Redunca sp. (1)

-4

Tachyoryctes splendens (17)

-4

A

B

Figure 9. d13C values of surface-collected bovid and rodent teeth from Karungu. A: Dottethe carbon isotopic composition of C4 used to calculate the C4 diet endmember. B:consumption.

J.T. Faith et al. / Journal of Hchronology. Paleoenvironmental evidence is largely lacking formany of these assemblages, but modern precipitation, which playsa key role in determining African vegetation structure (Sankaranet al., 2005; Good and Caylor, 2011), broadly varies along a longi-tudinal gradient (increasing to the west) in the region examinedhere (Hijmans et al., 2005). To the extent that contemporary pre-cipitation gradients can be extended into the past, this suggeststhat environment is an unlikely explanation for the variationobserved here. The northesouth geographic patterning evident inFig. 10 could potentially reect differential representation ofvarious site types. However, this is not the case here, as thenorthern and southern clusters include comparable proportions ofassemblages from caves/rockshelters and open-air sites (Fisher'sexact test: p 0.284). Although chronological control is generallypoor, we note the presence of relatively early Late Pleistocene MSAassemblages (>60 ka) in both the south (e.g., Mumba Bed VI;Gliganic et al., 2012) and north (e.g., Ardu Beds; Yellen et al., 2005)and relatively young Late Pleistocene MSA assemblages(~40e50 ka) in both the south (e.g., Mumba Beds III and IV; Gliganicet al., 2012) and north (e.g., Mochena Borago; Brandt et al., 2012).This suggests that the geographic differences observed in Fig. 10cannot be readily attributed to chronological variation. In theabsence of apparent differences related to environment, site type,or chronology, the geographic patterns documented here arepotentially indicative of regionally-distinct technological patterns.Such regional variation is consistent with behavioral divergenceduring periodic phases of allopatry, for which the equatorialdispersal barrier is a plausible mechanism.

While the previous analyses reveal geographic variationconsistent with an equatorial dispersal barrier, it is not clearwhether human dispersals were linked to phases of grasslandexpansion across equatorial East Africa. As an initial exploration ofthis scenario, we return to grassland-associated MSA assemblages

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004dietder

C4-dominated dietgrazer hypergrazer

-2 0 2 4

13C (VPDB) tooth enamel ()

-2 0 2 413C (VPDB) tooth enamel ()

>80% C4 >95% C4

e represents 100% C4 diet based on calculated 3*enamel-diet; gray box represents 1 SD oforyctes splendens enamel carbon isotopic composition and estimated percentage C4

Evolution xxx (2015) 1e18 13from Karungu and nearby Rusinga Island, two of the few assem-blages associated with detailed paleoenvironmental records. Thesetwo sites are regional outliers in terms of artifact assemblagecomposition, showing afnities with assemblages from the north(Fig. 10). To quantitatively conrm this pattern we calculated theDice coefcient between Karungu and Rusinga and all other as-semblages; Karungu and Rusinga show greater similarity withthose from the north (average 0.760) than with those from thesouth (average 0.670; t 3.700, p < 0.001). Although additionalarchaeological and environmental data are much needed fromthroughout East Africa, this observation is consistentwith a possiblenorth-to-south dispersal of archaeological (and thus homininbehavioral) patternsdand perhaps human dispersalsdduring apaleoenvironmental phase dominated by grasslands.

Discussion

Models of Quaternary vegetation change (Cowling et al., 2008)coupled with insights from the genetic structure of contemporaryvertebrates (Dehghani et al., 2008; Miller et al., 2011; Lorenzenet al., 2012) suggest that the opening and closing of the equato-rial East African forest belt during the Quaternary may have playeda key role in mediating northesouth dispersals of fauna andperhaps early modern humans. The paleoenvironmental andpaleontological evidence from Karungu is consistent with thesepredictions. Karungu's Late Pleistocene sedimentary archive in-dicates a semi-arid environment characterized by highly seasonalprecipitation and the dominance of C4 grasslands, likely accompa-nied by a substantial reduction in the size of Lake Victoria. Inagreement with hypotheses derived from genetic observations(Lorenzen et al., 2012), these conditions are associated with theconvergence of ungulate species whose geographic ranges aretodaydand presumably during previous climate phases with high


Table 5Artifact assemblage composition across East African MSA sites (from Tryon and Faith, 2013).

Locality Latitude Longitude Artifact type

Anvil Grindstone Platformcore

Discoidalcore

Levalloispreferential

core

Levalloisrecurrent

core

Levalloispoint/core

Bipolarcore

Blades Backedpieces

Retouchedpoint

Otherlargebiface

Heavy-dutytool

Misc.retouched

Magubike MSA 7.8 35.5 ? 1 1 1 0 ? 0 1 ? 1 1 0 ? 1Mtongwe, Locality KY-55 East, Upper Groupa 4.08 39.13 0 0 1 1 ? 0 0 0 1 1 0 0 0 1Mtongwe, Locality KY-55 East, Middle Groupa 4.08 39.13 0 0 1 1 ? ? 0 1 1 1 0 0 0 1Mtongwe, Locality KY-55 East, Lower Groupa 4.08 39.13 0 0 1 1 1 1 0 0 ? 1 0 0 1 1Mumba Bed III lower (Nasera Industry) 3.53 35.32 1 1 1 1 1 ? ? 1 1 1 1 0 1 1Mumba Bed V (Mumba Industry) 3.53 35.32 1 1 1 1 1 ? ? 1 1 1 1 0 0 1Mumba Bed VI-A (Kisele Industry) 3.53 35.32 1 0 1 1 1 ? 1 1 1 1 1 0 1 1Mumba Bed VI-B (Sanzako Industry) 3.53 35.32 0 0 1 1 1 ? 0 1 ? 0 1 1 1 1Nasera levels 6e7 (Nasera Industry) 2.74 35.36 1 1 1 1 1 ? ? 1 1 1 1 0 1 1Nasera levels 8/9e11 (Mumba Industry) 2.74 35.36 1 0 1 1 1 ? ? 0 1 1 1 0 0 1Nasera levels 12e25 (Kisele Industry) 2.74 35.36 1 0 1 1 1 1 1 1 1 1 1 0 1 1Karungua 0.84 34.16 0 0 1 1 1 1 1 1 1 0 1 0 0 1Prolonged Drift (GrJi11)a 0.48 36.1 0 0 1 0 ? 0 ? 0 0 0 1 0 0 1Wasirya Beds, Rusinga Islanda 0.42 34.17 0 0 1 1 1 1 1 0 1 0 1 0 0 1Muguruk Formation, Member 4, Pundo

Makwar Industrya0.08 34.63 1 0 1 1 1 ? 1 0 0 0 1 0 1 1

Muguruk Formation, Member 6, PundoMakwar Industrya

0.08 34.63 1 0 1 1 1 1 1 0 0 0 ? 0 1 1

Kibish Formation, Member II/III, site BNSa 5.41 35.9 0 0 1 1 1 1 1 ? 0 ? 1 0 0 1Mochena Borago S-group 6.9 37.76 0 ? 1 0 1 0 1 1 1 1 1 0 0 1Mochena Borago Upper T-group 6.9 37.76 0 ? 1 1 1 0 1 0 1 1 1 0 0 1Mochena Borago Lower T-group 6.9 37.76 0 ? 1 1 1 ? 0 0 1 0 1 0 0 1Porc Epic 9.63 41.87 0 1 0 1 1 1 1 0 1 1 1 0 0 1Shelter 7, Laas Geel (SU709-711) 9.7 44.3 ? ? 1 0 1 1 1 1 1 1 0 0 0 1Goda Buticha Lower Complex 10.42 40.52 ? 1 1 1 1 ? 1 0 1 0 1 1 0 1Ardu Beds B/C contact, Aduma site A5a 10.42 40.52 ? 1 1 1 1 ? 1 0 1 0 1 1 0 1Ardu Beds B, Aduma sites A4, A8, A8A,

VP 1/1, VP 1/3a10.42 40.52 0 1 1 1 1 ? 1 0 0 0 1 1 0 1

Ardu Beds B (base), Aduma site A1a 10.42 40.52 0 0 0 1 1 ? 0 0 1 0 1 1 0 1Midhishi 2 LSU III 10.95 47.37 0 0 1 1 1 ? 1 0 1 1 1 1 1 1Midhishi 2 LSU IV 10.95 47.37 0 0 1 0 1 ? 1 0 ? 0 1 1 1 1Midhishi 2 LSU V 10.95 47.37 0 0 1 0 0 ? 1 0 ? 0 1 1 1 1Midhishi 2 LSU VI 10.95 47.37 0 0 1 1 1 ? 1 0 ? 1 1 1 1 1

a Indicates open-air assemblages.

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umanmoisture availabilitydseparated by the equatorial East Africanforest belt (Fig. 8). A complementary pattern is seen in KibishFormation of southern Ethiopia, where sediments deposited duringhumid phases from the late Middle Pleistocene through the Holo-cene document a northward expansion of mesic-adapted ungulates(Rowan et al., 2015). These records provide intriguing support forthe argument that vegetation change across equatorial East Africaplayed a decisive role in species dispersals, a hypothesis to be tested

Rusinga

Prolonged Drift

0.40.30.20.1-0.1-0.2-0.3-0.4

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Southern assemblagesNorthern assemblages

Figure 10. Axis 1 and 3 of Principal Coordinates Analysis (PcOA) of artifact assemblagecomposition for Late Pleistocene MSA sites in East Africa (data from Table 5). Squarescorrespond to northern sites (>5 latitude) and diamonds correspond to southern sites(~at or below the equator).

J.T. Faith et al. / Journal of Hwith additional data from a broader time frame and widergeographic area.

Our analysis of the Late Pleistocene MSA record from East Africareveals previously unrecognized northesouth variation in assem-blage composition (Fig. 10), paralleling the geographic patternsobserved in the genetic records of ungulates (Lorenzen et al., 2012)and other vertebrates (Dehghani et al., 2008; Miller et al., 2011).Weinterpret these differences, reecting to some extent the variableoccurrence of bipolar cores, anvils, large bifaces, and Levalloispoints or point cores (Table 5), as potentially indicating the devel-opment of regionally distinct behavioral patterns during past epi-sodes of population fragmentation, for which the equatorialdispersal barrier is a probable driver. In agreement with Cowlinget al. (2008), this implies that the potential for northesouth hu-man dispersals across East Africa would have been maximizedduring climate phases that promoted an expansion of grasslandcover.

The grassland-associated MSA assemblages from Karungu andnearby Rusinga Island are characterized by a combination of artifacttypes that ismore typical of sites found further north of the equator.This may reect the southward dispersal of northern behavioralrepertoires during a grassy phase that facilitated dispersals,including those dispersals of northern ungulates such as Grevy'szebra and white rhinoceros (Fig. 8). This complements our previousobservations that the presence of small bifacial points at RusingaIsland (Tryon et al., 2010, 2012) and now reported from Karungu(Fig. 5) may reect the dispersal of a grassland associated tech-nology, as these are similar to those found throughout Rift Valleysites in East Africa (Tryon et al., 2012; Tryon and Faith, 2013; Faith

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004et al., in press). Such connections to the Rift Valley are furthersupported by the presence of exotic obsidian akes from Aringoand Kisaaka, the geochemistry of which are very similar to well-documented sources south of Lake Naivasha (Brown et al., 2013).While extensive mapping of the volcanics surrounding Lake Vic-toria has yet to document any local obsidian sources (Le Bas, 1977),it is highly unlikely that any undocumented local sources would begeochemically identical to the Naivasha obsidians. The mostparsimonious explanation is that the obsidian artifacts from Kar-ungu are derived from the Lake Naivasha region 250 km east. Thisplaces them at the upper range of documented long-distance rawmaterial transport in the MSA and likely indicates exchange andinteraction between social groups, as such a distance potentiallyexceeds that of deliberate collecting forays by a single group (seereview in McBrearty and Brooks, 2000). While this evidence forgrassland-mediated human dispersals is tentative and will requirea greater number of East African MSA sites with detailed paleo-environmental records to test in detail, the structure of the MSArecord is consistent with the hypothesis that vegetation changeacross equatorial East Africa mediated the dispersal and fragmen-tation of Pleistocene human populations.

Faunal turnover

Previous research on late Quaternary fossil assemblages fromEast Africa indicated thatdwith a few minor exceptions (Mareanand Gifford-Gonzalez, 1991; Marean, 1992)dan essentially mod-ern faunal community was in place by ~400 ka (Potts et al., 1988;Potts and Deino, 1995). However, the emerging evidence from theLake Victoria Basin reveals the long-term survival of archaic line-ages thought to have disappeared >500 ka, including Kolpochoerus,together with the many extinct bovids characterized by large bodymass or exceptional hypsodonty, including S. antiquus, Mega-lotragus, D. hypsodon, R. atopocranion, and Aepyceros sp. nov. (Faithet al., 2011, 2012, 2014; Faith, 2014). Of these, only S. antiquus andD. hypsodon are known from other Late Pleistocene faunal assem-blages in East Africa (Marean and Gifford-Gonzalez, 1991; Marean,1992; Faith et al., 2012; Rowan et al., 2015). The presence anddominance of numerous extinct forms at Karungu and nearbyRusinga and Mfangano Islands may be indicative of an endemicPleistocene fauna or a long-term refugium in the Lake VictoriaBasin. However, the relevant faunal collections from elsewhere arerelatively small (Assefa et al., 2008; Eren et al., 2014; Rowan et al.,2015) or derived from highly fragmented archaeological contexts(Mehlman, 1989; Marean, 1992; Assefa, 2006; Prendergast et al.,2007), potentially masking faunal diversity and raising the possi-bility that extinct lineages were geographically widespread buthave yet to be identied. The mesic-adapted faunal communityfrom the Kibish Formation includes only a few specimens ofD. hypsodon and may indicate that the dominance of extinct formsobserved in the Lake Victoria region is specic to relatively aridenvironments (Rowan et al., 2015). Whatever the explanation, theevidence from the Lake Victoria Basin leaves little doubt that pat-terns of late Quaternary faunal turnover and paleoecological changein East Africa are far more complex than previously imagined.

Conclusions

The opening and closing of biogeographic barriers are thoughtto have played an important role in mediating human dispersalsduring the Pleistocene (Vaks et al., 2007; Cowling et al., 2008; Cartoet al., 2009; Compton, 2011; Faith et al., in press), although precisedetails in East Africa are scarce due to a lack of archaeological dataassociated with paleoenvironmental records. With this in mind, we

Evolution xxx (2015) 1e18 15provide the rst detailed description of the fossil- and artifact-


there is intriguing evidence that vegetation change mediated the

Acknowledgments

Appendix A. Supplementary data

manGeochemical data documenting tephra correlations betweensites at Karungu and between Karungu and Rusinga Island can befound at http://dx.doi.org/10.1016/j.jhevol.2015.03.001.

References

Adams, W.M., 1996. Lakes. In: Adams, W.M., Goudie, A.S., Orme, A.R. (Eds.), ThePhysical Geography of Africa. Oxford University Press, Oxford, pp. 122e133.

Alemseged, Z., 2003. An integrated approach to taphonomy and faunal change inthe Shungura Formation (Ethiopia) and its implications for hominid evolution.J. Hum. Evol. 44, 451e478.

Allsopp, R., Baldry, D.A.T., 1972. A general description of the Lambwe Valley area ofSouth Nyanza District, Kenya. B. World Health Organ 47, 691e697.

Ambrose, S.H., Lorenz, K.G., 1990. Social and ecological models for the Middle StoneAge in southern Africa. In: Mellars, P. (Ed.), The emergence of modern humans:an archaeological perspective. Edinburgh University Press, Edinburgh,pp. 3e33.

Andrews, C.W., 1911. On a new species of Dinotherium (Dinotherium hobleyi) fromBritish East Africa. Proc. Zool. Soc. Lond. 81, 943e945.

Andrews, C.W., 1914. On the Lower Miocene vertebrates from British East Africa,collected by Dr. Felix Oswald. Q. J. Geol. Soc. Lond. 70, 163e186.

Andrews, C.W., 1916. Note on a new baboon (Simopithecus oswaldi gen. et sp. nov.)from the (?) Pliocene of British East Africa. Annls. Mag. Nat. Hist. 18, 410e419.Fieldwork at Karungu was conducted under research permitsNCST/RCD/12B/012/31 issued to JTF, NCST/5/002/R/576 issued toCAT, NCST/RCD/12B/01/07 issued to DJP, and NCST/5/002/R/605issued to EJB, and an exploration and excavation license issued bythe National Museums of Kenya (NMK). We thank Sheila Nightin-gale for providing the artifact illustrations. Our eldwork is madepossible through the support of the NMK and with nancial sup-port from the National Geographic Society Committee for Researchand Exploration (9284-13 and 8762-10), the National ScienceFoundation (BCS-1013199 and BCS 1013108), the Leakey Founda-tion, the Geological Society of America, the Society for SedimentaryGeology, the University of Queensland, Baylor University, the BaylorUniversity Department of Geology Dixon Fund, New York Univer-sity, the American School for Prehistoric Research, and HarvardUniversity. We thank Sarah Elton, the Associate Editor, and theanonymous reviewers for their helpful suggestions on a previousversion of this manuscript.biogeographic histories of both humans and fauna across equatorialEast Africa. Testing this hypothesis in further detail remains a pri-ority for future research and will require continued exploration ofthe East African MSA.bearing Pleistocene deposits from Karungu, an area that has beenintermittently explored by paleoanthropologists for over 100 years.Lithic artifacts recovered from surface collections and fromcontrolled excavation are typologically MSA. The presence of anassociated and well-preserved paleontological assemblage is rarefor the East African MSA and provides crucial paleoenvironmentalinsight. The combination of faunal, sedimentological, andgeochemical evidence indicates that the KarunguMSA is associatedwith a C4 grassland-dominated environment and a reduction inprecipitation, which probably contributed to a substantial reduc-tion in the size of Lake Victoria. Consistent with genetic evidence(Lorenzen et al., 2012), such conditions potentially facilitated thedispersal and convergence of grassland ungulates from variousregions surrounding the Lake Victoria Basin. Together with ouranalysis of variation in the regional Late Pleistocene MSA record,

J.T. Faith et al. / Journal of Hu16Andrews, P., 1981. A short history of Miocene eld palaeontology in Western Kenya.J. Hum. Evol. 10, 3e9.

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004Assefa, Z., 2006. Faunal remains from Porc-Epic: paleoecological and zooarchaeo-logical investigations from a Middle Stone Age site in southeastern Ethiopia.J. Hum. Evol. 51, 50e75.

Assefa, Z., Yirga, S., Reed, K.E., 2008. The large-mammal fauna from the KibishFormation. J. Hum. Evol. 55, 501e512.

Behrensmeyer, A.K., 2006. Climate change and human evolution. Science 311,476e478.

Behrensmeyer, A.K., Potts, R., Plummer, T.W., Tauxe, L., Opdyke, N., Jorstad, T., 1995.The Pleistocene locality of Kanjera, Western Kenya: stratigraphy, chronologyand paleoenvironments. J. Hum. Evol. 29, 247e274.

Beuning, K.R., Kelts, K., Russell, J., Wolfe, B.B., 2002. Reassessment of Lake Victoria-Upper Nile River paleohydrology from oxygen isotope records of lake-sedimentcellulose. Geology 30, 559e562.

Beverly, E.J., Driese, S.G., Peppe, D.J., Johnson, C.R., Michel, L.A., Faith, J.T., Tryon, C.A.,Sharp, W., 2015. Recurrent spring-fed rivers in a Middle to Late Pleistocene semi-arid grassland: implications for environments of early humans in the Lake Vic-toria Basin, Kenya. Sedimentology. http://dx.doi.org/10.1111/sed.12199 in press.

Blegen, N., Tryon, C.A., Faith, J.T., Peppe, D.J., Beverly, E., Jacobs, Z., Li, B., 2015. Distaltephras of the eastern Lake Victoria Basin, Equatorial East Africa: correlations,chronology, and a context for early modern humans. Quatern. Sci. Rev. sub-mitted for publication.

Blome, M.W., Cohen, A.S., Tryon, C.A., Brooks, A.S., Russell, J., 2012. The environ-mental context for the origins of modern human diversity: a synthesis ofregional variability in African climate 150,000e30,000 years ago. J. Hum. Evol.62, 563e592.

Boeda, E., 1994. Le concept Levallois: variabilite des methodes. Centre National de laRecherche Scientique, Paris.

Boeda, E., 1995. Levallois: a volumetric construction, methods, a technique. In:Dibble, H.L., Bar-Yosef, O. (Eds.), The denition and interpretation of Levalloistechnology. Prehistory Press, Madison, WI, pp. 41e68.

Bootsma, H.A., Hecky, R.E., 2003. A comparative introduction to the biology andlimnology of the African Great Lakes. J. Great Lakes Res. 29, 3e18.

Brandt, S.A., Fisher, E.C., Hildebrand, E.A., Vogelsang, R., Ambrose, S.H., Lesur, J.,Wang, H., 2012. Early MIS3 occupation of Mochena Borago Rockshelter,southwest Ethiopian highlands: implications for Late Pleistocene archaeology,paleoenvironments and modern human dispersals. Quatern. Int. 274, 38e54.

Broecker, W.C., Peteet, D., Hajdas, I., Lin, J., 1998. Antiphasing between rainfall inAfrica's Rift Valley and North America's Great Basin. Quatern. Res. 50, 12e20.

Brown, F.H., McDougall, I., Fleagle, J.G., 2012. Correlation of the KHS Tuff of theKibish Formation to volcanic ash layers at other sites, and the age of early Homosapiens (Omo I and Omo II). J. Hum. Evol. 63, 577e585.

Brown, F.H., Nash, B.P., Fernandez, D.P., Merrick, H.V., Thomas, R.J., 2013.Geochemical composition of source obsidians from Kenya. J. Archaeol. Sci. 40,3233e3251.

Buol, S.W., Southard, R.J., Graham, R.C., McDaniel, P.A., 2003. Vertisols: shrinkingand swelling dark clay soils. In: Soil Genesis and Classication. Wiley-Blackwell,Oxford, pp. 385e395.

Campbell, M.C., Tishkoff, S.A., 2010. The evolution of human genetic and phenotypicvariation in Africa. Curr. Biol. 20, R166eR173.

Carto, S.L., Weaver, A.J., Hetherington, R., Lam, Y., Wiebe, E.C., 2009. Out of Africaand into an ice age: on the role of global climate change in the late Pleistocenemigration of early modern humans out of Africa. J. Hum. Evol. 56, 139e151.

Cerling, T.E., Harris, J.M., 1999. Carbon isotope fractionation between diet andbioapatite in ungulate mammals and implications for ecological and paleo-ecological studies. Oecologia 120, 347e363.

Cerling, T.E., Harris, J.M., Passey, B.H., 2003. Diets of east African bovidae based onstable isotope analysis. J. Mammal. 84, 456e470.

Cerling, T.E., Levin, N.E., Passey, B.H., 2011. Stable isotope ecology in the Omo-Turkana Basin. Evol. Anthropol. 20, 228e237.

Codron, J., Duffy, K.J., Avenant, N.L., Sponheimer, M., Leichliter, J., Paine, O.,Sandberg, P., Codron, D., 2015. Stable isotope evidence for trophic niche parti-tioning in a South African savanna rodent community. Curr. Zool. in press.

Compton, J.S., 2011. Pleistocene sea-level uctuations and human evolution on thesouthern coastal plain of South Africa. Quatern. Sc. Rev. 30, 506e527.

Corbet, P.S., 1960. The food of a sample of crocodiles (Crocodilus niloticus L.) fromLake Victoria. Proc. Zool. Soc. Lond. 133, 561e572.

Cowling, S.A., Cox, P.M., Jones, C.D., MAslin, M.A., Peros, M., Spall, S.A., 2008.Simulated glacial and interglacial vegetation across Africa: implications forspecies phylogenies and trans-African migration of plants and animals. Glob.Change Biol. 14, 827e840.

Creveceour, I., Rougier, H., Grine, F., Froment, A., 2009. Modern human cranial di-versity in the late Pleistocene of Africa and Eurasia: evidence from NazletKhater, Pestera cu Oase, and Hofmeyr. Am. J. Phys. Anthropol. 140, 347e358.

Damuth, J., Janis, C.M., 2011. On the relationship between hypsodonty and feedingecology in ungulate mammals, and its utility in palaeoecology. Biol. Rev. 86,733e758.

Dehghani, R., Wanntorp, L., Pagani, P., Kallersjo, M., Werdelin, L., Veron, G., 2008.Phylogeography of the white-tailed mongoose (Herpestidae, Carnivora, Mam-malia) based on partial sequences of the mtDNA control region. J. Zool. 276,385e393.

Ditcheld, P., Hicks, J., Plummer, T., Bishop, L.C., Potts, R., 1999. Current research onthe Late Pliocene and Pleistocene deposits north of Homa Mountain, south-western Kenya. J. Hum. Evol. 36, 123e150.

Evolution xxx (2015) 1e18Doornkamp, J.C., Temple, P.H., 1966. Surface, drainage and tectonic instability in partof southern uganda. Geogr. J. 132, 238e252.


J.T. Faith et al. / Journal of Human Evolution xxx (2015) 1e18 17Eerkens, J.W., Lipo, C.P., 2005. Cultural transmission, copying errors, and the gen-eration of variation in material culture and the archaeological record.J. Anthropol. Archaeol. 24, 316e334.

Ehleringer, J.R., Cerling, T.E., Helliker, B.R., 1997. C4 photosynthesis, atmospheric CO2,and climate. Oecologia 112, 285e299.

Eren, M.I., Durant, A.J., Prendergast, M., Mabulla, A.Z.P., 2014. Middle Stone Agearchaeology at Olduvai Gorge, Tanzania. Quatern. Int. 322e323, 292e313.

Eriksson, A., Betti, L., Friend, A.D., Lycett, S.J., Singarayer, J.S., von Cramon-Taubadel, N., Valdes, P.J., Balloux, F., Manica, A., 2012. Late Pleistocene climatechange and the global expansion of anatomically modern humans. Proc. Natl.Acad. Sci. USA 109, 16089e16094.

Eronen, J.T., Puolamaki, K., Liu, L., Lintulaakso, K., Damuth, J., Janis, C., Fortelius, M.,2010. Precipitation and large herbivorous mammals I: estimates from present-day communities. Evol. Ecol. Res. 12, 217e233.

Faith, J.T., 2014. Late Pleistocene and Holocene mammal extinctions on continentalAfrica. Earth-Sc. Rev. 128, 105e121.

Faith, J.T., Choiniere, J.N., Tryon, C.A., Peppe, D.J., Fox, D.L., 2011. Taxonomic statusand paleoecology of Rusingoryx atopocranion (Mammalia, Artiodactyla), anextinct Pleistocene bovid from Rusinga Island, Kenya. Quatern. Res. 75,697e707.

Faith, J.T., Potts, R., Plummer, T.W., Bishop, L.C., Marean, C.W., Tryon, C.A., 2012. Newperspectives on middle Pleistocene change in the large mammal faunas of EastAfrica: Damaliscus hypsodon sp. nov. (Mammalia, Artiodactyla) from Lainyamok,Kenya. Palaeogeogr. Palaeoclimatol. Palaeoecol. 361e362, 84e93.

Faith, J.T., Tryon, C.A., Peppe, D.J., Fox, D.L., 2013. The fossil history of Grevy's zebra(Equus grevyi) in equatorial East Africa. J. Biogeogr. 40, 359e369.

Faith, J.T., Tryon, C.A., Peppe, D.J., Beverly, E.J., Blegen, N., 2014. Biogeographic andevolutionary implications of an extinct late Pleistocene impala from the LakeVictoria Basin. J. Mammal. Evol. 21, 213e222.

Faith, J.T., Tryon, C.A., Peppe, D.J., 2015. Environmental change, ungulate biogeog-raphy, and their implications for early human dispersals in equatorial East Af-rica. In: Jones, S.C., Stewart, B.A. (Eds.), Africa from MIS 6e2: PopulationDynamics and Paleoenvironments. Springer in press.

Fullinger, U., Sonye, G., Killeen, G.F., Knols, B.G.L., Becker, N., 2004. The practicalimportance of permanent and semipermanent habitats for controlling aquaticstages of Anopheles gambiae sensu lato mosquitoes: operational observationsfrom a rural town in western Kenya. Trop. Med. Int. Health 9, 1274e1289.

Garrett, N.D., Fox, D.L., McNulty, K.P., Tryon, C.A., Faith, J.T., Peppe, D.J., VanPlantinga, A., 2015. Stable isotope paleoecology of late Pleistocene Middle StoneAge humans from equatorial East Africa, Lake Victoria basin, Kenya. J. Hum.Evol. in press, http://dx.doi.org/10.1016/j.jhevol.2014.10.005.

Gentry, A.W., 1970. The Bovidae (Mammalia) of the Fort Ternan fossil fauna. In:Leakey, L.S.B., Savage, R.J.G. (Eds.), Fossil Vertebrates of Africa 2. Academic Press,London, pp. 243e323.

Gliganic, L.A., Jacobs, Z., Roberts, R.G., Domnguez-Rodrigo, M., Mabulla, A.Z.P., 2012.New ages for Middle and Later Stone Age deposits at Mumba rockshelter,Tanzania: optically stimulated luminescence dating of quartz and feldspargrains. J. Hum. Evol. 62, 533e547.

Good, S., Caylor, K.K., 2011. Climatological determinants of woody cover in Africa.Proc. Natl. Acad. Sci. USA 108, 4902e4907.

Gunz, P., Bookstein, F.L., Mitteroecker, P., Stadlmayr, A., Seidler, H., Weber, G.W.,2009. Early modern human diversity suggests subdivided population structureand a complex out-of-Africa scenario. Proc. Natl. Acad. Sci. USA 106,6094e6098.

Gutherz, X., Diaz, A., Menard, C., Bon, F., Douze, K., Lea, V., Lesur, J., Sordoillet, D.,2014. The Hargeisan revisited: lithic industries from shelter 7 of Laas Geel,Somaliland and the transition between the Middle and Late Stone Age in theHorn of Africa. Quatern. Int. 343, 69e84.

Hammer, ., Harper, D.A.T., Ryan, P.D., 2001. Paleontological statistics softwarepackage for education and data analysis. Palaeontol. Electron 4.

Harvati, K., Stringer, C., Grn, R., Aubert, M., Allsworth-Jones, P., Folorunso, C.A.,2013. The Later Stone Age calvaria from Iwo Eleru, Nigeria: morphology andchronology. PLos ONE 6, e24024.

Hijmans, R.J., Cameron, S.E., Parra, J.L., Jones, P.G., Jarvis, A., 2005. Very high reso-lution interpolated climate surfaces for global land areas. Int. J. Climatol. 25,1965e1978.

Isaac, G.L., 1977. Olorgesailie: archaeological studies of a Middle Pleistocene lakebasin in Kenya. University of Chicago Press, Chicago.

IUCN, 2013. IUCN Red List of Threatened Species. Version 2013.2. www.iucnredlist.org.

Johnson, T.C., Scholz, C.A., Talbot, M.R., Kelts, K., Ricketts, R.D., Ngobi, G.,Beuning, K.R., Ssemmanda, I., McGill, J.W., 1996. Late Pleistocene desiccation ofLake Victoria and the rapid evolution of cichlid shes. Science 273, 1091e1093.

Johnson, T.C., Kelts, K., Odada, E., 2000. The Holocene history of Lake Victoria.Ambio 29, 2e11.

Kendall, R.L., 1969. An ecological history of the Lake Victoria basin. Ecol. Monogr. 39,121e176.

Kent, P.E., 1942. The country round the Kavirondo Gulf of Victoria Nyanza. Geogr. J100, 22e31.

Kimanzi, J.K., 2011. Mapping and modelling the population and habitat of roanantelope (Hippotragus equinus langheldi) in Ruma National Park, Kenya. Ph.D.Thesis. School of Biology, Newcastle University.

Kimura, Y., Jacobs, L.L., Cerling, T.E., Uno, K.T., Ferguson, K.M., Flynn, L.J., Ratnaik, R.,

2013. Fossil Mice and Rats Show Isotopic Evidence of Niche Partitioning and

Please cite this article in press as: Faith, J.T., et al., Paleoenvironmental contKenya, and its implications for human and faunal dispersals in East Aj.jhevol.2015.03.004Change in Dental Ecomorphology Related to Dietary Shift in Late Miocene ofPakistan. PLoS ONE 8, e69308.

Kingdon, J., 1982. East African Mammals. University of Chicago Press, Chicago.Kingdon, J., 1990. Island Africa: The Evolution of Africa's Rare Animals and Plants.

Princeton University Press, Princeton.Koch, P.L., Tuross, N., Fogel, M., 1997. The effects of sample treatment and diagenesis

on the isotopic integrity of carbonate in biogenic hydroxylapatite. J. Archaeol.Sci. 24, 417e430.

Le Bas, M.J., 1977. Carbonatite-nephelenite volcanism: an African case history.Wiley, London.

Le Gros Clark, W.E., Leakey, L.S.B., 1950. Diagnoses of East African Miocene homi-noidea. Q. J. Geol. Soc. London 105, 260e262.

Leakey, L.S.B., 1974. By the Evidence: Memoirs 1932e1951. Harcourt Brace Jovano-vich, New York.

Leakey, M.D., 1971. Olduvai Gorge. In: Excavations in Beds I and II, 1960e1963,Volume 3. Cambridge University Press, Cambridge.

Lee-Thorp, J.A., van Der Merwe, N.J., 1987. Carbon isotope analysis of fossil boneapatite. S. Afr. J. Sci. 83, 712e715.

Lehmann, T., Peppe, D.J., Driese, S.G., Jenkins, K., Sanders, W.J., McNulty, K.P., 2014.New eldwork at Karungu (Early Miocene: Lake Victoria, Kenya): preliminarypaleontological and geological resul

faith et al in press

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