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Environmental Change, Ungulate Biogeography, and Their Implications for Early Human Dispersals in Equatorial East Africa


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To better understand the potential role of environmental change in mediating human dispersals across equatorial East Africa, this study examines the biogeographic histories of ungulates, including a summary of current knowledge and fossil evidence stemming from our fieldwork in the Kenyan portion of the Lake Victoria basin. Phylogeographic and paleontological evidence indicates that vegetation changes across Quaternary climate cycles mediated ungulate distributions and dispersals via the opening and closing of biogeographic barriers in equatorial East Africa. Dispersal capabilities would have been enhanced during phases of grassland expansion and diminished during phases of grassland contraction. We propose that the distribution and dispersal of diagnostic technological markers in the archaeological record may be similarly influenced by environmental changes. The Middle Stone Age record from the Lake Victoria region provides intriguing examples of possible environmentally mediated technological dispersals.
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Chapter 13
Environmental Change, Ungulate Biogeography,
and Their Implications for Early Human Dispersals
in Equatorial East Africa
J. Tyler Faith, Christian A. Tryon, and Daniel J. Peppe
Abstract To better understand the potential role of envi-
ronmental change in mediating human dispersals across
equatorial East Africa, this study examines the biogeo-
graphic histories of ungulates, including a summary of
current knowledge and fossil evidence stemming from our
eldwork in the Kenyan portion of the Lake Victoria basin.
Phylogeographic and paleontological evidence indicates that
vegetation changes across Quaternary climate cycles medi-
ated ungulate distributions and dispersals via the opening
and closing of biogeographic barriers in equatorial East
Africa. Dispersal capabilities would have been enhanced
during phases of grassland expansion and diminished during
phases of grassland contraction. We propose that the
distribution and dispersal of diagnostic technological mark-
ers in the archaeological record may be similarly inuenced
by environmental changes. The Middle Stone Age record
from the Lake Victoria region provides intriguing examples
of possible environmentally mediated technological
Keywords Grasslands Lake Victoria Late Pleistocene
Middle Stone Age Paleoenvironments Phylogeography
Range shift
The prehistory of early modern humans is characterized by
massive range expansions and population dispersals. Fossil
and genetic evidence indicate an African origin of our spe-
cies (Homo sapiens)*200 ka (McDougall et al. 2005;
Campbell and Tishkoff 2010; Brown et al. 2012; but see
Weaver 2012 for an alternate interpretation). These early
humans later diverged into multiple genetically (Campbell
and Tishkoff 2010) and morphologically diverse (Gunz et al.
2009) populations during the Late Pleistocene (12612 ka),
likely reecting intra-African population expansions and
dispersals (Soares et al. 2012). At least one of these popu-
lations migrated out of Africa *70 ka (Campbell and
Tishkoff 2010), setting the stage for the expansion of
humans across the globe and the replacement of all other
hominin species, including Neanderthals (Homo nean-
derthalensis) in Eurasia, and the enigmatic hobbit(Homo
oresiensis) in Indonesia.
East Africa features prominently in this history of early
modern humans, as it provides the earliest fossil remains of
Homo sapiens (Omo I and II from the Kibish Formation,
Ethiopia, at *195 ka; McDougall et al. 2005; Brown et al.
2012) and the probable source populations for their Late
Pleistocene dispersals out of Africa (Soares et al. 2012,2016).
Understanding the factors underlying these dispersals is the
subject of intense debate spanning the elds of archaeology,
paleontology, genetics, and climatology, among others
(Beyin 2011). One of the more common explanatory mech-
anisms includes climate-driven environmental change and its
effects on human demography and the opening and closing of
biogeographic barriers (e.g., Forster 2004; Finlayson 2005;
Vaks et al. 2007; Carto et al. 2009; Trauth et al. 2010;
Compton 2011; Blome et al. 2012; Eriksson et al. 2012;
Soares et al. 2012,2016). However, the precise role of envi-
ronmental change in East African human dispersals is poorly
understood, stemming from a lack of well-dated archaeolog-
ical sites associated with detailed paleoenvironmental
J.T. Faith (&)
School of Social Science, Archaeology Program, University of
Queensland, Brisbane, QLD 4072, Australia
C.A. Tryon
Department of Anthropology, Harvard University, Peabody
Museum of Archaeology and Ethnology, 11 Divinity Avenue,
Cambridge, MA 02138, USA
D.J. Peppe
Terrestrial Paleoclimatology Research Group, Department of
Geology, Baylor University, Waco, TX 76706, USA
©Springer Science+Business Media Dordrecht 2016
Sacha C. Jones and Brian A. Stewart (eds.), Africa from MIS 6-2: Population Dynamics and Paleoenvironments,
Vertebrate Paleobiology and Paleoanthropology, DOI 10.1007/978-94-017-7520-5_13
records. This is compounded by the high variability of the
regional Middle Stone Age (MSA), which limits our ability to
identify an archaeological signature of population movements
(Tryon and Faith 2013).
While many fundamental questions concerning the role of
environmental change in early human dispersals from East
Africa remain unclear, a growing body of evidence indicates
that Pleistocene environmental change played a central role
in the biogeographic histories of associated East African
faunas (e.g., Rodgers et al. 1982; Kingdon 1989; Marean
1992; Grubb et al. 1999; Wronski and Hausdorf 2008;
Lorenzen et al. 2012; Faith et al. 2013). Not only does this
imply that human population movements may be related to
broader biogeographic patterns, but also that these insights
into the relationships between changing climate, environ-
ments, and species ranges represent a useful starting point
for formulating new hypotheses about human dispersals. Our
aim here is to develop a framework for understanding the
potential role of environmental change in Late Pleistocene
human dispersals through an examination of ungulate bio-
geography. We focus on ungulates because they are well
represented in the fossil record and because many ungulate
species are clearly linked to specic habitats, making them
strong candidates for exploring how environmental change
mediates their biogeographic histories. This chapter provides
a brief review of current knowledge together with an
examination of paleontological and archaeological evidence
stemming from our ongoing eldwork in the Kenyan portion
of the Lake Victoria basin.
Ungulate Biogeography
In common use, the ungulates represent a paraphyletic group
of hoofed mammals, including in Africa the antelopes and
buffalo (Bovidae), suids (Suidae), zebras (Equidae), giraffes
(Girafdae), rhinos (Rhinocerotidae), elephants (Elephanti-
dae), and hippos (Hippopotamidae), among others. Ungulate
diversity in Africa is exceptional (Turpie and Crowe 1994;du
Toit and Cumming 1999), with the bovids (the most speciose
family) alone represented by 82 extant species (IUCN 2012)
and more than 100 fossil species (Gentry 2010).
The greatest diversity of African ungulates is found in
equatorial East Africa (Turpie and Crowe 1994), which
encompasses the boundaries between the Somalian, Suda-
nian, and Zambesian biogeographic regions for mammals,
birds, reptiles, amphibians, and plants (Linder et al. 2012)
(Fig. 13.1). These biogeographic regions, which are broadly
similar to previously identied zones based on expert
opinion (e.g., White 1983; Burgess et al. 2004), were sta-
tistically dened by Linder et al. (2012) using cluster anal-
ysis of species occurrences across 1°×1°(latitude and
longitude) cells for plants and vertebrate groups. We rec-
ognize that these zones are only a coarse measure of broad
biogeographic patterns, and we use them here as a heuristic
device to illustrate how biogeographic patterns changed in
the past. Some of the ungulates characteristic of these
regions include Grevys zebra (Equus grevyi) in the xeric
shrublands of the Somalian region, kob (Kobus leche) in the
edaphic grasslands of the Sudanian region, and wildebeest
(Connochaetes taurinus) in the secondary grasslands in the
Zambesian region. All of these taxa are found in East Africa,
but their ranges do not overlap, contributing to the high
spatial turnover (beta diversity) observed more broadly for
all East African mammals (Linder et al. 2012).
The main factors underlying these broad biogeographic
regions include the complex interactions between climate
and geomorphology (e.g., tectonics, topography, soil type)
and their inuence on the distribution of vegetation com-
munities, which in turn mediate the distribution of faunas
(e.g., Bell 1982;OBrien and Peters 1999; Linder et al.
2012). For example, a drier climate characterized by bimodal
rainfall distinguishes the Somalian region from both the
Sudanian and Zambesian regions, which are wetter and
receive primarily uni-modal rainfall (OBrien and Peters
1999). This aridity in the Somalian region translates to the
presence of dry scrub vegetation inhabited by arid-adapted
ungulates, including Grevys zebra and African wild ass
(Equus africanus). At the same time, species ranges are also
inuenced by geomorphological factors. In addition to
mediating vegetation cover and habitat suitability through
altitudinal gradients, tectonically driven uplift and rifting can
create dispersal barriers to biotic communities, as evidenced
Fig. 13.1 The distribution of Sudanian, Somalian, and Zambesian
biogeographic regions for mammals (after Linder et al. 2012)
234 J.T. Faith et al.
by the close correspondence between the boundary of the
Sudanian and Somalian regions in Ethiopia (Fig. 13.1) and
the location of the Ethiopian Rift Valley, which bisects the
Ethiopian highlands. Lastly, soil type can also determine
broadscale biogeographic patterns. For example, the domi-
nance of low-nutrient soils weathered from basement rock
accounts for the Miombo (Brachystegia) woodlands and
low-biomass ungulate communities characteristic of the
Zambesian region, in stark contrast to the nutrient-rich vol-
canic soils in some portions of the Somalian region, which
are associated with grasslands and high-biomass ungulate
communities (Bell 1982; East 1984).
Not only does the combination of climatic and geomor-
phological variables in East Africa translate to biogeo-
graphic zonation of ungulate species, but the same is also
true for populations within species. Lorenzen et al. (2012)
show that many broadly distributed species, including war-
thog (Phacochoerus africanus), African buffalo (Syncerus
caffer), hartebeest (Alcelaphus buselaphus), and giraffe
(Giraffa camelopardalis), among others, display genetic
substructuring that distinguishes between populations from
the Sudanian savannas, and those in East Africa and
southern Africa. Among some species there is also evidence
for substructuring between East and southern African pop-
ulations. The overall picture indicates that East Africa
encompasses the boundaries of genetically distinct lineages
from multiple regions.
A number of factors potentially contribute to this unique
taxonomic and genetic diversity. High spatial variability in
forage quantity and quality has been invoked as one possible
driver of ungulate species richness in East Africa (du Toit
and Cumming 1999), an argument supported by quantitative
analyses showing extreme spatial heterogeneity in East
African plant communities (Linder et al. 2012). However,
this does not explain the convergence of genetically distinct
lineages within species. In light of the phylogeographic
evidence, Lorenzen et al. (2012) propose that environmental
changes across late Quaternary glacial/interglacial cycles
played an important role in the taxonomic and genetic
diversity of East African ungulates. Equating glacial and
interglacial conditions with dry versus humid climates, they
suggest that the expansion of grassland vegetation during
glacial phases would have facilitated interchange of ungulate
populations throughout sub-Saharan Africa. During inter-
glacials, the expansion of tropical forests across equatorial
East Africa created a barrier that fragmented populations and
restricted gene ow (see also Cowling et al. 2008). If so,
then the distinct biogeographic regions and high spatial
heterogeneity of biotic communities found in East Africa
today (Linder et al. 2012) may be a Holocene phenomenon,
with a more homogenous supercommunity characteristic of
Pleistocene phases of grassland expansion.
The Fossil Record
Biogeographic evidence suggests that East Africa is a hub
around which ungulate ranges expand, contract, and frag-
ment across cycles of Quaternary environmental change.
One of the key predictions generated from this is that during
phases with expanded grassland cover, allopatric ungulate
species from both north and south of the equator will con-
verge in equatorial East Africa. The fossil record provides
the requisite empirical evidence for testing this hypothesis.
Compared to the record from southern Africa, which has
been a focus of modern human origins research for decades,
our understanding of the fossil history of East African
ungulates over the last *200 kyr is only beginning to come
to light (Marean and Gifford-Gonzalez 1991; Marean 1992;
Assefa 2006; Assefa et al. 2008; Faith et al. 2011,2012,
2013,2014). However, the emerging evidence provides
compelling examples of climate-driven range shifts that are
consistent with hypotheses derived from ungulate
The Records from Rusinga
and Mfangano Islands
Here we highlight some of the more prominent range shifts
documented in the fossil record, with an emphasis on the
Late Pleistocene ungulates from Rusinga and Mfangano
Islands in Kenyas Lake Victoria basin (Fig. 13.2). We focus
on these sites because: (1) all of the ungulate taxa involved
in major Late Pleistocene range shifts are documented here
(and in some cases elsewhere); and (2) the Lake Victoria
region is strategically situated along the equator in East
Africa, with geological evidence documenting massive
expansions and contractions in lake area, including periodic
desiccation, in response to late Quaternary climate change
(Stager and Johnson 2008; Stager et al. 2002,2011; Tryon
et al. in press). Seismic proles across Lake Victoria show at
least four desiccation surfaces (Johnson et al. 1996; Stager
and Johnson 2008), the most recent of which correspond to
extreme aridity during Heinrich Event 1 from 17 to 16 ka
and again during a subsequent dry phase from 15 to 14 ka
(Stager et al. 2002,2011); the other desiccation surfaces
correspond to undated phases of previous aridity and the
pre-lake surface. The vegetation of the Lake Victoria region
was historically characterized by bushland, thicket, and
forest (White 1983), although multiple lines of evidence
indicate that phases of lake contraction were associated with
expanded grasslands (Kendall 1969; Talbot and Laerdal
2000; Talbot et al. 2006; Tryon et al. in press).
13 Ungulate Biogeography and Human Dispersals 235
Details of our research on Rusinga Island and Mfangano
Island have been published elsewhere (Faith et al. 2011,2012,
2014; Tryon et al. 2010,2012,2014), and we provide only a
brief summary here. Rusinga and MfanganoIslands are located
within Lake Victoria (Fig. 13.2), with the former separated from
the mainland by a narrow channel and the latter situated
*10 km from the mainland. On both islands, the poorly con-
solidated Pleistocene deposits, known as the Wasiriya Beds
(Rusinga Island) and the Waware Beds (Mfangano Island), are
characterized by weakly developed paleosols and tuffaceous
uvial sediments documenting a complex cut-and-ll system.
The age of the Wasiriya Beds is constrained tobetween 100 and
33 ka, with the minimum provided by radiocarbon dates for
intrusive gastropods and the maximum by geochemical analy-
sis of tephra deposits, which suggest derivation from East
African Rift System (EARS) volcanoes that began erupting
*100 ka (Blegen et al. 2015). The Waware Beds have a similar
minimum age, also provided by radiocarbon age estimates for
intrusive gastropods, whereas tephra correlations suggest a link
to the Wasiriya Beds and a comparable maximum age (Blegen
et al. 2015). The artifacts recovered from the Wasiriya Beds are
typologically MSA (Fig. 13.3), and the same is likely the case
for those from the Waware Beds, although a larger sample is
needed to be certain.
Rusinga and Mfangano Islands have yielded some of the
larger and better preserved fossil assemblages from this time
period in East Africa (Table 13.1). Alcelaphine bovids and
equids dominate the assemblages, indicating the presence of
open grassland vegetation distinct from the historic vegeta-
tion (White 1983). Several extinct bovids are present,
including Rusingoryx atopocranion,Damaliscus hypsodon,
Megalotragus sp., Syncerus antiquus, and an unnamed
impala, all of which are characterized by dental or postcra-
nial adaptations to grazing in open habitats (Klein 1980,
1994; Faith et al. 2011,2012,2014). The presence of large
gregarious grazers on Mfangano Island, some of which are
migratory species, suggests a likely connection to the
mainland when the deposits accumulated, requiring a 25 m
reduction in lake level (Tryon et al. 2014). The precipitation
decline needed to drive this would have set in motion a
series of feedback mechanisms leading to a substantial
reduction, if not complete desiccation, of Lake Victoria
(Broecker et al. 1998; Milly 1999), leaving behind a topo-
graphically smooth grassy plain (Tryon et al. 2014). As
detailed below, there is strong evidence that the expansion of
grasslands and reduction in surface area of Lake Victoria
facilitated interchange of ungulates from north and south of
the equator.
Fig. 13.2 The location of Rusinga and Mfangano islands in Kenyan Lake Victoria and nearby archaeological sites mentioned in the text
236 J.T. Faith et al.
Grevys Zebra (Equus grevyi)
Grevys zebra historically ranged throughout arid to
semi-arid grasslands and shrublands in the Horn of Africa
(Fig. 13.4) (Williams 2002). Fossil remains are known from
Rusinga Island (Table 13.1) and many other Middle-to-Late
Pleistocene sites in southern Kenya and northern Tanzania,
including Karungu, Lukenya Hill, Lainyamok, and Kisese II,
documenting a south and westward range shift or expansion
of at least 500 km (Faith et al. 2013). Although the species is
primarily conned to the Somalian biogeographic region, its
fossil occurrences are found in areas that are today part of
the Somalian, Sudanian, and Zambesian biogeographic
regions. At the onset of the Holocene, Grevys zebra dis-
appeared from southern Kenya and northern Tanzania and
Fig. 13.3 Middle Stone Age artifacts from Rusinga and Mfangano Islands: acbifacial points, deLevallois blades variably retouched,
fLevallois core
Table 13.1 The presence/absence of ungulate species from Rusinga and Mfangano islands as of our 2012 eld season
Family Taxon Common name Rusinga Mfangano
Elephantidae Elephantidae cf. Loxodonta africana Elephant X
Rhinocerotidae Ceratotherium simum White rhinoceros X
Equidae Equus quagga Plains zebra X X
Equus grevyi Grevys zebra X
Suidae Kolpochoerus sp.Extinct bushpig X
Phacochoerus sp. Warthog X X
Potamochoerus sp. Bushpig X X
Hippopotamidae Hippopotamus sp. Hippopotamus X X
Bovidae Taurotragus oryx Eland X
Tragelaphus scriptus Bushbuck X
Tragelaphus strepsiceros Greater Kudu X
Tragelaphus cf. imberbis ?Lesser Kudu X
Oryx beisa Oryx X
Redunca fulvorufula/redunca Reedbuck X X
Redunca arundinum/Kobus kob Southern reedbuck/Kob X X
Aepyceros sp. nov.Large extinct impala X
Connochaetes taurinus Wildebeest X X
Damaliscus hypsodonSmall extinct alcelaphine X X
Megalotragus sp.Giant wildebeest X
Rusingoryx atopocranionExtinct alcelaphine X X
Alcelaphini cf. Alcelaphus buselaphus Hartebeest X X
Sylvicapra grimmia Common duiker X
Gazella thomsoni Thomsons Gazelle X X
Syncerus antiquusLong-horn buffalo X X
Syncerus caffer African buffalo X X
Ourebia ourebi Oribi X X
Oreotragus/Raphicerus Klipspringer/Steenbok X
Madoqua sp. Dik-dik X
= extinct
13 Ungulate Biogeography and Human Dispersals 237
became rare in the fossil record, likely reecting increased
precipitation, the contraction of dry grassland habitats, and
competition with mesic-adapted grazers (Faith et al. 2013).
Oryx (Oryx beisa)
The current distribution of oryx broadly corresponds to that
of Grevys zebra, but extends south into the Zambesian and
northwest into the Sudanian biogeographic regions
(Fig. 13.4). Oryx has a similar habitat preference as Grevys
zebra, and the two species are signicantly associated in the
fossil record (Faith et al. 2013). The presence of oryx on
Rusinga Island (Table 13.1) indicates a *250 km westward
range shift or expansion. Like Grevys zebra, its range and
abundance declined throughout East African fossil sites at
the beginning of the Holocene (Faith et al. 2013).
White Rhinoceros (Ceratotherium simum)
The white rhinoceros includes two subspecies, the northern
white rhinoceros (C. simum cottoni) and southern white
rhinoceros (C. simum simum), although some authorities
Fig. 13.4 The geographic ranges of Grevys zebra (Equus grevyi),
oryx (Oryx beisa), white rhinoceros (Ceratotherium simum), kob
(Kobus kob), and southern reedbuck (Redunca arundinum) relative to
their fossil occurrences on Rusinga and Mfangano islands (star). Range
maps are from Williams (2002) for Grevys zebra and the IUCN Red
List (2012) for all other species. Boxes correspond to fossil occurrences
mentioned in the text: (1) Karungu, (2) Lainyamok, (3) Lukenya Hill,
(4) Kisese II, (5) Prolonged Drift, (6) Mumba shelter
238 J.T. Faith et al.
place the former in its own species (C. cottoni) (Groves et al.
2010). Their geographic ranges are discontinuous, with the
southern white rhinoceros historically known from southern
Africa and the northern white rhinoceros known from central
Africa northwest of Lake Albert (Fig. 13.4). Several white
rhinoceros fossils have been recovered from Rusinga Island,
*430 km southeast of its historic range (assuming they
belong to the northern taxon), with an even greater Late
Pleistocene range extension (*775 km) documented at
Mumba rockshelter in Tanzania (Mehlman 1989). As evi-
denced by an additional fossil occurrence from Prolonged
Drift in central Kenya, a small and probably isolated popu-
lation persisted in equatorial East Africa into the late
Holocene (Gifford et al. 1980). The cause of its prehistoric
disappearance from Kenya is not well understood, but could
include long-term vegetation change, competition for forage
and water with pastoralists and their livestock, or stochastic
processes owing to small population size and isolation.
Kob (Kobus kob) or Southern Reedbuck
(Redunca arundinum)
Both Rusinga and Mfangano Islands yield dental remains of
a medium-sized reduncine, larger than Bohor reedbuck
(Redunca redunca), but smaller than waterbuck (Kobus
ellipsiprymnus), that are morphologically similar to and
overlap in size with modern kob and southern reedbuck.
Both taxa have a similar habitat requirement for fresh
grasses and year-round access to water, which is consistent
with the uvial nature of the fossil deposits. The ranges of
these two reduncines are allopatric (Fig. 13.4), with kob
occurring north and west of Lake Victoria in the Sudanian
savannas and southern reedbuck ranging from southern
Africa to just south of the Lake Victoria basin. Although it is
unclear whether the fossil specimens belong to kob, southern
reedbuck, or both, the occurrence of either implies a
*350 km range shift to the southeast (kob) or northeast
(southern reedbuck).
A Non-Analog Supercommunity
The convergence of various ungulate species with histori-
cally allopatric ranges on Rusinga and Mfangano Islands
supports the notion of a homogenous East African super-
community during Pleistocene phases of grassland expan-
sion. It follows that the distinct biogeographic zonation
found in East Africa today (Fig. 13.1; Linder et al. 2012)is
ephemeralprobably limited to the Holoceneand closely
linked to climate and its effects on vegetation structure.
Other variables that contribute to the establishment of bio-
geographic zonation in East Africa (e.g., tectonics, topog-
raphy, and soil type), unquestionably contributed to Late
Pleistocene vegetation structure, but these are expected to be
relatively stable over the timescale examined here, leaving
climate as the most likely driver of rst-order vegetation
While the non-analog supercommunity is consistent with
enhanced ungulate dispersal capabilities related to expanded
grasslands and a smaller Lake Victoria, it is also possible
that environments at the time were highly productive and
uniquely suited to supporting ungulate diversity. Across a
range of East and southern African ecosystems, ungulate
diversity and biomass peaks between 700 and 800 mm
annual precipitation (Coe et al. 1976; East 1984; Faith
2013). A decline in annual precipitation from the *1000 to
1200 mm/yr observed today, which is supported by the
inferred decline of Lake Victoria (Tryon et al. 2014), could
further underpin the diversity of the Late Pleistocene
ungulate community. Reduced atmospheric CO
tions may have also contributed to the diversity, by
enhancing foraging nutrient content, in turn supporting
higher biomass large herbivore communities (Faith 2011).
The presence of extinct grazing bovids characterized by
massive body mass (Syncerus antiquus and Megalotragus
sp.) or extreme hypsodonty (Damaliscus hypsodon,Rusin-
goryx atopocranion, and the unnamed impala), of which D.
hypsodon and R. atopocranion are dominant, also implies
the presence of non-analog environments. We have previ-
ously interpreted their presence, together with that of Gre-
vys zebra and oryx, as evidence for aridity (Tryon et al.
2010,2012; Faith et al. 2011,2013), although this is at odds
with the high diversity (see Faith 2013). A more detailed
exploration of this conict is beyond the scope of this study,
but possible explanations could include the presence of a
complex Late Pleistocene grazing succession (e.g., Brink
and Lee-Thorp 1992) or an extinct migratory system (e.g.,
Marean 2010; Faith and Thompson 2013).
Climatic and Tectonic Drivers
Range shifts documented on Rusinga and Mfangano Islands
illustrate the importance of vegetation change, particularly
the expansion of grassland vegetation, in the biogeographic
histories of ungulate populations. The mechanisms respon-
sible for the expansion and contraction of grassland vege-
tation in equatorial East Africa during the Pleistocene
include moisture availability, atmospheric CO
tions, and tectonically driven topographic shifts. The com-
plex interaction of these variables would have played an
important role in the opening and closing of dispersal
13 Ungulate Biogeography and Human Dispersals 239
corridors for ungulate populations, and we provide a sum-
mary of these mechanisms below.
Changes in moisture availability are sometimes equated
with glacial versus interglacial climates, which are typically
generalized as reecting more arid (glacial) versus more
humid (interglacial) conditions. However, although changes
in global moisture availability across glacial/interglacial
cycles may inuence equatorial East African climate, we
caution that this oversimplication ignores the complexities
of regional climate dynamics. Moisture availability in
equatorial East Africa is driven by the complex interplay
between orbital forcing, the position of the Intertropical
Convergence Zone (ITCZ), high-latitude climate events,
tropical ocean temperature gradients, and regional tectonics
(e.g., DeMenocal 1995,2004,2011; Trauth et al. 2003,
2005,2007,2009; Feakins et al. 2005,2013; Sepulchre et al.
2006; Verschuren et al. 2009; Blome et al. 2012). In addition
to these global and regional drivers, local factors may also
play an important role in vegetation change. For example,
today as much as 90% of water loss in Lake Victoria is due
to evaporation and 80% of the input is from direct precipi-
tation (rather than inow from streams and rivers) (Piper
et al. 1986; Crul 1995), such that precipitation change plays
a key role in lake size and moisture availability (Broecker
et al. 1998; Milly 1999). This sensitivity to precipitation
means that small changes in local rainfall patterns could
translate to more pronounced aridication and vegetation
change in the Lake Victoria region compared to other areas
of East Africa.
In addition to moisture availability, reduced atmospheric
concentrations during Pleistocene glacial phases may
also facilitate the expansion of grasslands due to the com-
petitive advantage of C
plants under such conditions
(Prentice et al. 2011). For example, the paleoenvironmental
record from Lake Challa on the Kenya/Tanzania border
shows that both humid and arid intervals from 12 to 25 ka
were dominated by C
vegetation, most of which are prob-
ably grasses, whereas C
vegetation only expands at the
onset of the Holocene (Sinninghe Damstéet al. 2011). This
may indicate that the past distribution of grassland habitats
in equatorial East Africa is more sensitive to atmospheric
than to precipitation.
Over longer timescales (>100 kyr) through the Pleis-
tocene, changes in ungulate ranges may also have been
inuenced by regional tectonics. Extension and uplift asso-
ciated with the EARS has dramatically altered the East
African landscape since the Oligocene by creating large rift
lakes such as Lakes Malawi, Tanganyika, Kivu, Albert and
Edwards, causing the opening and closure of connections
between major lakes, changing ow directions of major
rivers, and creating signicant differences in topography
(e.g., Rosendahl 1987; Chorowicz 2005). Lake Victoria,
though not a true rift lake, was created when extension and
uplift of the western and east arms of the EARS caused
backponding of rivers into a topographic low between the
two branches of the rift *1.60.4 Ma (e.g., Kent 1944;
Bishop and Trendall 1967; Ebinger 1989; Johnson et al.
1996; Talbot and Williams 2009). After its formation, con-
tinued rifting caused the lake basin to shift as much as 50 km
eastward (Doornkamp and Temple 1966; Stager and John-
son 2008). Through the creation of rift-inuenced lakes and
signicant topographic variability across the landscape, the
rifting of the EARS may have inuenced ungulate biogeo-
graphic histories by opening and closing potential dispersal
corridors. Although precipitation and atmospheric CO
concentrations are the primary drivers of vegetation change,
tectonically driven topographic changes probably also con-
tributed to habitat fragmentation and variability across East
Africa, which could have affected the ranges of ungulate
taxa throughout the Pleistocene.
There is little doubt that climate and tectonics strongly
inuence East African paleoenvironments during the Pleis-
tocene. However, as emphasized by Blome et al. (2012),
determining the precise nature of environmental changes and
their underlying mechanisms in the Lake Victoria basin and
across East Africa will require improved chronological
control and more rened paleoenvironmental records.
Implications for Early Human Dispersals
Biogeographic evidence suggests that climate-driven vege-
tation changes across equatorial East Africa played an
important role in mediating the distribution of ungulate
species, with the expansion of grasslands facilitating inter-
change across East Africa (Lorenzen et al. 2012). This is
corroborated by the fossil records from Rusinga and Mfan-
gano Islands, which show that ungulate species with his-
torically allopatric ranges converged in equatorial East
Africa at a time when Lake Victoria was much reduced, if
not desiccated, and grasslands were widespread (Tryon et al.
2014). Presumably, the loss of grasslands and expansion of
the equatorial forest belt at the onset of the Holocene and
during previous humid intervals with high atmospheric CO
concentrations (Cowling et al. 2008) would have prompted
range shifts and fragmentations in species distributions
approaching those observed historically. What are the
implications of these patterns for early modern human
240 J.T. Faith et al.
In the Paleolithic archaeological record, diagnostic lithic
technology represents one of the few means of tracking
human dispersals. On its own, the extent to which the
movement of technological markers reects the dispersal of
human populations (and their genes) is uncertain, but it at
least documents the dispersal of human behavioral reper-
toires. There is abundant ethnographic evidence showing
that the subsistence behaviors and associated technologies of
historic hunter-gatherers are very closely linked to the
environment (Oswalt 1973; Kelly 1995; Binford 2001;
Collard et al. 2005), in which case it is reasonable to suppose
that the movement of technological markers linked to
specic environments might parallel the broader patterns
observed in the ungulates. Below we explore some possible
links between the distributions of technologies in the Lake
Victoria region in relation to paleoenvironmental change.
The Lake Victoria MSA
Previous discussions of distinct technological markers from
the Lake Victoria region have focused on the Lupemban
industry, which represents one of the more distinct MSA
regional variants, characterized by the presence of large (>10
cm), thin, bifacially aked lanceolate points. These lanceo-
lates are well known from central Africa (Barham 2000;
Mercader 2002), although their distribution extends to the
eastern margins of Lake Victoria, including near-shore
islands (Leakey and Owen 1945; Nenquin 1971; McBrearty
1988; Tryon et al. 2012; Taylor 2016). Where paleoenvi-
ronmental records are available, the Lupemban is typically
associated with forested vegetation (Barham 2000; Mercader
2002; Taylor 2016).
The vegetation of the Lake Victoria region today repre-
sents a mosaic of endemic taxa from neighboring regions
(White 1983), attesting to the past expansion and contraction
of vegetation communities, a model consistent with the
implications of the ungulates from Rusinga and Mfangano
Islands (Table 13.1), the distribution of modern faunas (e.g.,
Kingdon 1989; Wronski and Hausdorf 2008), and
paleo-vegetation models (e.g., Cowling et al. 2008). To the
extent that the distribution of Lupemban artifacts is tied to
forested paleoenvironments, we expect that its easternmost
occurrences in the Lake Victoria basin to be associated with
an expanded equatorial forest belt. As shown in Fig. 13.5, all
of the Lupemban sites in the eastern portion of the Lake
Victoria basin lie along now submerged portions of major
rivers that traversed the basin prior to peak lake size some-
time during the Middle or Late Pleistocene (Temple 1966;
Scholz et al. 1998). These sites represent the easternmost
limits of the Lupemban, and include Muguruk on the Winam
Gulf in Kenya (McBrearty 1988), sites reported by Leakey
and Owen (1945) in the Yala River valley of Kenya, and on
Bugaia Island in Uganda (Nenquin 1971). The nearby rivers
would have likely provided naturally wooded corridors
facilitating the expansion of forest-adapted taxa and tech-
nologies, perhaps including the Lupemban, around the
margins of Lake Victoria.
The MSA assemblages from the Wasiriya and Waware
Beds of Rusinga and Mfangano Islands are typologically
distinct from Lupemban assemblages in the Lake Victoria
region or elsewhere, which is not surprising given the asso-
ciated grassy paleoenvironment. In light of the evidence from
ungulate biogeography, it is possible that the expansion of
grasslands would facilitate the movement of people or tech-
nological traditions associated with these environments from
broad East African regions north or south of the equator. In
previous studies (Tryon et al. 2012; Tryon and Faith 2013),
we identied one possible example of this. The lithic
assemblages from Rusinga and Mfangano Islands (Fig. 13.3)
include very small (24 cm in length) bifacially aked points
that overlap in size with those from MSA sites throughout the
East African Rift System. These include the Late Pleis-
tocene MSA or MSA/LSA assemblages from Nasera Rock-
shelter in Tanzania (*290 km southeast), site GvJm-16 at
Lukenya Hill in Kenya (*340 km east southeast), and
Aduma in Ethiopia (*1,390 km northeast). At all of these
sites, the associated faunas or other paleoenvironmental
records indicate grassland vegetation comparable to that
inferred for Rusinga and Mfangano Islands, raising the pos-
sibility that these small points represent either a human
population or (more likely) a technology associated with Late
Pleistocene tropical grasslands. This possible connection to
Rift Valley sites is further supported by the rare presence of
obsidian from the Wasiriya Beds, the nearest outcrops of
which are from Rift Valley sources *250 km to the east.
The small MSA points found on Rusinga and Mfangano
Islands and in the Rift Valley are rare to the west of Lake
Victoria, reported only from Kibwera in Tanzania (Reid and
Njau 1994), although unfortunately no illustrations or pho-
tographs are provided (Fig. 13.5). Assuming that points and
other artifacts produced by hunter-gatherers are to some
extent a reection of the environment in which they were
used, the geographic limits of different types of MSA point
(small points versus Lupemban lanceolates) along the mar-
gins of present-day Lake Victoria (Fig. 13.5) is consistent
with the hypothesis that this area is a nexus of environmental
changes that facilitated the movement of people and their
technological markers.
13 Ungulate Biogeography and Human Dispersals 241
Biogeographic evidence provides a compelling argument
that environmental changes across late Quaternary climate
cycles mediated the distributions and dispersals of ungulate
species via the opening and closing of barriers and dispersal
corridors in equatorial East Africa. For a broad range of
savanna ungulates, dispersal capabilities would have been
enhanced during phases of grassland expansion and dimin-
ished during phases of grassland contraction, leading to
repeated range expansions and fragmentations.
These patterns are of importance to human origins
research, as genetic evidence documents multiple East
African dispersals of early modern humans during the Late
Pleistocene, both within and out of Africa (Campbell and
Tishkoff 2010; Soares et al. 2012,2016). We propose that,
as is clearly the case for ungulates, the distribution and
dispersals of diagnostic technological markers in the
archaeological record may also be mediated by environ-
mental changes. The archaeological record from the Lake
Victoria region provides some intriguing examples of pos-
sible environmentally mediated technological dispersals, but
it is clear that a better sampled archaeological record and
improved chronology is crucial to eshing out these patterns.
Although such limitations are an ever-present problem that
can only be resolved through further eldwork, the patterns
explored here provide an initial framework for exploring the
dispersal of early human populations migrations and
expansions during a critical stage in human evolution.
Acknowledgments We thank Sacha Jones and Brian Stewart for
inviting us to contribute to this volume and the many collaborators who
have worked with us in the Lake Victoria basin, including Emily
Beverly, Nick Blegen, Steve Driese, David Fox, Niki Garrett, Zenobia
Jacobs, Kirsten Jenkins, Renaud Joannes-Boyau, Cara Roure Johnson,
Kieran McNulty, Sheila Nightingale, David Patterson, and Alex Van
Fig. 13.5 Buried river channels across the Lake Victoria basin,
simplied after Temple (1966). Note the proximity of the easternmost
Lupemban lanceolate sites to major east-west owing rivers that
traverse the basin. Smaller MSA points are not reported in the western
portion of the Lake Victoria basin except at Kibwera (illustrations
unavailable). Artifact sketches after Leakey and Owen (1945), Nenquin
(1971), and McBrearty (1988), and illustrated at same scale
242 J.T. Faith et al.
Plantinga. We also thank two anonymous reviewers and Sally Reynolds
(reviewer) for helpful comments on a previous version of this chapter.
Fieldwork was conducted under research permits
NCST/RCD/12B/012/31 issued to JTF and NCST/5/002/R/576 issued
to CAT and an exploration and excavation license issued by the
National Museums of Kenya (NMK). Our eldwork is made possible
through the support of the NMK and the British Institute in East Africa
and with nancial support from the National Science Foundation
(BCS-0841530, BCS-1013199, BCS-1013108), the Leakey Founda-
tion, the National Geographic Society, the University of Queensland,
New York University, and Baylor University. Lastly, none of this
would have been possible without the support of Cornel Faith, Rhonda
Kauffman, Violet Tryon, and Sholly Gunter.
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13 Ungulate Biogeography and Human Dispersals 245
... Previous work has shown that for G. pallidipes, the tsetse fly belts recognized by the Kenya Tsetse and Trypanosomiasis Eradication Council (KENTTEC) are not necessarily ecologically or evolutionarily distinct. Instead, there is a weak genetic break of recent origin with current gene flow between the Lake Victoria Basin and the Serengeti ecosystem and a strong biogeographic break caused by the expansion of the Great Rift Valley in central Kenya (Faith et al., 2016;Lehmann et al., 1999;Linder et al., 2012;Wilfert et al., 2006;Wüster et al., 2007; Glossina pallidipes has a generation time of approximately five per year, has variable dispersal rates on the order of 0.1-10 km per individual/generation (Brightwell et al., 1992;Cuisance et al., 1985;Hargrove, 1981;Rogers, 1977), and goes through population contractions during several arid periods of the year and expansions during rainy seasons (Camberlin & Wairoto, 1997;Devisser et al., 2010;Nnko et al., 2017;Pollock, 1982;Rogers & Randolph, 1985). ...
... CSE genetic distance has been shown to perform better than other genetic distance measures when there are missing data and when the relative distances between population pairs are being measured (Bouyer et al., 2015;Pless et al., 2021). To retain only the genetic distances that reflect contemporary environmental conditions rather than more ancient divergences such as those associated with the expansion of the Great Rift Valley (Faith et al., 2016;Lehmann et al., 1999;Linder et al., 2012;Wilfert et al., 2006;Wüster et al., 2007), we only included genetic distances between sampling sites within the two major genetic clusters east and west of the Great Rift Valley that were identified in previous studies (Bateta et al., 2020;Okeyo et al., 2018) and confirmed here with DAPC (File S1; Jombart, 2008). ...
... These differences are likely the result of the smaller sampling size for this sampling site (n = 7) compared to the average sampling size of 23 individuals. The site in the west (NGU) may have low accuracy because its assignment to the eastern genetic lineage was not fully supported in all analyses (Bateta et al., 2020), implying that genetic divergence from current landscape features could have been masked by the stronger signal of divergence from past vicariance events (i.e., expansion of the Great Rift Valley ~2-5 mya; Faith et al., 2016;Lehmann et al., 1999;Linder et al., 2012;Wilfert et al., 2006;Wüster et al., 2007). ...
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Vector control is an effective strategy for reducing vector‐borne disease transmission, but requires knowledge of vector habitat use and dispersal patterns. Our goal was to improve this knowledge for the tsetse species Glossina pallidipes, a vector of human and animal African trypanosomiasis, which are diseases that pose serious health and socioeconomic burdens across sub‐Saharan Africa. We used random forest regression to: (i) Build and integrate models of G. pallidipes habitat suitability and genetic connectivity across Kenya and northern Tanzania, and (ii) provide novel vector control recommendations. Inputs for the models included field‐survey records from 349 trap locations, genetic data from 11 microsatellite loci from 659 flies and 29 sampling sites, and remotely sensed environmental data. The suitability and connectivity models explained approximately 80% and 67% of the variance in the occurrence and genetic data, and exhibited high accuracy based on cross‐validation. The bivariate map showed that suitability and connectivity vary independently across the landscape and inform vector control recommendations. Post‐hoc analyses show spatial variation in the correlations between the most important environmental predictors from our models and each response variable (e.g. suitability and connectivity) as well as heterogeneity in expected future climatic change of these predictors. The bivariate map suggests that vector control is most likely to be successful in the Lake Victoria Basin, and supports the previous recommendation that G. pallidipes from most of eastern Kenya should be managed as a single unit. We further recommend that future monitoring efforts should focus on tracking potential changes in vector presence and dispersal around the Serengeti and the Lake Victoria basin based on projected local climatic shifts. The strong performance of the spatial models suggests potential for our integrative methodology to be used to understand future impacts of climate change in this and other vector systems.
... In contrast to the numerous well-sampled paleontological assemblages dating to the Early and Middle Pleistocene (e.g., the Turkana Basin and Olduvai Gorge), the sparse Late Pleistocene record is largely derived from fragmentary zooarchaeological assemblages (Marean, 1992a;Assefa, 2006;Lesur et al., 2016) and relatively small paleontological collections (Behrensmeyer and Boaz, 1981;Assefa et al., 2008;Rowan et al., 2015). Only recently has it become apparent that Late Pleistocene mammal communities were composed of numerous extinct species (reviewed in Faith, 2014) and frequently included extant species well outside of their historic ranges (Marean, 1992a;Faith et al., 2015Faith et al., , 2016Rowan et al., 2015;Lesur et al., 2016). It follows that there is still much to be learned about the latter phases of mammalian evolution in eastern Africa, especially if we are to understand the biogeographic processes that gave rise to the region's modern communities, which are today among the most diverse on the continent (Andrews and O'Brien, 2010). ...
... This is because the faunas reported here are constrained to a single depositional unit (Fig. 2), and although fluvial contexts can lead to considerable timeaveraging (Behrensmeyer, 1982), the absence of any MSA artifacts at Kibogo implies that older time periods (>36 ka) have not been sampled. Just as important, non-analog species pairs are ubiquitous in other Late Pleistocene assemblages from eastern Africa and frequently involve many of the same species (Mehlman, 1989;Marean and Gifford-Gonzalez, 1991;Marean, 1992a;Assefa et al., 2008;Faith et al., 2015Faith et al., , 2016Rowan et al., 2015). Thus, Kibogo is representative of a broader regional phenomenon. ...
We report on the Late Pleistocene (36-12 ka) mammals from Kibogo in the Nyanza Rift of western Kenya, providing (1) a systematic description of the mammal remains, (2) an assessment of their paleoenvironmental implications, and (3) an analysis of the biogeographic implications of non-analog species associations. Kibogo has yielded one of the largest paleontological assemblages from the Late Pleistocene of eastern Africa, and it is dominated by grassland ungulates (e.g., equids and alcelaphin antelopes), including an assortment of extralimital (e.g., Equus grevyi, Ceratotherium simum, Redunca arundinum) and extinct species (Syncerus antiquus, Damaliscus hypsodon, Megalotragus sp.). The composition of the fauna, in conjunction with the soils and topography of the region, indicate the local presence of edaphic grassland situated within a broader environment that was substantially grassier and likely drier than at present. In contrast to non-analog faunas from higher latitudes (e.g., North America and western Eurasia), the climatic niches of non-analog species associations strongly overlap, indicating that non-analog climate regimes during the Late Pleistocene of eastern Africa are not necessary to account for the former association of presently allopatric species. The Kibogo faunas add to a growing body of evidence implying that the composition of present-day African herbivore communities is distinct from those of the geologically recent past.
... This contemporaneous fragmentation in two geographically distant regions is best explained by the extreme dry-cold period during the MIS 6, characterized by extensive fragmentation of African forests (Maley, 1996). MIS 6 also marks the onset of episodes of climatic and ecological volatility that persisted throughout the late Pleistocene (Stewart & Jones, 2016), and are thought to have triggered profound changes in the local composition of ungulate species by opening and closing dispersal corridors (Faith et al., 2016). ...
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The evolutionary history of African ungulates has been largely explained in the light of Pleistocene climatic oscillations and the way these influenced the distribution of vegetation types, leading to range expansions and/or isolation in refugia. In contrast, comparatively fewer studies have addressed the continent’s environmental heterogeneity and the role played by its geomorphological barriers. In this study, we performed a range‐wide analysis of complete mitogenomes of sable antelope (Hippotragus niger) to explore how these different factors may have contributed as drivers of evolution in South‐Central Africa. Our results supported two sympatric and deeply divergent mitochondrial lineages in west Tanzanian sables, which can be explained as the result of introgressive hybridization of a mitochondrial ghost lineage from an archaic, as‐yet‐undefined, congener. Phylogeographic subdivisions into three main lineages suggest that sable diversification may not have been solely driven by climatic events affecting populations differently across a continental scale. Often in interplay with climate, geomorphological features have also clearly shaped the species’ patterns of vicariance, where the East Africa Rift System and the Eastern Arc Mountains acted as geological barriers. Subsequent splits among southern populations may be linked to rearrangements in the Zambezi system, possibly framing the most recent time when the river attained its current drainage profile. This work underscores how the use of comprehensive mitogenomic datasets on a model species with a wide geographic distribution can contribute to a much‐enhanced understanding of environmental, geomorphological, and evolutionary patterns in Africa throughout the Quaternary.
... This emerging perspective has been reinforced by ongoing research in the Kenyan portions of the Lake Victoria Basin since 2008, which has documented numerous extinct taxa (Rusingoryx atopocranion, Damaliscus hypsodon, Kolpochoerus, and others) in late Pleistocene sediments, including new species or those formerly thought to have disappeared from eastern Africa during the middle Pleistocene (e.g., Tryon et al., 2010Tryon et al., , 2012Tryon et al., , 2016Faith et al., 2011Faith et al., , 2014Faith et al., , 2015Jenkins et al., 2017). These new data show that Homo sapiens in eastern Africa evolved among non-analog faunal communities (e.g., Faith et al., 2016), as has long been recognized for southern Africa (e.g., Klein, 1980). A better understanding of the paleoecology of the extinct species that were a part of these communities is critical to paleoenvironmental and archaeological research. ...
Rusingoryx atopocranion is an extinct alcelaphin bovid from the late Pleistocene of Kenya, known for its distinctive hollow nasal crest. A bonebed of R. atopocranion from the Lake Victoria Basin provides a unique opportunity to examine the nearly complete postcranial ecomorphology of an extinct species, and yields data that are important to studying paleoenvironments and human-environment interaction. With a comparative sample of extant African bovids, we used discriminant function analyses to develop statistical ecomorphological models for 18 skeletal elements and element portions. Forelimb and hin-dlimb element models overwhelmingly predict that R. atopocranion was an open-adapted taxon. However, the phalanges of Rusingoryx are remarkably short relative to their breadth, a morphology outside the range of extant African bovids, which we interpret as an extreme open-habitat adaptation. It follows that even recently extinct fossil bovids can differ in important morphological ways relative to their extant counterparts, particularly if they have novel adaptations for past environments. This unusual phalanx morphology (in combination with other skeletal indications), mesowear, and dental enamel stable isotopes, demonstrate that Rusingoryx was a grassland specialist. Together, these data are consistent with independent geological and paleontological evidence for increased aridity and expanded grassland habitats across the Lake Victoria Basin.
... On the scale of the African Stone Age, various forms of bifacial technology are present in different regions and phases of the MSA, and from its very beginning (see McBrearty and Brooks 2000;McBrearty 2003;Tryon and Faith 2013). Most prominently, bifacial technology with large and carefully shaped points characterizes the Lupemban of central and eastern Africa at numerous sites (McBrearty 1988;Clark 2001;Taylor 2011Taylor , 2016Tryon et al. 2012;Faith et al. 2016). Bifacially flaked points of various morphologies have also been reported from MSA assemblages in the northeastern central African rainforest (Cornelissen 2016), the early Nubian complex of north-eastern Africa (Van Peer et al. 2003;Van Peer and Vermeersch 2007;Van Peer 2016), the long MSA sequences at Mumba, Goda Buticha and other sites in eastern Africa (McBrearty and Brooks 2000;Bretzke et al. 2006;Leplongeon et al. 2018), the Aterian of North Africa (Garcea 2004;Barton et al. 2009;Dibble et al. 2013;Scerri 2013), the Bambatan of Zimbabwe (Armstrong 1931) and throughout MIS 4-2 in West Africa (Chevrier et al. 2018). ...
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Stone artefacts are frequently used to identify and trace human populations in the Paleolithic. Convergence in lithic technology has the potential to confound such interpretations, implying connections between unrelated groups. To further the general theoretical debate on this issue, we first delineate the concepts of independent innovation, diffusion and migration and provide archaeological expectations for each of these processes that can create similarities in material culture. As an empirical test case, we then assess how these different mechanisms play out in both space and time for lithic technology across several scales of the African Stone Age record within the last 300 thousand years (kyr). Our findings show that convergence is neither the exception nor the norm, but a scale-dependent phenomenon that occurs more often for complex artefacts than is generally acknowledged and in many different spatio-temporal contexts of the African record that can crosscut the MSA/LSA boundary. Studies using similarly-looking stone tools to recognize past populations and track human dispersals in the Stone Age thus always need to test for the potential of independent innovation and not assume migration or diffusion a priori.
... Los estudios de fauna son parciales, en muchos casos antiguos y sin un estudio tafonómico completo que permita relacionarla con la ocupación humana, con el territorio, con el tipo de industria, etc. Sin embargo, sí se están realizando estudios de biogeografía que ayudan en esta dirección (Faith et al., 2016), aunque el siguiente paso ha de ser su correlación con las ocupaciones humanas. ...
... At a broad scale, genetic evidence, the geographic distribution of archeological sites, and biogeographic modeling using fossil data suggest an expansion in the geographic range and total population size of H. sapiens in Africa during~30-60 ka. 24,81,82 Direct evidence for changes in population density is rare. What evidence is available includes increased site occupation intensity over time at Nasera and Panga ya Saidi, 16 and in general, the regular use of beads, which can serve as visibly salient signals for communicating affiliation at a distance to non-kin, making them useful for navigating the complex social worlds characteristic of large or dense populations. ...
The Middle to Later Stone Age (MSA/LSA) transition is a prominent feature of the African archeological record that began in some places ~30,000–60,000 years ago, historically associated with the origin and/or dispersal of “modern” humans. Unlike the analogous Middle to Upper Paleolithic transition in Eurasia and associated Neanderthal extinction, the African MSA/LSA record remains poorly documented, with its potential role in explaining changes in the behavioral diversity and geographic range of Homo sapiens largely unexplored. I review archeological and biogeographic data from East Africa, show regionally diverse pathways to the MSA/LSA transition, and emphasize the need for analytical approaches that document potential ancestor‐descendent relationships visible in the archeological record, needed to assess independent invention, population interaction, dispersal, and other potential mechanisms for behavioral change. Diversity within East Africa underscores the need for regional, rather than continental‐scale narratives of the later evolutionary history of H. sapiens.
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Humans evolved in a patchwork of semi-connected populations across Africa 1,2 ; understanding when and how these groups connected is critical to interpreting our present-day biological and cultural diversity. Genetic analyses reveal that eastern and southern African lineages diverged sometime in the Pleistocene epoch, approximately 350–70 thousand years ago (ka) 3,4 ; however, little is known about the exact timing of these interactions, the cultural context of these exchanges or the mechanisms that drove their separation. Here we compare ostrich eggshell bead variations between eastern and southern Africa to explore population dynamics over the past 50,000 years. We found that ostrich eggshell bead technology probably originated in eastern Africa and spread southward approximately 50–33 ka via a regional network. This connection breaks down approximately 33 ka, with populations remaining isolated until herders entered southern Africa after 2 ka. The timing of this disconnection broadly corresponds with the southward shift of the Intertropical Convergence Zone, which caused periodic flooding of the Zambezi River catchment (an area that connects eastern and southern Africa). This suggests that climate exerted some influence in shaping human social contact. Our study implies a later regional divergence than predicted by genetic analyses, identifies an approximately 3,000-kilometre stylistic connection and offers important new insights into the social dimension of ancient interactions.
Site-specific habitat reconstructions in the form of faunal enamel stable carbon and oxygen isotope data allow for a finer assessment of the context of Homo sapiens in eastern Africa. To date, these studies have focused on a small collection of sites within a constrained spatiotemporal scope. Here, I analyse a compilation of faunal stable isotopes from the Kibish Formation and Porc Epic Cave, Ethiopia, and Rusinga and Mfangano Islands, Karungu, Lukenya Hill, and Panga ya Saidi, Kenya. New data for primate and notably Homo sapiens at Porc Epic are presented. Faunal isotope data indicate that the Lake Victoria and northern Lake Turkana basins were dominated by open grasslands between ~ 105 ka and 50 ka. Sites near the Ethiopian Rift and closer to the coast were at least in part buffered from the environmental changes that occurred further inland. In the following period, ~ 49 ka – 20 ka, inland sites see more wooded conditions while Panga ya Saidi at the coast becomes drier. This compilation provides evidence for spatial and temporal trends in local habitats necessary for understanding the mechanisms through which human populations exchanged genes, ideas, and behaviours during the Late Pleistocene.
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Glossina pallidipes is the main vector of animal African trypanosomiasis and a potential vector of human African trypanosomiasis in eastern Africa where it poses a large economic burden and public health threat. Vector control efforts have succeeded in reducing infection rates, but recent resurgence in tsetse fly population density raises concerns that vector control programs require improved strategic planning over larger geographic and temporal scales. Detailed knowledge of population structure and dispersal patterns can provide the required information to improve planning. To this end, we investigated the phylogeography and population structure of G. pallidipes over a large spatial scale in Kenya and northern Tanzania using 11 microsatellite loci genotyped in 600 individuals. Our results indicate distinct genetic clusters east and west of the Great Rift Valley, and less distinct clustering of the northwest separate from the southwest (Serengeti ecosystem). Estimates of genetic differentiation and first-generation migration indicated high genetic connectivity within genetic clusters even across large geographic distances of more than 300 km in the east, but only occasional migration among clusters. Patterns of connectivity suggest isolation by distance across genetic breaks but not within genetic clusters, and imply a major role for river basins in facilitating gene flow in G. pallidipes. Effective population size (Ne) estimates and results from Approximate Bayesian Computation further support that there has been recent G. pallidipes population size fluctuations in the Serengeti ecosystem and the northwest during the last century, but also suggest that the full extent of differences in genetic diversity and population dynamics between the east and the west was established over evolutionary time periods (tentatively on the order of millions of years). Findings provide further support that the Serengeti ecosystem and northwestern Kenya represent independent tsetse populations. Additionally, we present evidence that three previously recognized populations (the Mbeere-Meru, Central Kenya and Coastal “fly belts”) act as a single population and should be considered as a single unit in vector control.
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The Central African Middle Stone Age (MSA) is very poorly understood in comparison to the higher-resolution records of East and southern Africa. Severe taphonomic barriers to the construction of reliable chrono-stratigraphic, techno-typological, and paleoenvironmental frameworks continue to inhibit any nuanced understanding of post-MIS 6 technological change and behavioral adaptations. This chapter reviews existing knowledge of the earlier part of MIS 6-2 in the rainforests and woodlands of Central Africa from the perspective of the MSA Lupemban industry. Archaeological sequences on the woodland fringes of the Congo Basin bear witness to a technological shift characterized by the replacement of hand-held (Mode 2) Acheulean implements by distinctive tools suitable for hafting (Mode 3). While Mode 2 technology is absent from the contemporary equatorial rainforest zone, Mode 3 tools, including bifacial lanceolate points, core axes , and backed blades , are found across the region as the MSA Lupemban industry. As the earliest sustained archaeological signature in Central Africa, U-series dates of ~260 ka for the industry at Twin Rivers (Zambia) suggest the initial dispersal of pre-sapiens hominins into the equatorial forest belt during MIS 7. The development of sophisticated composite technologies in this ecological context bears directly upon current debates about the origins of behavioral and cognitive complexity in archaic Homo sapiens . In this chapter, current knowledge of the Lupemban is explored systematically with special reference to the hypothesis that it represents a late Middle Pleistocene rainforest and woodland adapted technology. A new site database is drawn upon to critically reassess the industry’s geographical distribution, stratigraphic integrity, chronological position, and paleoenvironmental associations, from which its potential evolutionary significance is reconsidered.
The various genetic systems (mitochondrial DNA, the Y-chromosome and the genome-wide autosomes) indicate that Africa is the most genetically diverse continent in the world and the most likely place of origin for anatomically modern humans. However, where in Africa modern humans arose and how the current genetic makeup within the continent was shaped is still open to debate. Here, we summarize the debate and focus especially on the maternally inherited mitochondrial DNA (mtDNA) and a recently revised chronology for the African mtDNA tree. We discuss the possible origin of modern humans in southern, eastern or Central Africa; the possibility of a migration from southern to eastern Africa more than 100 ka, carrying lineages within mtDNA haplogroup L0; the evidence for a climate-change-mediated population expansion in eastern Africa involving mtDNA haplogroup L3, leading to the “out-of-Africa” migration around 70–60 ka; the re-population of North Africa from the Near East around 40–30 ka suggested by mtDNA haplogroups U6 and M1; the evidence for population expansions and dispersals across the continent at the onset of the Holocene ; and the impact of the Bantu dispersals in Central, eastern and southern Africa within the last few millennia.
Late Pleistocene sedimentary, biogeochemical, and fossil data from the Lake Victoria basin (the largest lake in Africa) suggest that its reduction or desiccation during periods of increased aridity repeatedly facilitated the dispersal of C4 grassland ecosystems across the basin. Archaeological evidence from Middle Stone Age and Later Stone Age sites suggest that human groups diffused into the basin during intervals of declining lake levels, likely tracking the movement of the dense and predictable resources of shoreline environments, as well as the dense but less predictable C4 grass grazing herbivores. Repeated cycles of lake expansion and contraction provide a push–pull mechanism for the isolation and combination of populations in Equatorial Africa that may contribute to the Late Pleistocene human biological variability suggested by the fossil and genetic records. Latitudinal differences in the timing of environmental change between the Lake Victoria basin and surrounding regions may have promoted movements across, within, and possibly out of Africa.
Digital airgun seismic reflection data acquired on Lake Victoria during the 1995 IDEAL field program suggest evidence of major lake level fluctuations in the mid-late Quaternary. At least five discrete depositional packages can be clearly delineated in the upper 40–50 m of the sedimentary section, and are defined on the basis of stratal relationships and marked variations in acoustic character. The uppermost sequence boundary is observed lake-wide as a high-amplitude reflection, and is overlain by a very low-amplitude 3–9 m thick sequence. The high-amplitude reflection correlates with a soil horizon observed in sediment cores, which together suggest complete desiccation of the lake near the end of the Pleistocene. The lowermost sequence observed on the single-channel data is thickest on the far western margin of the lake, and thins dramatically to the east, the site of the modern depocenter. The timing of deposition of the older sequences and of the shift of the basin depocenter from west to east is unconstrained, but likely coincided with the uplift of the western rift shoulder that occurred during the mid-late Pleistocene. Multichannel seismic data show that unlike the extremely smooth, flat, and continuous nature of the lake floor, the basement topography underlying the lacustrine sediments is highly variable and irregular. Basement is typically observed between about 200 and 600 m below the modern lake surface on most seismic profiles. During this survey, approximately 1950 km of single channel and multichannel seismic reflection data were acquired in a series of transects across broad reaches of the lake basin.