Earliest human occupations at Dmanisi (Georgian Caucasus) dated to 1.85–1.78 Ma

Abstract

The early Pleistocene colonization of temperate Eurasia by Homo erectus was not only a significant biogeographic event but also a major evolutionary threshold. Dmanisi's rich collection of hominin fossils, revealing a population that was small-brained with both primitive and derived skeletal traits, has been dated to the earliest Upper Matuyama chron (ca. 1.77 Ma). Here we present archaeological and geologic evidence that push back Dmanisi's first occupations to shortly after 1.85 Ma and document repeated use of the site over the last half of the Olduvai subchron, 1.85-1.78 Ma. These discoveries show that the southern Caucasus was occupied repeatedly before Dmanisi's hominin fossil assemblage accumulated, strengthening the probability that this was part of a core area for the colonization of Eurasia. The secure age for Dmanisi's first occupations reveals that Eurasia was probably occupied before Homo erectus appears in the East African fossil record.

Full text

Earliest human occupations at Dmanisi
(Georgian Caucasus) dated to 1.85–1.78 Ma
Reid Ferring
a,1
, Oriol Oms
b
, Jordi Agustí
c
, Francesco Berna
d,2
, Medea Nioradze
e
, Teona Shelia
e
, Martha Tappen
f
,
Abesalom Vekua
e
, David Zhvania
e
, and David Lordkipanidze
e,1
a
Department of Geography, University of North Texas, Denton, TX 76203;
b
Department of Geology, Universitat Autònoma de Barcelona, 08193 Bellaterra,
Spain;
c
Institute of Human Paleoecology and Social Evolution, Catalan Institute for Research and Advanced Studies, 43005 Tarragona, Spain;
d
Department
of Earth Sciences “Ardito Desio,”Università degli Studi di Milano, 20133 Milan, Italy;
e
Georgian National Museum, 0105 Tbilisi, Georgia; and
f
Department of Anthropology, University of Minnesota, Minneapolis, MN 55455
Contributed by David Lordkipanidze, April 28, 2011 (sent for review February 27, 2011)
The early Pleistocene colonization of temperate Eurasia by Homo
erectus was not only a significant biogeographic event but also
a major evolutionary threshold. Dmanisi’s rich collection of homi-
nin fossils, revealing a population that was small-brained with
both primitive and derived skeletal traits, has been dated to the
earliest Upper Matuyama chron (ca. 1.77 Ma). Here we present
archaeological and geologic evidence that push back Dmanisi’s
first occupations to shortly after 1.85 Ma and document repeated
use of the site over the last half of the Olduvai subchron, 1.85–1.78
Ma. These discoveries show that the southern Caucasus was occu-
pied repeatedly before Dmanisi’s hominin fossil assemblage accu-
mulated, strengthening the probability that this was part of a core
area for the colonization of Eurasia. The secure age for Dmanisi’s
first occupations reveals that Eurasia was probably occupied be-
fore Homo erectus appears in the East African fossil record.
Lower Paleolithic
|
paleoanthropology
In recent years, paleoanthropologists have intensified the search
for evidence for one of the most significant events in human
evolution: the dispersal of early Homo from Africa to Eurasia.
That Homo erectus was the first hominin to leave Africa and
colonize Eurasia has been accepted by paleoanthropologists for
over a century. However, models that linked the first African
exodus to increases in stature, encephalization, and technolog-
ical advances (1–3) have been challenged by discoveries at
Dmanisi (4). Dmanisi is located in the southern Georgian Cau-
casus (41°20’10”N and 44°20’38”E), 55 km southwest of Tbilisi
(Fig. 1). The prehistoric excavations at Dmanisi have been
concentrated in the central part of a promontory that stands
above the confluence of the Masavera and Pinasauri rivers.
Lower Pleistocene deposits are preserved below the Medieval
ruins and above the 1.85-Ma Masavera Basalt (Fig. 1). Those
excavations yielded numerous exceptionally preserved hominin
fossils. Stratigraphic studies revealed that that all of those
hominin fossils are from sediments of stratum B, dated to ca.
1.77 Ma, based on
40
Ar/
39
Ar dates, paleomagnetism, and pale-
ontologic constraints (4, 5). In the main excavations, no artifacts
or fossils have been found in the older stratum A deposits, which
conformably overlie the Masavera Basalt. Dmanisi’s rich col-
lection of hominin fossils reveals a population with short stature
and cranial capacities of only 600–775 cc (4–9). Artifact as-
semblages are all indicative of a Mode I technology, with no
bifacial tools (10). Recently completed testing in the M5 sector
of Dmanisi has yielded in situ artifacts and faunal remains from
the older stratum A deposits, pushing back Dmanisi’s occupa-
tional history into the upper Olduvai subchron. These findings
indicate that African and Eurasian theaters for the evolution of
early humans had been established even earlier than thought
previously, with implications for the age of dispersals not only
within Eurasia but also between Eurasia and Africa. This article
describes the results of these investigations at Dmanisi and their
implications for future research.
Results
Geology and Geochronology of the M5 Section. The M5 test unit is
situated 85 m west of the block 1 excavations (Fig. 1). A narrow
geologic trench and then a 2 ×2-m test unit exposed 6.2 m of
deposits overlying the Masavera Basalt (Fig. 2). This thick expo-
sure of conformably bedded deposits is divided into nine strati-
graphic units, named A1 to B5 (SI Text and Table S1). At M5, as in
the main excavation areas, stratum A deposits display normal
geomagnetic polarity and are correlated with the upper Olduvai
subchron. The stratum B deposits all display reverse polarity and
are correlated with the earliest Upper Matuyama chron. Stratum
A1, which conformably overlies the Masavera Basalt, is a massive
to weakly laminated bed of silt and fine sand-sized black volcanic
glass shards and tears, with rare obsidian granules. The only
pedogenic features of these deposits are rare carbonate filaments.
These sediments and the Masavera Basalt contain olivine, in-
dicating rapid deposition with little weathering (SI Text). Here,
and across the site, the A1a ashes quickly filled the lowest
depressions on the irregular basalt surface. A1b deposits are glass
sands and fine obsidian granules, indicative of erosional sorting of
A1 sediments from a higher position.
Stratum A2 is a black, indurated fine to medium silt ash. These
sediments show evidence of moderate pedogenesis, including
many carbonate filaments, veins and concretions, and thin clay
and carbonate pore linings (Table S2). Micromorphological
analysis of stratum A2 in the main excavations record similar
pedogenic features (11). The substrata of A2 lack olivine and
contain clay minerals supporting the soil morphological evidence
for cyclic deposition and stability; however, the clear contacts
between the substrata indicate serial ash falls that promoted the
stratification of artifacts in this unit. Strata A3 and A4 are firm
dark reddish brown silt ashes with common carbonate filaments
and pore linings.
The weak to moderate soil development in each of the stratum
A deposits is illustrated by the weak structure, high porosity, and
lack of argillic (clay-enriched) horizons. All of the strata A soils
here have pedogenic carbonates, indicating a drier setting and
probably slower rates of weathering. However, above stratum
A2a, those carbonate fabrics are limited to filaments, pore linings,
and rhizomorphs; these are Stage I soil carbonates (12), indicating
brief periods of surface stability and weathering.
Author contributions: R.F. and D.L. designed research; R.F., O.O., J.A., F.B., M.N., T.S., M.T.,
A.V., and D.Z. performed research; R.F., O.O., F.B., and M.T. analyzed data; M.N., T.S., and
D.Z. conducted fieldwork; and R.F. wrote the paper.
The authors declare no conflict of interest.
See Commentary on page 10375.
1
To whom correspondence may be addressed. E-mail: ferring@unt.edu or dlordkipanidze@
museum.ge.
2
Present address: Archaeology Department, Boston University, Boston, MA 02215.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.
1073/pnas.1106638108/-/DCSupplemental.
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Accordingly, the entire suite of sediments in stratum A can be
viewed as a cumulic sedimentary profile consisting of a series of
ash fall events, alternating and overprinted by weakly developed
soils stabilized by grasses, a few shrubs, and rare trees (13). Al-
though stratum A deposits also accumulated in the areas of main
excavations, they experienced more erosion, leaving thinner and
sometimes incomplete sections. In those main excavations, all of
the hominin fossils and thousands of mammal fossils have been
recovered from reversely polarized strata B1x–B1z pipe and gully
sediments (4, 10), which are notably absent at the A4/B1 contact
in the M5 section (Fig. 2).
The M5 paleomagnetic data are in accord with the results of
previous studies in the main excavation areas (4, 5) as well as
lithostratigraphic correlation of the deposits between the two areas
of the site (Fig. 2 and Fig. S1). Although a single sample from the
top of stratum A exhibited normal inclination and reversed decli-
nation (i.e., south directed but downward dipping), this sample
is not sufficient to indicate the Olduvai/Upper Matuyama transi-
tion. Here, the magnetostratigraphy and
40
Ar/
39
Ar dating of the
Masavera Basalt (4) constrain the age of stratum A deposits and
the recently discovered artifact and faunal assemblages between
1.85 Ma and 1.78 Ma, the age of the Olduvai/Upper Matuyama
reversal (14). Moreover, the lowest artifacts, in stratum A2a, are
separated from the Masavera Basalt by the unweathered stratum
A1 ashes, showing that these artifacts must be close in age to the
basalt, i.e., just after 1.85 Ma.
Archaeological Assemblages. Excavations at M5 produced a total of
122 lithic artifacts, including 49 from stratum B (SI Text and
Tables S2 and S3). The 73 artifacts from stratum A were re-
covered over a vertical range of ∼1.5 m in strata A2a–A4a (Fig. 2
and Table 1). The bones were all unidentifiable but included 32
fragments from A4 and two long bone fragments from A2a; a
hyaena coprolite was recovered from A3. All of the bones were
quite weathered, in contrast to the well-preserved bones from the
rapidly deposited pipe and gully fills in the main excavation (5,
15). These M5 faunas and artifacts record serial living surfaces
as supported by the stratigraphic separations, fine-grained sedi-
ments, and associated soil features (SI Text and Table S1). The
location of M5 and the stratigraphic range of the recently discov-
ered finds emphasize that the site-wide spatial and stratigraphic
distribution of artifacts and faunas at Dmanisi is both extensive and
dense. This finding reveals that the site was inhabited many times,
implying an established, apparently quite mobile population.
The stratum A artifact assemblage is dominated by flakes but
includes cores and core/choppers (Table 1 and Fig. 3). No
retouched tools were found, but these are rare in the larger
samples of artifacts from the Dmanisi excavations (10). Of the 73
flakes in stratum A, 48 are complete or proximal fragments with
platforms. The size and raw materials of distal flake fragments
indicate that breakage has not unduly inflated the sample size. The
dorsal scar patterns on the flakes are predominantly unidirectional
(Fig. 3 B–E). However, four of the larger flakes, each of a different
raw material, reveal core rotation to produce thick flakes with one
sharp edge (Fig. 3 F–G). Dorsal cortex forms indicate that the
tuffs were principally acquired from Cretaceous bedrock exposed
near the site, whereas the other raw materials were well-rounded
alluvial cobbles from more distant channel and/or terrace sources.
The one complete core, mentioned above, has unidirectional
flaking from a roughly facetted platform of nearly 90°. The four
core fragments are all tuff and have flake scars on two or three
surfaces. Two core/choppers with bifacial platforms, one of green
tuff and the other basalt, were recovered in stratum A2b.
The artifacts from stratum A differ from those in stratum B in
terms of raw material selection and reduction intensity (Table 1
and Tables S3 and S4). Compared with stratum B raw materials,
stratum A artifacts have a high proportion of red tuff, which is very
rare in the materials from blocks 1 and 2. The stratum A sample
has no andesite and only two pieces of basalt; excluding tuffs,
those materials dominate artifacts from stratum B, both in M5
and the main excavation areas (10). Three flakes of rhyodacite,
a black, near-glassy material, are the first reported incidences of
this material recovered at Dmanisi (Fig. 3F). This material has
been found in outcrops ∼15 km west of the site and as cobbles in
the Masavera River gravels. A notable difference between the
strata A and B assemblages is that only 29% of the stratum A
flakes have dorsal cortex, compared with 71% in stratum B.
Debitage from stratum B in the main excavations has a similarly
high proportion of cortical pieces (10), suggesting that, during the
earlier occupations, either cores were more intensively reduced or
selected flakes were made elsewhere and carried to the site.
Larger samples, with good prospects for refitting, will allow
comparisons of Dmanisi’s earliest assemblages with those from
contemporary and earlier African sites. Progress in the study of
Mode I industries (16–18) reveals knapping skills that were nei-
ther simplistic nor static and that raw material quality was a major
factor in technological variation among these early assemblages.
Discussion
The stratified lithic assemblages at M5 affirm that the site was
occupied repeatedly during the late Olduvai subchron, ca. 1.85–
1.78 Ma. The stratified finds in stratum B deposits, including all
of the Dmanisi hominins, extend the range of Dmanisi’s occu-
pations to ca. 1.77 Ma, with a minimum age of ca. 1.76 Ma, based
on stratigraphic correlation of Dmanisi sediments to the nearby
Zemo Orozmani locality (4). It is now clear that Dmanisi was
occupied repeatedly over an interval of as much as 80 ka,
strongly suggesting a sustained regional population. The recently
discovered data show that Dmanisi was occupied at the same
time as, if not before, the first appearance of Homo erectus in
east Africa (1, 19). This scenario has important implications for
understanding the origins, dispersal, and biological variability of
our first cosmopolitan ancestor. The case for a possible Eurasian
Fig. 1. Dmanisi promontory and map of excavation areas. Sediments be-
neath Medieval ruins in blocks 1 and 2 yielded Dmanisi’s assemblage of early
Homo fossils, dated to ca. 1.77 Ma. The recent discovery of stratified stone
artifacts in Unit M5, push back even farther the age of Dmanisi’sfirst
occupations to the late Olduvai subchron, 1.85–1.78 Ma.
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origin of Homo erectus (1, 20) is increasingly supported by chro-
nometric and biogeographic evidence.
The initial occupations of Dmanisi are possibly older than the
first appearance of Homo erectus in East Africa. With the ex-
ception of the surface find of a human occipital fragment (KNM-
ER 2598) at Koobi Fora, the earliest appearance of African Homo
erectus is considered to be ca. 1.78 Ma (21) but probably is closer
to 1.65 Ma (22). The newly dated horizons at Dmanisi also ac-
commodate the increasingly older ages documented for hominin
fossils in both eastern and western Eurasia. Human presence in
China is dated to ca. 1.7 Ma (23, 24), and Homo erectus fossils
in Java are dated to ca. 1.6 Ma (25). The earliest occupations of
Flores are now dated in excess of 1 Ma (26). The record of col-
onization of Western Europe is also >1 Ma (27–29). The in-
creasingly older age of Eurasian occupations by early Homo is
important for defining patterns of dispersal and adaptations in
environmental context (3, 30–32).
The possibility that Homo erectus evolved in Eurasia provokes
two obvious corollaries. The first, that a more primitive ancestor
arrived from Africa more than ca. 1.85 Ma (1, 19), is consistent
with anatomical analyses of both the Dmanisi fossils (17) and
those of Homo floresiensis (33). The second, that Homo erectus
Table 1. Lithic artifacts from M5
Raw material
Stratum A Stratum B Total, %
A2a A2b A2c A3 A4 B1a B1c B2 A B
Red tuff 8 6/2 6 2 2 1 35.6 2.0
Brown tuff 1 13/1 4/2 3 1 32.9 2.0
Tan tuff 4 5 1 1/1 1 8/3 13.7 28.6
Green tuff 2/1 2 3 6.8 6.1
Vitreous green tuff 1 4 10.2
Rhyolite 2 1 1 1 4.1 2.0
Andesite −/1 2/1 1/4 18.4
Rhyodacite 2 1 4.1
Basalt −/1 1 −/1 9/2 2.7 24.5
Aplite 1 2.0
Diorite 1 2.0
Chert 1 2.0
Total 11 28/5 11/2 11 6 2/2 6/2 28/9 73 49
Single digits are counts of flakes; n/nshows counts of flakes/cores.
Fig. 2. Stratigraphy and archaeological discoveries in Unit M5. The 6.2-m section shows that Dmanisi’s sedimentary/geomagnetic record spans the late
Olduvai subchron (stratum A) through earliest Upper Matuyama chron (stratum B). Test excavations recovered 73 stone artifacts from strata A2–A4, which are
firmly dated to 1.85–1.78 Ma.
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may have migrated back to Africa, receives support from the
conclusion that Homo erectus and Homo habilis survived as
contemporaries after the appearance of the former in the East
African fossil record (34).
Although the presence of hominins beyond East Africa as
early as 1.9 Ma is documented at Ain Hanech in North Africa
(35), claims for occupations of that age or somewhat earlier in
Israel (36) and Pakistan (37, 38) are based on lithic materials
collected from gravels. Although it seems ever more probable
that hominins were in Eurasia before Dmanisi was first occupied,
well-dated materials in unequivocal contexts are required. Both
the age and evolutionary affiliations of the earliest hominins to
arrive in Eurasia remain to be determined by new discoveries.
This important, unresolved issue in human evolution is a call for
the aggressive survey for evidence of even earlier colonists.
Methods
For magnetostratigraphic study, one to four samples were obtained from each
studied horizon. All samples were collected by hand after exposure of fresh
sediment that was oriented with a magnetic compass. Remanent magneti-
zation measurements were carried out with a 2G Enterprises high-resolution
cryogenic magnetometer with superconducting quantum interference device
(SQUID) sensors at the Paleomagnetism Laboratory of the Scientific Technical
Services of Barcelona University. After measuring the natural remanent
magnetization, a stepwise demagnetization was applied at least to one
specimen per horizon. Demagnetization of 99 samples was done thermally
because it was observed to be an efficient method in previous studies (4, 10).
Samples were demagnetized from room temperature to 600 °C, generally
with an 8- to 10-step protocol. Both normal and reverse polarities are found
along the section. Reverse polarity levels display a low-temperature second-
ary component, which was completely removed at 200 °C. For all of the
studied levels, a high-temperature component (between 200° and 600 °C)
was used to calculate a primary component, considered a characteristic
remanent magnetization (see declination and inclination values in Fig. 2). See
also SI Methods.
ACKNOWLEDGMENTS. We thank Gilberto Artioli, Giuseppe Corti, Alberto
Agnelli, and Michael Rhodes for conducting and/or interpreting the miner-
alogical analyses, and Gocha Kiladze and the entire Dmanisi team for their
fine research. We also thank Bernard Wood, Jay Quade, and Philip Rightmire
for helpful comments on the manuscript. This research was supported
by National Science Foundation Grants BCS-0324567 and BCS-1025245, the
L. S. B. Leakey Foundation, the Georgian National Science Foundation, a Rolex
Award for Enterprise, BP Georgia, the Fundación Duques de Soria, Spanish
Ministry of Science and Innovation Projects GENCAT09-324 and MICIN09-7986,
and the Italian Ministry of Foreign Affairs.
1. Dennell R, Roebroeks W (2005) An Asian perspective on early human dispersal from
Africa. Nature 438:1099–1104.
2. Antón SC, Swisher CC, III (2004) Early dispersals of Homo from Africa. Annu Rev
Anthropol 33:271–296.
3. Antón SC, Leonard WR, Robertson ML (2002) An ecomorphological model of the
initial hominid dispersal from Africa. J Hum Evol 43:773–785.
4. Gabunia L, et al. (2000) Earliest Pleistocene hominid cranial remains from Dmanisi,
Republic of Georgia: Taxonomy, geological setting, and age. Science 288:1019–1025.
5. Lordkipanidze DL, et al. (2007) Postcranial evidence from early Homo from Dmanisi,
Georgia. Nature 449:305–310.
6. Rightmire GP, Lordkipanidze D, Vekua A (2006) Anatomical descriptions, comparative
studies and evolutionary significance of the hominin skulls from Dmanisi, Republic of
Georgia. J Hum Evol 50:115–141.
7. Gabunia L, et al. (2002) Discovery of a new hominid at Dmanisi (Transcaucasia,
Georgia) (Translated from French). C R Palevol 1:243–253.
8. Vekua A, et al. (2002) A new skull of early Homo from Dmanisi, Georgia. Science 297:
85–89.
9. Lordkipanidze D, et al. (2005) Anthropology: The earliest toothless hominin skull.
Nature 434:717–718.
10. de Lumley H, et al. (2005) Pre-Oldowan lithic industries from the early Pleistocene site
of Dmanisi in Georgia (Translated from French). Anthropologie 109:1–182.
11. Mallol C (2004) Micromorphological Observations from the Archaeological Sediments
of ‘Ubeidiya (Israel), Dmanisi (Georgia) and Gran Dolina-TD10 (Spain) for the
Reconstruction of Hominid Occupation Contexts. PhD thesis (Harvard Univ,
Cambridge, MA).
12. Gile LH, Peterson FF, Grossman RB (1966) Morphological and genetic sequences of
carbonate accumulation in desert soils. Soil Sci 101:347–360.
13. Messager E, Lordkipanidze D, Kvavadze E, Ferring CR, Voinchet P (2010) Palaeoenviron-
mental reconstruction of Dmanisi Site (Georgia) based on paleobotanical data. Quat Int
223-224:20–27.
14. Horng C-S, et al. (2002) Astronomically calibrated ages for geomagnetic reversals
within the Matuyama Chron. Earth Planets Space 54:679–690.
15. Tappen M, et al. (2007) Are You In or Out (of Africa)? Breathing Life into Fossils:
Taphonomic Studies in Honor of C. K. Brain, eds Pickering TR, Schick K, Toth N (Stone
Age Institute Press, Bloomington, IN), pp 119–135.
16. Roche H, et al. (1999) Early hominid stone tool production and technical skill 2.34 Myr
ago in West Turkana, Kenya. Nature 399:57–60.
17. Braun DR, Hovers E (2009) Introduction: Current issues in Oldowan research.
Interdisciplinary Approaches to the Oldowan, eds Hovers E, Braun DR (Springer,
Dordrecht, The Netherlands), pp 1–14.
18. Carbonell E, Sala R, Barsky D, Celiberti V (2009) From homogeneity to multiplicity: A
new approach to the study of Archaic stone tools. Interdisciplinary Approaches to the
Oldowan, eds Hovers E, Braun DR (Springer, Dordrecht, The Netherlands), pp 25–37.
19. Rightmire GP, Lordkipanidze D (2009) Comparisons of Early Pleistocene skulls from East
Africa and the Georgian Caucasus: Evidence bearing on the origin and systematics of
Fig. 3. Lithic artifacts from stratum A deposits at Dmanisi. These flakes (A–G), all from stratum A2 (Fig. 2), were recovered from two of the five occupation
horizons defined thus far in the 1.85- to 1.78-Ma deposits in the M5 unit. Although simple unidirectional flaking is dominant (B–E), three of these pieces have
scar patterns showing core rotation to permit removal of large flakes with sharp edges (A,F, and G). (Drawn by O. Bar-Yosef, Department of Anthropology,
Harvard University, Cambridge, MA.)
Ferring et al. PNAS
|
June 28, 2011
|
vol. 108
|
no. 26
|
10435
ANTHROPOLOGY SEE COMMENTARY

genus Homo.The First Humans, Origins and Early Evolution of the Genus Homo, eds
Grine FE, Fleagle JG, Leakey RE (Springer, Dordrecht, The Netherlands), pp 39–48.
20. Morwood MJ, Jungers WL (2009) Conclusions: Implications of the Liang Bua
excavations for hominin evolution and biogeography. J Hum Evol 57:640–648.
21. Gathogo PN, BrownFH (2006) Revised stratigraphy of Area 123, KoobiFora, Kenya, and
new age estimates of its fossil mammals, including hominins. J Hum Evol 51:471–479.
22. Asfaw B, et al. (2002) Remains of Homo erectus from Bouri, Middle Awash, Ethiopia.
Nature 416:317–320.
23. Zhu RX, et al. (2004) New evidence on the earliest human presence at high northern
latitudes in northeast Asia. Nature 431:559–562.
24. Zhu RX, et al. (2008) Early evidence of the genus Homo in East Asia. J Hum Evol 55:
1075–1085.
25. Larick R, et al. (2001) Early Pleistocene
40
Ar/
39
Ar ages for Bapang Formation hominins,
Central Jawa, Indonesia. Proc Natl Acad Sci USA 98:4866–4871.
26. Brumm A, et al. (2010) Hominins on Flores, Indonesia, by one million years ago.
Nature 464:748–752.
27. Carbonell E, et al. (2008) The first hominin of Europe. Nature 452:465–469.
28. Oms O, et al. (2000) Early human occupation of Western Europe: Paleomagnetic dates
for two Paleolithic sites in Spain. Proc Natl Acad Sci USA 97:10666–10670.
29. Arzarello M, et al. (2007) Evidence of earliest human occurrence in Europe: The site of
Pirro Nord (Southern Italy). Naturwissenschaften 94:107–112.
30. Bettis EA, 3rd, et al. (2009) Way out of Africa: Early Pleistocene paleoenvironments
inhabited by Homo erectus in Sangiran, Java. J Hum Evol 56:11–24.
31. Roebroeks W (2001) Hominid behavior and the earliest occupation of Europe: An
exploration. J Hum Evol 41:437–461.
32. Agustí J, Blain H-A, Cuenca-Bescós G, Bailon S (2009) Climate forcing of first hominid
dispersal in Western Europe. J Hum Evol 57:815–821.
33. Brown P, et al. (2004) A new small-bodied hominin from the Late Pleistocene of
Flores, Indonesia. Nature 431:1055–1061.
34. Spoor F, et al. (2007) Implications of new early Homo fossils from Ileret, east of Lake
Turkana, Kenya. Nature 448:688–691.
35. Sahnouni M, et al. (2002) Further research at the Oldowan site of Ain Hanech, North-
eastern Algeria. J Hum Evol 43:925–937.
36. Ron H, Levi S (2001) When did hominids first leave Africa? New high-resolution
magnetostratigraphy from the Erk-el-Ahmar Formation, Israel. Geology 29:887–890.
37. Dennell RW, Rendell HM, Hailwood E (1988) Late Pliocene artefacts from Northern
Pakistan. Cur Anthro 29:495–498.
38. Dennell R (2009) The Paleolithic Settlement of Asia (Cambridge Univ Press,
Cambridge, U.K.).
10436
|
www.pnas.org/cgi/doi/10.1073/pnas.1106638108 Ferring et al.