nd
os
ul
.D
ersi
r e
ficio
atio
es,
f Va
acc
mains from the mainstream of discussions concerning the
emergence of Homo sapiens. Since then, a hominid mandible
about 1 million years ago (Pickering, 1961; Mac Intyre et al.,
The lower fossiliferous unitdwhich corresponds to Mehl-
man’s Beds A, B, and C, or red soilsdconsists of over 3 m
artifacts overlie the massive clay. Overlying these conglomer-
ates, small- to medium-sized stromatolites and oncolites have
been observed locally in a sandy matrix. The conglomerates
are more extensively covered by a highly weathered volcanic
* Corresponding author. Tel.: þ34 916332161; fax: þ34 913946008.
E-mail address: manueldr@ghis.ucm.es (M. Domı´nguez-Rodrigo).
Available online at www.sciencedirect.com
Journal of Human Evolutioand occipital fragments have been discovered (Mehlman,
1989; Brauer and Mabulla, 1996). Recently a new frontal
bone was retrieved from the lake sediments in association
with a core and flake industry classified within the early
MSA (Middle Stone Age) tradition (Domı´nguez-Rodrigo
et al., 2007). All these specimens come from the areas of
Northeast Bay and West Bay into which the fossiliferous Eyasi
region can be divided (Mehlman, 1987, 1989; Fig. 1).
Lake Eyasi is an asymmetric lacustrine basin in relation to
the Tanzanian Divergence Zone of the Gregory Rift. It is situ-
ated south of the Crater Highlands and is formed by a tectonic
step constituted by the escarpment resulting from a northwest
fault. A flexure zone can be documented to the east where
the Proterozoic and Archaean basement outcrops (Ebinger
et al., 1997). The Eyasi lake basin adopted its modern form
of sandy clays and red or brown zeolitic and edaphic clays.
These clays are well-cemented and show evidence of extensive
bioturbation consisting of sandy rootcasts. These clays are
locally tuffaceous and orange, and form a hardground surface
on the top. The lower fossiliferous unit has yielded abundant
fossil remains of typical savanna fauna, among which hippo-
potamus remains are abundant. The layers in this unit under-
went some folding after their deposition.
The upper fossiliferous unitdMehlman’s capping horizond
is more heterogeneous. At the base of the unit, over the
erosive contact with the lower fossiliferous unit, are encrusted
stromatolites with medium to large size bioherms. Then,
approximately 1.5 m of green, massive, slightly sandy clays
overlie the stromatolites. Approximately 0.3e0.4 m of con-
glomerates containing well-preserved fossils and lithicThe Kohl Larsen expeditions to Lake Eyasi (Tanzania) in
the early 20th century discovered the remains of three hominid
skulls, one of them fairly complete (Eyasi 1), of unknown
Middle Pleistocene age (Mehlman, 1984, 1989). The lack of
chronological control resulted in the exclusion of these re-
strate horst relief. Previous geological test pits in these deposits
yielded a maximum thickness of 11.5 m before reaching a vitre-
ous trachitic tephra at the bottom of the sequence (Mehlman,
1989). Our study of the upper beds, where most fossils are lo-
cated, indicate that there are two fossiliferous units (Fig. 2).News a
A new archaic Homo sapiens f
M. Domı´nguez-Rodrigo
a,
*
, A. Mab
J. Rink
e
, P. Bushozi
b
,F
a
Department of Prehistory, Complutense Univ
b
Archaeology Unit, University of Da
c
Fundacio´n Conjunto Paleontolo´gico de Teruel, Edi
d
Department of Medical Physics and Applied Radi
e
School of Geography and Earth Scienc
f
Department of Prehistory and Archaeology, University o
Received 22 July 2007;
Keywords: Early Homo sapiens; Hominid; Frontal bone; Middle Stone Age
Introduction and general stratigraphy0047-2484/$ - see front matter  2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.jhevol.2008.02.002Views
sil from Lake Eyasi, Tanzania
la
b
, L. Luque
c
, J.W. Thompson
d
,
ı
´
ez-Martin
f
, L. Alcala
c
ty, Prof. Aranguren s/n, 28040 Madrid, Spain
s Salaam, Dar es Salaam, Tanzania
Dino´polis, Avda. Sagunto s/n, 44002 Teruel, Spain
n Sciences, McMaster University, Ontario, Canada
McMaster University, Ontario, Canada
lladolid, Plaza del Campus s/n, 47011 Valladolid, Spain
epted 1 February 2008
1974; Ebinger et al., 1997; Foster et al., 1997). The fossilifer-
ous outcrops are situated at the north side of a Proterozoic sub-
n 54 (2008) 899e903

of900 M. Domı´nguez-Rodrigo et al. / Journaltuff. Finally, about 1 m of clayey sands complete the sequence.
In the West Bay, this sequence appears condensed, reworked,
and with few outcrops. In the North Bay, the sequence is more
extensively exposed. This bed is covered with recent sandy
deltaic, eolian, and lacustrine deposits.
The distribution of the fossiliferous sediments and the geo-
morphological study of the eastern side of the lake basin indi-
cate that the red soils (lower fossiliferous unit) occur over
a large area, and correspond to a lacustrine mudflat deposit
with vegetation and large periods of subaerial exposure. The
gray sands (upper fossiliferous unit) are associated with an
old fan-delta active during the Pleistocene, indicating the course
of the paleo-Barai River. Both units were produced during
a high lake-level, and in-between both units, a lake regression
and tectonic subsidence enabled the erosion of the lower deposit
and its tectonic deformation. The sequence reflects variations of
the lake level during the Middle Pleistocene. Stromatolites ap-
pear frequently in lake basins during the Quaternary. High con-
tent in authigenic palygorskite and analcime suggest a semiarid
climate and an alkaline water depositional environment.
Discovery and taphonomic information
of the EH 06 locality
The new hominid fossil was found on the surface of the
gray sands (upper fossiliferous unit: UTM coordinates
Fig. 1. Location of Lake Eyasi in the divergence zone of the Gregory Rift in
the north of Tanzania and exposure of the two fossiliferous areas: North Bay
and West Bay. The location of the hominid discovery is indicated by a star.757747-961414) together with abundant fossils (see Online
Supplemental Material), some of which were also located in
situ in this unit through excavation. The hominid was located
within a cluster of stone tools and fossils eroding out of a low-
relief (<1 m) outcrop.
The fossils found with the hominid in the clays and sands
along the outcrop include several types of anatomical elements
from small and large animals. Horn fragments, teeth (the most
abundant), vertebrae, and scapulae, together with long bones
make up the bulk of the assemblage at this locality. The pres-
ervation of all specimens is very good, which allowed careful
scrutiny for bone surface modifications and no traces of micro-
abrasion or polishing typical of bone transport were detected.
Most fossil surfaces were dark-colored, similar to bones af-
fected by manganese. The representation of elements belong-
ing to diverse anatomical parts from several carcass sizes,
which present different physical resisting properties to water
transportation, the presence of very small fragments (2 cm)
in combination with very large ones (>30 cm), the similar
preservation of these specimens, and the lack of any tapho-
nomically detectable trace of transportation (on their cortical
surfaces) supports the interpretation that most of the speci-
mens retrieved in this locality are autochtonous and did not
undergo any significant water transport. This receives further
support from the discovery of two fossils in situ in the exca-
vated clay deposit. It can confidently be said that the fossils
in this locality, including the hominid fragment, are strati-
graphically situated in the upper unit, characterized by the
Gray Sands. The teeth used for the present dating study
were obtained in the same bone assemblage and lacked any
traces of microabrasion or polishing, thereby indicating lack
of transport and the same provenience as the remainder of
the assemblage.
Age estimates of EH 06
Electron spin resonance (ESR) age calculations were at-
tempted for five teeth found on the surface of the Gray Sands.
Dental tissues were selected for isotopic analysis and
230
Th/
234
U (U-series) age calculations. Results are presented
for the tooth for which we have concordant ESR and
230
Th/
234
U data (EYJR 2; wildebeest); results on the remain-
ing teeth were inconclusive. For methodological details, see
Gru¨n et al. (1988), Ivanovich and Harmon (1992), Rink
et al. (1994), Rink (1997), Brennan et al. (1997), and Jones
et al. (2004). The full methodological coverage of EYJR 2
and the inconclusive samples are reported in the Online Sup-
plemental Material.
EYJR 2 was found at UTM 757948-961414 on the surface
of the Lake Eyasi beach within 5 m of the eroding shelf out-
crop of Gray Sands. Due to the unusually high concentration
of thorium in the dental tissues, calculation of the ESR ages
required particular care. Software limitations precluded the
possibility of determining a coupled ESR/U-series age. How-
ever, EYJR 2 yielded agreement between the ESR age and the
230 234
Human Evolution 54 (2008) 899e903Th/ U (closed-system) age for the tooth, which indicates
early-uptake (closed-system) behavior.