Post by djoser-xyyman on Sept 2, 2010 12:42:13 GMT -5
Too large to upload but. . . .
===
Evolution at the Crossroads:
Modern Human Emergence in Western Asia
There is long-standing disagreement regarding Upper Pleistocene human evolution in Western Asia, particularly the Levant.
Some argue that there were two dilierent populations, perhaps different species, of Upper Pleistocene Levantine
hominids. The first, from the Israeli silcs of Qafzeh and Skhul. is anatomically modern. The second, from sites such as
Amud. Kcbara. and Tabun, is archaic, or "Neandertal" in morphology. Others argue that ihis is a false dichotomy and that
all of lliese hominids belong to a single, highly variable population. In this paper I attempt to resolve this issue by examining
posteranial measures reflective of body shape. Results indicate that the Qaf/eh-Skhul hominids have African-like, or
tropically adapted, proportions, while tliosc from Amud, Kebara. Tabun. and Shanidar (Iraq) have more European-like, or
cold-adapled. proportions. This suggests that iherc were in fact two distinct Western Asian populations and that the
Qaf/ch-Skhul hominids were likely African in origin—;i result consistent with the "Replacement"' model of modern human
origins, [modern human origins, NeunJertals, Qafzeh-Skhul hominids, body shape
Western Asia, and particularly the Levant, can be
considered the "crossroads" of the Old World,
for it is here that the continental landmasses of
Asia, Africa, and Europe meet, and it is through this region
that numerous faunal migrations and exchanges have occurred
since at least the middle Miocene (Tchernov 1992;
Thomas 1985). This region has also long figured prominently
in the debate surrounding modern human origins
(Bar-Yosef 1993; Clark and Lindly 1989; McCown and
Keith 1939; Stringer et al. 1984; Trinkaus 19X4, 1992;
Vandermeersch 1981). with numerous sites yielding Upper
Pleistocene human remains. Recently, however, there have
been developments that have greatly altered the character
of this debate. In particular, new radiometric (TL [thermoluminescence],
U-series [uranium series], and ESR
[electron spin resonance]) dates for the Middle Paleolithic
Israeli sites of Amud, Kebara, Qafzeh, Skhul. and Tabun
(Griin and Stringer 1991; McDermott et al. 1993; Mercier
et al. 1995; Valladas et al. 1987. 1988) have caused scientists
to reconsider their view of modem human emergence
in the region. Prior to these dates, many workers considered
the Qafzeh-Skhul hominids to be essentially modern
in morphology and therefore of relatively recent age (e.g.,
Wolpoll 1980). On the other hand, the hominids from
Amud, Kebara. and Tabun (and now Dcderiyeh—
Akazawa et al. 1993. 1995) were considered more archaic
or "Neandertar in morphology and were therefore considered
to be more ancient. The hominids from these sites
could thus be arranged in a unilineal evolutionary scheme,
with Neandertals from sites such as Amud considered ancestral
to the Qafzeh-Skhul group (e.g., Trinkaus 1984).
The new dates, however, indicate that the hominids from
Qafzeh and Skhul1 are ca. 80,000 to 100,000 years old,
while the remains from at least Amud and Kebara are considerably
younger (ca. 50.000 B.P. and 60,000 B.P., respectively).
The dating of Tabun, however, remains somewhat
problematic. First, there is debate concerning from
which level the Tabun Cl skeleton is derived—that is. is it
truly from level C, level D, or could it be an intrusive burial
from level B? (see Lieberman 1993 and comments for a recent
discussion). There are some discrepancies regarding
the radiometric dates for Tabun, as well. Thermoluminescence
(TL) dating indicates an age of ca. 160,000-180,000
years ago (160-180 Kya) for Tabun level C (Mercier et al.
1995). Electron spin resonance (ESR) and some U-series
dates suggest a somewhat younger age of 100-120 Kya
(Griin and Stringer 1991; McDermott et al. 1993). However,
recent U-series dates (Schwarcz et al. 1998) ranging
from 19 ± 2 Kya (EU-femur) to 34 ± 5 Kya (EU-mandible)
suggest that the Tabun specimen is among the last of
the Neandertals (but see Millard and Pike 1999). Thus, the
Tabun Cl skeleton could be quasi-contemporaneous with
the other Neandertal sites or it could, in fact, be much
older. Despite this complication, the fact that the Qafzeh-
Skhul hominids seemingly antedate the Neandertals from
Amud and Kebara makes it extremely unlikely that the
Neandertals are ancestral to the Qafzeh-Skhul hominids.
Conclusions
The current study demonstrates African-like affinities in
the body shape of the Qafzeh-Skhul hominids. This finding
is consistent with craniofacial evidence (Brace 1996) and
with zooarchaeological data indicating the presence of African
fauna at Qafzeh (Rabinovich and Tchernov 1995;
Tchernov 1988, 1992). Since the Neandertals do not exhibit
African-like body proportions, it is also consistent
with the "two-population" model of the Levantine Upper
Pleistocene, as well as the "Replacement" model for modern
human origins—or perhaps an intermediate model
(e.g., Brauer 1992; Smith 1994). These findings do not,
however, support the hypothesis of local genetic continuity
in the Levantine Upper Pleistocene, nor do they indicate
that there was a single, highly variable population of humans
inhabiting the region from 120-50 Kya.
One important final conclusion to be drawn from this
analysis concerns the center of the presumed single origin
of modern humanity following the Replacement model.
The early dates of Qafzeh and Skhul have led some to
speculate that perhaps modern humans emerged first in
Southwest Asia, and not Africa (e.g.. Waddle 1W). The
African-like affinities of the Qafzeh-Skhul hominids, however,
argue against this possibility and strongly suggest
that equatorial Africa was the original ing point for modern
humanity.
References Cited
Akazawa, T.. Y. Dodo, S. Muhesen. A. Abdul-Salam. Y. Abe.
O. Kondo, and Y. Mizoguchi.
1993 The Neanderthal Remains from Dederiyeh Cave. Syria.
Interim report. Anthropological Science 101:361-387.
Akazawa,T.. S. Muhesen. Y. Dodo. O. Kondo, and Y. Mizoguchi
1995 Neanderthal Infanl Burial. Nalure377:585-586. "
Allen, J. A.
1877 The Influence of Physical Conditions in the Genesis of
Species. Radical Review 1:108-140.
Arensburg. B.
1991 The Vertebral Column^ Thoracic Cage and Hyoid Bone.
In Le squelette mouslerian de Kebara 2. O. Bar-Yosef and B.
Vandermeersch.eds.Pp. 113-146. Paris: Editions CNRS.
Arensburg, B.. and A. Belfer-Cohen
1998 Sapiens and Neandertals: Rethinking the Levantine
Middle Paleolithic Hominids. In Neandertals and Modern
Humans in Weslem Asia. T. Ak:i/:i\vj. K. Aoki, and C). Bar-
Yosef. eds. Pp. 31 1-322. New York: Plenum.
Bar-Yosef, O.
198S The Date of the South-Wesl Asian Neandertals. In
L"HommedeNe:indertal,vol.3:L"Anatomic M.Otte.ed.Pp.
31-38. Liege: ERAUL.
1993 The Role of Weslem Asia in Modern Human Origins.
In The Origins of Modern Humans and ihe Impact ol'Chronometric
Daling. M. J. Aitken, C. B. Slnnger. and P. A.
===
Evolution at the Crossroads:
Modern Human Emergence in Western Asia
There is long-standing disagreement regarding Upper Pleistocene human evolution in Western Asia, particularly the Levant.
Some argue that there were two dilierent populations, perhaps different species, of Upper Pleistocene Levantine
hominids. The first, from the Israeli silcs of Qafzeh and Skhul. is anatomically modern. The second, from sites such as
Amud. Kcbara. and Tabun, is archaic, or "Neandertal" in morphology. Others argue that ihis is a false dichotomy and that
all of lliese hominids belong to a single, highly variable population. In this paper I attempt to resolve this issue by examining
posteranial measures reflective of body shape. Results indicate that the Qaf/eh-Skhul hominids have African-like, or
tropically adapted, proportions, while tliosc from Amud, Kebara. Tabun. and Shanidar (Iraq) have more European-like, or
cold-adapled. proportions. This suggests that iherc were in fact two distinct Western Asian populations and that the
Qaf/ch-Skhul hominids were likely African in origin—;i result consistent with the "Replacement"' model of modern human
origins, [modern human origins, NeunJertals, Qafzeh-Skhul hominids, body shape
Western Asia, and particularly the Levant, can be
considered the "crossroads" of the Old World,
for it is here that the continental landmasses of
Asia, Africa, and Europe meet, and it is through this region
that numerous faunal migrations and exchanges have occurred
since at least the middle Miocene (Tchernov 1992;
Thomas 1985). This region has also long figured prominently
in the debate surrounding modern human origins
(Bar-Yosef 1993; Clark and Lindly 1989; McCown and
Keith 1939; Stringer et al. 1984; Trinkaus 19X4, 1992;
Vandermeersch 1981). with numerous sites yielding Upper
Pleistocene human remains. Recently, however, there have
been developments that have greatly altered the character
of this debate. In particular, new radiometric (TL [thermoluminescence],
U-series [uranium series], and ESR
[electron spin resonance]) dates for the Middle Paleolithic
Israeli sites of Amud, Kebara, Qafzeh, Skhul. and Tabun
(Griin and Stringer 1991; McDermott et al. 1993; Mercier
et al. 1995; Valladas et al. 1987. 1988) have caused scientists
to reconsider their view of modem human emergence
in the region. Prior to these dates, many workers considered
the Qafzeh-Skhul hominids to be essentially modern
in morphology and therefore of relatively recent age (e.g.,
Wolpoll 1980). On the other hand, the hominids from
Amud, Kebara. and Tabun (and now Dcderiyeh—
Akazawa et al. 1993. 1995) were considered more archaic
or "Neandertar in morphology and were therefore considered
to be more ancient. The hominids from these sites
could thus be arranged in a unilineal evolutionary scheme,
with Neandertals from sites such as Amud considered ancestral
to the Qafzeh-Skhul group (e.g., Trinkaus 1984).
The new dates, however, indicate that the hominids from
Qafzeh and Skhul1 are ca. 80,000 to 100,000 years old,
while the remains from at least Amud and Kebara are considerably
younger (ca. 50.000 B.P. and 60,000 B.P., respectively).
The dating of Tabun, however, remains somewhat
problematic. First, there is debate concerning from
which level the Tabun Cl skeleton is derived—that is. is it
truly from level C, level D, or could it be an intrusive burial
from level B? (see Lieberman 1993 and comments for a recent
discussion). There are some discrepancies regarding
the radiometric dates for Tabun, as well. Thermoluminescence
(TL) dating indicates an age of ca. 160,000-180,000
years ago (160-180 Kya) for Tabun level C (Mercier et al.
1995). Electron spin resonance (ESR) and some U-series
dates suggest a somewhat younger age of 100-120 Kya
(Griin and Stringer 1991; McDermott et al. 1993). However,
recent U-series dates (Schwarcz et al. 1998) ranging
from 19 ± 2 Kya (EU-femur) to 34 ± 5 Kya (EU-mandible)
suggest that the Tabun specimen is among the last of
the Neandertals (but see Millard and Pike 1999). Thus, the
Tabun Cl skeleton could be quasi-contemporaneous with
the other Neandertal sites or it could, in fact, be much
older. Despite this complication, the fact that the Qafzeh-
Skhul hominids seemingly antedate the Neandertals from
Amud and Kebara makes it extremely unlikely that the
Neandertals are ancestral to the Qafzeh-Skhul hominids.
Conclusions
The current study demonstrates African-like affinities in
the body shape of the Qafzeh-Skhul hominids. This finding
is consistent with craniofacial evidence (Brace 1996) and
with zooarchaeological data indicating the presence of African
fauna at Qafzeh (Rabinovich and Tchernov 1995;
Tchernov 1988, 1992). Since the Neandertals do not exhibit
African-like body proportions, it is also consistent
with the "two-population" model of the Levantine Upper
Pleistocene, as well as the "Replacement" model for modern
human origins—or perhaps an intermediate model
(e.g., Brauer 1992; Smith 1994). These findings do not,
however, support the hypothesis of local genetic continuity
in the Levantine Upper Pleistocene, nor do they indicate
that there was a single, highly variable population of humans
inhabiting the region from 120-50 Kya.
One important final conclusion to be drawn from this
analysis concerns the center of the presumed single origin
of modern humanity following the Replacement model.
The early dates of Qafzeh and Skhul have led some to
speculate that perhaps modern humans emerged first in
Southwest Asia, and not Africa (e.g.. Waddle 1W). The
African-like affinities of the Qafzeh-Skhul hominids, however,
argue against this possibility and strongly suggest
that equatorial Africa was the original ing point for modern
humanity.
References Cited
Akazawa, T.. Y. Dodo, S. Muhesen. A. Abdul-Salam. Y. Abe.
O. Kondo, and Y. Mizoguchi.
1993 The Neanderthal Remains from Dederiyeh Cave. Syria.
Interim report. Anthropological Science 101:361-387.
Akazawa,T.. S. Muhesen. Y. Dodo. O. Kondo, and Y. Mizoguchi
1995 Neanderthal Infanl Burial. Nalure377:585-586. "
Allen, J. A.
1877 The Influence of Physical Conditions in the Genesis of
Species. Radical Review 1:108-140.
Arensburg. B.
1991 The Vertebral Column^ Thoracic Cage and Hyoid Bone.
In Le squelette mouslerian de Kebara 2. O. Bar-Yosef and B.
Vandermeersch.eds.Pp. 113-146. Paris: Editions CNRS.
Arensburg, B.. and A. Belfer-Cohen
1998 Sapiens and Neandertals: Rethinking the Levantine
Middle Paleolithic Hominids. In Neandertals and Modern
Humans in Weslem Asia. T. Ak:i/:i\vj. K. Aoki, and C). Bar-
Yosef. eds. Pp. 31 1-322. New York: Plenum.
Bar-Yosef, O.
198S The Date of the South-Wesl Asian Neandertals. In
L"HommedeNe:indertal,vol.3:L"Anatomic M.Otte.ed.Pp.
31-38. Liege: ERAUL.
1993 The Role of Weslem Asia in Modern Human Origins.
In The Origins of Modern Humans and ihe Impact ol'Chronometric
Daling. M. J. Aitken, C. B. Slnnger. and P. A.