Australia: The Land Where Time Began |
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WLH 50 - Migrations Versus Sources
The issue of the number of sources which contributed to the colonisation
of Australia has been debated for a long time (Kirk & Thorne (eds.),
1976; O’Connell & Allen, 2004). Originally the question was framed in
terms of migrations. Though the migration interpretations have continued
(Reyes-Centeno et al., 2014),
focus shifted from the numbers of migrations to the numbers of sources
when Thorne first stated his interpretation of 2 migrations, in terms of
“robust and gracile” groups, using robustness to suggest ruggedness and
gracility as less rugged (Thorne, 1976, 1977). Description of
H. soloensis was replaced
by robustness and Negrito-like cranial anatomy was replaced by
gracility, though these have become terms that are misleading and
inaccurate (6) that could reflect many things besides ancestry, which
include environmental adaptation (Bulbeck, 2001) and activities that are
economically related (Collier, 1989). When they were defined, they were
perceived as anatomical contrasts that did not come from migrations,
instead reflecting 2 distinct geographical sources, they were specific
(Thorne, 1984). This allowed the possibility that at varying times
throughout the prehistory of Australia colonisation could have involved
many migrants, in particular, arrivals from Indonesia and East Asia
(China). As Thorne often put it, after migrants began arriving by sea,
why not expect that they continued arriving throughout the prehistory
and history of Australia? When it is accepted that the question was
about sources “Robustness” and “Gracility” descriptions of cranial
anatomy became the wrong contrast to apply to this comparison (contra
Curnoe & Thorne, 2006a), as primitives and modern is the wrong contrast
that was applied in earlier formulations. Wolpoff & Lee agree that valid
contrast is in features relating to geographic origin.
The potential for models of complex population history was led to by the
recognition of several different geographic sources for indigenous
Australians, as there is no mechanism that could have kept populations
of hunter-gatherers who arrived from different geographic sources
separated or distinct. According to Pardoe (Pardoe, 2006: 14) it is not
conceivable that groups with morphologies that differ widely could
coexist for tens of thousands of years at the same place. Ancient mtDNA
from fossil crania that were regarded as “gracile” and “robust” were
analysed (Adcock et al.,
2001) who found that most (7) belong to a single mtDNA clade that also
includes the sequences that have been found in living indigenous
Australians, which supports this notion. Different cranial morphologies
were not associated with different mtDNA lines. The migrants from
different regions mixed thoroughly, and the mixing evidently occurred
long before the fossils were living people. In support of this
interpretation the features of some specimens from the 2 large fossil
samples at Kow Swamp and Coobool Creek, suggest they had some ancestry
from Indonesia and some other specimens lack these Indonesian features
but have other anatomies that suggest some East Asian ancestry.
Different sets of features are combined in different crania and the most
reasonable interpretation of this is that they had a mixed ancestry (8).
According to Wolpoff (Wolpoff, 1980: 327-330), in Kow Swamp 15 the
browridge is continuously developed, with only a slight dip over the
nose, and the thickness of the browridge is close to the average for
Solo. A sagittal keel (9) is retained in the frontal of Kow Swamp 1that
continues almost to the browridge and the forehead, eliminating the
groove between the browridge and the forehead. In Kow Swamp 9 the outer
part of the browridge follows the temporal line backwards, forming a
triangle that is backward-pointing at the upper corner of the orbit
[frontal trigone]. (Wolpoff, 1980: 327-330)
Though at the same time, in the Keilor crania the resemblances are with
Liujiang and Zhoukoudian Upper Cave (Thorne, 1980; Curnoe, 2007).
Similarities are also shown with East Asians in other specimens such as
Mungo 1 and 3, which are 2 of the earliest dated remains in Australia.
Yet Mungo 1 bears close resemblances to Kow Swamp 4 and 16, while Mungo
3 (male) resembles Kow Swamp14 and 15 in frontal curvature. I.e., the
range at this site encompasses most of the known fossil material from
Australia (Wolpoff, 1980: 330).
Though it may be suggested by the variations in the anatomy of
indigenous Australians, such as those described above, that indigenous
Austrians arrived from multiple geographic sources, such as Indonesia or
East Asia, it is misleading to pick through the fossils and recent
specimens in order to find specific individuals with ancestry from
Indonesia, East Asia or Africa, and is an invalid use of the data,
because all of the skeletal samples are of mixed ancestry. Based on
current evidence the migration or migrations to the Australian continent
began some 50,000 BP (Hiscock, 2008; O’Connell & Allen, 2008, 2012), and
by 40,000 BP humans had dispersed throughout the continent (O’Connell &
Allen, 2004; Pardoe, 2006). No fossil or archaeological evidence has
been found to date which would suggest that Australian populations were
isolated from the remainder of the world after the beginning of
migration, and there is every indication that there was significant gene
flow throughout the continent (Habgood & Franklin, 2008).
Was there a Single Source Population?
A single source is the alternative to multiple sources for indigenous
Australians, though the ultimate source of all human populations in the
Pleistocene was Africa. The question with regard to Australia is about
proximal sources. This has proven to be a more complicated discussion
than for most other regions.
At the time multiple sources for indigenous Australian were being
discussed the hypothesis that there need not have been more than a
singles geographic source region, and that variation among indigenous
Australians subsequently evolved
in situ from it was put forwards by a number of workers (Abbie,
1968; Brown, 1987; Bulbeck, 2001; Cameron & Groves, 2004; Habgood, 1986;
Howells, 1977; Pardoe, 1991, 2006; Pietrusewsky, 1990; Stone & Cupper,
2003; Wright, 1976). This contention is not simple to disprove, as the
adaptive changes in Australia parallel changes occurring other parts of
eastern Asia (Brown, 1992; Brown & Maeda, 2004), and more broadly in
other parts of the Old World. The likelihood of adaptive changes
occurring during the Pleistocene and Holocene is quite high, whatever
the number of sources, which provides an alternative explanation for the
pattern and details of variability in Australia (Pardoe, 2006) that has
been difficult to disprove. There was also limited consensus on where
the single source region might have been.
Whether the early Australian migrants were directly descended from an
African population whose ancestors left Africa a comparatively short
time ago is a possibility that can be addressed (Mellars et
al., 2013; Oppenheimer,
2009). Archaeological evidence that there was a direct migration from
Africa to Australia has not been found (Habgood & franklin, 2008), and
to date no unambiguous evidence of a diagnostic African anatomy has been
demonstrated in the fossil record of Australia. Systematic comparisons
of WLH 50 to earlier African crania have failed to demonstrate unique
descent from these Africans, which provides evidence for rejecting a
direct African origin for indigenous Australians. However, these
comparisons cannot exclude the possibility of some African ancestry for
indigenous Australians.
The Simplest Origins Hypothesis
When geography and the Pleistocene pattern of ocean currents are
considered, the proximate geographic origin for Aboriginal Australians
the most likely possibility was in the regions that are closest to
Australia – in eastern Asia and Island Southeast Asia. Indonesia was
among the islands that some of the earlier scientists suggested, and an
Indonesian origin, in one way or another, or what is more precise, the
idea that one of the source populations for Aboriginal
The populations of Australia evolved throughout part of the Pleistocene
that the continent had been occupied by humans, archaeologically,
demographically and anatomically. The second hypothesis of Wolpoff & Lee
is that the pattern and direction of their evolution was similar to
evolution in other regions of the world; specifically that WLH 50 is
different from Ngandong in ways that reflect the pattern of evolution
from the Late Pleistocene in other parts of the world. This is not
parallelism. It would imply there were significant archaeological and
biological connections between Australia and its neighbours; therefore
the continent could not be considered to be an isolated
cul-de-sac.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |