Australia: The Land Where Time Began
WLH 50 is not the most complete Australian skeleton among the fossils that have been found in Australia in the latter part of the 20th century, though it is by far the most provocative discovery. WLH 50 is a male calotte, determined on the basis of its size and cranial superstructures development, was found with some fragmentary facial bones in 1980 on a lunette surface near Lake Garnpung in the area of the Willandra Lakes, New South Wales, Australia. The ancestry of Australian Aboriginal people is usually assessed as being mostly Southeast Asian (Dennell & Porr, 2014), date assessments of the Pleistocene Australian human fossil record are sufficiently recent for the expectation that additional ancestry from either Indonesian (Ngandong) or African populations from the Late Pleistocene could potentially be found.
A number of estimates for the WLH 50 site, and the fossil itself, have been published (Caddie et al., 1987; Simpson & Grün, 1998); in the view of Wolpoff & Lee the most recent determination of its age (Grün et al., 2011) is the best grounded, supplanting earlier assessments of age. According to Grün et al. if reworking or burial is considered, the age of the remains of WLH 50 is between 12.2 ± 1.8 ka and 32.8 ± 4.6 ka, with the remains most likely to date to around 26 ka though realistically it will fall into an age range of 16.5 – 37.4 ka (Grün et al., 2011: 604).
According to Grün et al. WLH 50 is an adult, probably a young to middle aged male based on the closures of cranial sutures. The sutures that have been preserved for WLH 50, present a mosaic of fusion and closures, as is commonly found. All of the cranial sutures are closed, though they are visible to differing extents. It has been shown (Meindl & Lovejoy, 1985) that ectocranial closure is superior to Endocranial suture closure as an indicator of age. The endocranium was divided by them into 2 regions for analysis of the closure of sutures at specific points, the vault system and the lateral-anterior system, which was comprised of pterion, the mid-coronal point, sphenofrontal point, inferior sphenofrontal point, and the superior sphenofrontal point. For the assessment of age it was found that the lateral anterior system was superior to the vault system. In WLH 50 the mid-coronal suture was the only suture remains of the lateral-anterior suture system. The coronal suture of WLH 50 is minimally closed and remains easily visible ectocranially, at least to the top of the vault to the position of the temporal lines (stephanion). In the mid-coronal position it matches the “minimum closure” that is illustrated by Buikstra & Ubelaker, 1994: Fig. 22b). The lambdoidal suture is only slightly more closed, e.g. not as closed as the examples of “significant closure.” The lambda position on the lambdoidal and the bregma position is not closed on the coronal sutures, and a younger age is supported by the condition of the other sutures that have been preserved rather than an older age assessment. Contrasting with this the sagittal suture is fully fused and externally it is obliterated, though remains somewhat visible internally. According to Meindl & Lovejoy (1985) it is not usual for a younger adult to have the advanced closure stage of the sagittal suture, as is its combination with the minimum closure of the coronal suture, though ectocranial closure of the sagittal suture is independent of age (Hershkovitz et al., 1977), and therefore not reliable for estimating age.
WLH 50 is arguably the largest and most rugged known of the Australian Aboriginals dating to the Late Pleistocene. Though neither its size nor its anatomical features are anomalous or unique for a hominid from the Late Pleistocene, and the observations that most of its characteristics are found in other crania that are more recent from the Australian fossil record, as well as persisting in some historic individuals, suggests that WLH 50 can validly inform the contention that indigenous Australians descend from more than a single geographic source, and the hypothesis that one of those sources is Indonesians from the Late Pleistocene.
WLH 50 provides a unique opportunity to address issues of the ancestry of Indigenous Australians, because of its geologic age and its anatomy, and this discussion is approached in a comparative context. It is important to have a detailed description and comparison of the cranium of WLH 50 in order to examine many of the relationships that have been proposed for Australian fossils and for addressing issues of multiple sources for Australian Aboriginals, including the Indonesians from Ngandong that date to the Late Pleistocene. The closest cranial sample in space and time, from outside Australia, is the Ngandong remains.
The WLH 50 cranium age is between the ages that have been estimated for Ngandong and the Kow Swamp/Coobool Creek Australian samples. There is no doubt that the estimated date for Ngandong is earlier (Antón et al., 2007; Indriati et al., 2007; Huffman et al., 2010, who discuss all issues of provenance). There are other Australian samples that date to the Late Pleistocene-Early Holocene that have been described as retaining some features that are Indonesian-like that may overlap with the latest portion of the age estimate of WLH 50, but they are most probably later. The Coobool Creek (n=126) are the largest of these, where there are uranium/thorium dates of 12,400 ± 400 (Brown, 1987) and 14,300 ± 1,000 (Brown, 1989) for Coobool Creek 50.65, and Kow Swamp (n=22), with a date reported of 22-19 ka (Stone & Cupper, 2003).
The WLH 50 systematic comparison with the crania from Ngandong addresses specifically questions of whether Ngandong could be one of the ancestors of WLH 50. The issue is not about whether WLH 50 is part of the Ngandong sample; anatomy, geography and estimates of date demonstrate that it definitely isn’t.
And the issue discussed here is not whether WLH 50 should be considered to be an anatomical link or an intermediary between Ngandong and Aboriginal Australians that are living or recent. It has been shown by history that these interpretations could seem as though there was a single, unique line of descent from Ngandong to WLH 50 and this is not a hypothesis that is considered or believed by Wolpoff & Lee to be valid. The interpretation of WLH 50 as anatomical link might be possible, if there had been a unique line of evolution leading from Ngandong to WLH 50 to later Australian Aboriginal People, but the contention in this paper is that these relationships are more complex than linear evolution as at each point mixture with other populations is involved. The interest here is whether Ngandong is one of the ancestors of WLH 50. Evidence that ancestors of Australian Aboriginal People were Indonesians from the Pleistocene would be provided by this.
And this issue is not whether it is possible to describe WLH 50 as “archaic,” “modern,” or intermediate,” or is part of the same taxon as Ngandong if that taxon is different from Homo sapiens.
The focus here is on a question of ancestry, one that can be addresses as a testable hypothesis: Is it indicated by WLH 50 that Ngandong-like populations are among the ancestors of Australian Aboriginal People? There may be significant ways in which WLH 50 is different from the Ngandong crania; the question is whether these are ways in which other recent crania recovered in Australia also do not resemble Ngandong.
This hypothesis of ancestry is addressed phenetically, on the basis of similarities, or their absence, as in this case it is not possible to address a hypothesis of ancestry cladistically. The putative ancestors of WLH 50 are related to WLH 50 too closely for any formal cladistic assessment to be accurate, whatever the correct taxonomy is (Curnoe, 2003; Hawks, 2004; Westaway & Groves, 2009), if for no other reason than for so close a relationship, many times more data would be required for accuracy to be reasonable than actually exist. To do so, in this paper a detailed comparative study of the data collected for WLH 50 (11), and the comparisons of anatomy and statistics that address hypotheses of ancestry and normality for WLH 50.
Measurements were used to quantify many of these comparisons. The grand measurement set from which measurements of WLH 50 were defined is comprised of measurements that are standardised from R. Martin (1928), the Biometrika School, the W. W. Howells data set, as well as other sources that are normally used. Measurements developed to allow comparisons of cranial remains that are fragmentary which are too incomplete for standard measurements to be possible. This has provided a measurement set containing many more measurements than has ever been used before in comparisons with WLH 50, and one that was particularly designed to maximise comparisons of crania that are incomplete.
The descriptions that follow also include systematic anatomical comparisons (12) with the Ngandong criteria. In this paper Weidenreich’s (1951) allocations of sex, though with some scepticism. Though the estimate of Weidenreich, is that 4 of the 6 complete calottes are male, in this paper it is recognised that there is a tendency to overestimate the number of males in fossil hominid populations (Weiss, 1971), and though the assessment of Weidenreich for Ngandong is accepted by the authors of this paper, in their view, the determination of sex within this sample of calottes that are missing the face and lack postcranial remains will remain problematic. There the comparisons here are with the individual crania and not with the sample means, or with the means of the putative males.
Some limited comparisons are also made with later fossil crania from Australia. These comparisons are not meant to be systematic, instead for the purpose of determining whether the anatomical features of WLH 50 can also be found within the later Australian fossil sample. The authors of this paper want to establish, within reason, if WLH 50 is part of a normal range, or an unusual and unexpected, or possibly an anomalous or pathological Australian fossil. Comparisons with males from the large samples from Kow Swamp and Coobool Creek inform the issues of uniqueness and/or purported pathology or of artificial alterations of WLH 50. Though these comparisons of Kow Swamp and Coobool Creek are sampled from a wide range of anatomies, it is believed by the authors they are sufficient to address the question as to whether WLH 50 is normal or unique in that it demonstrates some contribution to the ancestry of Australian Aboriginal People from Ngandong. No feature, or combination of features, appears to demonstrate clearly that an African source was the only, or the unique ancestor.
Where it is considered to be appropriate, the authors of this paper cited the observations on WLH 50 that were published by Webb; Web also based his remarks on the study carried out on the original specimen. Additional comparisons with other Australian fossils have been published (Curnoe, 2009, 2011; Curnoe & Thorne, 2006a). These are also cited as appropriate. There has already been a considerable discussion about WLH 50, though a systematic description is lacking and its place in human evolution (Curnoe, 2009, 2011; Hawks et al., 2000; Miller, 1991; Stringer, 1998; Stuart-McAdam, 1992; Webb, 1989, 1990, 2006; Westaway & Groves, 2009; Wolpoff & Lee, 2001).
|Author: M.H.Monroe Email: email@example.com Sources & Further reading|