Australia: The Land Where Time Began

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WLH 50 Description of and Comparison with Ngandong Samples

Condition and Preservation

The WLH 50 vault that was reconstructed by Thorne is comprised of a calotte with no face and most of the base is missing. As the vault has not been completely preserved Wolpoff et al. limited their observations, comparisons and measurements to the aspects if WLH 50 that could ascertained directly. Though this might seem obvious, they wanted to make clear that this is the only factor which delimited the information they presented (11).

For the most part the bone that remains is well preserved, though there are many portions of the outer bone table that are abraded (Curnoe, 2011, see Figure 5 & text), as well as other exceptions that are noted below. Bone surface extends continuously, with a few exceptions gaps that have been filled by red wax, from the frontal, which includes most of the full supraorbital torus, a description of which is below. A piece of the orbital roof, 22 mm x by 31.5 mm, length x breadth, is preserved adjacent to the lateral torus on the left side. The external bone surface is mostly complete from a position at or very close (14) to the glabella on the medial-most part of the right side of the supraorbital torus, posteriorly to the upper part of the nuchal plane of the occipital, 6 mm beyond (anterior and inferior to) the tuberculum linearum on the superior nuchal line. In this document the tuberculum linearum is defined as the union of the superior nuchal lines and the midline, where they meet the external nuchal crest.

The supraorbital crest extends laterally on both sides to a position that is not quite as lateral as the fontozygomatic suture. But, posterior to this, nothing has been preserved of the orbital notch with the exception of just below the temporal ridge. Behind the supraorbital, the left (more complete side) preserves a broken inferior edge that arches in parallel to the temporal ridge up to the position of the coronal suture, and then continues the arch posteriorly and inferiorly to a position 14 mm anterior to the parietal notch (at the parietal mastoid angle).

The posterior portion of the temporal remains on the left side but without any of its petrous region or the root of the zygomatic arch; the posterior portion of the supramastoid crest is preserved on the right. The bone surface is preserved 26.5 mm anterior to the front edge of the mastoid; this is the most lateral aspect of the roof (the tegmen of Weidenreich) above the external auditory meatus or any part of the tympanic. Most of the mastoid process remains on the left side, including its anterior and posterior edges, though it is not evident that the tip remains.

Posterior to this, the broken surface of the bone is an irregular arch across the nuchal plane of the occipital, and the inferior nuchal line is not preserved anywhere, and with its most posterior extent just anterior to the tuberculum linearum, as described above. The surface of the bone is clearly eroded across the cranial posterior, especially inferior to the supreme nuchal line. This means that effectively an unknown amount of outer bone table has been lost from the nuchal torus and with it the crania’s posterior projection. The bone thickness measurements that are affected have not been reported. The positions of the tuberculum linearum and the inion can be approximated easily from the anatomy that remains. As defined here the inion is superior to it, the midline point marked by a chord between the superior nuchal lines and in their most superior position (lateral to be beginning of the downward arc where they dip down to form the tuberculum linearum. At the inion and tuberculum linearum positions bone thicknesses are not certain because of the erosion of the bone, but According to Wolpoff et al. they are confident that the linear or arc measurements to these points on the external surface are close to their original values. The top of the torus, effectively the supreme nuchal line, does appear to be preserved without significant erosion, though difficult to identify on photographs.  Opisthocranion occurs on the supreme nuchal line and measurements to it are also correct. The internal occipital protuberance is coincident with the supreme line and Wolpoff et al. say they are confident of the thickness of the occipital at this position as well.

The inferior-most edge of cranium is less complete on the right side, from the position of the mastoid base anteriorly. A small portion of the posterior temporal squama extends 34.5 mm anterior to the parietal notch, and 20 mm superior to it. The posterior parietal here is not well preserved, with an irregular break that more or less parallels the lambdoidal suture for 62 mm, about 30 mm anterior to it. From its most superior extent the break is a jagged, zigzagging surface that continues anteriorly to the most lateral extent that is preserved to the right supraorbital surface, which is described as follows. The broken edge continues 63 mm anterosuperiorly, to a point in the middle of the parietal that almost reaches the sagittal suture.  The broken surface then continues some 60 mm inferiorly, irregularly for 34 mm anterosuperiorly to the position of the temporal line, and 88 mm inferoanteriorly until it reaches the most lateral surface of the right supraorbital, as described above.

The internal surface of the vault is preserved in a corresponding manner. Its internal table is not complete on the preserved portion of the left temporal, and especially behind the supraorbital torus where 20 mm of the left-most lateral portion of the orbital roof remains, extending 30 mm to the supraorbital notch. The anterior surface of what appears to have been a frontal sinus is exposed for 32.5 mm, to the midline. It is noted by Webb (Webb, 1989: p. 35):

“the size of the left sinus is estimated to have been about 6.8 cm3. This is based on the following dimensions: 22 mm deep (anterioposteriorly), 28 mm wide and about 11 mm high. The form and size of frontal pneumatisation in WLH 50 corresponds more closely to that of the Ngandong crania … than it does with the small Zhoukoudian sample.”

Sources & Further reading

  1. Habgood, P. J. (2016). "WLH 50: How Australia Informs the Worldwide Pattern of Pleistocene Human Evolution By Milford H. Wolpoff and Sang-Hee Lee PB - PaleoAnthropology 2014: 505−564. DOI:10.4207/PA.2014.ART88." Archaeology in Oceania 51(1): 77-79.

 

Author: M. H. Monroe
Email: admin@austhrutime.com
Last updated: 27/05/2017
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                                                                                           Author: M.H.Monroe  Email: admin@austhrutime.com     Sources & Further reading