Australia: The Land Where Time Began
WLH 50 Vault as a Whole
As Wolpoff et & Lee described it, WLH 50 is a large male calotte with an estimated cranial capacity of 1540 cc (Curnoe, 2009, citing Brown’s web site: http://www-personal.une.edu. au/~pbrown3/palaeo.html). This is more than 30 % larger than the Ngandong male mean (1177 cc, n=4) and larger than the biggest Ngandong male, Ng 10 at 1231 cc. Though it is on the large end of the recent Aboriginal Australian range, this size is not completely unexpected; e.g., lying 2σ above the mean male value of 1295 cc reported by Morant (1927, Table VI) for a sample of 146 from Queensland, Victoria, New South Wales, South Australia and Western Australia. According to Wolpoff & Lee there is no compelling reason to believe that the standard deviation of 120 [?] that has been reported for these Australian Aboriginal males could be used to estimate the standard deviation for Ngandong males, though if this assumption is made for demonstration, WLH 50 would be 3σ larger than the mean for Ngandong males. This comparison is in contrast with the 2σ difference of WLH 50 from the recent Australian Aboriginal mean, the larger estimated difference from Ngandong is regarded as significant by Wolpoff & Lee. To put it simply, the vault is quite large, though at approximately 2 standard deviations above the mean, not so large that it would not be expected among recent Australian Aboriginal people.
Larger than WLH 50 are 2 of the largest crania from the fossil record dating to the Pleistocene (Herto VP-16/1 and Amud). Wolpoff & Lee noted that for the most part, neither of these larger crania have cranial thickness that is exceptional throughout the vault (15), or shares any other of the special features of WLH 50 that align it with the Ngandong crania. WLH 50 is significantly larger than the Ngandong males (as described above, and in Table 2). This is one of the key differences between the Willandra calotte and the earlier remains from Ngandong. The hypothesis that is examined here, however, that the WLH 50 anatomy indicates that populations of Ngandong-like people are among the ancestral forms of WLH 50, and therefore the ancestors of Australian Aboriginals, is not refuted by the larger size of WLH 50. Virtually all cranial samples of sufficient size from samples that are more recent than the Ngandong sample are, on average, larger than Ngandong. The size of WLH 50 does not make its cranial thickness, or any of the aspects of its cranial shape and anatomy, into exceptional or unexpected features that require special explanation.
The thick vault is absolutely long, and relatively high and narrow compared to the Ngandong, with the position of maximum breadth low across the base of the cranium at the supramastoid crests. Otherwise it is of similar shape and proportions in the occipital view to specimens from the Ngandong sample, though it is not exactly like any of them. The posterior view of Figure 16 is standardised to cranial breadth and therefore illustrates the greater relative height of WLH 50. The Coobool remains also exhibit this shape of the vault, with some of the larger specimens, such as Coobool Creek 50.76 sharing a number of anatomical details, including the sagittal keeling, and the contour of the cranium as seen in posterior view including low maximum breadth, and a prominent nuchal torus that covers most of the rear of the cranium (Figure 10).
The length of WLH 50, more than 212 mm, is within the range of the Ngandong sample, being exceeded by 1 of the 6 Ngandong crania (Ng 5, see Table 2). The vault of WLH 50 is, on the whole, more arched than the Ngandong crania, though the arching is formed by 3 flattened surfaces, as described below, rather than the more generally rounded surfaces of the Ngandong crania. These shape comparisons are illustrated in Figure 11. The cranial shape that is more vaulted is described by the index of the arc to chord relation of glabella-opisthocranion (see Table 3), above the range of Ngandong. Curvature of the top of the vault is reflected in most of this difference. This is demonstrated further by the index for glabella-lambda that is also high in relation to Ngandong, while the index for curvatures of the occipital from lambda is lower, within the range for Ngandong.
Distances are determined from the auricular point, projected into the sagittal plane, to quantify further these aspects of the cranial shape. Remembering that the WLH 50 is larger, volumetrically, than any known from Ngandong, the auricular distance to glabella in the anterior and the opisthocranion in the posterior are within the range for Ngandong, while at bregma and lambda, the distance to the top of the vault, are above the range for Ngandong. Measurements once again show that the top of the vault is higher and more rounded. At the nuchal torus position the occiput is not especially projecting (remembering that this structure is eroded away). The occiput projects more rearward at its most superior position (lambda) than any known Ngandong cranium. Therefore, along the occipital plane the posterior face of the occiput is oriented more vertically than in any known Ngandong cranium, and from lambda is actually leaning a little backwards in the approximations of Wolpoff & Lee of the Frankfurt Horizontal (in this regard Ng 1is most similar, though differs in the orientation of the occipital plane as described above). In the Ngandong crania the surfaces along the top of the vault on the midline are more-or-less evenly rounded, while, as noted, in WLH 50 this surface is comprised of 3 flatter portions, a frontal, top, and backwards projecting rear aspect. For WLH 50 these surfaces meet at distinct angles, the frontal angle is at metopion, as described below, while the rear portion is the flattened posterior parietal region beginning some 57 mm posterior to bregma and extending to lambda.
These comparative details are illustrated clearly in Figure 11 (16).
The height of the cranium can only be described from the auricular-bregma distance, projected into the sagittal plane. For WLH 50 this measure of height is larger than the mean for Ngandong, actually being well above the Ngandong range, corresponding to comments by other authors such as Brown (Brown, 1992: 239), acknowledging that the vault is long, though also extremely high. The height/length index of WLH 50 calculated from the auricular-bregma distance (54.4) is larger than any Ngandong (48.8-53.1, n=6), though just barely, Ng 10 is almost as relatively tall. The similarities of shape between WLH 50 and Ng 10 are evident; comparisons of the crania when shown at the same size allow a visual assessment of shape. In WLH 50 the position of the maximum cranial height is at the bregma, the condition in some (Ng 5, Ng 10) though not all of the Ngandong crania.
At more than 212 mm, the length of WLH 50 is within the range of Ngandong, which is exceeded by 1 of the Ngandong crania (Ng 5). The vault is, overall, more arched than the crania from Ngandong, though the arching is formed by 3 flattened surfaces instead of the more generally rounded surfaces of the Ngandong crania. The index for the arc to chord relation of glabella-opisthocranion, above the Ngandong range, describes the more vaulted cranial shape. The curvature of the top of this vault reflects most of this difference. The index for the glabella-lambda, that is also high relative to Ngandong, further demonstrates this, while the index for occipital curvature from lambda are lower, within the Ngandong range.
The cranial vault in WLH 50 is narrow compared with specimens of Ngandong; its cranial dimensions are maximum, maximum parietal breadth, biauricular breadth, and biastrionic breadth all fall within the lower part of the range of Ngandong, but they are always higher than the minimum for Ngandong. The maximum cranial breadth is low on the vault, as in the case of the Ngandong crania, and is substantially larger than the biparietal breadth. Maximum cranial breadth of WLH 50 is the closest cranial breadth to the corresponding mean for Ngandong, slightly more than 1 mm less. Of the 6 Ngandong crania, 4 are narrower, 2 are broader. The cranial breadth relative to length is similarly the mean for Ngandong crania, though encompassed within the range. The breadth-length index of WLH 50, which is relatively narrow (or dolichocranic) is 71.4, which is less than all except Ng 5 of the Ngandong crania, and Ng 5 is the only Ngandong cranium that is dolichocranic, the remainder of the Ngandong crania being mesocranic. Though the greatest breadth of the WLH 50 cranium as seen from above is far to the posterior, it is no more so than Ngandong crania such as Ng 5. The shape of the WLH 50 vault in this view appears to be elongated, and not tear-dropped, as is the cases in specimens that are more brachycranic.
Therefore, the minimum frontal breadth is more similar to the greatest cranial breadth than is usual in Ngandong crania, ratio 75.9, which is slightly greater than the maximum for Ngandong crania (68.9-73.7, n=6). In WLH 50 the relative cranial base breadth (biauricular breadth/cranial length) also reflects narrowing; it is relatively narrower than Ng 5, and, it is actually relatively narrower than all known earlier hominids of the genus Homo, though a cranium that is almost as relatively narrow is OH 9.
WLH 50 has a low, broad sagittal keel that begins anterior to the position of the bregma and extends posteriorly for 57 mm. There is no keel on the frontal anterior to it. Surfaces that are basically flat, being very slightly concave, border the keel to either side, and in totality form the root of the vault. There is some kind of sagittal keeling pattern on all of the Ngandong crania, none of which are precisely the same. Ng 9 is similar to WLH 50, and Ng 11 appears to be the same as it, though the anatomy of its frontal is obscured somewhat by healed wounds. There is a distinct sagittal keeling on Ng 9 which begins at the bregma and extends posteriorly to the beginning of the posterior flattening. Throughout the fossil record from the Pleistocene there are many sizes and shapes of sagittal keeling, while it has been reported (Wu, 1998) that in the Middle Pleistocene the North Asian form of the Keel is different from the South and Southeast Asia, it was noted (Balzeau, 2013) that in Homo erectus the sagittal keeling is not an autapomorphy.
Ng 9 has a flattened portion of the superior surface that has a triangular shape and covers the back of the parietals and the upper portion of the occipital plane. Behind the sagittal keel of WLH 50 the back of the parietals is similarly flattened in the shape of a triangle, the apex of which is above the point, which was described above, at the end of the sagittal keel and the base roughly along the lambdoidal suture. There is no prelambdoidal depression on the WLH 50 crania, such as is present on the Ng 11 and other Ngandong crania, and the flattened region of the WLH 50 crania extends to the lambda position, as was described (Weidenreich, 1951). There is also a prelambda depression on the crania of some Australian Aboriginal people who were recently living. Below and behind the flattened area of the posterior face of the WLH 50 cranium defined by the occipital plane is, as has been discussed above, tall and more or less vertical, and extending about 45 mm from the most posterior part of the lambdoidal flattening on top of the supreme nuchal line. This is quite to the rear of the Ng 1 cranium.
The superficial appearance of an occipital bun is formed by the posterior flattening of WLH 50, and the specimen has been described as having one (Curnoe, 2009: 984), an opinion with which Wolpoff & Lee disagree. The lambdoidal flattening extends onto the occipital in the Neanderthal chignon which leaves it a much shorter vertical face than is shown on WLH 50. When the Neanderthal bun is present its sides are often defined by a vertical flattening of the posterior parietals, also extending onto the occiput. None of these are present on WLH 50. There is a large, shallow lateral fossa on the posterior border of the angular torus, left side of WLH 50, with what appears to be a resorptive surface encompassing the suture which extends medially for 34 mm, up to a slight vertical elevation, or ridge, that separates it, and forms the lateral border of the suprainiac fossa, described below in the occipital section. The lateral fossa, which is bordered medially by the angular torus, has a height of 24 mm above the supreme nuchal line, thereby it incorporates most of the lateral-most corner of the occipital plane. As a result of the fossa extended to the angular torus, a small section of the lambdoidal suture is incorporated into it, coming as close as 14.8 mm from asterion. On the right side there is no corresponding fossa. There is a striking similarity between the anatomy of Ng 9,that has fossae on both sides of the cranial rear, that correspond closely to the condition in WLH 50, except that in Ng 9 they are larger and deeper. Ng 10 and Ng 11 are also similar to WLH 50 in this region; the tori and ridges in these Ngandong crania, which were described above, are developed strongly with a deep fossa and extends medially. The sides are symmetric in these 3 Ngandong crania. Ng 5 has a similar, though not as extensive, fossa bordering the angular torus on the left, though this is barely visible on the right side so that, as with WLH 50, the sides are asymmetric.
Other tori ridges, such as muscle-related features are well developed. The supraorbital torus/superciliary arch, which is described below, is present. The nuchal process, as defined by the supreme and superior nuchal lines, was tall, appearing to have been substantial, though its surface, as described below in the section on the occipital, is eroded so that the thickness of the torus cannot be ascertained and the appearance of the torus is misleading.
The temporal line, which is also preserved best on the left side, extends posteriorly from the temporal notch as a raised ridge or crest, flattening to a line across the parietal that is barely discernible. It becomes a prominent ridge that is well developed but less sharpened, towards the posterior aspect of the bone, and is ultimately expressed as an angular torus, as it curves downwards and approaches, but doesn’t quite reach the lambdoidal suture. The angular torus is prominent and thickened, about 15 mm superior to asterion with its posterior border 4.8 mm anterior to the lambdoidal suture. The back of the angular torus extends downwards and slightly anteriorly from the most posterior projection of the torus; its posterior border travels along the lambdoidal suture with the toral structure ending at asterion where the occipitomastoid, parietomastoid, and lambdoidal sutures come together. The anterior border of the angular torus, the superior temporal line, continues to arc towards the parietal mastoid angle, its most anterior extent ending 4.5 mm short of it. Along the base of the parietomastoid suture, the base of the angular torus, so defined, extends 20 mm anteriorly from asterion.
The angular torus most closely approaches the lambdoidal suture in a lower position (closer to asterion) in Ngandong than it does in WLH 50. There is, however, more similarity in how closely the angular torus approaches the lambdoidal suture. It has been described; the anterior shift of the posterior end of the superior temporal line, and the marked separation of it from the lambdoidal suture that results (Kaifu et al., 2006) as a Ngandong autapomorphy, though in fact some of the Ngandong crania lack this character state. The temporal line in Ng 9 reaches the lambdoidal suture as an angular torus. The angular torus in Ng 1 is weakly developed but the temporal line extends back to the lambdoidal suture, though close to asterion. On the right of Ng 5 there is an expression of this featured that is very similar to WLH 50. The distance between the lambdoidal suture and the back of the angular torus is 4.8 mm in WLH 50 and 6.7 mm in Ng 5. Therefore, though the anatomy described for Ngandong does not characterise WLH 50, as noted above, this anatomical description is not expressed consistently in the Ngandong sample, which actually encompasses WLH 50 in its range. The range of recent/modern humans for these anatomies in Australia is quite similar; the most posterior aspect of the temporal line touches the lambdoidal suture in Coobool 50.16, but is interior to it in Coobool 50.36.
The WLH 50 cranial vault, as with the Ngandong remains, has the form of a house with a gabled roof and sides that are curved slightly inward-slanting from the cranial base, the broadest part of the cranium. The parietal walls inferior to the temporal line are curved evenly and lack any development of boss. Beginning with the distinct angle of the temporal ridge, the cranial roof is gabled up to its peak where there is a low and wide parietal keel on the anterior portion of the parietal, as described above. These details of the rear of the cranium are present in the Ngandong sample, the greatest similarity is with Ng 5.
WLH 50 is similar to the Ngandong cranial sample in many of its details, apart from the large size of WLH 50; with exceptions or specifications as noted, most of the character states of WLH 50 are a good match within the Ngandong sample in the sense of falling within the range of the individual specimens. Those features of WLH 50 which differ from the Ngandong sample, such as the enlarged size of the cranium, higher and more rounded sagittal contour of the cranial vault, reduced supraorbital structures and their division into central and lateral structures, and greater contribution of the diplöe to vault bone thickness, reflect evolutionary changes that occurred in the Late Pleistocene that characterised all regions of the world to some extent. These resulted in anatomical details in vault in WLH 50 that are much like other fossils and Australian Aboriginal anatomy. The existence of detailed anatomical similarities with some or all of the Ngandong crania, including various measures of ruggedness, suggests that the cause of these anatomical similarities cannot be the neurocranial size alone (contra Curnoe, 2009) (17).
|Author: M.H.Monroe Email: firstname.lastname@example.org Sources & Further reading|