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Tuesday, December 10, 2019

Chapala "homo erectus" brow ridge revisited


A lmost nine years ago I posted about a superciliary arch unearthed in Mexico (See post), and a link to the paper itself:


Link: Irish, J. D., S.D. Davis, J.E. Lobdell, and F.A. Solórzano, (2000), Prehistoric Human Remains from Jalisco. Mexico, Current Research in the Pleistocene 17, 2000 pg. 95-96


Image (source):



The authors state that:


"One Chapala superciliary arch deserves specific mention due to its large size. Studies by Solórzano show the bone resembles that in archaic Homo sapiens at Arago, France. In an unpublished 1990 report, Texas A&M osteologists suggest the brow’s thickness and robustness are comparable to those of KNM-ER 3733 (African Homo erectus). Our measurements show the central torus thickness is 13.3, compared with 8.5 mm for KNM-ER 3733; the lateral torus thickness is 11.5 versus 9.0 mm (Rightmire 1998). Thus for the sake of comparison, the brow is more like that of Zhoukoudian Skull XI (Asian Homo erectus), with a central torus thickness of 13.2 +/- mm; lateral torus thickness was not measured (Rightmire 1998). Modern brows are too diminutive to allow these measurements. The brow also shows pneumatization (air pockets) along its length.
However, to reiterate the findings of the Texas A&M workers, these comparisons do not imply that pre-Homo sapiens were in the Americas. No phylogenetic or age implications are intended. Instead, the comparisons demonstrate the size relative to most New World specimens, although brows on the Lagoa Santa skull (Bryan 1978) and on recent Tierra del Fuego and Patagonia crania (Lahr 1995; C.L. Brace pers. comm. 1998) appear comparable.
"



Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2019 by Austin Whittall © 

7 comments:

  1. Dear Austin, that browridge has always fascinated me too after seeing it on your blog. My question is, do you know where it is now? NeilB

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    1. Hi Neil, They say it is lost, who knows where it is!
      Maybe in some Mexican museum...

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  2. The morphology of this superciliary arch indeed speaks for itself…its resemblance to H erectus, or similarly evolved species is so, but so obvious… that clearly explains why this evidence never could have complied with orthodoxy´s standards about “suitable candidates” for early peopling of America (which, even today, are around a fairly behaviourally modern H. sapiens).
    In this sense, Chapala´s supraorbital ridge (as well as other remains, among them Lagoa Santa´s skullcap unearthed by Waters in 1958, covered in your post of September 7, 2019) belongs to a kind of fossils that are absolutely inconvenient evidence for the prevailing model…and therefore, it should not be surprising that they are more likely to “get lost” from some museum´s collections…
    Referring to the paper whose link you have provided, and particularly respect to its tentative correlation with a Late Pleistocene geological context, I would have my reserves about this…unless what the authors are considering would be a minimum age at the “Early” Late Pleistocene, that is to say during MIS5 substages (from 130 to 80 Ka ago)… not only because there was still presence of H. erectus in Asia, but too because of the heavy mineralization that this fossil seems to present.
    This last aspect frequently rules up C14 as a feasible approach for direct dating, as these bones usually lack collagen due to extreme diagenization, or simply their age is well beyond the limits of the method …being perhaps 230Th/234U direct on bone , if applicable ( because of its considerable restrictions), the only method capable to, at least, shed some light on the true antiquity of this type of remains.
    It´s right to say that the lack of “in situ” finding, as well as that´s of a valid age up to now, are indeed severe limitations…but, in no way should they imply that such an impressive and suggestive sign of “other than H sapiens” Homo developing their existence on these lands, can be denied.

    Best regards
    Marcelo

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  3. The male Horn Shelter Skull also possesses very archaic, pre agricultural features. I can't speak to its measurements, but his brow is large.
    When comparing that specimen to a smooth brow male of that area of 1000 A.D. time period, is like comparing a upper paleolithic European skull to today's caucasians. We know archaic genetics (neanderthal) were in upper paleolithic homo Sapien Europeans.
    Do these same archaic genetics of paleo native Americans reflect a similar admixture or interbreeding? Do you think adopting agriculture can explain all the reduction in brows and other morphological attributes?
    Can the example of Australian aboriginal people show us the mechanism at work?
    Is it introgression by more derived and technological sophisticated people? Agriculture? Is it both?

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  4. Indeed, the skull from Horn Shelter TX has a very odd shape. I am going to read more about it. For those interested in this skull, see this link it has an image of it:
    https://www.nationalgeographic.com/magazines/pdf/011415_NGM_Jan_Int/static/img/carousel/p134_135.jpg

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  5. I believe that is Homo Erectus, or some other pre-Sapien species.

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