April 29, 2008

Archaic Homo sapiens from Lake Eyasi, Tanzania

Wikipedia entry on Lake Eyasi. From the paper:
The best estimate of the burial age of EYJR 2 is an age range that encompasses the uncertainty in the model EU-ESR ages of EYJR 2: 88–132 ka. We use this estimate to infer the age of the associated finds, including EH06.

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If the latter possibility is correct, EH06 shows an interesting continuation of the primitive features shown in Eyasi 1, in a period for which other areas have yielded, from a morphological standpoint, substantially more modern-looking specimens.


These modern-looking features are defined in broadly contemporary hominids by the expansion of the frontal area of the skull, with a more elevated and rounder slope of the frontal bone, together with a reduction of the supraorbital torus, supratoral area, and postorbital constriction. These are some of the features that morphologically differentiate Homo sapiens from earlier hominids. These features can be observed on the Omo and Herto crania (Ethiopia) and the Ngaloba (Tanzania), Jebel Irhoud (Morocco) and Florisbad (South Africa) crania, dated between 265,000 and 120,000 years ago ([Wolpoff, 1999], [White et al., 2003] and [McDougall et al., 2005]).
This ties in well with the idea of persistence of archaic features within African populations long after the appearance of more modern features, with the fully modern Omo coming before Homo sapiens idaltu from Herto, with its mix of archaic and modern traits, coming before more archaic EH06 from Lake Eyasi.

Journal of Human Evolution doi:10.1016/j.jhevol.2008.02.002

A new archaic Homo sapiens fossil from Lake Eyasi, Tanzania

M. DomĂ­nguez-Rodrigo et al.

(no abstract)

Link

4 comments:

  1. This ties in well with the idea of persistence of archaic features within African populations long after the appearance of more modern features

    If L0 in Khoisan was already an expansion of Modern Sapiens, and the fossils and tools do suggest that, then what would be the lineages for this Archaic Hominin component in sub-Saharans?

    Furthermore, aren't the skulls of sub-Saharans fully Modern, with none of these features you mention, which is better than Neanderthal characteristics in Europeans.

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  2. >> what would be the lineages for this Archaic Hominin component in sub-Saharans?

    Almost all the mtDNA diversity of 100kya+ ago is now extinct.

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  3. Furthermore, aren't the skulls of sub-Saharans fully Modern, with none of these features you mention, which is better than Neanderthal characteristics in Europeans.

    Not sure what you mean by "better". Both current Europeans and Sub-Saharan Africans are fully modern today.

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  4. I think morphology has now ceased playing such an important role as to whether a fossil is archaic or not.
    In Klasies River Cave in South Africa anatomically modern humans have been found dating back to 125000 BC. Their behavioral patterns though seem not to be so modern at all!
    That's why scientists have said that in order to define what is early modern and what is recent modern we have to focus on the behavior and not so much on anatomy.
    Being modern requires a behavioral modernity than a possible anatomical!
    Orrorin tugenensis was promoted by some scientists as being the real ancestor of Humankind and not the Ardipithecus and Australopithecus lines.
    The reason is that Orrorin shows some remarkably Human characteristics in such an old age.
    Of course the same had been suggested for Oreopithecus in the 20th century.
    Until now scientists are reluctant in accepting the idea that remarkably modern anatomical features can alone indicate humanity and if that goes for fossils of millions of years old, how much more careful should we be about fossils that we know their gradient i.e. modern and we just want to verify if the are early modern or recent modern.

    http://en.wikipedia.org/wiki/Klasies_River_Caves

    http://en.wikipedia.org/wiki/Orrorin_tugenensis

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