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    New Missing Link - Or Maybe Not
    By Patrick Lockerby | April 10th 2010 05:23 AM | 6 comments | Print | E-mail | Track Comments
    About Patrick

    Retired engineer, 60+ years young. Computer builder and programmer. Linguist specialising in language acquisition and computational linguistics....

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    New Missing Link - Or Maybe Not


    The recent suggestion that Australopithecus Sediba is an intermediate species has aroused controversy.

    The following extracts are from naturenews.

    Claim over 'human ancestor' sparks furore

    Researchers dispute that hominin fossil is a new species.

    Michael Cherry

    Witwatersrand in Johannesburg, South Africa, has revealed two remarkably well preserved hominin fossils aged just under two million years old. The fossils were discovered at Malapa cave, part of a site known as the Cradle of Humankind, some 40 kilometres west of Johannesburg. But the researchers' suggestion that the fossils represent a transitional species in human evolution, sitting between Australopithecus  and Homo  species, has been criticized by other researchers as overstated.

    ...

    Controversially, the researchers have named the fossils as a new species, Australopithecus sediba. 'Sediba' means fountain or wellspring in Sotho, which is one of the 11 official languages of South Africa. Berger deems this an appropriate name, as he says that A. sediba  is a good candidate for being the transitional species between the southern African hominin, Australopithecus africanus, and early Homo  species — either the earlier Homo habilis  or even a direct ancestor of the more recent Homo erectus. The research is published in Science1,2.

    ...

    But palaeoanthropologist Tim White of the University of California, Berkeley, says that A. sediba  and A. africanus are merely chronospecies: names given to describe slightly different anatomy in fossils from a single evolving species. White says that the suggestion by Berger and his team that this lineage split before the emergence of Homo  is "fossil-free speculation", adding that "the obsession with Homo  in their title and text is difficult to understand outside of a media context".

    ...

    Anthropologist Fred Grine of Stony Brook University in New York says that the authors have "not undertaken any competent analysis of variation within A. africanus  — something I do not understand in the context that three further skeletons have been found by the same team at Malapa".

    ...

    But in a press conference on 7 April, Berger defended the classification of A. sediba as a new species. The fossils "morphologically fundamentally differ from other fossil species that have been found", he said. The arms of the new fossils are long, like those of A. africanus, but the pelvises are strikingly like those of H. erectus.

    ...

    Alan Morris of the University of Cape Town in South Africa is more upbeat about the findings. "It is the presence of modern behaviours and the concomitant expansion of the brain and restructuring of the pelvis for running that defines Homo, but the evolving line that led to these developments has not been clearly visible. The Malapa specimens will rekindle the debate about the validity of the taxon Homo habilis, and will make us look more carefully at the variability of Australopithecus africanus  and her sister species," he says.

    Francis Thackeray, director of the Institute for Human Evolution at the University of the Witwatersrand, agrees that the latest finds raise important questions about the ancestry of humans. "The new fossil has a suite of characters which confirm that there is no clear boundary between Australopithecus africanus  and Homo," he says.

    References

    1. Berger, L. R. et al. Science 328, 195-204 (2010). | Article | ChemPort |

    2. <!-- . -->Dirks, P. H. G. M. et al. Science 328, 205-208 (2010). | Article | ChemPort |

    3. <!-- . -->Smith, H. F.&Grine, F. E. J. Hum. Evol. 54, 684-704 (2008). | Article




    Looks like the jury is still out on that one, then.

    Comments

    Patrick, don't take this the wrong way, my friend, but who cares?
    Gerhard Adam
    It's important to all those people with an interest in researching their family tree. :)
    Mundus vult decipi
    LOL Gerhard! : )
    logicman
    Gerhard:  definitely Another Way To Annoy The Relatives

    Eric:  I was thinking that about my Arctic ice series - who cares?  In fact, I need to explain that we should care. 

    As to this old fossil picking up a story about a dispute about Australopithecus Sediba: Missing Link Discovered ... Again: I get about 2 hits a month from Google searches looking for hominid fossil articles.  Must be those darned Lockerby genealogists!
    Gerhard Adam
    Well, in tracing my own family tree, and after making several assumptions and presumptive leaps, I concluded that about 30,000 years ago I had ancestors living in a cave in France.  I did happen to notice that one of the pictures on the wall, looked like it might've been a note to descendants.

    From here things became a bit more dicey, but with a few more assumptions and presumptive leaps, I was able to go back nearly a half million years before things really started to become questionable.  Part of the problem is that cave drawings aren't the best way to keep records ... oh well. 
    Mundus vult decipi
    logicman
    I did happen to notice that one of the pictures on the wall, looked like it might've been a note to descendants.
    Nah!  It was an I.O.U. from my folks next door.