Ancient Ancestor Was Mosaic of Human and Ape Features

By Gemma Tarlach | April 11, 2013 1:33 pm

Composite reconstruction of Au. sediba. For comparison, a small-bodied female modern H. sapiens is shown on the left, and a male Pan troglodytes on the right. Image courtesy of Lee R. Berger/University of the Witwatersrand

It’s not as awkward as figuring out the seating at Thanksgiving, but finding the right spot for one of the newest additions to our family tree continues to puzzle researchers.

First found in 2008 and named in 2010, features of the two million year old hominid Australopithecus sediba continue to defy categorization. Nearly-complete skeletons and partial remains of Au. sediba from the fossil-rich site of Malapa in South Africa display both primitive and derived, or further evolved, traits, creating controversy over whether the early hominid was our ancestor or a distant relative.  A growing body of evidence, including six papers in the April 12 edition of Science, doesn’t rule out either scenario — but suggests Au. sediba is an unexpectedly complex mosaic of evolutionary fits and starts.

The upper limbs of Au. sediba are the most complete of any early hominid known, according to one of the studies, and suggest it was well-suited to climbing trees and suspending itself. Another study, however, found that Au. sediba’s lower limbs — studied from the relatively complete skeleton of an adult female — suggest it walked bipedally, with a hyper-pronating gait and fully extended leg, different from other australopiths.

An examination of the thorax of the early hominid revealed the upper portion was narrow and ape-like, not broad like humans’ — a trait linked to our locomotive ability to walk long distances and run. Au. sediba’s lower thorax, however, is less flared than apes and more closely resembles that of humans. While the findings do not resolve Au. sediba’s place in evolution, the fossils themselves are significant: due to the particularly fragmentary nature of hominin ribs, it is difficult for researchers to attempt any kind of reconstruction, but they were able to do so for Au. sediba.

Au. sediba remains were also complete enough to reconstruct its back, and researchers discovered its vertebral column had the same configuration as modern humans, with five non-rib-bearing lumbar vertebrae and five sacral elements, which distinguishes it from other early hominids, according to one of the studies. Au. sediba also appears to have had a longer and more flexible back than earlier australopiths, and more closely resembles Homo erectus in that respect.

A study of highly heritable dental traits revealed that Au. sediba appears distinct from Au. afarensis, previously posited as a close relative, but that it is closely related to another southern African hominid, Au. africanus. According to a second study by researchers examining other elements of Au. sediba’s dentition, where the Au. sediba differed from Au. africanus, it appeared most similar to early examples of Homo, strengthening one theory that Au. sediba could be one of our ancestors.

The Malapa site is considered among the richest hominid fossil collection in the world and has already yielded more than 300 early human ancestor remains, including those of Au. sediba. Researchers working at the site expect to uncover many more fossils — some of which may one day definitively place Au. sediba, at last, at its rightful spot in hominid history.

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  • http://twitter.com/boblevel boblevel

    Another ‘transitional fossil’ found. Will young Earth creationists finally take this mountain of evidence as proof of evolution? Doubt it.

    • Arlin Jordan

      Ok . Boblevel

  • http://twitter.com/Uberharty Thom McCann

    Horsefeathers and Blarney.

    There is a systemic problem especially in archaeology
    and paleontology.

    On December 9, 2010 in The New York Times science
    writer Nicolas Wade wrote: “Anthropologists have been thrown into turmoil
    about the nature and future of their profession after a decision by the
    American Anthropological Association at its recent annual meeting to strip the
    word ‘science’ from a statement of its long-range plan.”

    On her July 2010 radio show (WOR 710AM in New York)
    national talk-host Joan Hamburg spoke about her early career as a
    paleontologist and confessed “When we dig up something we don’t really know
    anything. We just make it up.”

    Read pro-evolutionist Bill Bryson’s best seller
    “A Short History of Nearly Everything” and discover on almost every
    other page the charlatanism, chicanery, lies, outright fraud—even
    murder—rampant in the sciences——even murder in paleontology and archaeology.

    READ HIS BOOK AND FIND OUT FOR YOURSELF.

    The American Museum of Natural History has a
    life-sized African diorama with a hairy male and female ape-like homonids
    walking upright—based on the finding of a set of footprints!

    When Bryson asked the curator of the museum and
    paleoanthropologist, Ian Tattersall, if “he was troubled about the amount of
    artistic license that was taken in reconstructing the figures, Tattersall
    replied, “It’s always a problem in making recreations. You wouldn’t believe how
    much discussion can go into deciding details like whether Neanderthals had
    eyebrows or not…We simply can’t know the details of what they looked like… If I
    had to do it again, I think I might have made them slightly more apelike and less
    human. ”

    He also wrote “If you correlate [fossil] tool
    discovery with the species of creature most found nearby, you would have to
    conclude that early hand tools were mostly made by antelopes…”

    In 2004 National Geographic tested four paleoartists
    by giving them the same fossil bones at different times without telling them
    other paleoartist would be creating drawings from the fossils. Not one of the
    drawings looked like the others—and none of them had any body hair on them!

    The biography, “Schliemann of
    Troy: Treasure and Deceit,” by Dr. David Traill, a classics professor at the
    University of California, shows that Heinrich Schliemann, excavator of the
    sites of Troy and Mycenae, was an unscrupulous, deceitful and repeatedly guilty
    of falsifying his excavation reports concluding that the famous archaeologist
    was a pathological liar. The trove of gold, silver, bronze and rock crystal
    attributed to King Priam of the Homeric period was an assemblage of artifacts
    collected at several places and on different occasions. Archeologists rallied
    to defend him stating that his excavations are a reliable foundation for modern
    scholarship despite the fact that truthfulness of researchers is of even more
    importance in archeology than in most other fields. Dr. Traill said the
    reluctance of archeologists to condemn Schliemann is understandable. The data
    they use to construct theories are based on excavation reports. Then someone
    comes along and puts as lot of knowledge in disrepute…so they dismiss the
    criticism. Dr. Machteld Mellink, an archaeologist at Bryn Mawr College and former president of
    the Archaeological Institute of America, expressed her impatience in the
    matter, “We don’t make much progress on Troy by digging up this old gossip.”

    From a NYT article, “Archeologists Rally to Defend a
    Suspect Giant”January 6, 1996

    A NY Times (March 12, 1961) article, “There Are
    Neanderthals Among Us” discussed fossil skeletons found in La Chapelle in
    Europe which turned out to be those of recently departed residents who were bent
    over from bone disease.

    From a WSJ book review of The Half-Life of
    Facts:

    “The story of Brontosaurus, the lovable, distinct
    herbivore we all grew up with—never existed. Originally described in 1879 by
    Othniel Marsh, the Brontosaurus was soon determined to be a type of dinosaur
    that Marsh had already discovered in 1877, the Apatosaurus. But since the
    original Apatosaurus was just “a tiny collection of bones,” while the
    Brontosaurus that Marsh named “went on to be supplemented with a complete
    skeleton, beautiful to behold,” the second discovery captured the public’s
    imagination and the name “Brontosaurus” stuck for nearly a century.
    Only recently has the name “Apatosaurus” started to gain traction.

    Reconstructed
    Face of Extinct “Hobbit” Species Is Startlingly Humanlike

    By Kate Wong |
    December 11, 2012

    A third possibility, embraced by a few researchers,
    is that the tiny bones are simply the remains of diseased
    modern humans.

    Hobbit Hullabaloo

    New findings challenge the idea of a mini human
    species on Flores

    By Kate Wong
    Scientific American

    In recent months researchers have published several
    papers favoring the minority view of the skeptics. Hobbit proponents, however,
    think that the evidence for the hobbit as a separate human species is stronger
    than ever. The stakes are high. Proponents now believe the finds suggest that
    the first human ancestors to leave Africa may have been far more anatomically
    primitive—and may have left far earlier—than previously thought. If they are
    right, the Flores remains rank among the most important paleoanthropological
    discoveries of all time, one that will revolutionize our understanding of human evolution. If they
    are wrong, “it will be worse than Piltdown” in terms of its effect on the
    field, as one anonymous observer put it, referring to the 1912 hoax that
    combined modern human and orangutan fragments.

    This whole field has proven again and again that many
    of these researchers have lied and continue to lie. The most brazen—and
    unfounded—theories are proclaimed only to find the research was faked or
    non-existent.

    This is chicanery not science.

    This is weird imagination run wild.

    This is absolute fraud.

    Talk about honesty in the “sciences.”

    This is pure bunk.

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