early hominid femur wades

From: Marc Verhaegen (fa204466_at_skynet.be)
Date: 09/25/04 

Date: Sat, 25 Sep 2004 23:17:22 +0200

PALEOANTHROPOLOGY
Oldest Human Femur Wades Into Controversy
http://www.sciencemag.org/cgi/content/summary/305/5692/1885a?etoc
Science 305 p. 1885

PARIS - Tempers flared last week in a sweltering salon at the French Academy
of Sciences here* as scientists hotly debated the attributes of anthropology
's most famous thighbone, the 6-million-year-old femur of an ancient Kenyan
hominid called Orrorin tugenensis. More than 100 scholars packed the academy
's opulent, wood-paneled Grande Salle to witness the first face-to-face
gathering of the discoverers of the three oldest putative hominids. In talks
and a panel discussion, the researchers discussed whether Orrorin and other
contenders for the title of earliest human ancestor walked upright and in
what manner. Bipedalism is a traditional hallmark of membership in the human
family rather than being an ancestor of chimpanzees, gorillas, or
quadrupedal apes. The speakers were particularly interested in learning more
about Orrorin's legs. Paleontologist Brigitte Senut of the National Museum
of Natural History in Paris presented recently published computed tomography
(CT) scans of Orrorin's thighbone (Science, 3 September, p.1450). According
to Senut, the scans show that the bone is thicker on the bottom of the
subhorizontal neck of the femur, indicating that weight was put on the top
of the bone. Other features also suggest that the hips were stabilized in a
manner similar to those of modern humans. In fact, Senut proposed that
Orrorin's gait was more humanlike than that of the 2- to 4-million-year-old
australopithecines. If so, australopithecines would be bumped off the direct
line to humans - a dramatic revision of our prehistory. But
paleoanthropologist Tim White of the University of California, Berkeley,
immediately attacked this view of Orrorin. He said that the resolution of
the CT scans was so poor that it was impossible to be certain of the pattern
of bone thickness. CT scan expert James Ohman of Liverpool John Moores
University in the U.K., who was not at the meeting, agreed that the
published scans were taken at the wrong angle. White further grilled Senut
about the fossil analysis, asking if her team had directly measured the
internal structure of the bone at a pre-existing break, a more reliable
means of gathering the data than CT scanning. Senut responded that
colleagues had suggested doing the scans to make her case stronger and added
in an interview that the bone was broken in a zigzag pattern that made it
difficult to photograph. In her view, other features on the bone make it
clear that Orrorin had walked upright-so there was no need to unglue the
bone and measure it. White accepts that Orrorin walked upright and so is one
of the first members of the hominid family. But he says Senut has offered
little evidence as to Orrorin's gait. "Was it human, an Australopithecus
pattern, or something different?" he asked. Even standard x-rays would help
answer that question. As the discussion grew more heated, White called Senut
's displacement of australopithecines "une position créationniste," because
it suggests that Orrorin's femur was quite modern 6 million years ago,
rather than evolving in stages. Senut declared indignantly that she is not a
creationist - and then asked White to provide his own evidence about the
mysterious Ardipithecus ramidus. A partial skeleton of that
4.4-million-year-old species was discovered by White's team, the Middle
Awash Research Project, in Ethiopia from 1994 to 1996, but the bones remain
unpublished. White responded by projecting images of the Ardipithecus skull
for the first time in public. The CT scans were startling: The skull was so
crushed that the top of the vault was smashed almost to the base, forming a
slab of hundreds of chalky pieces. White described it as "road kill". The
reconstruction uses micro-CT scans to reassemble the specimen. "This is the
most fragile hominid skeleton ever found," says White. "We are very sorry it
's taken us this long to do, but I think you want the right answer instead
of the quick answer." -ANN GIBBONS

IOW, Senut was right, White wrong & ridiculous ("creationniste"): early
hominids were arguably more bipedal than later apiths, IOW, apiths seem to
have been evolving in Afr.ape direction (eg, more KWing), just as we
"predicted": Orrorin was near the Homo-Pan split: it could evolve into Pan
direction by becoming less bipedal & more KWing; into Homo direction by
becoming less climbing & more bipedal.

Marc Verhaegen
http://www.onelist.com/community/AAT
http://allserv.rug.ac.be/~mvaneech/Verhaegen.html

Relevant Pages

  • Re: early hominid femur wades
    ... >hominid called Orrorin tugenensis. ... Bipedalism is a traditional hallmark of membership in the human ... Paleontologist Brigitte Senut of the National Museum ... >of the bone. ...
    (sci.anthropology.paleo)
  • Re: Shit birthday
    ... The x-ray looks exactly the same as 6 weeks ... putting a reamer down the middle of the femur, taking a bone graft ... the operation has around an 80% success rate, which is not as high as ...
    (uk.rec.motorcycles)
  • Re: Shit birthday
    ... The x-ray looks exactly the same as 6 weeks ... putting a reamer down the middle of the femur, taking a bone graft ... arm since. ...
    (uk.rec.motorcycles)
  • Re: Shit birthday
    ... The x-ray looks exactly the same as 6 weeks ... putting a reamer down the middle of the femur, taking a bone graft ...
    (uk.rec.motorcycles)
  • Re: Shit birthday
    ... The x-ray looks exactly the same as 6 weeks ... putting a reamer down the middle of the femur, taking a bone graft ...
    (uk.rec.motorcycles)