A new Orrorin femur study

[Daryl Habel]

For the press release:
CLICK HERE

For the article in Science:CLICK HERE

which doesn't get to my library shelf until next week.  Since I failed in the attempt to get "additional photos" downloaded from the press release, it was fulfilling to find that the Science journal's Supporting Online Material, freely downloadable to registered users who are not subscribers at: CLICK HERE has some very informative cross-sectional scans of the femur neck.  

Dar
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Science, Vol 305, Issue 5689, 1450-1453 , 3 September 2004

External and Internal Morphology of the BAR 1002'00 Orrorin tugenensis Femur
 
K. Galik,1;  B. Senut,2; M. Pickford,3; D. Gommery,4; J. Treil,5 ; A. J. Kuperavage,6; R. B. Eckhardt,6*

Late Miocene fossils from the Lukeino Formation in Kenya's Tugen Hills are assigned to Orrorin tugenensis. Of 20 fossils recovered there to date, 3 are proximal femurs. One of these, BAR 1002'00, preserves an intact head connected to the proximal shaft by an elongated neck. Although this fossil is comparable in size to Pan troglodytes, computerized tomography scans of the neck-shaft junction of BAR 1002'00 reveal that the cortex is markedly thinner superiorly than inferiorly, differing from the approximately equal cortical thicknesses observed in extant African apes, approaching the condition in later hominids, and indicating that O. tugenensis was bipedal.

1 Orthopedic Biomechanics Laboratory, Allegheny General Hospital, Pittsburgh, PA 15212, USA.
2 Département Histoire de la Terre, Muséum national d'Histoire naturelle, UMR 5143 du CNRS, Case Postale 38, 57, rue Cuvier, 75231 Paris Cedex 05, France.
3 Chaire de Paléoanthropologie et de Préhistoire, Collège de France, et UMR 5143 du CNRS, Département Histoire de la Terre, Muséum national d'Histoire naturelle, UMR 5143 du CNRS, Case Postale 38, 57, rue Cuvier, 75231 Paris Cedex 05, France.
4 UPR 2147 CNRS, 44, rue de l'Amiral-Mouchez, 75014 Paris & GDR 983 du CNRS, 8, rue Buffon, 75005 Paris, France.
5 Service du Radiologie, UMR 8555 du CNRS et Service de Radiologie, Clinique Pasteur, 45, Avenue de Lombez, 31300 Toulouse, France.
6 Laboratory of Comparative Morphology and Mechanics, Department of Kinesiology, Pennsylvania State University, University Park, PA 16802, USA.

* To whom correspondence should be addressed. E-mail: eyl@psu.edu
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Copyright © 2004 by The American Association for the Advancement of Science. All rights reserved.

[Mikey Brass]

For the press release:
CLICK HERE

For the article in Science:CLICK HERE

which doesn't get to my library shelf until next week.  Since I failed in the attempt to get "additional photos" downloaded from the press release, it was fulfilling to find that the Science journal's Supporting Online Material, freely downloadable to registered users who are not subscribers at: CLICK HERE has some very informative cross-sectional scans of the femur neck.  

Dar
***********************************

Science, Vol 305, Issue 5689, 1450-1453 , 3 September 2004

External and Internal Morphology of the BAR 1002'00 Orrorin tugenensis Femur
 
K. Galik,1;  B. Senut,2; M. Pickford,3; D. Gommery,4; J. Treil,5 ; A. J. Kuperavage,6; R. B. Eckhardt,6*

Late Miocene fossils from the Lukeino Formation in Kenya's Tugen Hills are assigned to Orrorin tugenensis. Of 20 fossils recovered there to date, 3 are proximal femurs. One of these, BAR 1002'00, preserves an intact head connected to the proximal shaft by an elongated neck. Although this fossil is comparable in size to Pan troglodytes, computerized tomography scans of the neck-shaft junction of BAR 1002'00 reveal that the cortex is markedly thinner superiorly than inferiorly, differing from the approximately equal cortical thicknesses observed in extant African apes, approaching the condition in later hominids, and indicating that O. tugenensis was bipedal.

The last paragraph reads:

"Our results show that the internal distribution of cortical bone in its femoral neck constitutes direct evidence for frequent bipedal posture and locomotion in this Late Miocene ancestor. In known features, external and internal, BAR1002'00 exhibits a total morphological pattern distinct from African apes, diagnostic of bipedal locomotion, and appropriate for a population standing at the dawn of the human lineage."

Interestingly, the authors did not - in this study - compare the femur with any australopith femur.