quote:
None of the feathered dinosaurs turned out to be birds.
Terry D. Jones showed that
Caudipteryx' body construction resembles more like those of birds than dinosaurs
Quote from here:
http://www.findarticles.com/...158/65301566/p1/article.jhtml
Jones contends it's unlikely that Caudipteryx's ancestors would have abandoned a body structure and style of walking that proved successful among all other bipedal dinosaurs. Instead, he says, the most likely explanation for the animal's distinct body proportions is that Caudipteryx is a bird that for some reason lost the ability to fly. Says Jones: "It's almost ludicrous to think that this animal reorganized its body so that it could run like a bird."
and the original paper in Nature :
Nature 406, 716 - 718 (2000); doi:10.1038/35021041
Cursoriality in bipedal archosaurs
TERRY D. JONES*, JAMES O. FARLOW, JOHN A. RUBEN*, DONALD M. HENDERSON & WILLEM J. HILLENIUS
* Zoology Department, Oregon State University, Corvallis, Oregon 97331, USA
Department of Geosciences, Indiana-Purdue University, Fort Wayne, Indiana 46805, USA
Department of Cell Biology and Anatomy, School of Medicine, The Johns Hopkins University, Baltimore, Maryland 21205, USA
Biology Department, College of Charleston , Charleston, South Carolina 29424, USA
Present address: Department of Biology, Stephen F. Austin State University, Nachogdoches, Texas 75962, USA.
Modern birds have markedly foreshortened tails and their body mass is centred anteriorly, near the wings. To provide stability during powered flight, the avian centre of mass is far from the pelvis, which poses potential balance problems for cursorial birds. To compensate, avians adapted to running maintain the femur subhorizontally, with its distal end situated anteriorly, close to the animal's centre of mass; stride generation stems largely from parasagittal rotation of the lower leg about the knee joint. In contrast, bipedal dinosaurs had a centre of mass near the hip joint and rotated the entire hindlimb during stride generation. Here we show that these contrasting styles of cursoriality are tightly linked to longer relative total hindlimb length in cursorial birds than in bipedal dinosaurs. Surprisingly, Caudipteryx , described as a theropod dinosaur, possessed an anterior centre of mass and hindlimb proportions resembling those of cursorial birds. Accordingly, Caudipteryx probably used a running mechanism more similar to that of modern cursorial birds than to that of all other bipedal dinosaurs. These observations provide valuable clues about cursoriality in Caudipteryx , but may also have implications for interpreting the locomotory status of its ancestors.
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