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Re: Jeholornis - long-tailed bird in today's Nature
Well, not seen the paper, but i will be up to the advocate Tim has
offered and suggest this disclaimer, to advocate ajn alternate hypothesis
to a dino-bird link. The animal is a theropod dinosaur, small that evolved
several convergent features in common with birds, but it is clearly not a
bird as it lacks feathers. Note that in the Yixian, all birds have
feathers or are clearly modified in way only associated with feathers or
flight, such as a long pygostyle, large sternae, etc. Quite obviously,
this animal evolved convergent arm structure with birds, not because of
flight, but because the animal had a need to exapt its limbs for grabbing
things, á la Ostrom's series, or for arboreal scampering, which is seen in
many primates that similarly evolve very long arms with needs for
opposability in the foot and a balancing tail. It does not in the least
advocate an origin for birds from theropods.
Now, having said this, note that I am not an advocate for the
non-dinosaurian origin of birds, but I do like thinking on the other side
of the coin.
Jaime A. Headden
Little steps are often the hardest to take. We are too used to making leaps
in the face of adversity, that a simple skip is so hard to do. We should all
learn to walk soft, walk small, see the world around us rather than zoom by it.
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