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Re: Bird flight once more (was Re: What is a Dinosaur? and semilunate carpal)
<<First, it would be good to clarify that dorsoventral movement of the wrist
only occurs if the
arm is held outward, level to the horizon.>>
Chris Fisher (firstname.lastname@example.org) wrote:
<Imagine a traffic cop waving cars past - this is the movement of the hand I
orientation of the arm too. Could a maniraptor direct traffic? :)>
probably not. The first maniraptoran with the ability to level the elbow to
the height of the
shoulder was *Unenlagia*, thus only Avialae among Dinosauria can do this.
Chris also writes:
<I'm thinking all these changes made the arm and hand better for HOLDING prey
but not very good
for FEEDING - like using the hand to bring food to the mouth>
Hmm... Predation does not pertain to the feeding on the animal itself; unless
the jaws are used
to kill the animal, as in cats or canines [dogs, wolves, etc.], jaws are not
part of the equation.
<But what about movement between the metacarpals and the carpal block - the
distal surface of the
semilunate carpal. Could this act as a hinge? How was this contact strengthemed
- or that between
There is no joint between the distal carpals and the metacarpals in
contact is broad, and the semilunate is firmly appressed to the metacarpals.
There is to a degree
one in *Allosaurus* and *Acrocanthosaurus*, but this contact is firmed by
several pedicels that
prevent any joint from occuring. There is no way for a joint to be present
between carpal and
metacarpal elements in any dinosar except for, possibly, *Blikanasaurus* and
have the proximal tarsals contact the proximal surface of the metatarsals.
However, this is not
Jaime A. Headden
Where the Wind Comes Sweeping Down the Pampas!!!!
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