[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: New alvarezsaurid
><< Theropods, and
> espcially the "flightless" ones still have mobile wrists which are
> incongruent with forelimb function as " prey holders ". >>
>Of course they had mobile wrists, because the wings of their ancestral
>retained considerable grasping ability. Having a mobile wrist (and even
>opposable manual digit I) is not at all incongruous with "prey
>ancestral forms were nowhere near as highly adapted fliers as are
>birds, so their flightless cursorial descendants retained considerably
>the non-flying forelimb functions than did, for example, flightless
>maniraptorans or more modern flightless forms.
Flying requieres considerable control over the movements of the manus
in birds. All birds, basal and derived, had more control over the
movements of the manus. Larry Martin has shown that even Archaeopteryx
had a heart-shaped ulnarae. All enantiornithines had heart-shaped
ulnarae. The only thing that really makes the basal bird manus more "
primitive " is that the fingers were more mobile. Regardless, a mobile
manus is not a predatory design. A manus where the phalanges are
parallel to the radioulna is better for "prey handling" because it
resists strain and is inheritantly more stable.
Get Your Private, Free Email at http://www.hotmail.com