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Re: I knew it!
Greg Paul wrote:
I've always been skeptical about this because it makes no functional sense
for animals that used their hands for manipulation to have such limited
lower arm and hand rotation. [snip]
Am very suspicious of arguments that this was true of any dinosaur, except
perhaps those with such reduced arms that it does not matter.
Another likely exception is the higher Maniraptora. The manual digits of
oviraptorosaurs and deinonychosaurs have a tendency to show reduced
mobility, on account of (1) the locked interphalangeal joints and/or (2) the
close appression of the proximal metacarpals. (The oviraptorid _Heyuannia_
even shows some carpometacarpal fusion).
Thus, maniraptoran hands would have been capable of limited manipulation
anyway. The biomechanical studies of Gishlick indicate that deinonychosaurs
could only grasp objects using both hands, and this may have been true for
oviraptorosaurs as well. There may have been an adaptive advantage to this
inflexible manus (such as for grasping large prey, in the case of some
deinonychosaurs), or it might be a relict of an ancestry among flying
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