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Re: New alvarezsaurid
> I mean mobile in the way the semilunate makes it mobile. "Better"
> in this context means 'more suitable'. >>
>In this context, this is hardly illuminating. I don't think there's any
>you can show that a maniraptoran hand makes maniraptorans better
>than the looser, relatively shorter, more mobile hand of earlier
>Can you, for example, accumulate statistics on the kill ratios among
>maniraptorans versus those among earlier theropods, and then relate
>ratios to the structure of the hand?
It sounds like you misunderstood. My point was that the maniraptoran
hand is not suited for hunted and they did not hunt using it as a main
Of course you cannot accumulate stats on the kill ratios, however nice
it may be. I'm not saying that because ( in my view ) the maniraptoran
hand was really unsuited for hunting that they weren't effective hunters
( in the predaceous clades ). What I am saying is that the hand is
really suited for other tasks.
>I think your predilection for the BADD paradigm has led you to the
>that the maniraptoran manus must somehow have been better for predation
>why would it have appeared in cursorial predators?), and that you are
>searching for a way to demonstrate this presently undemonstratable
You misunderstand. I'm saying that it did not evolve for hunting.
And I think you are assuming that I believe in the " ground-up " origin
of flight; I believe in the trees-down origin of flight.
>In the BCF paradigm, the structure of the maniraptoran hand doesn't
>kind of explanation; this kind of hand is retained in cursorial,
>maniraptorans simply because it was present in their flying ancestors.
>was present in the flying ancestors as a stage in the evolution of the
>bird wing; we know this because the modern bird wing has a basically
Of course. Though I would not say flying ancestors, it may have
evolved for climbing like Chatterjee proposes.
><<In phorusrhacids, the ancestral manus was of a flying form, and it
>did not stay that way. I ask _why_ did phorusrhacids lose the ability
>for the manus to "swivel"? Attention must be put on the function of the
>forelimb and manus of phorusrhacids. They both were used for subduing
>prey; using this exapmle you can see that a manus with limited rotation
>can be used for prey seizing. Most birds have a rounded carpal block,
>which allows them to tuck their wing. Phorusrhacids have a squared
>carpal block, which means that the manus lies parallel to the
>Using the phorusrhacids as an example, it can be shown that a stiffened
>manus in the sense of rotation, is very advantageous for bipedal
>predators that are similiar to theropods. >>
>Here again, we have no idea what phorusrhacids used their stunted wings
>Have you ever seen a phorusrhacid hunt, or read an eyewitness account
>it did with its wings? The arguments about how phorusrhacids hunted are
>endless and circular, and lead to no confirmable conclusions. Their
>anatomy may have the differences you describe, but there is no way you
>ascribe those changes to "hunting advantages" or anything else. To
>state that phorusrhacid wings were used to subdue prey is simply bad
>since you have no way to show this to be the case.
Let's look at something. You yourself state that the maniraptoran
manus and carpus is a step toward the modern bird carpometacarpus. Now
then, if that is true we should look for an analog for the what would
happen if a flying hand is coopted for hunting like in phorusrhacids.
Since the maniraptoran manus is that of a flying form and does not
confrom to the predaceous phorusrhacid manus, then we can assume that
the maniraptorans did not have a manus that is suitable for hunting as
Padian and Gautheir suppose. This shows that the frequently sited
"predatory stroke" of the maniraptorans is not for predation. These
posts were actually an argument against the "ground-up" hypothesis. You
have misunderstood what I have been saying about phorusrhacids, I did
not describe any specific hunting modes or styles, I just stated that
the phorusrhacids had forelimbs adapted for predation. Since
maniraptorans ( the predaceous ones ) did not have the same sort of
forelimb that phorusrhacids had, it can be said that the maniraptoran
forelimb was not evolved for predation and was a minor or nonexistent
factor in predation. I am making an informed judgement on the function
of maniraptoran forelimbs using a frequently sited analog. The judgement
on maniraptoran forelimbs is that they had no predatory advantage and
did not evolve for predation. I am not saying that they were inferior
predators or anything else like that. I am not conjecturing on the
phorusrhacid style of hunting. I am not a supporter of the "ground-up"
hypothesis. I am a supporter of BAMM and believe Chatterjee's notion of
the evolution of the maniraptoran manus. I hope there will be no more
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