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Re: Ah ha! That's where therizinosaurs came from



<GSP1954@aol.com> wrote:

> The rather poor success of Cenozoic continental flightless birds is not
> applicable to the  Mesozoic neoflightless protobird hypothesis because derived
> birds may have trouble being competitive without useful arms.


Personally, I think theropod arms are overrated.  Which is why so many
theropods shortened them.


> And will not rediscuss my extensive discussion in the literature of why
> reversed halluxes are not critical for arboreality, why Archaeopteryx did have
> enough of reversable hallux for climbing (with pictures and everything), why
> forms in the process of becoming arboreal should not be expected to have a
> full suite of arboreal characters, yadda, yadda.


Archaeopterygids had a hallux that was not reversed, not incumbent,
and not especially large.  It takes special pleading to reconstruct
any archaeopterygid (or any deinonychosaur, for that matter) as a
percher.


That said, I have no objection to certain paravians using the hallux
in climbing.  I agree that the pes of archaeopterygids, jeholornithids
and microraptorines show incipient arboreal characters.  But what's
curious is that the aerial specializations of the integument are so
highly derived, and yet the pedal specializations for climbing and
perching were so piss-weak.  If flight began in the trees, and these
critters (archaeopterygids, jeholornithids, microraptorines) were
arboreal - why was the pes so poorly adapted for arboreality?  A "full
suite of arboreal characters" is one thing.  A complete lack of a
perching pes is another.


> Someone said I am inconsistent in rejecting cladograms that contradict the
> neoflightless hypothesis while accepting those that do.


Yes, I said that.  Worse, you cherry-pick parts of the *same*
cladogram.  What if a cladogram recovers an
archaeopterygid-deinonychosaur clade, but fails to support an
omnivoropterygid-oviraptorosaur clade?  Do you then claim one part of
the tree is "right" but another part is "wrong"?  It's the *same*
cladogram!  The different parts of the cladogram were drawn from the
same taxa and the same character states.





Cheers

Tim