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Re: PAGATIA DO NOT MEAN VOLANT ANCESTRY



In a message dated 8/21/98 5:30:58 PM Eastern Daylight Time,
m_troutman@hotmail.com writes:

<< There are few osteological correlates for pagatia>>

I've heard others say that, but I've never heard or read any description of
what those osteological indicators are.  What are they?  Any references to
those works?

<< (Patagia) really don't leave any signs.  So far, the earliest evidence for
a pagatium (in the dino/bird lineage) is the Early Cret. enantiornithine?
_Noguerornis_ and  (possibly) in _Confuciusornis_, but not in _Archaeopteryx_.
As far as I  can tell, _Caudipteryx_ and _Protarchaeopteryx_ both lack a
pagatium. >>

I'm not sure I follow this.  It doesn't seem to square with your first
statement that there are a few osteological indicators.  If patagia (actually
it's the propatagia we're discussing) "really don't leave any signs," what
criteria were used to determine the earliest evidence of patagia or for
concluding that C and P didn't have patagia?

<< The arm posture found in _Oviraptor_ and all other maniraptoriforms 
 including birds is not really indicative of a pagatium. >>

It's certainly not conclusive, but it is an arm posture that would be expected
if a creature did possess a propatagia.

<<Within the animal world "flight" features have not always meant "descend 
from a volant ancestor". >>

True enough.  Feathers are a good example.  But some features do indicate a
volant ancestry--such as the ossified limb bones of the flightless
Alvarezsaurids as evidence that they evolved from volant birds that possessed
a fused carpometacarpus.  The fossil record shows that the fused
carpometacarpus evolved after powered flight (Archaeopteryx, Eoalulavis and
Confuciusornis for example).  Given the way the Patagialis muscles and the
carpometacarpus function together, my personal feeling is that the propatagia
probably did as well--although I'm still trying to work the sequencing out in
my own mind.