Re: Pygostyle

[dbensen <dbensen@gotnet.net>]

>>
It has been my experience that everything can be used to argue anything in
this field, and therefore nothing has any meaning. Pygostyle schmygostyle.
Think whatever you like; it makes no difference.<<

I disagree here.  Things like that DO mean something because it seems that
ONLY ADVANCED BIRDS have pygostyles.  If the oviraptor was taken alone, then
that would work out; the oviraptor is a flightless bird that hasn't lost a
feature of its ancestors.  However, less advanced (more basal, whatever)
oviraptors than this one DO NOT have pygostyles, and so we know that the
feature is not  something from its ancestors.  This fossil has very far
reaching effects as I see it.  Either
a) GS Paul (and other's) hypothesis that the oviraptors are flightless birds
is wrong (I certainly hope it isn't), or
b) the pygostiles are convergent (is such a feature useful enough to be
evolved independently?  Do regular pygostiles and the oviraptor's share enough
features that we know they are actually the same, not just superficially
similar structures?)
c) Caudipteryx and all the other dinosaurs we consider more basal than this
unnamed one are actually more derived and have lost this pygostyle (doubtful,
since they were earlier than the unnamed one and we more primitive in many
respects)
e) This thing isn't an oviraptor at all (I don't think so, but how much do we
REALLY KNOW about this creature.  "So mister Oviraptor, if that _is_ your real
name . . .":)
f)The pygostyle was glued on by a Chinese farmer or a graduate student (You
know those farmers:)

As I look at this list, I think that a or b is the most probable solution
(given Occam's razor, a is the best), but I really like Dr. Paul's theory
about flightless birds and it makes sense in every other instance.  I hope
that there is just a simple answer that I haven't thought of.

Dan