Caudipteryx et al

[Ronald Orenstein <ornstn@inforamp.net>]

Well, I'm still reeling from all the news - including the NGS press
conference, which I just listened to on the net.  However, some points
already occur to me:

Currie et al state (tentatively) that Caudipteryx and Protarchaeopteryx
support the ground-up view of bird origins and the origin of fathers for
some purpose other than flight.  I do not dispute either of these
hypotheses, but I am not as convinced that these finds are conclusive in
these areas.  This is because the specimens postdate Archaeopteryx.

The postdating argument is often raised by opponents of the bird-dinosaur
connection - I am NOT doing that here (if Caudipteryx isn't a nail in the
coffin of the Feduccia-Martin view I don't know what is - they haven't
proposed that the tail fan of Caudipteryx is a set of flukes for swimming,
have they?).  However, the important point about the age of these fossils
is that they were coeval with "true" birds like Confuciusornis (to me, the
most eye-popping image in the NG article is the photo of the pair of the
latter with the amazing tail plumes on the [presumed!] male).

That means that Caudipteryx may represent, not an image of what the common
ancestor of birds and dinosaurs looked like, but a derived survivor of that
ancestor living in a world where the small-flyer niche had been taken over
by the more "advanced" flyers derived from Archaeopteryx and its kin.  It
may have survived because it could coexist with smaller flyers better than
a small volant or semi-volant animal lacking the adaptations of more
specialized "true" birds may have been able to do.

A comparison may be made with the palaeognathous ratites.  We now know
that, in early days, there were a lot of small, volant palaeognaths - but
with the advent of the neognaths these disappeared, leaving as survivors
only tinamous and a collection of large, secondarily flightless creatures
that occupy a quite different niche from that of any neognathine bird.

Thus Caudipteryx may represent a type of "dino-bird" that would, perhaps,
have been atypical in the early Jurassic, but which was able to coexist
(and apparently coexist very successfully) with birds once they appeared.
If there were small volant or semi-volant pre-Archaeopteryx dino-birds I
would not have expected them to last long once true birds appeared (any
more than I would expect to find an Archaeopteryx alive today), except as
relicts perhaps.

I am NOT speculating one way or the other as to whether Caudipteryx was
secondarily flightless!  Currie et al certainly seem to think otherwise.  I
am only suggesting that we have to be careful in using such survivors as
Caudipteryx to draw conclusions about what the original dino-bird was like
- much as we have to do in drawing conclusions about the early monotremes
from the platypus or the echidna.


--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court                 
Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@inforamp.net