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Re: Dinosaur Genera List update #196



Mickey Mortimer wrote:

> Dino Guy Ralph wrote-
>
> > Hey, how come _Cryptovolans pauli_ didn't make headlines in 2002?  It
> looks to be
> > what _Archaeovolans_ was purported to be.

That was very sloppy on my part.  I meant _Archaeoraptor_, not _Archaeovolans.

(Mickey wrote):

>  Probably because-
> 1. It was not described in Science or Nature.

Yes, it only appeared in a Brief Communication in _Nature_.  It was not named in
the _Nature_ paper.

> 2. It was described so very poorly, with virtually no useful described
> morphology or line drawings.

While I would wholeheartedly agree that a more rigorous paper is called for, and
more figures would be greatly appreciated, I think you exaggerate.  Papers with
less information and documentation have made a bigger splash in the popular
press than this paper, and the gratuitous color photographs of the specimens are
way more than you will see in a any budget minded journal.

On the other hand, I can understand that when a paper comes from an unfamiliar
source -- or a source that is considered lacking in credibility for whatever
reason -- this is bound to make a difference.  _The Dinosaur Museum Journal,
Volume 1 :Feathered Dinosaurs and the Origin of Flight_, is unorthodox, to say
the least, and it is not as easily obtained as _Nature_ or _Science_.  The tone
of the writing alone is enough to put readers off.  I understand this.  I also
want to make it clear that I strongly disagree with much of the content of this
book, particularly regarding the ancestry of birds and what does and what does
not constitute a theropod.  On the other hand, I am swayed to consider that we
may have here a flying deinonychosaur.  Either that or a very unusual bird.  The
more bird-like the non-avian dinosaur, and the more non-avian-like the bird, the
harder it becomes to tell which is which.  Just look at _Mononykus_ and its
kin.  The completeness and the quality of preservation come into play, too.

Mickey wrote:

Even though it seems to be a dromaeosaur, this is only based on the elongate

> distal caudal prezygopophyses and chevrons.

In the _Nature_ paper, the authors were sufficiently impressed with the slabs to
refer to the original fossil as that of a "dromaeosaur."  We are free to
disagree with this interpretation, of course.

>  The fused sternal plates are an
> avian character that could put it at the base of the Avialae.  If this were
> true, it would not be good evidence of secondary flightlessness.

Could it then be a dromaeosaur that is also a basal avialian?  Could subsequent
nonvolant dromaeosaurs have lost this feature?  Generally speaking, the oldest
deinonychosaurs are the most bird-like, as would be expected in a sister taxon
to _Aves_, whether the MRCA be a flying animal similar to _Cryptovolans_ or a
flightless animal.  Could _Cryptovolans_ and its closest kin have independently
acquired advanced flight features?  The fossil record is notoriously incomplete
with respect to delicate, hollow skeletons, leaving details of coelurosaur
phylogeny unresolved.

In _Dinosaurs of the Air_, Gregory S. Paul has forwarded his criteria for
secondary flightlessness in a fossil maniraptoran.  Where do you think his
character profile is wrong, and what features would you propose as being more
appropriate?

While I am comfortable with cladistics and the use of parsimony as the best
techniques available to science, the necessary bias against reversals must lead
to the erection of incorrect phylogenies in some instances.  Is not uncertainty
fundamental to the nature of science?

Dino Guy Ralph wrote:

   > Hopefully _Archaeovolans_ will get its due in mainstream

> > paleontological circles soon, and hopefully more wonderful finds will
> issue forth
> > from the astonishing fossil beds of China.

Aaargh!  I meant _Cryptovolans pauli_.  I apologize for the mix-up.  Apparently,
_Archaeovolans_ is nothing new, although it's nice to see new photos.  I would
like to see intensive independent analysis of _Cryptovolans_ to see what other
paleontologists have to say about the specimens.  We have read Gregory S. Paul's
support for the interpretation by Czerkas et al. that this looks to be a genuine
flying dromaeosaur.  Let's see what other scientists make of it.

----------Ralph W. Miller III
               ralph.miller@alumni.usc.edu