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Comments on the Birdy National Geographic.



This is long overdue but finally I got some time.

I'm still in awe of the excellent fossil photographs in the new issue of
National Geographic. The Confuciousornis couple is astounding.

Looking at the new great specimen of Sinosauropteryx I couldn't help to
notice a clump of 'structures' precisely at the tip of the tail (never seen
before), I think somebody in the list already noticed this. But I would
like to stress the point again.
You can discern clearly the difference between the fibers that run along
the tail and turn into a fan of at least seven  of what I'd call 'feathers
without quills'. So Sinosauropteryx had TWO kinds of dermal structures.

Now, interpretrations can go either way: the fibers turned into
protofeathery clumps (that would be the standard view, and also very
acceptable to me)
or... the protofeathers 'disintigrated' into fibers. So the structures we
can see at the end of Sinosauropteryx tail could be the original
protofeathers.

A hypothetical BCF scenario would be that the protofeathers were first and
localized all along the tail (and back) that was used as an aerodinamic
rudder in the jumps from tree to tree.
 I think there has been too much stress in later discussions  about
'flight' but a lot less about 'arboreality'.
In the BCF scenario, the primitive dinosaurs were arboreal but still NOT
flying in the strict sense of the word. A strong case of this scenario is
that most or all known compulsory bipedal animals have gone through an
arboreal phase (as far as I know)in their evolution.
I could add that an active creature with a different  metabolism and
aerobic capacity demanded insulation, and dispersed the rudder structures
into filaments that finally covered most of the body. Something kept (or
lost) in one form or another in the complicated process of becoming fully
terrestrial.

Returning to National Geographic, I found the cladogram very peculiar. I
think flightlessness should have been kept as an option, if just because
Caudipteryx and Protarchaeopteryx show a very high degree of
specialization.
In fact Caudipteryx 'looks' more bird-like than Archaeopteryx itself, only
that Caudipteryx is obviously a non-flying or maybe secondarily flightless
animal.
I also have doubts about the restoration of the Velociraptor hands (I have
seen better ones that challenge the one depicted here with a frontal
'grasping' motion. In reality Velociraptor should have been restored as
with specialized, clawed 'wings' with a restricted movement.
On the other hand the restoration of Unenlagia in the cladogram is
completely, beautifully outlandish. I don't think we have evidence for the
skull, or have we?

And about the models, well... Sinosauropteryx really let me down with its
'boxed', lizard-like skull and lame protofeathers. Caudipteryx is not bad,
but the head looks too artificial to me.
Brian Cooley is a fantastic sculptor (and one of my favourites), but I have
the feeling that this time he could have done better.
I know, I'm just being fastidious... so much work.

More later.

Luis Rey

Visit my website at http://www.ndirect.co.uk/~luisrey