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Re: Feathery Symposium Encore



More things are coming to mind as time passes by.
One last remark concerning the arboreal tiny wonder: it had obvious
prehensile feet. The hallux was completely retroverted and (maybe because
defective preservation) the grasping of the feet reminded me of a chameleon!

Answering the questions of Nick Pharris:

>First, it was mentioned that various theropod integumentary structures
>were viewed IN MICROSCOPIC DETAIL.  Am I to take this to mean that the
>structure of the integumentary fibers in _Sinornithosaurus_,
>_Beipiaosaurus_, _Sinosauropteryx_, etc. has been clarified somewhat?

To this eyes and the majority of researchers (as far as I know... even
Larry Martin kept silent in front of Sinornithosaurus... the bristles were
too evident), there's no doubt that the integument is external, fibrous and
exhibit branching. Not only that, in the microscopic photographs of
Sinosauropteryx (presented by Phil Currie) you could see clearly the
branching at the tip of the fibers. Sinornithosaurus doesn't even need the
microscope to see the fibers one by one.
All this was also illustrated and documented by Richard Prum in his paper
"Development and Origin of Feathers".


>Second, I recall from last year's SVP that it was found that, at least in
>_Confuciusornis_ fossils, bone glows green and keratin glows orange under
>UV light.  Have any of the other bristly theropods been subjected to
>similar treatment yet to establish the presence of keratin in their
>integumentary structures?

The Beta Keratin test has already been performed by Mary Schweitzer in the
fibers of Shuuvuia. And it was positive. I'm not aware of any other at the
moment.

>Third, Luis mentioned that the tail previously supposed to belong to
>"Archaeoraptor" was lined with feathers.  What kind of feathers are we
>talking about here?  Vanes and barbs, or bristles?

I recall there were traces similar to  the tail of Archaeopteryx, but I
might be wrong . I couldn't study the ultraviolet photographs in detail
(the only way the feather 'fan' was visible). The base of the tail was
clearly bristly like Sinornithosaurus or the others. We'll have to wait for
publication.

>Finally, it was mentioned that Xu Xing has dug up some sort of feathered
>missing link between dromaeosaurs, oviraptorosaurs, and troodonts.  Can
>anyone give any more details without stepping on any fingers?

"A New Feathered Maniraptoran Dinosaur" Xu Xing
"In the summer of 1999, a juvenile maniraptoran was collected in the quarry
that produced a few Caudipteryx specimens. It preserved filamentous
integuments along the tail and represents the sixth non-avian theropod
species with feathers or feather-like integumantary structures from this
area. It is extremely similar to early birds but resembles oviraptorosaurs,
dromaeosaurids and troodontids..."

For more details I'm afraid we'll have to await publication.

Concerning Gauthier's rebuttal of Feduccia's 'warhorse' (the embryological
evidence of digit development in vertebrates)Gauthier presented the counter
arguments a while ago at SVP with his 'digit homology' paper (I'm finally
getting the paper to understand its complexities), which talks about the
doubtful certainty about the number and order of digit condensation during
embryological development...is it 1-2-3 for dinosaurs or 1-2-3 and 2-3-4
for birds? Or maybe another sequence as demonstrated in kiwis? Or maybe all
this is irrelevant for an argument against the dinosaur-bird link?.
I don't have all the details right now but Gauthier's devastating attack
"live" was enough to make Feduccia hesitate and falter a bit (for the first
time in the whole meeting). This is what Ralph Chapman is writing about,
and I agree with him that the debates were quite insufficient and rather
mediocre. Maybe everybody is tired of so many circular arguments.


Luis Rey

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