Re: Dinofest

[augwhite@neosoft.com (Toby White)]

Jonathan wrote:

>>Is Currie supposing patches of feathers all over the body?  Couldn't have
>>been many of them.
>
>He is and sure there could've.  Most of them simply rotted away with
>the rest of the flesh.

I've read this about Currie's argument since my inquiry.  Sounds reasonable.

>>In fact, this argument appears to be about the biophysical properties of
>>protein fibers in general.  I'd bet (i.e. speculate) that the properties in
>>question are not very sensitive even to the chemistry.  Take any protein
>>fiber, stretch it, dry it, and randomly shear it.  Does it tend to adopt
>>erect structures with a tendency toward hollow cylinders?  I don't know,
>but
>>the answer could well be that it does.
>
>That is true, anything is possible, some things are just less likely
>than others.

Sorry.  I'll be more direct but, perforce, more technical.  Protein fibres
are always (AFAIK) built up from cross-linked helical monomers.  The basic
helical pattern is dictated by bond angles and electrostatic forces.
However, the exact periodicity and conformation is heavily influenced by
hydration (the result of some interesting thermodynamics, the details of
which I've long forgotten).  The strands are also cross-linked, normally by
hydrogen bonding which is also, inter alia, influneced by hydration.
Decrease the hydration and shear the strands.  What happens?  Probably you
torque the strands so that they twist away from the axis of the original
fibre, quite possibly forming a thing that sticks out and curls like Geist's
collagen.  Hollow?  Yes.  Sheared and broken strands will hydrogen-bond
along their margins forming cylindrical structures.  What will it look like
after 65 Myr?  I don't know, but Sinosauropteryx "feathers" are not an
improbable result.  

>The people in Geist's lab work on the physiology
>of extant animals (and I'm sure they do great work) and are not trained
>paleontologists (to my knowledge).  It seems to me that they know almost
>next to nothing about dinosaurs, let alone interpreting fossils (at least
>that's the idea I get when I read their papers on dinosaurian anatomy).

The folks in Ruben's lab I'm familiar with (which doesn't include Geist) are
reasonably experienced and are frequently published in peer-reviewed
journals on matters dinosaurian.  They have also been quite careful to study
avian and crocodillian anatomy in detail.  Whether their anatomical studies
have been fruitful, I'll leave to those more expert.  However, whatever the
merits of their conclusions, their credentials are more than adequate.  

  --Toby White