Re: COMPSOGNATHUS FEATHERS

["Tim Williams" <twilliams_alpha@hotmail.com>]

Pete Buchholz <Tetanurae@aol.com> wrote:

> I am not sure if it's all that clear Compsognathus lacked feathers.  The 
> specimen, as it is, doesn't preserve any skin to speak of.  So as they say, 
> absense of evidence is not evidence of absense.

Yep, I'll go along with that.  What I should have specified is that the 
absence of feathery integument in _Compsognathus_ if *real* would indicate 
sedondary loss, considering its phylogenetic position.

> Most of the feathers preserved in Archaeopteryx are the large primaries on 
> the wings and tail.  As far as I know, none of the softer contour feathers 
> are preserved in any specimen of Archaeopteryx.

This is a sore point, since according to some sources the Berlin specimen of 
_Archaeopteryx_ once showed feathers (albeit faint) elsewhere on the body 
(neck, torso, leg), but these were prepared away.  Then again, the same 
could have been true for the Solnhofen _Compsognathus_.  Nevertheless, you 
(and Mike) make a valid point: the absence of *any* preserved integument in 
_Compsognathus_ makes the absence of feathers in this maniraptoriform 
equivocal.


> There are even some specimens, where the primaries are so lightly 
> preserved, that it was unclear they even were present (the Eichstat and/or 
> Solnhofen specimen, and the Haarlem specimen), until advanced techniques 
> found them in the limestone.

To reinforce your point, the bird specimens from the Messel show various 
degrees of preservation when it comes to feathers.  These are neornithine 
taxa, so the presence of body contour feathers and tertials in the living 
birds is undisputed.  However, of all the feathers (when present), those of 
the outer are almost always the best-preserved, and the rest of the plumage 
may be poorly preserved or undetectable.  Hence, there is an apparent 
preservational bias favoring the primaries.  This could be the product of a 
stronger attachment, in life and death; it is the primaries at the distal 
wing that require the greatest resistance to torsional forces during flight.




Tim

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