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Re: really big question



Cliff Green (dinonaut@emerytelcom.net) wrote:

<... Ralph Miller says that birds where found on the site with feather
impressions. Fish where found with scale and internal tissue preservation.
Pelecanimimis was found with skin, tissue, and keritaneous preservation,
and no, repeat no plumage impressions. Saying that with all the other
animals at the site having this amazing amount of preservation, and
Pelicanimimis's feathers not showing up because of bad preservation is at
best, miraculous.
  Pelecanimimis's feathers didn't show up anywhere on it because it didn't
have any. This is a best guess estimate based on Occham's Razor, not on a
theory that states it has to have feathers because so and so's cladiogram
says it does.>

  Indeed, if pitted against Occam's famous razor, we could conclude that
the majority of animals show their natural state of integument. However, I
 feel I must continue to beat this dead horse for the sake of ONE
incarnation in this argument:

  Fossils in some lagerstätten do not show consistent preservation. No
such argument can be made to imply that all *Archaeopteryx* was bare, nor
that all were feathered, using Occam's razor on the same principle as
Cliff endorsed, to affirm that *Archaeopteryx* was a feathered animal
given that over 25% of the known urvogel fossils lack plumage of any sort.
In different environments, and depending on modes of preservation (Las
Hoyas being different than Solnhofen, both being different from the
various levels in the Yixian Formation), animals will NOT show consistent
forms of preservation. While it is true several birds show feathers, not
all of them at Las Hoyas do so. Nor is it true all birds at the various
Yixian localities show consistent preservation, nor even within the single
Sihetun site. Algal preservation, effect of lithology on taphonomy, and
the manner of death, all affect how a corpse ends up, especially given
integumental preservation. Note that while at Solnhofen, preservation of
integument is impressional, whereas that of the Yixian appears to be
carbonaceous: if the integument decays fast enough, nothing becomes
impressed, and nothing leaves carbonaceous traces.

  However, this avoids what appears to have been my point: I never argued
that *Pelecanimimus* had feathers or dinofuzz, or otherwise, but rather
than the skin preservation was NOT impressional, as appears to not occur
at Las Hoyas, but carbonaceous, meaning the keratin WITHIN the skin is
present, and conforms to a pattern of collagen found in most organismal
skin, instead of the surface of the skin itself; the nature of the
collagenous/keratin preservation, does not allow one to determine naked
skin versus feathery integumnet, as far as I can tell.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


                
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