Re: eureka moment [ptero histology]

[Mickey Rowe <rowe@psych.ucsb.edu>]

I still don't know what or why, but it appears something in the
listprocessor's configuration got zorched at USC yesterday.  I suspect
other messages were sent and not distributed.  So far this is the only
one that's been bounced to me.  I'll pass along others if/when they
come in.  -- MPR

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Date: Sat, 12 Jun 2004 12:12:37 -0500
From: Mike Hanson <mhanson54@comcast.net>
Subject: Re: eureka moment [ptero histology]
To: davidrpeters@earthlink.net
Cc: dinosaur@usc.edu

David Peters wrote:

>Cartilage, like concrete, is good at holding a shape, but it is
>vulnerable to outside forces. It can break easily. To make concrete
>stronger takes rebar. Find the rebar in pterosaur cartilage and you've
>got your answer to the perplexing problem of pterosaur growth.

I doubt pterosaurs were any different form the rest of all vertebrates 
as far as ossification, in fact, WHY would baby pterosaurs have 
cartilaginous skeletons? What advantage would a cartilaginous skeleton 
have opposed to an ossified skeleton? Also, while cartilage can hold its 
shape it would be extremely flimsy when it would be only micrometers 
thin. No matter what, pterosaur bones would have to be ossified for the 
pterosaur to be able to function, thin supports would not be enough to 
support cartilaginous tubes.

>I realized, just this morning, that I've seen the rebar in pterosaur
>bone histology papers. How it worked can be metaphorically seen [to
>quote G. Marx again] "in an ordinary object found everyday around the
>house." And it's a great bit of evolutionary ingenuity that works.

But what would be the reason for cartilaginous skeletons and a 
specialized supports? I'm sure that fully ossified bones would be a 
simpler, more reliable "bit of evolutionary ingenuity."

>I'll leave it at that for now.
>
>In an effort to exonerate Wang and Zhou from any blame regarding the
>misidentification of the "embryo" in the egg, I should also say that
>they are not the only ones who have published errors and oversights. I
>should have included Unwin, Bennett, Padian, Kellner, Wild, Wellnhofer,
>Dalla Vecchia and yours truly, David Peters, in that long list. I don't
>trust anyone's description, including my own. Test. Always test.

Which is all well and good, but it seems that you do seem to trust your 
description, possibly a bit too much. All the evidence you show against 
this being an embryo seems to rely extremely heavily on these 
discolorations and surface features being babies, as you claim. Others 
have tested and found no more than discolorations from ash, algae, 
bacteria, paint, weather, minerals, among many other things. Others have 
found chisel marks, stones, other sediment features, shadows, other 
artifacts of preservation and preparation, all of these where you find 
these supposed babies. Couldn't this be just another possibility to 
consider?

- -------------------------------------
Mike Hanson
Email: mhanson54@comcast.net
Website: http://www.archosauria.org
The Pterosauria: http://www.archosauria.org/pterosauria/
Dinosauricon Art Gallery: http://dino.lm.com/artists/display.php?name=mike

- --i5CHDrE18652.1087060734/listproc.usc.edu--
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