Re: Is there a feathered juvenile *Psittacosaurus* specimen?

[David Marjanovic <david.marjanovic@gmx.at>]

> --- Ursprüngliche Nachricht ---
> Von: "Jaime A. Headden" <qilongia@yahoo.com>
> Datum: Tue, 13 Dec 2005 18:46:43 -0800 (PST)
>
> David Marjanovic (david.marjanovic@gmx.at) wrote:
>
> <Today morning I received, for reasons I don't quite
> understand at the moment,>
>
>   Perhaps a response to earlier comments on the issue?

I had already been pointed to the pdf. -- It turns out it was a 
misunderstanding on my part.

>   This is actually possibly what the study on random fibers in collagen
> bundles would be preserved as, not regular pennate-like structures that
> would immitate feathers, which is nice when it happens once, randomly,
> in a small area, but not regularly, over the entire fossil, in shapes
> mimicking feathers, and in so many fossils including matching the same
> structures in birds, that to call them collagen fibers rather than
> feathers is stretching things.

Well said.

> and since bone surfaces rarely seem covered in ANY integumental features
> in Jehol-biota fossils, excluding them as surface integument (i.e.,
> skin) is presumptuous, as well as attributing them below the ribs, when
> it is also possible they were parts of the intercostal tissues, thus
> neither above nor below the ribs.

As I mentioned, it is below the ribs. In places where the rib is missing, 
the striations continue in and through the groove left by the rib. This is 
well visible in parts of fig. 13A and maybe 13B.

> This specimen is nice to document the issue, but it's not "news", as
> specimens by the dozens, including *Monjurosuchus* and
> *Keichousaurus* specimens are also known by such specimens,

You mean specimens not preserving feathers?

Anyway, you don't mean *Keichousaurus*. I don't know what you mean, but 
*K.* is a Triassic pachypleurosaur from somewhere in southern China.

> *Sinosauropteryx* is perhaps the most fascinating of
> these for it's implications as a first bird

?

> Theagarten-Soliar

Theagarten Lingham-Soliar. I don't know what his parents were thinking, 
but "Theagarten" really seems to be his first name. ~:-|

> In addition, the authors argue against the filamentous nature of the
> structures in *Sinornithosaurus* (Dave, NGMC 91) but later stress they
> are bird allies but not theropods,

Very good point. I hadn't read most of the text yet.

> so if they were feathers, _that's okay_. No, actually, it's not,
> because if they ARE feathers, you see, their entire use of
> random structures to identify feathering collagen patterns [...] and
> the paper was a waste of time.

Yep.

>   Now, just imagine, if they are right, if the outlines of the
> *Monjurosuchus*, *Jeholotriton*, and various dinosaurs, as well as
> ichthyosaurs, are collagen imprints of natural body outlines, they
> would have been some massively blubbery skins, and skins so thick the
> salamanders would have suffocated and dehydrated to death for lack of
> the ability to aspire and absorb moisture through the dermis. Ah,
> c'est la vie.

The salamanders are all supposed to be larvae or neotenic aquatic adults, 
right? So at least they wouldn't dehydrate!

> <On to the last new claim about a fossil. Illustrating an apparently
> unpublished specimen of *Pelecanimimus*,>
>
>   That's actually the holotype of *Pelecanimimus polyodon*, LH 7777.

Really? So that they write "Unprepared fossil" means the photo was taken 
before preparation? ~:-|

The text says both "LH 7777" and "a new specimen".

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