RE: [Feathers are not magical things...]

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: archosaur@usa.net [mailto:archosaur@usa.net]
>
> "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu> wrote:
> > >with the
> > >same covering (not placed anatomically;
> >
> > Don't know what you mean "not placed anatomically": the
> integuement for most
> of these specimens is clearly in position relative to the body
> (pointed side
> pointing towards the bone, frayed or broad side towards the outside).
> >
> +++++++++++++++++++++++++++++
>
> If you read the papers on _Sinosauropteryx_ _Beipiaosaurus_ or
> _Sinornithosaurus_ they all state how the "fuzz" is not placed in an
> anatomical position on the body.

Actually, I've studied the specimens in person.

> The stuff is either pointing
> away from the
> body or at an awkward angle or even not articulated with the
> body.

Pointing away from the body IS anatomical position.  See, for example, the
non-contraversial wing and tail feathers of _Archaeopteryx_.  Now, granted,
some of these (the Yixian forms) have fuzz which is spread out around the
body, but this is to be expected when you bury something in mud and preserve
it in closer to 2D than 3D.

> Falling on
> some Mesozoic plant during death (or floating into it) could preserve just
> such a formation.

Actually, only pointing away from the body would apply only in such cases
where the dino fell directly on the crown or other center of growth of a
plant.  Otherwise, you'd expect just as many cases of the leaves with
pointing towards the body and at various other angles to the body as
pointing away.

> > >mind you) seems a little dubious.
> >
> > Actually, the similar preservation isn't that weird: that's why we call
> such
> > sites Konservat-Lagersta:tten.  Given a particular rare set of
> depositional
> > and sedimentological circumstances, it is possible to preserve some
> features
> > that otherwise might be lost in fossilization.  The fact that only the
> > theropods (including birds) show the feather structures, while
> other taxa
> > from the exact same quarries and bedding planes do not (and instead show
> > either nothing or show impressions and carbonizations of integument
> > consistent with the known condition in those clades (scales on
> fish, scales
> > on non-theropod reptiles, fur on mammals, etc.)) is wholly
> consistent with
> > the hypothesis that the Yixian Fm. is preserving records of integument
> > rather than some non-integumentary growth.
>
> ++++++++++++++++++++++++
>
> I can agree with that; though I'd still be more comfortable
> reading on some of
> these other finds.

I will try and hunt up the mammal and insect and flower references today or
tomorrow: you can also search the web for these. (_Archaeofructus_ is a
plant taxon that comes to mind; I *THINK* _Jeholodens_ was a Liaoning mammal
preserved with fur, but my mind isn't as good for mammals as for theropods).

Needless to say, there has been a push to describe the theropods *first*
because, as high profile specimens, they have the best chance of getting
into high profile, short publication time, journals.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796