Yixian _Psittacosaurus_

[Josh Smith <smithjb@sas.upenn.edu>]

In a message dated 9/16/99 6:35:33 AM Pacific Daylight Time, 
LOKICORP@compuserve.com writes:

<< we haven't
 found ornithischians from the Yixian (or any other formation) with a
 similar degree of preservation. >>

Then  DV wrote:
  Yixian psittacosaurs exhibit the scaley tuberculed type of hide
according to posts from June of last year. DV.

1. Please don't interpret this as my supporting the idea that
ornithischians are feathered or that we should "expect" to see it in
them because there are saurischians with such structures.

2.  There is, to my knowledge (and I am about 98% sure that nothing
published to date contradicts this, but at the rate that stuff comes out
of this bloody place, who knows...) only a single psittacosaur from the
Yixian (interested parties are welcome to look at the faunal list from
my Ostrom Symposium ms).  This psittacosaur is, to my understanding
represented by a single specimen from Sihetun (from Sihetun itself, I am
pretty sure, not from Jianshanghou or Heitizigou or the like).

3.  As I write this, I am sitting here looking at a photo of this
critter, _Psittacosaurus_ sp., that I took.  My memory and the photo
show only a small place on the slab (the normal Yixian siltstone bedding
plain with the specimen preserved mostly in only two dimensions) where
any sort of "carbonized remains" or "integumentary structure" is
preserved.  There certainly are not any feathers, but there is also no
real evidence for any structure to the hide.  Indeed, it would be a
stretch to say that this black stuff MUST be related to the specimen.

-Josh

Josh Smith
Department of Earth and Environmental Science
University of Pennsylvania
471 Hayden Hall
240 South 33rd Street
Philadelphia, PA  19104-6316 USA