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RE: [Re: Liaoning Freak Show at Dinofest ]

Whoa.  A whole lotta stuff in my inbox.  Here's an easy one to start with:
> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Caleb Lewis

[commenting on all those great coelurosaur fossils from Liaoning]

> It seems questionable to me
> that all these
> really magnificent fossils of very similar nature have come out
> all so close
> together (correct me if I'm wrong.)
>    So, I'm writing this for two reasons: first, to voice my
> concern over this;
> second, too wonder why this is happening. Is it just that they've really
> stepped up their paleontological efforts, or blind luck, or what?

You are right to be concerned, in so far as the demonstrable existence of
fakes (anything for a buck, or a yuan), so that any particular fossil should
be scrutinized.  However, the real deals DO come out of the rock there
(which is why there *is* a market for fakes).

This is an example of a Fossil-Lagerstatt (specifically, a
Preservat-Lagerstatt, to use Seilacher's terminology): a fossil unit which,
due to particular geologic circumstances (fine-grained sediment, possibly
anoxic bottom water (or at least some mode of reducing bioturbation, etc.)
to preserve the fine details of all the critters (dinosaurs, choristoderes,
mammals, insects, flowers, etc.) that became part of the unit.

Because conditions necessary for particular types of Preservat-Lagerstatten
only rarely occur, we get small windows here and there that allow us to
glimpse at some aspect of the paleoworld that would otherwise be missing.
The Yixian allows us to see the integument of many Cretaceous critters: had
conditions been correct in the Cloverly or the Dinosaur Park or the Arundel,
we'd be seeing it there and not in China.  The Burgess Shale and the
Chengjiang allow us to see the soft tissues of Cambrian taxa that are not
visible at most other localities: this isn't some money-making scheme of the
folks in British Columbia or in China, but a couple of lucky rolls of the
taphonomic crap shoot.  Some others:
        *The Mazon Creek localities: concretions preserve soft-tissue 
of Pennsylvanian aquatic fauna.  Includes the only fossil record of lampreys
and hagfish;
        *The Messel Shale: allows us to see the (not-unexpected) presence of 
on Tertiary mammals;
        *The Holzmaden localities: allows us to see the carbonized remains of 
soft tissue of ichthyosaurs: without these, we wouldn't know about their
dorsal fins.

So, yes: watch out for fakes from Liaoning, but don't be surprised that the
wonderful specimens happen to clump together in time and space.

Hope this helps.

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