RE: Tarbosaurus?

["Tracy Ford" <tlford@ix.netcom.com>]

    The pat answer I was talking about was "population sampling in formation
A is automatically the same as in formation B without evidence to the
contrary", not the number of tyrannosaur species argument that's based on
it.

> but to me the signal is so strong that it overwhelms the
>complications, which often work against one another and cancel (for
example,
>there may be a low tyrannosaurid ratio in a facies, but collectors take all
>they can find, increasing the ratio through collection bias). The taphonomy
>is like noise; you can sometimes filter out the effects to get at the
>underlying information.

One of the things about taphonomy from a river/flood isn't a real idea of
that area. The animals died somewhere else and floated to where they were
buried. For example, Dinosaur National Monument in Utah has several
skeletons that 'floated' to where they are now. They originated most
probably somewhere in Colorado. Could have floated for miles before sinking.
The same is true for the marine dinosaurs. The San Diego Ankylosaurid was
found miles from the shoreline in hundred or so feet of water.
Cleveland-Lloyd is a good indication of that environment. An eolian or sand
dune deposit is a good indication of that area. River beds are not.
Tracy