Siamotyrannus and early tyrannosaurids

["Tim Williams" <T.Williams@cclru.randwick.unsw.edu.au>]

Dinogeorge writes (quoting a UPI newswire):
 
> The discoverers, led by Eric Buffetaut of the Centre National de la
> Recherche Scientifique in Paris, are defending their find as the
> oldest and most primitive known tyrannosaurid, ancestral to all the
> later ones.

I wondered about this.  Aren't there at least two tyrannosaurs of 
equal or older age than _Siamotyrannus_?

I heard of a braincase from the Dinosaur National Monument of Utah 
(i.e. Late Jurassic) that supposedly comes from a small tyrannosaur.  
The last I heard of this braincase is that it had been provisionally 
referred to _Stokesosaurus_ (which was regarded as a tyrannosaurid by 
Jim Madsen back in the 1970's).

There's also a small, headless tyrannosaurid from the Early 
Cretaceous of Mongolia.  (I only know of this one through 
Dinogeorge.)  _Tonouchisaurus_ is it's name (_still a nomen nudum_ 
as far as I know).

Any takers?