postorbital bars

[GSP1954@aol.com]

It is good to see the existence of a complete postorbital bar in Archaeopteryx
 finally verified. I knew that a postorbital was present but was not sure how 
complete it was. I discuss the probably existence of the postorbital bar at 
length in DA. As I explained, the quadrate in very procumbent in Archaeopteryx, 
so the short postorbital process of the jugal is far enough forward to 
articulate with the jugal process of the postorbital (as it does in 
ornithomimids). 
So yet another supposed avian feature of the basal deinonychosaur Archaeopteryx
 dies. 

It is all the more interesting that Xu both in Nature (as a pers comm) and 
when I was doing a skeletal restoration insists that Microraptor probably 
lacked 
a complete postorbital bar. The quadrate is nearly vertical in the 
dromaeosaur, and the postorbital process of the jugal is short, so it does not 
look like 
contact with the postorbital is possible. In my hi res photos of the complete 
but badly crushed skull of sinornithosaur NGMC 91-A I think I can see a 
slender jugal with a short postorbital process with no contact with the 
postorbital. 

As for Confuciusornis I have seen good skulls that clearly show the 
postorbital bar was complete and had a normal archosaur articulation. This 
included a 
beautifially preserved skull being prepped at Tyrrell. 

GSPaul