Hollow theropod bones

[tidwell@ix.netcom.com (Virginia Tidwell)]

Tom Holtz:

Ken set me straight on this one.  My mistake, the medullary cavity had 
been present on this specimen originally.  The cavity was essentially 
filled in when one side of the bone was crushed, giving it a solid look.

The Carnosauria has been a problomatic grouping ever since its 
inception. I know that D.Norman, et all, have moved tyrannosaurids out 
of Carnisauria, but in the Dinosauria, Molnar retains them on his 
Carnisauria cladogram. He does not list any arguments for doing so, 
however.  He may still be using Carnosauria as a catch-all for "all the 
big theropods that don't fit in any other group". Why do you think that 
they don't fit on the Carnisaur clade?

                      Still slightly puzzled in Denver
                            Virginia Tidwell