Re: Albertosaurinids

[pharrinj@PLU.edu]

On Sat, 6 Jan 1996 Stang1996@aol.com wrote:

> OK, I've got _PDW_ in my hands (I love the way the glue smells in this book
> by the way...) and it is turned to the Albertosaur page.
> 
> We have got _Albertosaurus sarcophagus_ which seems now to be the only valid
> species of _A_, right?
> 
> Then we have got _Gorgosaurus libratus_ which is only the skull AMNH 5458 (in
> the book anyway).
> 
> Then we have _Gorgosaurus sternbergi_ which is much more gracile than _G. l._
> and represented by AMNH 5664 and FMNH PR308.
> 
> Next is _Gorgosaurus arctunguis_ which is maybe represented by TMP 81.10.1.
> 
> Now _Dasplateosaurus torosus_ is recognised as an Albertosaurinid, and
> _Dinotyrannus (=Albertosaurus) megagracilis_ and _Nanotyrannus lancensis_as
> Tyrannosaurinids.
> 
> Is this right?  Is this making any sense?
> 
> I do _not_ like the name _Gorgosaurus_ AT ALL by the way.
> 
> Oh, also, that giant Morrison Megalosaur that Bakker was blathering on about
> could be _Brontoraptor_ too (watch him be a lurker on the list...).
> 
> Peter Buchholz
> Stang1996@aol.com
> 

Well, I tend to think of _Nanotyrannus_ as more primitive than any other 
known group of tyrannosaurs.  Its wedge-shaped skull, narrow beak, large 
orbits, forward-pointing parasphenoid, and infratemporal fenestra without 
any large rostral process of the quadratojugal and squamosal make it the 
most troodont- or ornithomimid-like tyrannosaur known (i.e. the most 
primitive).  That not all of these features are strictly size-related can 
be seen by examining the skulls of other small tyrannosaurids (_Alioramus 
remotus_, _Gorgosaurus sternbergi_, _Maleevosaurus novojilovi_), which 
have broad snouts and, in particular, large rostral processes across the 
infratemporal fenestra.