Re: T-Tip

[NJPharris@aol.com]

In a message dated 1/10/2000 7:56:18 AM Pacific Standard Time, 
The-Diehl@t-online.de writes:

>  > Have you read up on other early
>  > tyrannosaurs? (Alectrosaurus from Mongolia, Siamotyrannus from Thailand).
>  > The earliest theropod with tyrannosaur-liek features (particularly the
>  > braincase) is Stokesosaurus clevelandi from Late Jurassic North America.
>  > Its not a good idea to put together and evolutionary scenario by choosing
>  > just three species and ignoring a host of others.
>  
>   Hm... I never heard of Siamotyrannus and Stokeosaurus (especially this 
one 
>  could be interesting for me). I will surely look to find somthing about 
them.

Unfortunately, there isn't much to _Stokesosaurus_ beyond the braincase, an 
ilium, and a few other scraps.  And _Siamotyrannus_ is more likely some sort 
of carnosaur than a basal tyrannosaur.  _Tonouchisaurus_ is also supposed to 
be some kind of tyrannosaur relative, though I have yet to see anything 
published on it.

A point about an earlier post.  Coelurosauria is a well-defined taxon, 
diagnosed by much more than mere size.  Tom Holtz pointed out a few years 
back that tyrannosaurs are coelurosaurs, so some coelurosaurs grew very large 
indeed.  Other large coelurosaurs include _Dryptosaurus_ and _Deltadromeus_, 
large therizinosauroids, and _Deinocheirus_.


>   Interesting. I don't know what I should say about the Troodontids (raptor-
> like 
>  claws, a perlvis, similar to the ornitishian's) but I will also look about 
> this. 

A number of advanced coelurosaurs had more or less dromaeosaur-like claws 
(_Rahonavis_, _Megaraptor_, rudimentary in _Archaeopteryx_), and there are 
significant differences in the foot claws of troodonts and dromaeosaurs.  
Troodont pelves have a forward- or downward-pointing pubis, unlike birds, 
dromaeosaurs, and ornithischians.  But I concede that they don't look a whole 
lot like tyrannosaurs or ornithomimosaurs, either.

--Nick Pharris