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In a message dated 1/10/2000 7:56:18 AM Pacific Standard Time,
> > 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
> could be interesting for me). I will surely look to find somthing about
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-
> claws, a perlvis, similar to the ornitishian's) but I will also look about
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.