Re: Tyrannosauridae (Alioramus, etc.)

[HPB1956@aol.com]

Dear list members,

just welcome another member of the infamous "I did press the wrong button"
group, that means me. In a pressure situtation (my eight year old son and a
friend of him being behind me) while connecting to AOL I sent accidentally a
first and incomplete draft of an eMail. So sorry for that and how do I learn?
Yes, by trying again.


Alessandro Marisa wrote on 07/13/2001:

> Sorry, but I don't think that Siamotyrannus is an earliest Tyrannosaurids,
> I think that _Siamo_ is a Sinraptoridae, there are some evidence in the
> pelvic girdle.

In the description of Siamotyrannus ("The earliest known tyrannosaur from the
Lower Cretaceous of Thailand" by Buffetaut, Suteethorn & Tong in Natur, vol.
381,  p. 391) I found the following statement, which strikes me as very odd.

"Contrary to one hypothesis, because of the primitive state of the obturator
notch of the pubis in Siamotyrannus, tyrannosaurids cannot be derived from
allosaurids, in which this character is more advanced. However, this would
not preclude derivation from sinraptorids, in which the obturator notch is
more primitive."

So here Siamotyrannus is described both as a tyrannosaurid and a possible
sinraptorid. This would of course mean that Tyrannosauridae would be the same
as Neotetanurae (Allosauroidea + Coelurosauria).

Cheers


Heinz Peter Bredow