Re: Coelurosaur ischium unique?

[NJPharris@aol.com]

In a message dated 12/19/01 11:13:39 PM Eastern Standard Time, 
kinman@hotmail.com writes:

>     Does the coelurosaur ischium always possess at least two of the 
>  following three features?   Each of these features is occasionally lacking 
>  in a few coelurosaurs, but I believe that all coelurosaurs have at least 
two 
>  of the three (and most would have all three):
>       Ischium (1) reduced to less than 2/3 length of the pubis; (2) lacking 
>  an ischial foot; and (3) possessing a prominent, triangular obturator 
>  process (placed more than 25% down the ischial shaft).

Tyrannosaurs and ornithomimosaurs generally have ischia more than 2/3 the 
length of the pubis, and at least some specimens of each have obturator 
processes placed less than 25% down the ischial shaft.

  
>       And the flipside (converse?) of this question is---Are there any 
>  non-coelurosaurs which also display at least two of those three ischial 
>  characteristics?

Not sure.  Coelophysoids can't really be said to have obturator processes at 
all.  I am pretty sure I have never seen a non-coelurosaur with the classic, 
_Ornitholestes_- or _Deinonychus_-type triangular obturator process.

--Nick P.