Re: New theropod (or is it?) from Poland

[David Marjanovic <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Dawid Mazurek" <dawidmazurek@wp.pl>
Sent: Tuesday, August 12, 2008 9:28 PM

> Oh, the museum actually is in Lisowice! The brick pit is in Lipie ÅlÄskie
> though.

Oh.

Apologies, BTW, for butchering the spelling that badly. I knew there's no n 
in it, and I knew there's an e at the end, and I even knew why! Must have 
been the time pressure; I left for Serbia the same day, to see most of that 
branch of the family for the first time... I came back this morning.

> >Both features occur throughout rauisuchians and never in theropods.
>
> Isn't "rauisuchian" just a term for a grade? They don't have any
> autapomorphies, don't they?

The last few phylogenetic analyses have indeed found them to be 
paraphyletic. But none of them are reasonably large, as far as I know, and 
most date to 1994 and before. (The *Qianosuchus* paper from 2006 finds a big 
polytomy...) The main reason, as lamented in the description of *Postosuchus 
alisonae* (JVP June 2008), is that detailed descriptions don't exist for 
most "rauisuchian" species. I simply tried to cut this long story short.

Given the unique gait (vertical femur with dorsally-pointing head and 
ventrally-pointing acetabulum -- seen very nicely in the *Lotosaurus* 
exhibited in Beijing) that is said to characterize all rauisuchians plus 
aetosaurs, I wouldn't be surprised if they turned out to be monophyletic. 
But I have no idea how widespread it really is, how many grades of it exist, 
and so on. I'm not among the very few experts on those animals.