Re: Yandangornis - my 2c

["Timothy Williams" <twilliams_alpha@hotmail.com>]

I'm not too sure what to make of this fossil.  Of course, I haven't seen it 
with my own eyes, but based on the photos accompanying the description, I'm 
surprised at some of the details described by Cai and Zhao.  The orientation 
of _Yandangornis_'s pubis, for example - for a specimen preserved 
two-dimensionally in ventral aspect only, the determination that the pubis 
is oriented backwards is a little brave on the part of the authors (IMHO).  
Same goes for some of the details of the femur.

If someone showed me the photos and told me that the specimen belonged to a 
small _Elmisaurus_-like nonavian theropod, I think I would have believed 
them.  (It's not clear though, either from the photos or the author's 
reconstruction, if the foot is arctometatarsal.)

By the way, the specimen shows no trace of feathers or any other 
integumentary structure.  This is not to cast doubt on the avian affinities 
of _Yandangornis_, it's just that I forgot to mention it in my last post.

My 2c.


Tim

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