RE: weird jurassic dinobird with very weird feathers

[Tim Williams <twilliams_alpha@hotmail.com>]

Jaime Headden wrote:


> We actually only have one therizinosaur with a decent tail, and it seems to 
> be a basal taxon. We assume 
> reduction was occuring with a reasonable certainty, but after 
> *Beipiaosaurus*, graviportality seems to 
> have coincided with elevation of the dorsum and MASSIVE pneumatization of the 
> vertebrae, which helps
>  posteriorize the center of gravity back in front of the hips (but this is in 
> the bulkier, bigger taxa). 
[snip]
>shortening and elevation of the dorsum coincide also with shortening of the 
>dorsals and incorporation of 
> the dorsals into the elevated cervicals, as in *Nanshiungosaurus*.


Yep, well said.  It's amazing how therizinosaurs converge on sauropods in so 
many ways.  


> oviraptorosaurs, which have also undergone a distal shortening of the tail, 
> production of a pygostyle, 
> and so forth. 


Yes - any ideas why oviraptorosaurs did this?  They don't seem to have had an 
avian-style locomotory style, with the femur held near-horizontally (not even 
_Caudipteryx_), so the truncation of the oviraptorosaur tail is odd.


Cheers

Tim

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