Re: Archaeopteryx chimaera

[jconrad@lib.drury.edu]

--On Monday, February 22, 1999, 12:00 PM -0500 tsg94001@uconnvm.uconn.edu
wrote: 

> 
> Does anybody know why certain theropods (dromaeosaurids, birds,
> therizinosauroids) have the pubis pushed back?  I have heard that
> ornithischians have an opisthopubic pelvis because it makes space for a
> bigger gut (always helpful when digesting cellulose-rich, nutrition-poor
> plant matter).  This could apply to therizinosauroids too, but why did
> dromaeosaurids and birds do it?
> 

Reduced tails (as far as mass goes).