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Re: New alvarezsaurid

In a message dated 98-03-26 02:26:20 EST, m_troutman@hotmail.com writes:

<< >Alvarezsaurids came up with the keel and opisthopubic pelvis, it seems, 
 >independent of the hesperornithiforms or whoever else developed the 
 keel 
 >back before the K-T boundary.
 
    Why does it seem that they evolved it independly of other birds? 
  >>

The keeled sternum goes back at least as far as allosaurids; the new
allosaurid at Dinosaur National Monument has a keeled sternum.