The only taxa which are currently known to have tails stiffened with elongate prezygopophyses and chevrons are dromaeosaurids, Achillobator, Bambiraptor, Sinornithosaurus, cf. Sinornithosaurus and Microraptor. Other theropods like troodontids, Rahonavis, Archaeopteryx and alvarezsaurids lack such structures.<
Also include in the "have" list _Coelophysis bauri_. See my abstract on the NAPC webpage for a few more details. Peace, Rob
Student of Geology Northern Arizona University Biological Science Tech Manti-La Sal National Forest AIM: TarryAGoat http://www.geocities.com/elvisimposter/dinopics.html http://www.cafepress.com/RobsDinos "A _Coelophysis_ with feathers?"
_________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com