Quadraped Sailbacks-All non-dinos?

[cristeaj@pt.Cyanamid.COM]

     I was recently talking to an Earth science high school teacher about 
     how he teaches his kids about what makes a dinosaur different from 
     other prehistoric animals.  He told me that he uses "quadraped 
     sailbacks" (i.e. Dimetridon) as one discrimination as to what is _not_ 
     a dinosaur.  I told him that there were other (better) ways to 
     discriminate a dinosaur such as: (1) Lived only in the Mesozoic Era, 
     (2) Walked with legs directly under the body (not sprawled), (3) Lived 
     primarily on land, (4) Had unique anatomical structure (i.e. hips, 
     etc), and (5) All dinos were reptiles.  
     
     Although he uses some of the above, he still put in "Quad. Sailbacks". 
     Are there any quadraped sailback dinos?  I think the five 
     qualifications above are enough to qualify for dinosaurian without the 
     confusion of "Quad. Sailbacks".  What do you think?  Thanks!
     
     *************************************************************** 
     Jim Cristea                      
     Princeton, NJ                           
     <cristeaj@pt.cyanamid.com>                   
     
     These opinions are not American Cyanamid's
     ... They may not even be my own...
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%