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Re: Quadraped Sailbacks-All non-dinos?



On Tue, 25 Apr 1995 cristeaj@pt.Cyanamid.COM wrote:
 
>      ...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.  

The first three are very good criteria.  The anatomical features uniting the 
dinosaurs are rather subtle.  A large, heavy tail carried off the ground is 
I think the most obvious (but glyptodonts had one too, and perhaps some 
synapsids).  I don't like using paraphyletic groups like reptiles - and 
sooner or later someone is going to ask him how to distinguish reptiles from
non-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!

Some dinosaurs had sails, smaller than those of Dimetrodon, Edaphosaurus, 
etc.  Spinosaurus and Ouranosaurus are examples, and if I remember rightly 
both of these are thought to have been largely quadrupedal.
                                                                Bill Adlam