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RE: Quadraped Sailbacks-All non-dinos?



A response to Jim Cristea's posting:

Taxonomic diagnoses should include what a taxonomic group IS rather than 
what it is NOT!   A few dinosaurs did survive the KT boundary and lived 
(briefly) during the early Paleocene (Tertiary) so the generalization ONLY 
Mesozoic doesn't hold.  Lots of "reptilian" vertebrates primarily live on 
land so this isn't apt.  Dimetrodon was a "reptile" as well; best to abandon 
reptile and talk about diapsids, synapsids, archosaurs, lepidosaurs, etc. 
and focus on the definitive characters for these groups.  I have been doing 
this successfully with 4-5th graders.
 ----------
>From: dinosaur
To: Multiple recipients of list
Subject: Quadraped Sailbacks-All non-dinos?
Date: Tuesday, April 25, 1995 4:38PM


     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...
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