Dinosaur Sorting Exercise for Primary Students

[Amado Narvaez <anarvaez@umd5.umd.edu>]

I am planning a dinosaur unit for primary grade students, and one of the 
exercises is sorting dinosaurs by different characteristics. They will 
have the following models from the Carnegie Collection:
        Apatosaurus     Brachiosaurus
        Diploducus      Stegosaurus     
        Allosaurus      Tyrannosaurus
        Triceratops     Iguanodon
        Euoplocephalus  
They will sort the dinosaurs as 1) plant eaters vs meat eaters; 2) biped vs 
quadruped (with Iguanodon as a sort of fence sitter); 3) lizard-hipped or 
bird-hipped.

My question is: If I also want the kids to sort them as sauropod, 
theropod, or ornithopod--what can I do about Stegosaurus, Triceratops and 
Euoplocephalus?

Any suggestions? (The easiest thing would be to just leave them out and 
have them sort only the other six. But the brighter kids might ask why 
there isn't a "-pod" classification for the omitted ones.)

----- Amado Narvaez
      anarvaez@umd5.umd.edu