8th Ed. Critter base sizes?

I've got an old-school Stegadon that came without a base, and am looking to proxy some other models/toys for a Carnosaur or Bastiladon. What base size do they go on?
For that matter, what base size do Salamanders and Razordons have?

Thanks!

 

Stegs/carnasaurs are 50mm X 100mm ~ 2"x4"

Kroxigor/razordons/salamanders are 40mm x 40mm

Slann are 50mm x 50mm

 

Thanks n810!