From a biological standpoint, wheels would never work.
1) Won't work on most types of terrain
2) Bones would wear down badly, could only work on creatures with a VERY short life
3) Occam's Razor, wheels are much more complex to evolve then a pair of legs or a flipper. There is a progression from nubs to legs, how would one evolve a wheel?
So basically even if some creature went through all of the impractical steps toward creating wheels instead of legs, it would have died out because it would be horribly disadvantaged, essentially unable to travel and easily injured by rocks that would break its wheels.