Actually, the number of legs is much earlier in evolutionary terms than even than amphibians.
Pretty much all larger live on earth has 4 limbs, even fish.
head, shoulders, ribs, back, hips, and optional tail seem to be the way of life here.
If your world has 6 legged toads, maybe its just that everything on their world has 6 limbs rather than 4.
Wierder things have happened, just look at trichordites.
Pretty much all larger live on earth has 4 limbs, even fish.
head, shoulders, ribs, back, hips, and optional tail seem to be the way of life here.
If your world has 6 legged toads, maybe its just that everything on their world has 6 limbs rather than 4.
Wierder things have happened, just look at trichordites.