Which specific physiological characteristic, besides dome shape and land preference, defines a member of Family Testudinidae?

Answer

Non-webbed feet

The fundamental difference between a tortoise and other Testudines members often comes down to the specific profile: dome shape, non-webbed feet, and a strong preference for land.

Which specific physiological characteristic, besides dome shape and land preference, defines a member of Family Testudinidae?
animalclassificationreptiletortoisetestudine