Science has nothing to do with it ( you can't make a science out of anything you can't totally control the parameters )... they are all .carbonaria - just from different locations - so maybe [ at best ] they are sub-species!
Without going into any details.. mine outside are separated by a wall and that's because I don't want any cross-breeding. NO I am not talking out of both sides of my mouth! Early on I mixed Northerns and Brazilians ( cherries and red foots? ).. no aggression.. just different looking redfoot tortoise hatchlings - different meaning colors.
And who started [ back whenever ] the nonsense that a male and female redfoot together is potential for domination? How could that possibly be a risk? I've yet to see any domination from any of the .carbonaria locales since 1998.
Plus of course I have to do the usual disclaimer to keep them - whoever them is - from getting all indignant.... "There is always exceptions and extremes"!