Each species has a different scale count on the face & head.. I don't know them off the top of my head but with a little google work I'm sure you can locate it...
Most/All Columbian Tegus are wild caught and are available in any number of sizes/ages...
Arg Tegus are almost exclusively captive bred these days. Since they will only breed in the spring, any cb Arg Tegu born in the northern Hemisphere will be lazy (hibernation) and fairly large (20" or so)...
There is a possibility that you will stumble one that is farm bred/born in South America that will be not much more than a hatchling (12" or so this time of year) but if I saw a 12" Tegu in early April I would assume it was Columbian unless proven otherwise (and the sellers word is not "proof").
Keep in mind a lot of sellers may be honestly selling the animal as it was labeled when they got it, but their supplier mislabeled it... So don't assume everyone with a questionably labeled animal is a bad guy.
Most/All Columbian Tegus are wild caught and are available in any number of sizes/ages...
Arg Tegus are almost exclusively captive bred these days. Since they will only breed in the spring, any cb Arg Tegu born in the northern Hemisphere will be lazy (hibernation) and fairly large (20" or so)...
There is a possibility that you will stumble one that is farm bred/born in South America that will be not much more than a hatchling (12" or so this time of year) but if I saw a 12" Tegu in early April I would assume it was Columbian unless proven otherwise (and the sellers word is not "proof").
Keep in mind a lot of sellers may be honestly selling the animal as it was labeled when they got it, but their supplier mislabeled it... So don't assume everyone with a questionably labeled animal is a bad guy.