I think that the snappers from texas belong to the same normal serpentina serpentina but since texas is has its own climate and ecological status I assume that they can have their own unique version of genes and they certanly belong to snapper world and if you like them what a heck
Thouse are some of the most amazing turts. Since you have a copple I really must ask you to at least try to bred them because they are some of the most endangered turts on this planet, females are really hard to come by, breeding in captivity is unfornatly still extremely rare, importacion is virtualy no existent, the captive population both in the US and in Europe is becoming seriously old (and with 8 years old yours are very young and yes they are very slow growers) and in the wild this species is being literaly eaten out of existence