[Titus Quinctius Cincinnatus]

What kinds of genetic changes did they find? Any?

Well, the very fact that these lizards are quite a bit different (entirely different gut structure???) would seem to presuppose genetic changes, since genetics (genotype) is what controls their phenotype.

I wonder if these lizards could or would mate with members of the original species which was implanted in 1971?

[Question_Assumptions]

You can have quite a bit of differentiation without much genetic change or change in species. If I'm not mistaken, all domestic dogs are the same species, right? In fact, both wolves and domestic dogs belong to the species canis lupus with domestic dogs being the sub-species familiaris and wolves the subspecies lupus.