I fail to see this as "evolution" - they are still the same species, are they not?
What is a species?
How do we tell, objectively, one species from another?
For example, how much evolution, or what kind of evolution, would it take to decide that a new species has developed?
Why is the development of novel species the minimally sufficient requirement for demonstration of evolution?
Have you thought about what the answers to these questions are?
No, it's not whatever. If you do not understand evolution you have no sound basis upon which to reject it.
Here's some food for thought. All mammals are members of the same class,
Mammalia, while also members of the same subphylum
Vertebrata, and simultaneously members of the same phylum
Chordata, the same superphylum
Deuterostoma, and the same kindgom
Animalia. All mammals will always be mammals, which means they will always be vertebrates, which means they will always be chordates, deuterostomates, and animals. Regardless, they still managed to evolve into cows, whales, apes, and dogs. Now if nothing stopped the mammals from evolving into that diversity of species, what exactly is stopping this species of skink from evolving into subspecies, and subsubspecies, and subsubsubspecies? Hmm?
You see evolution isn't so much about turning one thing into another, as it is the increasing diversification of biological life
within classifications. No vertebrate will ever evolve into an invertebrate, and no mammal will ever evovle into a fish. Evolution does not propose that they will, and in fact would be falsified if they did.