the Cuban anole (Anolis sagrei sagrei)
i'm from an hour or two south of there. brown anoles are ALL OVER the place, and have been since i was born. your story was very nice and convincing even, except for the fact that i've lived around these things all my life.
they can change the lightness and darkness of their skin, and i think the patterns, according to environment. they're nowhere near as good at it as chameleons, but that is probably the origin on the statistical differences.
-- although, the anoles surviving the colder weather up in g'ville may indeed be evidence of speciation.