Yes, as a matter of fact I indeed do know where they come from. However, it seems no one wishes to believe me, they all want to believe they are something special. "Blues" that I have been shown, that I've seen in pictures clear enough to determine characteristics, are nothing more than T.merianae with black noses. So, where do "Blues" come from? Well, they come from anywhere T.merianae comes from. Basically, east of the Andes to the Atlantic ocean, from northern Argentina north to the south shore of the Amazon.
However, for the point of clarity so as to avoid people telling me I'm full of bovine fecal matter, I've been done here in South America for a year and a half. Every time I point to what hobbyists refer to as a "blue tegu", and ask a local scientist, particularly one of the ones originally involved in designating and describing a number of the Tupinambis species, I'm informed that they are T.merianae.
Furthermore, I'm currently living in Rio Claro, Sao Paulo state of Brazil - ie. no where near Colombia. There are LOTS of those black nosed T.merianae around here. And as for the claim of them being the most gentle tegus of them all, I don't contest the captive ones can be, but the wild ones have a tendency to charge and attack people.
And lastly for this rant (sorry, russ1066, I truly apologize, I am not exactly directing this tirade at you, just everyone who doesn't want to believe because some breeder ((albeit a respected and highly successful breeder)) claims otherwise) that in pairs that I have bred down here, pairs of positively identified T.merianae where neither parent is a "blue", in the clutches produced we get some "blues". I haven't tested it, but I'm pretty sure if you breed a "blue" with a "blue" you'll likely get mostly, if not all black nosed tegus- ie. "blues". Therefore, my claim, and I keep asking people to provide me with the scientific evidence to contradict me (anyone? anyone?) what I know of as "blues" (and admittedly, maybe I've never seen a true "blue", which would indicate that those I have been shown and were claimed as as "blues" were not true "blues"
are not a distinct species, nor are they a distinct subspecies, they are merely a morph. Whew.
That being said, they're sure pretty.