"but it seems like science is being re-written daily"
What we are seeing is not rewriting science, it's simply variations on breeding similar or differential traits on same or nearly related species. To have a true scientific declaration of species or traits you need to have a much more detailed description than varying color patterns or tail lengths for example. The most accurate and definitive method for species origins and linage is to do DNA research to determine true species specific traits and this would also lead to determining if similar looking species are variations of the same species or have evolved entirely apart from one another. I suspect that there are many varying traits on similar specimens due to varying regions that each is found. Captive breeding would seem to back this up. The road is seems we are going down here is the same that the Carp/Koi is going. This is where there is a base species that is breed to have offspring of differing selective traits. The same could be said for dogs and cats. This of course would require a lot of research to determine how much is true different species and how much is varying traits among the same or very closely related species.
One thing for sure is that this type of breeding is or will be driven by market prices for selective traits much like koi or specially breed dogs or cats. Also this type of breeding has nothing to do with determining what the origin species was especially if you don't know for sure if its only varying traits vs. hybridizing differing species.
"In the US 500 or less live blackrays IMO."
There's more than you think. I recently went to the Dallas World Aquarium (where zoodiver and I used to work) for a leafy seadragon symposium and they have a tons of back area holding tanks where there were at least a couple hundred Leo/henlei rays not to mention what they had on display in the exhibits.
2cts.