Yes, turquoises used to be considered a differant species than the green. Personally I still think they should be seperate. Obviously Kullander knows more about this than I do, but I would believe that turq's and rotkiels would be local variants of the same species and greens a seperate species.
Both turq's and rotties share a much smaller adult size than what greens get, both show the same breeding coloration, and they are found in close relation to each other, while greens are found hundreds of miles away.
Just My opinion though.