Thank you for the detailed answer. I hope someone does do that study. It would be great to get it finally sorted. I imagine it would be tricky to get the samples for R. armeniacus and R. bifrons when it came to U.S. pools. I suppose that to be safe, the bifrons samples could come from the eastern states, and the armeniacus samples from the western states, but then, maybe that would be compromising the goal of getting the full range for each. 
Do you have an opinion on how we should handle the iNat taxa in the meantime?