OK, they can't interbred, but they're the same species?
Are you actually serious?! Then how do you define species?
The article didn't say that they couldn't interbreed. It said that they had "changes in courtship behavior."
I suspect that if you lock any species in a jar for 49 generations there will be some who tend to exhibit some deviant sexual attitudes.
Fish and turnips are different species. That is all you need to know.