They are nice rays but yes from the pic you posted they are not a Xingu sp. The multiple spine rows are very noticeable even a pup of a true xingu and your defiantly appear to be a single row.
I do have a question of another way to possibly tell the difference of then and that is the texture of your rays? Is the skin smooth looking like that of a leo or is it kind of grainy that of like a marbled motoro?
Just curious
i would have to take a closer look. he is currently in a pond, so it it hard to tell.
