I have an adult female who is a marble x motoro and she regularly breeds with my marbled male. I agree these rays are the same species so I am unsure the pups these two produce are 'hybrids' but are clearly lableled as what they are.
I have a female ray that was fathered by a marble and mothered by a motoro. The mother motoro is about 3x the size of the father marble, so I'm curious to see how large my pup will get. The pup is pretty. A lighter green than your average motoro and the spots are a much brighter yellow. I haven't seen any marbling yet though.