Nice ray.
The marine guy where I work wiped out a whole lot of tanks that day. lost quite a few fish. I don't think it was the devils work, more likely the work of a dumbass!
Looks like a Peruvian Morph to me! A very nice one.. I've come across quite a few of these in my day and the patterns will vary slightly..
some are labelled Motoro 'Dumerelli' Flower when they get older, and demand a higher price, some have a striking pattern as well, one of my favorites under-rated rays. Attached is a pic.
The one you got could be any of the similiar morphs, but when they are 'Teacup' size they are usually sold as mislabeled 'Hystrix' as you well know.. I have seen these in a wide variety of patterns and species as well, and are also known as 'Raya Common' to some Peruvians. Heres a few shots of a mixture of Peruvian "Hystrix", including one with a nice purple hue around it's disc.
I assuming just about every 'Teacup' ray you will see for a long while will be these type of rays, due to the ban of export from Brazil. They are the least expensive of the rays when very young and usually become neglected and improperly shipped as they attempt to fit as many per box as possible.