Just acquired this one. From briefly searching my best guess is it's a Den. atroviolaceum hybrid. I'm curious to hear what others think, and if anyone has experience growing something similar.
Well, it is a Latouria Dendrobium. They are easy to care for-- don't let them dry out. I do not know the specific cultivar. This is my Dendrobium atroviolaceum V. compactum. It flowers profusely-- I don't see as many flowers on yours. I wonder if it is an intergeneric cross?
Mine looks like it was a bit neglected. It was completely dry and falling out of its pot. Most of the roots are dead but it does have a couple live ones left. I gave it a soak in some seaweed extract and am going to pot it up tonight.