Hi Luis, definitely looks like something in
Section Didactyle, but beyond that I don't know. All the plants I've seen in that section open their flowers much wider, so yours seems pretty unusual (which might make it easy to ID if you can find a species description). Unfortunately I've never been able to find much info about these; my Bulbophyllum books don't really cover the New World ones and my books on Brazilian orchids tend to ignore them, too. Good luck, it's a cool one!
--Nat