Oh Lin, I believe you've hit the nail on the head!
It certainly looks like a match with Oeceoclades maculata!
And the 'Flora do Brasil' has Oeceoclades maculatai as the only species of the genus present in the Rio de Janeiro state!
http://floradobrasil.jbrj.gov....
The bit left of the bug shewed leaf of mine gave the right hint of the shape shown on the photo of the species. It seems to only have one leaf at soil level.
