Please help me identify this white (tree) frog

[RemyW]

Hi all, I've been searching the internet for a tree frog that my girlfriend found in Cuyabeno, Ecuador. Because of its distinct whitish color (and eyes) I figured it would be easy to identify, however I can't find anything resembling it.

The local guide was surprised to see it and afterwards they could not find it in any of their books...

Any help (family name) would be appreciated! Thanks!