Plethodontohyla notosticta closeup, Nosy Mongabe, Madagascar

Sometimes the common name "Narrow-mouthed frog" is used for this species, but that's not accurate, because it is the common name of the genus, which contains 9 species, all endemic to Madagascar. I narrowed those 9 down based on distribution and believe to have found a species match, based on this reference image:

http://www.alamy.com/stock-photo-narrow-mouthed-frog-plethodontohyla-notosticta-nosy-mangabe-madagascar-87793154.html

That still does not make it a sure match, as various sources are conflicting in what their real distribution is.

Small frogs (and chameleons) for us were a very pleasant surprise in Nosy Mangabe, like discovering a whole new category of life. As the island has almost no birds, it's an interesting category to turn your attention to, not to forget the lemurs of course. Here is a habitat shot for an idea of its size: