
Plethodontohyla notosticta habitat shot, 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
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. Closeup:

''Plethodontohyla notosticta'' is a species of frog in the Microhylidae family. It is endemic to Madagascar.
Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical moist montane forests, and heavily degraded former forest. It is threatened by habitat loss.