Scinax funereus
(Cope, 1874)
Madre Selva field station, Depto Loreto, Peru. January 19, 2014.
Found in a low, wet area close to the Madre Selva field station. A fairly common frog in the area, the mottled flanks and yellow flash marks on the interior of the thighs (see photo below) are key diagnostics.
My Flickr album for this species is here.