Ranitomeya uakarii
(Brown, Schulte, and Summers, 2006)
Madre Selva field station, Depto Loreto, Peru. January 9, 2011.
These tiny frogs are fairly common on the trails during the day, and we can find them in the bromeliads that are in the small trees around the field station.
My Flickr album for this species is here.