Osteocephalus deridens is a species of frog in the family Hylidae. It is found in the Napo and Pastaza River drainages in eastern Ecuador and in the Loreto Region, northern Peru. The specific name deridens is derived from Latin deridere, meaning "make fun of someone". This alludes to the males calling from the treetops that sound "as if they are laughing at the collectors' vain attempts to reach them". Common name funny slender-legged treefrog has been coined for this species.

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