Nyctimantis arapapa, also known as Bahia's broad-snout casque-headed tree frog, is a species of frog endemic to the Atlantic Rainforest of southern Bahia, Brazil.

[1] The frogs of the genus Nyctimantis are distinguished by a bony plate on top of their heads, referred to as "casque-headed".

Casque-headed frogs are characterized by their phragmotic behavior.

N. arapapa is further characterized by the long bill-shaped "snout" they possess, similar to that of Triprion petasatus, a head longer than it is wide, and their small size (male snout-vent length 57.4–58.1 mm).

This has two known purposes: warding off predators from the frog as well as their young (the male performs this action), and trapping moisture.