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

Atlantic Rainforest The Atlantic Forest ( pt, Mata Atlântica) is a South American forest that extends along the Atlantic coast of Brazil from Rio Grande do Norte state in the northeast to Rio Grande do Sul state in the south and inland as far as Paraguay and the ...

of southern

Bahia Bahia ( , , ; meaning "bay") is one of the 26 Federative units of Brazil, states of Brazil, located in the Northeast Region, Brazil, Northeast Region of the country. It is the fourth-largest Brazilian state by population (after São Paulo (sta ...

, Brazil. 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 ''Triprion petasatus'' is a species of frog in the family Hylidae found in Belize, Guatemala, Honduras, and Mexico. Its natural habitats are subtropical or tropical dry forests, moist savanna, freshwater marshes, intermittent freshwater marshes, ...

'', a head longer than it is wide, and their small size (male snout-vent length 57.4–58.1 mm). This species, and all species of ''Nyctimantis'', use their unique head shape to seal off the leaves of bromeliads, the plant they inhabit solely. This has two known purposes: warding off predators from the frog as well as their young (the male performs this action), and trapping moisture.

References

{{Taxonbar, from=Q2858126 arapapa Amphibians of Brazil Endemic fauna of Brazil Amphibians described in 2009