The steadfast tube-nosed fruit bat (Paranyctimene tenax) is a species of megabat in the family Pteropodidae found in West Papua, Indonesia, and Papua New Guinea.

[2] The epithet tenax, derived from the Latin for 'steadfast', was intended to describe the conservation work of Peter Nijhoff, whose retirement was announced when the new species was discovered.

[2] The subspecific epithet marculus, derived from Latin, translates as 'little hammer' and the diminutive form of Marc Argeloo's name, a dedication to his collections of bats for the Amsterdam Zoological Museum.

Two subspecies were recognised by Mammal Species of the World (2005).

[3] The species is larger than Paranyctimene raptor, with recorded forearm measurements of 51.0 to 54.9 millimetres, and the greatest length of the skull in a range of 25.2–27.2 mm for both subspecies.