The steadfast tube-nosed fruit bat was described from a small set of specimens around New Guinea. In the nominate subspecies, the recorded coat was dark brown above and yellowish white below.
In the nominate subspecies, fur on the sides of the head was pale grayish brown. The back was medium to dark brown, darkest between the shoulders; the breast and belly were yellowish white and the flanks yellowish brown.
In a 2008 New Guinea survey, Paranyctimene bats were caught in primary forest near fruiting figs and in secondary forest. The authors said those specimens might be P. tenax, but did not confirm the identification.
An extinction-risk assessment has not been added yet.