Pseudopostega tanygnatha is a moth of the family Opostegidae.

It was described by Donald R. Davis and Jonas R. Stonis, 2007.

[1] It is known from north-western Costa Rica The length of the forewings is about 2.3 mm.

The species name is derived from the Greek tany (meaning long) and gnathos (meaning jaw) in reference to the slender, greatly elongated caudal lobe of the male gnathos.

This article relating to the family Opostegidae is a stub.