The Ancient Antwren occurs in lowland forest in southeastern Ecuador and northern Peru. It has yellowish sides of the head and underside, with white wing bars on a gray back.
The sides of its head and underside are yellowish. White feather edges and tips form two or three bars across the otherwise dark-gray upperparts.
It lives in moist, sandy-soil lowland forest below 200 m. It often joins mixed-species flocks and forages among thin branches and leaves in the upper trees. Its food is poorly known but is thought to include small invertebrates.
An extinction-risk assessment has not been added yet.