Aripuanã Antwren

The Aripuana antwren is 11 to 12 cm (4.3 to 4.7 in) long and weighs about 11 g (0.39 oz). Adult males have a black crown and nape, a long whitish supercilium, and a black streak through the eye. The rest of their upperparts are gray. Their wings are black with white tips on the coverts and white edges on the flight feathers. Their tail is black with large white feather tips and white edges on the outermost. Their throat is pale creamy white and their breast and belly whitish. Adult females have an orangish forehead and a black crown with white streaks. Their upperparts are gray. Their throat is a creamier white than the male's and the rest of their underparts are whiter than the male's.

The Aripuana antwren was first described from the area between the rios Aripuanã and Machado (the interfluvium) in Rondônia. It is now known somewhat more widely along the right bank of the Rio Madeira and along the Rio Roosevelt in more of Rondônia, southeastern Amazonas, and northwestern Mato Grosso. It primarily inhabits old-growth campinarana forest on nutrient-poor soil. The trees seldom exceed 20 m (66 ft) in height. It also occurs in tall undisturbed terra firme where it favors areas with Lepidocaryum tenue palms.

The Aripuana antwren's diet is known only from the stomach contents of specimens, which were the remains of insects and spiders. It forages singly, in pairs, and in family groups and frequently as a member of a mixed-species feeding flock. It mostly forages in the canopy by gleaning prey from vegetation.