Aripuana Antwren occurs in the south central Amazon Basin, where it appears to be restricted to a small area on the east side of the upper Madeira River in Brazil. This species first was discovered (by ornithologist Douglas Stotz) in 1986, but initially was believed to be an isolated population of Black-capped Antwren (Herpsilochmus atriciapillus) of eastern South America. Later research established that Aripuana Antwren merits recognition as a separate species, and so in 2013 it was named after its discoverer. The upperparts of Aripuana Antwren are primarily gray, but it has a black crown, tail, and wings, the latter with white wingbars. There is a conspicuous whitish supercilium, and the throat is pale creamy white, becoming whitish on the breast and belly. The sexes are similar, but the female has an orangish forecrown, and the crown has short white streaks. Aripuana Antwren is similar in plumage to several related species (including Black-capped Antwren), especially in the male; but females are distinguished from related species by the details of the color and pattern of the forecrown and throat. Fortunately Aripuana Antwren is more readily distinguished from related species by the pace and structure of the song. Like other species of Herpsilochmus, pairs regularly join mixed species foraging flocks, and primarily occupies relatively low stature forest on nutrient poor upland terraces. Recently fledged juveniles have been observed in July and August, although the nest itself has not been described. Otherwise this is a very poorly known species, and little is known about the natural history of Aripuana Antwren.