Rufous or cinnamon colors are found on the males of most species of Drymophila antwrens, but this is not the case for the Dusky-tailed Antwren. The upperparts of the male are primarily olive gray, while the head and and breast are white, streaked with black. The female is cinnamon brown above, and buffy brown below. Both sexes have long, graduated tails, as do other species of Drymphila. The Dusky-tailed Antwren is restricted to the southeastern Brazil and adjacent regions of Paraguay and Argentina. Pairs or family groups forage for arthropods in the understory of humid forest and at forest edge. The Dusky-tailed Antwren seems to require dense tangles, and while it may occur in bamboo thickets, it is less strongly associated with bamboo than are most other species of Drymophila.