The Large-tailed Antshrike is a large, dark antshrike of southern Brazil, eastern Paraguay, and extreme northeastern Argentina (Missiones). The male is black with small white speckles on the upperparts and flanks. The female is black with heavy buffy-golden mottling throughout. It occurs low in thickets, particularly bamboo, often at the forest edge or in clearings. Individuals or pairs move hop through dense vegetation, gleaning arthropods. Despite its large size, the Large-tailed Antshrike is not always easy to see; more often they are detected by the song, a loud, fast whistled series.