Small, chunky bird with a short tail endemic to the Brazilian Amazon. Male has black extending from face to chest and a bright white tuft. Female lacks those features and has a chestnut breast and a long, white line over the eye. Note its limited range south of the Amazon River and between the Tapajós and Tocatins Rivers, which helps separate it from Chestnut-belted Gnateater. Male Black-breasted has more extensive black on the underparts extending to the chest. Female looks almost identical. Stays low inside the rainforest, and usually seen sitting quietly on a low perch, where it may suggest a small antpitta. Song is a descending, stuttering trill; also gives abrupt buzzing and wheezing calls. Formerly treated as a subspecies group of Chestnut-belted Gnateater.