It was formerly considered a subspecies of P. erythropthalmus, but under the common name red-eyed thornbird. When split, P. erythropthalmus is known as the orange-eyed thornbird. Unlike that species, the orange-breasted thornbird has dark reddish-brown eyes, extensive rufous to the underparts, a relatively large rufous crown-patch, and dark central rectrices (which contrast with the rufous outer rectrices). The two also have different voices and are locally sympatric in São Paulo without evidence of interbreeding.Simon, J. E., Pacheco, J. F., Whitney, B. M., Mattos, G. T., & Gagliardi, R. L. (2008). Phacellodomus ferrugineigula (Pelzeln, 1858) (Aves: Furnariidae) é uma espécie válida. Revista Brasileira de Ornitologia 16(2): 107-124.
