Cercomacra raucisona Cavarzere, Breviglieri & Silveira, 2026, sp. nov.

Cercomacra raucisona sp. nov. Cercomacra caerulescens [non Formicivora caerulescens Ménétries, 1835] – Pelzeln (1868: 84). Cercomacra sclateri (partim) [non Cercomacra sclateri Hellmayr, 1905] – (Hellmayr 1905: 288). Holotype. MZUSP 107661. Male collected on 8 July 2016. Recorded by Bret M. Whitney (25674-75) and prepared by C. Gregory Schmitt. Tissue LSUMZ B-90-017. Type locality. Right bank Rio Aripuanã, base 3, Floresta / Santa Maria, Colniza, Mato Grosso, Brasil (9°12’08”S; 59°21’02”W). Paratypes. MZUSP 97410. Male collected on 26 June 2013 on the left bank of Rio Sucunduri, 5, 6 km below da BR- 230, Bato I, Amazonas, Brasil (6°45’20”S; 59°4’44”W); MZUSP 961000. Female collected on 29 July 2012 at left bank of Rio Sucunduri, above Ilha do Castanho, Amazonas, Brasil (5°57’02”S; 59°10’28”W). Description of the holotype. A typical dark gray morphotype, overall dark gray except for the white interscapular patch on the back, fimbriae on the wings, and wider tail tips. The bill is black, measuring 11.15 mm long, 5.25 mm wide, and 4.85 mm high. Wing chord = 65.15 mm, tail length = 71.45 mm, and the tarsus, which is grayish black, measures 20.20 mm. Total length = 158 mm, weight = 16.5 g. Iris brown, upper maxilla black and tomium black, lower maxilla gray. Tarsus also gray. Skull 100 % ossified, and absence of body fat or bursae. Left testis measured 2 × 2 mm. Diagnosis. The taxon is identified by the unique disyllabic phrases with exclusively raspy notes, distinguishing this loudsong from the other four species, with no overlapping ranges of the number and proportion of raspy notes. Etymology. From the Latin raucus, meaning raspy, hoarse, and sonus, sound. The species’ specific name reflects its vocal distinctive feature, characterized by a loudsong composed of disyllabic phrases exclusively composed of raspy notes. Distribution. It is found in the Madeira-Tapajos interfluve, south of the Amazon River. Its presence in the mid Beni River, Bolivia, shows that this river does not separate the species’ vocalizations, as recordings from the right bank of the Beni River (and from both banks of the Madre de Dios River) clearly belong to C. mura sp. nov. We suggest the Mamoré River as the western limit of this species, which extends eastward to the left bank of the Tapajós and Teles Pires Rivers in the states of Mato Grosso and Pará, central Brazil. Remarks. It differs in overall plumage from C. cinerascens, which is lighter. Although there is some overlap, females have significantly larger tail tips (compared to C. cinerascens and C. iterata stat. nov.) and wings (compared to C. cinerascens); males have significantly larger tail tips than C. cinerascens (Fig. S 6). Several significant differences among species occur in vocal features (Table S 7), but they overlap.