Myrmotherula menetriesii ( d’Orbigny, 1838 )

Isler, Morton L., Chesser, R. Terry, Stryjewski, Katherine Faust & Whitney, Bret M., 2025, Systematics of three pan-Amazonian antwren lineages (Aves: Passeriformes: Thamnophilidae: Myrmotherula and Isleria), Zootaxa 5722 (1), pp. 45-78 : 61-62

Myrmotherula menetriesii ( d’Orbigny, 1838) sensu stricto

Western Gray Antwren

Includes the study populations designated menetriesii and berlepschi in the analysis.

Diagnosis. Myrmotherula menetriesii ( sensu stricto) is distinguished from M. cinereiventris and M. omissa by vocalizations and male plumage. Songs of Myrmotherula menetriesii s.s. are comprised of notes that differ substantially in structure from notes of M. cinereiventris and M. omissa (Fig, 6), and Long Calls of Myrmotherula menetriesii s.s. differ in the sequence of note types from those of both M. cinereiventris and M. omissa ( Fig. 7). Male M. menetriesii differs from M. cinereiventris and M. omissa in its black throat and upper breast, compared to the gray throats and upper breasts of the latter two species.

Description of plumage. Nominate male bluish-gray, paler below; wing coverts with black sub- terminal bar and white tips; throat and upper breast black, feathers variably tipped gray. Nominate female upperparts Gray tinged Olive (slightly darker than 5Y5/1), browner on wings and tail with pale feather edgings; underparts Yellow Ochre (10YR7/6), paler on chin and sides of head.

Distribution. Bounded on the north by the Rio Amazonas and Rio Marañón; on the east by the lower Rio Madeira/Rio Aripuanã (refer to Remarks under M. m. berlepschi); on the south by Amazonian forest limits. including extreme northeastern Santa Cruz, Bolivia; and on the west by Andean foothills, extending to the base of the Andes in Bolivia.

Remarks. Female M. m. berlepschi is distinctly browner than the nominate subspecies, especially on upperparts. Specific status for Myrmotherula menetriesii s.s. is supported by mtDNA genetic distances of ~5.0% with M. cinereiventris and with M. omissa .