taxonID	type	description	language	source
F442FE66742B135F69C0E9F68174D9E0.taxon	description	Includes study populations designated longipennis- E and longipennis- W in the analysis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66742B135F69C0E9F68174D9E0.taxon	diagnosis	Diagnosis. Myrmotherula longipennis (sensu stricto) is distinguished from M. garbei and M. paraensis by vocalizations and female plumage. Notes in Songs of M. longipennis differ structurally from those of M. garbei and M. paraensis (Fig. 2). Notes in M. longipennis Songs decline in frequency, whereas those of M. garbei and M. paraensis rise in frequency, and notes in Series Calls of M. longipennis differ structurally from those of M. garbei and M. paraensis (Fig. 3). In addition, the pace of M. longipennis Songs is significantly slower than the pace of Songs of M. paraensis. Plumage differences are limited to females. M. longipennis females are diagnosable primarily by having extensively white posterior underparts which in M. garbei and M. paraensis are either a color similar to the breast, or whitish tinged with brownish- or olive yellow (in some subspecies of M. paraensis). Furthermore, M. longipennis differs from M. garbei in having upperparts brown rather than gray and from M. paraensis in having wings and tail brown rather than grayish brown or reddish brown.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66742B135F69C0E9F68174D9E0.taxon	description	Description of female plumage. Females have upperparts olive-brown to yellowish-brown (2.5 Y 4 / 3 – 10 Y 4 / 4); wings and tail dark brown (10 YR 3 / 3 – 4 / 4); wing edgings contrasting light reddish yellow-brown (7.5 R 6 / 6); throat and breast pale yellowish buff (2.5 Y 8 / 4 – 7 / 4); posterior underparts white; and flanks olive-gray (2.5 Y 5 / 1 – 5 / 2).	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66742B135F69C0E9F68174D9E0.taxon	distribution	Distribution. North of the Rio Amazonas (Solimões), Brazil, and the Rio Napo, Peru and Ecuador; south of the region immediately south of the Rio Orinoco, Venezuela, and the north bank of the Rio Guaviare, Colombia, extending south of the headwaters of the Rio Guaviare along the base of the Andes.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66742B135F69C0E9F68174D9E0.taxon	discussion	Remarks. Compared to M. garbei and M. paraensis, males tend to have a more restricted throat patch, darker underparts, and fewer white-tipped feathers on the sides of the head. No diagnostic differences were found between subpopulations designated longipennis- E and longipennis- W. The companion molecular-based phylogeny found sequence divergence of 5.9 % between M. longipennis (sensu stricto) and both M. garbei and M. paraensis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66742A135F69C0EE5B8547DE7A.taxon	description	Includes the study populations designated garbei and zimmeri in the analysis	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66742A135F69C0EE5B8547DE7A.taxon	diagnosis	Diagnosis. Myrmotherula garbei is distinguished from M. longipennis and M. paraensis by vocalizations and female plumage. The shape of notes in Songs of M. garbei differ from those in Songs of M. longipennis and M. paraensis (Fig. 2). Furthermore, the pace of M. garbei Songs is significantly slower than the pace of Songs of M. paraensis, and notes in M. garbei. Songs rise in frequency whereas those of M. longipennis decline. Note shapes in Series Calls of M. garbei differ from those of M. longipennis, and note shapes in Multi-note Calls of M. garbei differ from those of M. paraensis (Fig. 3). Diagnosable plumage differences are limited to females. Principally, the very dark gray upperparts of M. garbei are distinctive, distinguishing this species from both of its sister species, although upperparts of some populations of M. paraensis are a more olive-gray. The color of posterior underparts of M. garbei is similar to that of the breast, in contrast to those of M. longipennis, which are white.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66742A135F69C0EE5B8547DE7A.taxon	description	Description of female plumage. Upperparts dark gray tinged olive to olive gray (5 Y 4 / 1 – 4 / 2), wings and tail very dark olive-gray to dark gray-tinged olive (2.5 Y 3 / 1 – 5 Y 4 / 1), and wing edgings pale olive-brown to pale olive-gray (2.5 Y 5 / 4 – 5 Y 6 / 2). Underpart colors appear to distinguish two subspecies, but see Remarks. Breast of the nominate form is pale olive yellow (2.5 Y 7 / 6) and of zimmeri reddish yellow to yellow brown (7.5 YR 5 / 8 – 10 YR 5 / 8). Posterior underparts of the nominate form are pale olive yellow to yellow ochre (2.5 Y 7 / 7 – 10 YR 7 / 6); posterior underparts of zimmeri are light reddish yellow brown to brownish yellow (7.5 YR 6 / 8 – 10 YR 6 / 8).	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66742A135F69C0EE5B8547DE7A.taxon	distribution	Distribution. South of the Rio Amazonas (Solimões) and Rio Napo, Brazil, Ecuador, and Peru; east of the Andes in Ecuador, Peru, and Bolivia; and west of the Rio Madeira and Rio Beni in Brazil and Bolivia.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66742A135F69C0EE5B8547DE7A.taxon	discussion	Remarks. Chapman (1925) described M. l. zimmeri as a subspecies distinct from nominate longipennis and M. l. paraensis, but he did not have specimens of M. l. garbei for comparison. Although in comparisons of vocalizations we found no diagnostic differences between zimmeri and garbei, females of available specimens of zimmeri and garbei differed in coloration. An mtDNA genetic distance (~ 0.6 %) between them suggests that they may be evolving independently, but our only tissue samples of zimmeri were from Ecuador, distant from the putative barrier between them. The subspecies M. g. zimmeri should be maintained at least until additional specimens are obtained for plumage comparisons and genetic analysis. If subspecies status is supported, the likely barrier between them is the Rio Marañón, Peru.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66742A135F69C0EADD8097DFC4.taxon	diagnosis	Diagnosis. Myrmotherula g. garbei is distinguished from M. garbei zimmeri by diagnosable differences in female plumage characters provided in the description of M. garbei.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66742A135F69C0EADD8097DFC4.taxon	distribution	Distribution. South of the Rio Amazonas (Solimões) and Rio Marañón, Brazil and Peru; east of the Andes in Ecuador, Peru, and Bolivia; and west of the Rio Madeira and Rio Beni in Brazil and Bolivia.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667429135C69C0EC8A87A7D9E4.taxon	diagnosis	Diagnosis. Myrmotherula garbei zimmeri is distinguished from the nominate form of M. garbei by diagnosable differences in female plumage characters provided in the description of M. garbei and considered a subspecies of M. garbei based on the consistency of their vocalizations.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667429135C69C0EC8A87A7D9E4.taxon	distribution	Distribution. South of the Rio Napo, north of the Rio Marañón, and east of the Andes in Ecuador and Peru.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667429135C69C0EC8A87A7D9E4.taxon	discussion	Remarks. Refer to remarks under M. garbei. If confirmed, the conclusion that this subpopulation should be considered a subspecies of M. garbei is supported by the phylogeny.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667429135C69C0EE5E8060DF35.taxon	description	Includes the study populations designated ochrogyna (both subclades) and paraensis in the analysis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667429135C69C0EE5E8060DF35.taxon	diagnosis	Diagnosis. Myrmotherula paraensis is distinguished from M. longipennis and M. garbei by vocalizations and female plumage. The shape (structure) of notes in Songs of M. paraensis differs from note shapes in both M. longipennis and M. garbei Songs (Fig. 2). The pace of M. paraensis Songs is faster than the pace of Songs of M. longipennis and M. garbei. Notes in M. paraensis Songs rise in frequency, whereas the frequency of notes in M. longipennis Songs declines. Note shapes in the Series Call of M. paraensis differ from those of M. longipennis, and note shape of the Multi-note Call of M. paraensis differs from that of M. garbei (Fig. 3). Diagnosable plumage differences are limited to females. Although females of two of the three subspecies of M. paraensis have grayish upperparts, they differ diagnostically from the very dark gray upperparts of M. garbei. Females of two of the M. paraensis subspecies have whitish bellies tinged with buff and differ diagnostically from the white-bellied M. longipennis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667429135C69C0EE5E8060DF35.taxon	description	Description of female plumage. Myrmotherula paraensis encompasses three subspecies that differ substantially in coloration. Upperparts of M. p. paraensis are dark grayish olive brown to olive gray (2.5 Y 4 / 2 – 4 / 3 to 5 Y 4 / 2 – 4 / 3); those of transitiva are olive brown or yellowish brown (2.5 Y 4 / 4 – 5 / 6 or 10 YR 5 / 6); and those of ochrogyna are reddish yellow brown (7.5 YR 4 / 6 – 4 / 4). Wings and tails of p. paraensis and transitiva are very dark grayish olive brown (2.5 Y 3 / 2); those of ochrogyna are reddish yellow brown (7.5 YR 4 / 3). Wing edgings of p. paraensis are light yellowish olive-brown (2.5 Y 6 / 4); those of transitiva are pale yellowish olive brown (2.5 Y 7 / 4); and those of ochrogyna are buffy brown (10 YR 7 / 4). Underparts of the three subspecies also differ as follows. The throat, breast and belly of p. paraensis are pale olive yellow (2.5 Y 7 / 4 – 7 / 6), and the flanks and crissum are light olive brown (2.5 Y 6 / 4 – 5 / 4). The throat and belly of transitiva are white tinged pale olive yellow (2.5 Y 7 / 6), the breast is pale yellow olive (2.5 Y 7 / 4 – 7 / 6), and the crissum and flanks are light olive brown (2,5 Y 6 / 4 – 5 / 4). The throat, belly, and crissum of ochrogyna are white tinged brownish yellow (10 YR 6 / 8), and the breast (creating a breast band) and flanks are brownish yellow ochre (10 YR 7 / 6 – 6 / 8).	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667429135C69C0EE5E8060DF35.taxon	distribution	Distribution. Brazil south of the Rio Amazonas; east of the Rio Madeira, west of the Rio Pindaré, Maranhão, and west and north of southern Amazonian forest limits; southern Isla Marajó.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667429135C69C0EE5E8060DF35.taxon	discussion	Remarks. Hellmayr (1929) described M. l. transitiva and compared plumages of paraensis, ochrogyna, and transitiva. He found coloration differences to be limited to females (e. g., in depth of color, brightness and rufescence of upperparts, and warmth and depth of buffy underparts), with transitiva being nearer paraensis. Our results are consistent with Hellmayr’s observation that ochrogyna and paraensis differ more in coloration than do transitiva and paraensis. Consistency of vocalizations among the three populations indicates that ochrogyna and transitiva are best considered subspecies of paraensis. Given the lack of known significant vocal differences, we maintain both transitiva and ochrogyna as subspecies pending additional field data from the region.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667428135D69C0EC8A80D5D9BD.taxon	diagnosis	Diagnosis. Myrmotherula p. paraensis is distinguished from M. p. transitiva and M. p. ochrogyna by diagnosable differences in female plumage provided in the description of M. paraensis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667428135D69C0EC8A80D5D9BD.taxon	distribution	Distribution. Brazil south of the Rio Amazonas; east of the Rio Tapajós and Rio Teles Pires, west of the Rio Pindaré, Maranhão, and west and north of southern Amazonian forest limits; southern Isla Marajó.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667428135D69C0E85985C1DDD7.taxon	diagnosis	Diagnosis. Myrmotherula paraensis ochrogyna is distinguished from M. p. paraensis and M. p. transitiva by diagnosable differences in female plumage provided in the description of M. paraensis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667428135D69C0E85985C1DDD7.taxon	distribution	Distribution. Brazil east of the Rio Madeira, south of the Rio Amazonas, and west of the Rio Tapajós and Rio Teles Pires. Southern limits are uncertain.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667428135D69C0E85985C1DDD7.taxon	discussion	Remarks. This subpopulation is considered a subspecies of M. paraensis, rather than a species, based on the absence of vocal differences with the nominate, a conclusion supported by the genetic results. Refer to additional remarks under M. p. transitiva.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667428135D69C0EDEC8772DBEE.taxon	diagnosis	Diagnosis. Myrmotherula paraensis transitiva is distinguished from M. p. paraensis and M. p. ochrogyna by diagnosable differences in female plumage provided in the description of M. paraensis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667428135D69C0EDEC8772DBEE.taxon	distribution	Distribution. Brazil east of the Rio Madeira, north of southern Amazonian forest limits, and west of the Rio Teles Pires. Northern limits are uncertain.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667428135D69C0EDEC8772DBEE.taxon	discussion	Remarks. This subpopulation is considered a subspecies of M. paraensis, rather than a species, based on the absence of vocal differences with the nominate form. In the companion genetic analysis, subclades containing individuals of M. p. transitiva and M. p. ochrogyna were not geographically based. Female plumage appears to differ between transitiva and paraensis, but additional specimen and vocal data are needed from the Madeira- Tapajós interfluvium to substantiate their maintenance as subspecies. The genetic data in the companion paper indicate that ochrogyna / transitiva is more closely related to M. garbei than M. paraensis, but these results are poorly supported and based solely on mtDNA (Chesser et al. 2025).	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667428135969C0EA1684D2DD8A.taxon	description	Vocalizations. We identified four types of vocalizations: Songs and three types of calls: Long Calls; Chatters and Short Calls. Songs were highly stereotyped series of clear whistles, consisting on average of about eleven (5 ‒ 20) repetitions of similarly shaped notes. Long Calls were also consistently patterned but were shorter in duration and included a rapidly delivered series of abrupt notes. Chatters were irregularly delivered mixtures of abrupt and longer notes without a consistent pattern. Short Calls consisted of a single note. Sample sizes refer to examples that were measured (songs) or compared visually (calls). Songs. Songs consisted of a rising series of clear whistles that gradually shortened in duration and increased in amplitude. Note shape distinguished Songs of the cinereiventris superclade from those of the menetriesii and omissa superclades. Notes in Songs of the cinereiventris superclade started with an upslur but were primarily downslurred, gradually becoming more chevron-shaped (Fig. 6 A). Notes in Songs of the menetriesii and omissa superclades were upslurred, gradually becoming steeper in spectrograms (Fig. 6 B). Visual examination of spectrograms in Figure 6 also suggests variability in pace, in related measures of note and space duration, and in change in note frequency. Table 4 provides selected measures of these characteristics for populations. Notes in all Songs started at about the same frequency, but peaks rose to higher frequency and at a faster pace in the cinereiventris population. The only significant differences, however, were between the cinereiventris and menetriesii / berlepschi populations because some examples of Songs in berlepsch i and omissa were intermediate in pace and frequency change. No diagnostic differences were found between vocalizations of subpopulations pallida - W (n = 15) and pallida- E (n = 6) nor between omissa- W (n = 12) and omissa- E (n = 20). Calls. Long Calls included two types of notes, abrupt notes and longer downslurred notes. Superclades differed diagnostically in the sequence of the two note types. Notes in Long Calls of the menetriesii superclade (n = 27) were limited to abrupt notes (Fig. 7 A). In the cinereiventris superclade (n = 55), the series of abrupt notes was preceded by a downslurred note, and in about half of our sample the abrupt notes were followed by a downslurred note (Fig. 7 B); in rare instances downslurred notes were doubled. In the omissa superclade (n = 32), the series of abrupt notes was followed by downslurred notes (Fig. 7 C), most often consisting of three notes but sometimes fewer or more; shapes of downslurred notes varied among individuals from narrow band width and dropping slightly in pitch to wider band width and substantial pitch drop. Chatters consisted of irregularly delivered series of broad-band vertical notes and narrower abrupt notes of varying shapes and sizes (Fig. 7 D). Chatters are unusual in Myrmotherula antwrens. They were delivered softly and were difficult to record, and no differences between populations were identified. Short Calls were variable in shape as exemplified by a flight call (Fig. 7 E) and a contact call (Fig. 7 F). Single notes of Long Calls were also delivered as Short Calls. Because Short Calls were most often recorded in mixed flocks, few were identified with confidence in available recordings, and differences among populations were not diagnosable. Vocalization summary. In Songs, different note shapes constituted a significant vocal character between the cinereiventris superclade and the menetriesii and omissa superclades, and there were also quantitative differences in pace and frequency change among populations; those between the cinereiventris and the menetriesii / berlepschi populations were diagnostic. The most consistent vocal differences among the three superclades were Long Calls, which differed diagnosably in the sequence of abrupt and long notes. Analysis of recordings did not identify significant differences among populations in Chatters or Short Calls. Morphology. A black patch on the throat and upper breast of adult males distinguished the menetriesii superclade, although some males of populations in the other two superclades, especially omissa, had a scattering of black spots on the throat and / or upper breast. Besides the absence / presence of a black throat patch, no other diagnostic male plumage differences between populations were found despite variance in the depth of color. Among females, coloration of berlepschi was most distinct with olive-brown upperparts and brownish-yellow underparts. Brownish-yellow underparts were also characteristic of omissa - E and omissa - W, but these populations had upperparts graytinged-olive as did the remaining populations (cinereiventris, pallida, and menetriesii), whose underparts were shades of yellow ochre. Within this general description, populations varied in darkness and color mix (e. g., extent of olive in upperparts, extent of yellow in underparts). Classification of female specimens incorporating spectrophotometry measurements and using discriminant analysis resulted in 90 percent of all specimens identified correctly to population, with only six of 81 specimens inaccurately placed in superclades (Table 5). Noteworthy results included perfect discrimination of subpopulations within the cinereiventris superclade (although three samples were incorrectly assigned to one of the other superclades) and perfect discrimination within the menetriesii superclade (although two samples were assigned to the cinereiventris superclade). Of the twelve samples correctly assigned to the omissa superclade, only one omissa - E female and one omissa- W female were incorrectly assigned to each other’s population. Skull ossification information was unavailable for the large majority of specimens, and it was possible that some misplaced specimens are subadults. In another study, visual sorting of specimens of 20 samples of cinereiventris and pallida only misplaced two specimens, both of which had incompletely ossified skulls (L. Naka, Universidade Federal de Roraima, written comm., 2013). Morphology summary. The black patch on the throat and upper breast of males of the menetriesii superpopulation was diagnostic. Although they do not meet our tests of diagnosability, differences in female coloration of populations currently described as subspecies were consistent with their maintenance as taxa under the “ 75 % rule ” (Amadon 1949).	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667433134769C0EA71862BDA0C.taxon	description	Includes the study populations designated menetriesii and berlepschi in the analysis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667433134769C0EA71862BDA0C.taxon	diagnosis	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.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667433134769C0EA71862BDA0C.taxon	description	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 5 Y 5 / 1), browner on wings and tail with pale feather edgings; underparts Yellow Ochre (10 YR 7 / 6), paler on chin and sides of head.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667433134769C0EA71862BDA0C.taxon	distribution	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.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667433134769C0EA71862BDA0C.taxon	discussion	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.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667432134769C0E8BB853DDFC6.taxon	description	Includes the study populations designated cinereiventris, pallida- E, and pallida- W in the analysis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667432134769C0E8BB853DDFC6.taxon	diagnosis	Diagnosis. Myrmotherula cinereiventris is distinguished from M. menetriesii s. s. and M. omissa by vocalizations and plumage. The structure of notes in M. cinereiventris Songs differs from that of M. menetriesii Songs (Fig. 6), and the note pattern in M. cinereiventris Long Calls differs from those in M. menetriesii and M. omissa in the sequence of types of notes (Fig. 7). The male differs from male M. menetriesii in having a gray rather than black throat and upper breast.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667432134769C0E8BB853DDFC6.taxon	description	Description of female plumage. Females of the nominate population have upperparts between Olive Gray and Olive (5 Y 4 / 2 – 5 Y 4 / 3), wings and tail with pale feather edgings colored like underparts; and underparts Yellow Ochre (10 YR 7 / 6), paler on chin and sides of head.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667432134769C0E8BB853DDFC6.taxon	distribution	Distribution. Bounded on the north in Colombia by the Rio Inírida, extending north to Meta along Andean foothills, and in Venezuela by the Rio Orinoco; on the northeast by the Atlantic Ocean in the Guianas; on the east by the Atlantic Ocean in Brazil; on the south by the Rio Amazonas and Rio Marañón; and on the west by Andean foothills.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667432134769C0E8BB853DDFC6.taxon	discussion	Remarks. Coloration of male of M. c. pallida is similar to nominate but paler, and female is distinctly grayer above and darker below compared to nominate. Specific status for Myrmotherula cinereiventris is supported by distinctions in vocalizations (Song and Long Call differ from those of both M. menetriesii s. s. and M. omissa) and in plumage (female coloration and the absence of the male breast patch of M. menetriesii s. s). Species status is reinforced by mtDNA genetic distances of ~ 5.0 % among the three species that formerly constituted M. menetriesii sensu lato.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667432134769C0EE77875DDC41.taxon	diagnosis	Diagnosis. Female upperparts Olive Brown (between 2.5 Y 4 / 4 and 2.5 Y 5 / 6); underparts Brownish Yellow (10 YR 6 / 8, paler on breast), differing diagnosably from the nominate in brown rather than gray coloration.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667432134769C0EE77875DDC41.taxon	distribution	Distribution. Bounded on the northeast in the region between the lower Rio Madeira / lower Rio Aripuanã / lower Rio Roosevelt and the headwaters of the Rio Teles Pires; on the northwest by the upper Rio Madeira, and on the south by Amazonian forest limits extending to extreme northeastern Bolivia.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667432134769C0EE77875DDC41.taxon	discussion	Remarks. M. m. berlepschi is considered a subspecies of Myrmotherula menetriesii s. s., rather than a species, based on similarity of vocalizations and male plumage, whereas designation as a subspecies is based on female coloration distinctly browner than that of nominate M. menetriesii. Subspecies status is supported by a mtDNA genetic distance of ~ 2.9 % with the nominate form. The intersection of the geographic ranges of M. menetriesii berlepschi and M. omissa is unclear and awaits field exploration.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667431134469C0EC8A87E5DADD.taxon	diagnosis	Diagnosis. Female plumage differs subtly from nominate in coloration. Upperparts Dark Olive Grayish Brown (2.5 Y 4 / 1 – 2.5 Y 4 / 2), brown wings and tail with pale feather edgings colored like underparts; underparts Yellow Ochre (10 YR 7 / 6).	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667431134469C0EC8A87E5DADD.taxon	distribution	Distribution. Bounded on the north in Colombia by the Rio Inírida extending north to Meta along Andean foothills and in Venezuela by the Rio Orinoco; on the east in Venezuela by the physical barriers of the Roraima- Rupununi savannas, the Gran Sabana, and the Rio Paragua, and in Brazil by the Rio Branco and lower Rio Negro; on the south by the Rio Amazonas and Rio Marañón; and on the west by Andean foothills.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667431134469C0EC8A87E5DADD.taxon	discussion	Remarks. M. c. pallida is considered a subspecies of Myrmotherula cinereiventris, rather than a species, based on the similarity of their vocalizations. Subspecies status is supported by differences from cinereiventris s. s. in female plumage and an mtDNA genetic distance of ~ 2.3 %. Male plumage is generally paler than nominate but the differences are not diagnostic. No diagnostic vocal or morphological differences were found between pallida - E and pallida- W. Geographic range in Venezuela is based on Naka (2010, 2011).	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667431134469C0EF0486B7DE7F.taxon	description	Includes the study populations designated omissa- E and omissa- W in the analysis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667431134469C0EF0486B7DE7F.taxon	diagnosis	Diagnosis. Myrmotherula omissa is distinguished from M. cinereiventris and M. menetriesii s. s. by vocalizations and plumage. The structure of individual notes distinguishes Songs of Myrmotherula omissa from those of M. cinereiventris (Fig. 6), and the sequence of abrupt notes and longer downslurred notes in Long Calls of Myrmotherula omissa differs from those in Long Calls of both M. cinereiventris and M. menetriesii (Fig. 7). Males of omissa differ from M. menetriesii s. s. by the absence of black patches on throat and upper breast.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667431134469C0EF0486B7DE7F.taxon	description	Description of female plumage. Female upperparts are Olive Gray (generally 5 Y 4 / 1 for omissa- E and 5 Y 4 / 2 for omissa – W, but with intermediates); underparts typically Brownish Yellow (10 YR 6 / 8) but sometimes as light as Yellow Ochre (10 YR 7 / 6) and therefore not entirely distinguishable from those of menetriesii s. s. or cinereiventris, but tend to be paler on chin and sides of head.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667431134469C0EF0486B7DE7F.taxon	distribution	Distribution. Bounded on the north by the Amazon River, forest limits in central Isla Marajó, and the Atlantic Ocean; on the east by the Rio Pindaré, Maranhão; on the southeast by Amazonian forest limits; and on the southwest in the region between the lower Rio Madeira / lower Rio Aripuanã / lower Rio Roosevelt and the headwaters of the Rio Teles Pires.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667431134469C0EF0486B7DE7F.taxon	discussion	Remarks. Some male specimens of M. omissa have a scattering of black spots on the throat and upper breast. Specific status for Myrmotherula omissa is reinforced by mtDNA genetic distances of ~ 5.9 % among the three species that formerly constituted M. menetriesii. The intersection of the geographic ranges of M. omissa and M. menetriesii berlepschi is unclear and awaits further field exploration. The genetic analysis identified mtDNA genetic distances of 1.6 % between study populations omissa - E and omissa- W, but no diagnostic vocal characters were found, although female plumage may differ.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667431134169C0EAA18009D908.taxon	description	Study populations hauxwelli- C and hauxwelli- E encompassed subclades that were also considered in the analysis. Two subclades in hauxwelli- C separated by the middle and upper Rio Madeira with a sequence divergence of 0.6 % were identified as study populations hauxwelli- C-W and hauxwelli- C-E. Two subclades in hauxwelli- E separated by the Rio Tapajós with a sequence divergence of 0.9 % were identified as study populations hauxwelli- E-N and hauxwelli- E-S (Fig. 10). Finally, the phylogeny placed the main clades into two superclades separated by 7.8 % sequence divergence. These superclades correspond to the species I. guttata and I. hauxwelli. Vocalizations. Vocalizations were categorized into four types: Song; Alarm Call; Hook Call; and Rattle. The Song was a consistently patterned multiple-note vocalization of unusually long duration for a thamnophilid that was irregularly repeated at often long intervals and thus was especially difficult to record in an unsolicited context. The Alarm Call was a multiple-element note of brief duration that typically was repeated, sometimes in long series. The Hook Call was a continuous note that went up, down, and then up again in frequency. The Rattle consisted of multiple abrupt notes given in a rapid, often downslurred series, the notes of which were barely distinguishable. Songs. Songs of all populations consisted of a long series of similar notes (10 – 75 notes) that gradually became shorter in duration and wider in frequency band width. Within that general pattern, however, the shape of the notes of Songs of guttata (Fig. 11 A) differed from those of all populations of hauxwelli. In addition, the overall band width (difference between the highest and lowest frequency) differed significantly between populations of guttata (1099 – 1926 Hz, ξ = 1459, SD = 256, n = 12) and hauxwelli (1971 – 4340 Hz, ξ = 3183, SD = 557; n = 55). We found no significant geographic variation among Songs of guttata. Within hauxwelli populations, notes of hauxwelli- W were frequency-modulated (Fig. 9, single note enlarged in Fig. 11 D), a characteristic lacking in notes of other populations exemplified by the Song of hauxwelli- C (Fig. 11 C, single note enlarged in Fig. 11 E). Non-overlapping ranges of frequency measurements found among hauxwelli populations did not meet our significance test but indicate the need for further frequency analysis when additional samples are obtained. Calls. The most commonly recorded call of Isleria taxa was termed an Alarm Call because this behavioral context was often noted by field workers. Alarm Calls differed diagnosably between guttata and hauxwelli populations. Alarm Calls of guttata (Fig. 12 B) were long (5 ‒ 7 elements, ξ = 5.8; duration 0.088 ‒ 0.144 sec, ξ =, 0.111; n = 10), whereas those of hauxwelli populations (Fig. 12 A) were shorter (2 ‒ 4 elements, ξ = 2.6; duration 0.032 ‒ 0.068 sec, ξ =, 0.043; n = 10). To the human ear, guttata Alarm Calls were harsh and raspy (n = 34), whereas hauxwelli Alarm Calls were burry (n = 71). Alarm Calls were often repeated or delivered in long series. Differences of Rattles (Fig. 12 C and 12 D) and Hook Calls (Fig. 12 E) among populations were not significant, although the Hook Call was not recorded among our sample of 54 recordings of hauxwelli E – S. Vocalization summary. Characteristics of Songs (note shape and frequency band width) and Alarm Calls (number of elements and duration) distinguished I. guttata from all I. hauxwelli populations. The only vocal character distinguishing populations of I. hauxwelli was the frequency modulation of notes in the Song of hauxwelli- W. Morphology. Comparison of 29 specimens of I. guttata with 142 specimens of I. hauxwelli confirmed that I. guttata and I. hauxwelli (both sexes) differ diagnostically in underpart coloration and in wing edgings and terminal spots as described in the literature (e. g., Zimmer & Isler 2003). No plumage differences were found in samples of I. guttata. In comparing plumages of populations of I. hauxwelli, using both visual and spectrophotometry comparisons within the large samples (72 males, 70 females), the only diagnosable difference was the lack of a white interscapular patch distinguishing both sexes of hellmayri. Variation in darkness of male plumage of I. hauxwelli appeared to be clinal, and individuals of adjoining populations were indistinguishable. Zimmer (1932) noted that darker specimens had smaller spots on the wings and tail, but considerable overlap in spot size was found among adjoining populations. In our comparisons the darkest males originated in the northwest (hauxwelli- W), and the palest males were from the Huanchaca region of northeast Bolivia (hauxwelli- C). Although not as pale as adjoining populations, males of hellmayri were also relatively pale, and half of the available male specimens (4 of 8) had whitish edges to feathers in the underparts giving a scalloped appearance, but these were present on a few individuals from other populations. These could be signs of immaturity, or transition to definitive plumage. In blind tests, darker hellmayri females were almost perfectly distinguishable from lighter females of hauxwelli- E (both subclades). The darkest females were those of hellmayri and hauxwelli- W, located at the geographic ends of the overall distribution. However, in neither blind arrays nor spectrophotometry measurements could females of hellmayri be separated diagnostically from the paler females of hauxwelli- E, nor could the darker females of hauxwelli- W be separated from the paler females of hauxwelli- C. The palest female specimens of hauxwelli- C originated in the Huanchaca region of northeastern Bolivia, as did the palest males.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134E69C0EC8A8539DAD5.taxon	description	Includes the population designated guttata in the analysis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134E69C0EC8A8539DAD5.taxon	diagnosis	Diagnosis. Distinctions in note structure and frequency band width distinguish Songs of I. guttata from those of I. hauxwelli (Fig. 11), and Alarm Calls differ in the number of elements and duration (Fig. 12). Male I. guttata differ from male I. hauxwelli in having tawny rather than gray posterior underparts and larger, pale cinnamon rather than white wing and tail spots.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134E69C0EC8A8539DAD5.taxon	description	Description of plumage. Male foreparts gray, throat paler; interscapular patch white; wings and tail blackish brown, remiges edged cinnamon; wing covert tips and spots on tertials and tail pale cinnamon; posterior underparts and crissum tawny. Female like male except upperparts olive gray, anterior underparts grayish olive.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134E69C0EC8A8539DAD5.taxon	distribution	Distribution. Guianan Shield and northeastern Amazonia north of the Rio Amazonas, east of the Rio Negro, and south of the Rio Orinoco.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134E69C0EC8A8539DAD5.taxon	discussion	Remarks. Specific status is supported by mtDNA genetic distance of ~ 7.8 % between I. guttata and I. hauxwelli.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134E69C0EF108041DE43.taxon	description	Includes the populations designated hauxwelli- W, hauxwelli- C, hauxwelli- E, and hellmayri in the analysis.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134E69C0EF108041DE43.taxon	diagnosis	Diagnosis. Distinctions in note structure and frequency band width distinguish Songs of I. hauxwelli from those of I. guttata (Fig. 11), and Alarm Calls differ in the number of elements and duration (Fig. 12). Male differs from I. guttata in having gray rather than tawny posterior underparts and smaller white (rather than pale cinnamon) wing and tail spots.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134E69C0EF108041DE43.taxon	description	Description of plumage. Male is gray, paler below, throat whitish; interscapular patch white (except I. h. hellmayri); wings and tail blackish brown, remiges edged white; wing covert tips and spots on tertials and tail white. Female like male except upperparts paler gray washed cinnamon-rufous; underparts tawny-cinnamon, throat paler, flanks tinged olive; remiges edged cinnamon.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134E69C0EF108041DE43.taxon	distribution	Distribution. Bounded on the north in Brazil by the Rio Amazonas west along the south bank of the Rio Solimões to the mouth of the Rio Japurá, Brazil; thence north, south of the Rio Japurá, to the vicinity of Rio Guainía, Colombia; thence west to near the base of the Andes in Meta, Colombia; thence south along the base of the Andes to La Paz, Bolivia; and thence east, north of Amazonian forest limits from Pando, Bolivia, to eastern Pará and western Maranhão, Brazil.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134E69C0EF108041DE43.taxon	discussion	Remarks. Within I. hauxwelli, a vocal distinction in the Song of study population hauxwelli- W and the absence of an interscapular patch in study population hellmayri support three subspecies within I. hauxwelli: I. h. hauxwelli in the west, I. h. hellmayri in the east; and I. h. clarior (as below) in the center of the range. In an apparent clinal pattern, males become darker in plumage from east to west (except paler in northeastern Bolivia), with no diagnostic differences in coloration between adjoining populations. Female coloration provides less of a clinal pattern than males as I. h. hellmayri females are dark in contrast to the pale males of that subspecies.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134F69C0EAB98173D99C.taxon	diagnosis	Diagnosis. Song differs from those of other subspecies of I. hauxwelli by the frequency modulation of individual notes. Plumage differs from that of I. h. hellmayri by having a white interscapular patch.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134F69C0EAB98173D99C.taxon	distribution	Distribution. Bounded on the north by the Rio Japurá, Brazil, from its mouth north to the vicinity of Rio Guainía, Colombia, thence west to near the base of the Andes in Meta, Colombia; on the west by the Andes from Meta, Colombia, south to the vicinity of the Rio Cushabatay, Peru; and on the east by the Rio Ucayali from the mouth of the Rio Cushabatay north.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743B134F69C0EAB98173D99C.taxon	discussion	Remarks. Although initially the type locality of nominate hauxwelli was identified simply as “ e. Peru ” (Sclater 1857), a subsequent publication by the same author (Sclater 1858) pinpointed the locality as Chamicuros, which is south of the Río Marañón and west of the Río Ucayali. The frequency modulation distinguishing Songs recorded in this region was characteristic of Songs recorded north of the Rio Marañón, the region currently ascribed to I. h. suffusa. Furthermore, no morphological differences were found between populations north and south of the Rio Marañón. Consequently, suffusa is considered a synonym of the nominate form, a conclusion supported by the phylogeny. The nominate subspecies differs by 2.5 – 3.0 % in mtDNA from other subspecies of I. hauxwelli.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743A134F69C0EDCF85AADCC6.taxon	diagnosis	Diagnosis. Song differs from that of I. h. hauxwelli in lacking frequency modulation of notes. Plumage differs from that of I. h. hellmayri by having a white interscapular patch.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743A134F69C0EDCF85AADCC6.taxon	distribution	Distribution. South of the Amazon River from the mouth of the Rio Xingu, Brazil, west to the mouth of the Rio Ucayali, Peru; thence south, east of the Rio Ucayali from its mouth to the vicinity of the Rio Cushabatay, Peru; thence south, east of the Andes, to La Paz, Bolivia; thence east, north of Amazonian forest limits, to the Rio Xingu, Brazil.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743A134F69C0EDCF85AADCC6.taxon	discussion	Remarks. Although the study populations included in this subspecies exhibited variation in vocal and morphological characters, non-overlapping vocal differences among populations did not meet our criteria for diagnosability. With the assembly and analysis of additional recordings and specimens, some study populations are likely to warrant taxonomic recognition. This supposition is supported by the branching patterns and mtDNA distances in the phylogeographic results. Further vocal analysis should emphasize Song frequency. Frequency measurements suggested that there might be diagnostic differences among hauxwelli populations. Frequency was typically higher east than west of the Tapajós / Teles Pires. Differences were especially noticeable across the Teles Pires at Alta Floresta and across the lower Tapajós. However, Songs of female-plumaged birds appear to be higherpitched than those of males, and such analyses should control for sex. This subspecies differs by 2.5 – 3.0 % in mtDNA from other subspecies of I. hauxwelli, but the genetic data indicate that hauxwelli- C is more closely related to hauxwelli- W than to hauxwelli- E. Nuclear data would provide further insight on the discrepancy between the song and mtDNA data.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743A134F69C0E90181A1DE64.taxon	diagnosis	Diagnosis. Song differs from that of I. h. hauxwelli in lacking frequency modulation of notes. Plumage differs from that of other subspecies in lacking a white interscapular patch.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743A134F69C0E90181A1DE64.taxon	distribution	Distribution. South of the Amazon River from the right bank of the Rio Xingu, Brazil, to the Atlantic Ocean, including the southern portion of Marajó Island; bounded on the east and south by the Rio Araguaia, Maranhão, and by Amazonian forest limits extending southwest to the upper Rio Xingu.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743A134F69C0E90181A1DE64.taxon	discussion	Remarks. This subspecies differs by mtDNA genetic distance of 2.8 % from other subspecies of I. hauxwelli.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743D134869C0EEE685A8DEF4.taxon	description	Isleria h. hauxwelli (90 recordings). COLOMBIA: Parque Nacional Amaca-yacú 2; Mitú 1 Nuevo Mundo 1. ECUADOR: Coca 1; Cuyubeno 2; Kapawi Lodge 1; La Selva Lodge, N bank Río Napo 10; Maxus Road, km 37 5; Sacha Lodge 3; Shiripuno Lodge 1; Tiputini Biodiversity Station 4; Estación Cientifica Yasuni 5; Yuturi Lodge 1. PERU: Allpahuayo-Mishana Reserve 6; Contamana, 84 km WNW on Río Cushabatay 1; El Tigre 2; Expetroleros 1; Explorama Inn 4; Intuto 2; 1.5 km S Libertad 1; Muyuna Lodge 3; Nuevo Peru 4; Pithecia Biological Station 3 ♀; San Lorenzo 1; Porvenir 5; Río Samiria 1; Quebrada Sucusari 18; middle Río Tigre 1, Yanamono 1. Isleria h. clarior. (186 recordings) BRAZIL: AMAZONAS: Rio Bararati 1; Barra de São Manuel 4; Barro Vermelha 1; Benjamin Constant 1; Igarapé Boa Esperança 1; Rio Branco 1; Careiro 1; Colares 1; Foz do Breu 1; Rio Ipixuna 1; Lagoa do Jacaré 2; Maués 2; Nova Olinda do Norte 5; mouth of Rio Palomitas 1; Porto do Meio 1; Pousada Jurumé 1; Pousada Rio Roosevelt 4; Igarapé Seringal 1; P. N. Serra do Divisor 2; Rio Sucunduri 2; Uará 1; MATO GROSSO: Alta Floresta 14; Rio Cristalino 48; Palmeiras 1; Paranaíta 2; PARÁ: Parque Nacional Amazonia 9; Caima 1; Itaituba 1; km 220 S of Itaituba 5; Santarém-Cuiabá Road km 83 – 87 1; Floresta Nacional do Tapajós 3; R bank Rio Teles Pires near mouth of Rio São Benedito 1; Vila Braga 5; RONDÔNIA: Casa do Adelson 1; Machadinho D’Oeste 1; Cachoeira Nazaré 1; Porto Velho 1; Fazenda Rancho Grande, 3. BOLIVIA: Flor de Oro 2; P. N. Noel Kempff Mercado 1; Puesto Ganadero 1; Puesto Heath 2. PERU: ARCC Lodge 2; Ccolpa de Guacamayos 8; Cocha Cashu Biological Station 1; Cocha Salvador 1; Explorer’s Inn 10; Manu Lodge 4; Manu Wildlife Centre 4; Pantiacolla Lodge 4; Parrot Inn 1; Puesto San Antonio, 1; Santa Rita 1; Quebrada Shicotsa 1; Cerro Tahuayo 1; Tambopata Jungle Lodge 2; Yarapa Reserve 5. Isleria h. hellmayri (47 recordings). BRAZIL: PARÁ: Breves 1; Serra dos Carajás 14; Caxiuanã 7; Kayapó 6; Novo Repartimento 2; Paragominas 8; Vale de Rio Paraupebas 2; Pinkaiti 1: Porto de Moz 1 ♂; Fazenda Rio Capim 4; Fazenda Rozinho 1.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743D134969C0EB1281BEDCD0.taxon	description	Myrmotherula garbei zimmeri (39 recordings). ECUADOR: Canelos 1; Kapawi Lodge 4; 15 – 80 km W Loreto 3; La Selva Lodge on S bank Río Napo 1; Miazal 5; Maxus Road km 37 1; Río Suno 1; Tiputini Biodiversity Station 9. PERU: Explorama Inn 1; Explorama Lodge 6; Huampami 1; Quebrada Orán 2; Roca Eterna 2; upper Río Tigre 1; Yanamono 1. Myrmotherula g. garbei (86 recordings). BOLIVIA: Río Abuña 3; Cobija 2; San Juan de Nuevo Mundo 4. BRAZIL: ACRE: Boca de Tejo 1; Catuaba (reserva da UFAC) 1; P. N. Serra do Divisor 9; Seringal Ocidente 1; AMAZONAS: Rio Autaz-Mirim 1; Barro Vermelha 1; Benjamin Constant 9; ca 8 – 15 km W Benjamin Constant 5; km 38 – 45 Cruzeiro do Sul / Santa Barbara road 1; Humaitá 2; Reserva Natural Palmarí 13; Igarapé Santa Maria 1; Tupana Lodge 6. PERU: Abujao 1; Cocha Salvador 2; Explorer’s Inn 7; Ccolpa de Guacamayos 7; ca. 86 km SE Juanjui 1; Manu Lodge 5; Manu Wildlife Centre 1; Cerro Tahuayo 2. Myrmotherula p. paraensis (114 recordings). BRAZIL: MATO GROSSO: Rio Cristalino 13; Praca, Lagoa da 2; PARÁ: 15 km S Altamira R bank Xingu 2; Serra dos Carajás 12; Caxiuanã 33: Igarapé Guará 2; Kayapó, Res. Ind. 12; Paragominas 9; Porto do Meio 2; Riosinho 12; Fazenda Rio Capim 10; Fazenda Rozinho 2; near mouth of Rio São Benedito 2; Senador José Porfirio 1; Vale de Rio Paraupebas 2. Myrmotherula paraensis transitiva (54 recordings). BRAZIL: AMAZONAS: near mouth of Rio Madeirinha 2; Pousada Rio Roosevelt 25; MATO GROSSO: Casa do Xavier Capa, 4; mouth of Rio São Benedito, 1; mouth of Rio São Tome 2; RONDÔNIA: Alta Floresta 7; L bank Cachoeira Nazaré 2; Serra dos Pacaás Novos, 3; Palmeiras 5; R bank Rio Jiparaná opposite Palmeiras, 2; Fazenda Rancho Grande 1. Myrmotherula paraensis ochrogyna (112 recordings). BRAZIL: AMAZONAS: Rio Acarí 3; Igarapé Arauàzinho at mouth 1; Rio Aripuanã opp. Ilha do Quadro 2; Rio Atininga 1; Rio Bararati 5; Barra de São Manuel 3; Igarapé Biribá 2; Igarapé Boa Esperança 1; Borba 2; Rio Mapía 33 km S Borba 10; Igarapé da Cabaça 1; Rio Cararucu 1; Rio Ipixuna 1; 52 km W Jacareacanga 1; Maués 4; Manicoré 1; Nova Olinda (Rio Aripuanã) 1; Novo Aripuanã 2; Rio Palomitas at mouth 1; Rio Parauri near Cachoeira Tambo 2; Igarapé Pedral 1; Ponto Nove, Rio Sucunduri 1; Ponto Seis, Rio Sucunduri 1; Prainha Nova 4; Posto do Canumã 2; Pousada Aripuanã 1; Pousada Jurumé 4; Ramal Sauré 3; Igarapé Seringal 1; Rio Sucunduri near BR 230 11; Rio Sucunduri near mouth Rio Acari 3; Terra Preta 4; Vila do Carmo 2; PARÁ P. N. Amazonia 1; Boim 7; Jacareacanga 4; km 230 – 235, S of Itaituba, 10; Vila Braga 6.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE66743C137669C0E8EF8076DB00.taxon	description	Myrmotherula m. berlepschi (27 recordings). BOLIVIA: Flor de Oro 7; Los Fierros 1; P. N. Noel Kempff Mercado 1. BRAZIL: AMAZONAS: L bank Rio Aripuanã opp. Ilha do Quadro 1; Nova Olindo L bank Rio Aripuanã 2; L bank Pousada Rio Roosevelt 6; Trilha Irapuru 1; MATO GROSSO: L bank Casa do Xavier Capa 2; RONDÔNIA: L bank Cachoeira Nazaré 2; Rio Caracol 1; Casa do Adelson 1; Guajará- Mirim 1; Serra dos Pacaás Novos, 1. Myrmotherula c. cinereiventris (42 recordings). BRAZIL: AMAPÁ: Serra do Navio 5; AMAZONAS: Presidente Figueiredo 1; 60 – 90 km N of Manaus 3. FRENCH GUIANA: Laussat Mana 1. GUYANA: Baramita 1; Maipama Creek 1; Rewa River 1. SURINAME: Brownsberg Nature Reserve 6; Foengoe Eiland 1; Kabalebo Nature Reserve 3; Mozeskreek 1; Raleigh Vallen 1; Voltzberg 2. VENEZUELA: Campamento Rio Grande 1; El Palmar 5; La Escalera 8; Santa Elena de Uairén 1. Myrmotherula cinereiventris pallida (115 recordings). BRAZIL: AMAZONAS: Lago Amanã 3; Barcelos 2; P. N. do Jaú 2; Lago Mamirauá 4; São Gabriel da Cachoeira 2; across river from São Gabriel da Cachoeira 2. COLOMBIA: P. N. Amaca-yacú 4; P. N. N. Chiribiquete 1; Mitú 1. ECUADOR: Canelos 2; Reserva Cuyubeno 3; La Selva Lodge, N bank 4; La Selva Lodge, S bank 3; 15 – 80 km W of Loreto 5; Maxus Road, km 37 1; Miazal 1; Sacha Lodge 7; Tiputini Biodiversity Station 21; P. N. Yasuni 1. PERU: Colmena 1; El Tigre 4; Explorama Inn 1; Intuto 1; Iquitos 1; Nueva Esperanza 1; Puerto Almendra 1; Quebrada Orán 2; Río Amazonas island west of Quebrada Orán 2; Porvenir 4; Sachacocha 2; Quebrada Sucusari 3; middle Río Tigre 1; Yanamono 3. VENEZUELA: Territorio Amazonas location unknown 1; Caura Forest Reserve 2; Río Capuana 1; Junglaven Camp 5; Maripa 1; P. N. Yapacana 1. Myrmotherula omissa (198 recordings). BRAZIL: AMAZONAS: Rio Acarí 3; Pousada Aripuanã 1; R bank Rio Aripuanã opposite Nova Olinda 1; Rio Bararati 4; Barra de São Manuel 1; Igarapé Boa Esperança 1; Borba 1; Igarapé da Cabaça, 3; Rio Cararucu 1; Rio Ipixuna 1; 52 km W Jacareacanga 1; Pousada Jurumé 4; Rio Mapía 33 km S of Borba 3; mouth of Rio Palomitas 2; Rio Parauri near Cachoeira Tambo 4; Igarapé Pedral 1; Ponto Nove (Rio Sucunduri) 1; Ponto Oito (Rio Sucunduri) 1; Prainha Nova 1; Pousada Rio Roosevelt (R bank) 2; Ramal Sauré 2; Rio Sucunduri near BR 230 13; Rio Sucunduri near mouth Rio Acari 3; Igarapé Tucumã 1; MATO GROSSO: Alta Floresta 5; Serra dos Caiabis 1; Rio Cristalino 20; mouth of Rio São Tome 1; PARÁ: P. N. Amazonia 3; Aveiro 1; Belterra 1; Boim 4; Caxiuanã 23; Serra dos Carajás 17; Igarapé Guará 1; Rio Itacaiúnas 1; km 220 – 235 S of Itaituba 5; Jacareacanga 3; Mirituba 3; Paragominas 8; Vale de Rio Paraupebas 4; Porto do Meio 1; Fazenda Rio Capim 14; Riosinho (R. I. Kayapó) 8; Fazenda Rozinho 6; Senador José Porfirio 1; F. N. do Tapajós 3; Pousada Thaimaçu 1; Vila Braga 3; R bank Rio Xingu 15 km S of Altamira 1; TOCANTINS: Tocantins 1.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667403137669C0EFB38606DE1C.taxon	description	Isleria h. hauxwelli. COLOMBIA: Morelia 2 ♀, 1 ♂; Puerto Umbría 3 ♀; Río San Miguel 1 ♂; Villavicencio 1 ♀. PERU: La Poza 1 ♀, 2 ♂; 1.5 km S Libertad 3 ♀, 4 ♂; Limoncocha 4 ♀, 2 ♂; Quebrada Orán 2 ♀, 2 ♂; Pithecia Biological Station 3 ♀; Río Yanayacu 1 ♀, 2 ♂. Isleria h. clarior. BRAZIL: AMAZONAS: Arimã 1 ♀, 3 ♂; Borba 2 ♂; Huitanaã 4 ♀, 4 ♂; Igarapé Auará 2 ♀; Rosarinho (Rio Madeira) 3 ♀, 3 ♂; Santo Isidoro 1 ♀; Villa Bella Imperatriz 3 ♀, 6 ♂; PARÁ: Igarapé Amorim 1 ♀; Igarapé Brabo 4 ♂; Colônia do Mojuy 3 ♀, 4 ♂; Mirituba 2 ♀, 2 ♂; Vila Braga 4 ♀, 2 ♂; RONDÔNIA: Cachoeira Nazaré, R bank 1 ♂; Pedra Branca (Rio Anari) 1 ♀, 1 ♂; Rio Roosevelt Camp 8 1 ♂; Rio Roosevelt; Camp 17 2 ♂. BOLIVIA: Chatarona 1 ♂; 45 – 50 km E of Florida 2 ♀, 2 ♂; 86 km ESE of Florida 2 ♀, 2 ♂; Puerto Salinas 1 ♀, 1 ♂; Yacuma-Rurrenbaque Road 1 ♀. PERU: Atalaya 1 ♂; Balta 4 ♀, 4 ♂; Río Colorado at mouth 2 ♀; Ccolpa de Guacamayos 1 ♂; Río Manu 30 – 40 km from mouth 1 ♀; Cordillera del Pantiacolla at base 1 ♂; Shintuya 1 ♂. Isleria h. hellmayri. BRAZIL: PARÁ: Belém 4 ♀, 4 ♂; Porto de Moz 1 ♂; Tapará 1 ♀; Vilarinho do Monte 5 ♀, 1 ♂; MARANHÃO: Turiaçu 1 ♀, 2 ♂.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667403137769C0EA2B8694D9B8.taxon	description	Myrmotherula garbei zimmeri. ECUADOR: 1.5 km S Libertad 2 ♀, 2 ♂; Río Suno 1 ♂; Río Suno Abajo 1 ♀, 1 ♂; Taisha 5 ♂. Myrmotherula g. garbei. BOLIVIA: 12 – 20 km SW Cobija 4 ♀, 4 ♂; Palmasola 1 ♀, 1 ♂. BRAZIL: AMAZONAS: Arimã 1 ♀, 1 ♂; Huitanaã 1 ♀, 2 ♂; Nova Olinda (R Purus) 3 ♀; Rosarinho (Rio Madeira) 1 ♀, 2 ♂; Santo Isidoro 1 ♂; São Paulo de Olivença 1 ♀, 4 ♂; Tefé 2 ♀. PERU: Balta 2 ♀, 3 ♂; 20 km SW Chiriaco 1 ♂; Santa Elena 1 ♀, 1 ♂; Cerro Tahuayo 3 ♀, 6 ♂; Río Vanilla 1 ♀, 1 ♂. Myrmotherula p. paraensis. BRAZIL: PARÁ: 52 km SW Altamira 1 ♀, 1 ♂; Belém 2 ♀, 4 ♂; Benevides 2 ♀; Colônia do Mojuy 1 ♀, 1 ♂; Mirituba 1 ♀, 4 ♂; Santa Helena 1 ♀; Vitória 1 ♂. Myrmotherula paraensis transitiva. BRAZIL: RONDÔNIA: Barão de Melgaço 1 ♂; Calama 1 ♂; Cachoeira Nazaré, L bank 1 ♂; Pedra Branca, (Rio Anari) 3 ♀, 1 ♂; Rio Roosevelt Camp 21 1 ♂. Myrmotherula paraensis ochrogyna. BRAZIL: AMAZONAS: Igarapé Auará 5 ♀, 2 ♂; Borba 1 ♀; Vila Bella Imperatriz 3 ♀, 3 ♂; PARÁ: Vila Braga 4 ♀, 4 ♂.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
F442FE667402137769C0EDC7860CDC68.taxon	description	Myrmotherula m. berlepschi. BOLIVIA: 21 km SE Catarata Arco Iris 1 ♀; 45 – 50 km E of Florida 1 ♂; 86 km ESE of Florida 1 ♂; 4 km from mouth of Río Paucerna 1 ♂. BRAZIL: RONDÔNIA: L bank Cachoeira Nazaré 1 ♀, 1 ♂; Pedra Branca (Rio Anari) 2 ♀ 1 ♂. Myrmotherula c. cinereiventris. BRAZIL: AMAPÁ: Porto Platon 2 ♀, 2 ♂; Serra do Navio 1 ♀, 2 ♂; PARÁ: Faro 4 ♀, 1 ♂; Obidos 2 ♀; RORAIMA: Sorocaima 1 ♂. FRENCH GUIANA: Saut Tamanoir 4 ♀, 4 ♂. GUYANA: Acarai Mountains, 1 ♂; Baramita 1 ♀; Georgetown, 1 ♂; mouth of Onoro River 1 ♀; Sipu River 1 ♀. VENEZUELA: Río Yuruán 1 ♀, 3 ♂. Myrmotherula c. pallida. BRAZIL: AMAZONAS: Serra Curicuriari 1 ♀, 4 ♂; Iucaí 1 ♀, 1 ♂; Iauaretê, 1 ♀; Iaunari 1 ♀; Mirapinima 2 ♂; São Gabriel da Cachoeira 1 ♂; Tabocal 2 ♀, 5 ♂; Umarituba 6 ♀, 5 ♂. COLOMBIA: Morelia 1 ♀, 1 ♂; Puerto Umbria 2 ♀, 2 ♂; Río San Miguel 1 ♂; opposite Tauá, Brazil 1 ♂. ECUADOR: Limoncocha 4 ♀, 2 ♂. PERU: Caterpiza 1 ♂; Libertad 6 ♂; Quebrada Orán 2 ♀, 1 ♂; Quebrada Sucusari 1 ♀, 1 ♂; Urakusa 1 ♂; Río Yanayacu 1 ♂. VENEZUELA: upper Río Caura 2 ♂; Cerro Curiche 1 ♀; Caño Mabanagui 2 ♀; Cerro Yapacana 4 ♂. Myrmotherula omissa. BRAZIL: Pará: 52 km SW Altamira 1 ♀; Belém 1 ♀, 1 ♂; Benevides 1 ♀, 4 ♂; Caxiuana 1 ♂; Mirituba 2 ♀, 1 ♂; Tauari 3 ♀, 1 ♂.	en	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): 45-78, DOI: 10.11646/zootaxa.5722.1.2, URL: https://doi.org/10.11646/zootaxa.5722.1.2
