A team of ornithologists from the United States, Colombia and Denmark has described six new cryptic species in the rufous antpitta (Grallaria rufula) complex from montane forests of South America.
The rufous antpitta complex is a group of passerine birds that includes three species — the Muisca antpitta (Grallaria rufula), the bicolored antpitta (Grallaria rufocinerea) and the chestnut antpitta (Grallaria blakei) — and numerous subspecies.
These birds inhabit humid montane forests and borders of the Andes from northern Colombia and adjacent Venezuela to central Bolivia.
Their tawny to cinnamon-colored plumages are generally uniform, featuring subtle variation in hue and saturation across their range.
In contrast to their conservative plumage, substantial song differences occur among geographically isolated populations.
“In the final decades of the 20th century, field workers began to record vocalizations of rufous antpittas, noting substantial structural and tonal differences among populations,” said Dr. Morton Isler of Smithsonian Institution and colleagues.
“Since that time, it has been generally recognized that multiple species are involved.”
In the new study, the researchers carried out a taxonomic revision of the rufous antpitta complex based on geographic variation in songs supported by patterns of plumage coloration and by genetic variation.
They identified 16 distinct populations, including seven populations previously described as subspecies and, remarkably, six new species.
The newly-identified antpitta species are listed below:
(i) the Chami antpitta (Grallaria alvarezi), endemic to Colombia in Western Andes from Paramillo, northwestern Antioquia, south to northwestern Cauca;
(ii) the Graves’s antpitta (Grallaria gravesi), endemic to Peru on east Andean slope in Amazonas and San Martín south and east of the Río Marañón, south to Huánuco north of Río Huallaga;
(iii) the O’Neill’s antpitta (Grallaria oneilli), occurs on the East Andean slope in Huánuco and Pasco, Peru, south of the Río Huallaga and north of the Río Perené;
(iv) the Oxapampa antpitta (Grallaria centralis), endemic to Peru on east Andean slope from Huánuco south of the Río Huallaga through Pasco to Junín west of the Río Ene and north of the Río Mantaro;
(v) the Ayacucho antpitta (Grallaria ayacuchensis), endemic to Peru on east Andean slope in Ayacucho west of the Río Apurímac between the Río Mantaro and Río Pampas;
(vi) the Puno antpitta (Grallaria sinaensis), occurs in the Department of Puno, Peru, and extreme western La Paz, Bolivia.
The scientists elevated six subspecies to species rank: the Junín antpitta (Grallaria obscura), the Urubamba antpitta (Grallaria occabambae), the Bolivian antpitta (Grallaria cochabambae), the Perijá antpitta (Grallaria saltuensis), the Sierra Nevada antpitta (Grallaria spatiator) and the Cajamarca antpitta (Grallaria cajamarcae).
They described a new subspecies within one newly-elevated species: Grallaria occabambae marcapatensis.
They also resurrected a currently synonymized subspecies, the equatorial antpitta (Grallaria saturate), elevating it to species rank.
“Finding this large number of unrecognized species in this complex was not a total surprise given that other wide-ranging Andean species with conserved plumage (e.g. species in the genus Scytalopus) have proven to be composed of multiple species,” the authors said.
Morton L. Isler et al. 2020. Taxonomic evaluation of the Grallaria rufula (Rufous Antpitta) complex (Aves: Passeriformes: Grallariidae) distinguishes sixteen species. Zootaxa 4817 (1): 001-074; doi: 10.11646/zootaxa.4817.1.1