«[…] Species of Andean humid forest are distributed over relatively narrow elevational ranges that can extend for many hundreds of kilometers, providing ample opportunities for geographical isolation across elevational and habitat discontinuities. Such discontinuities are especially prevalent in Colombia, where the Andes split into 3 main cordilleras and where other isolated highlands, such as the Sierra Nevada de Santa Marta, are present, and in Peru, where large rivers, such as the Marañón, the Huallaga, and the Apurímac/Ene, form deep arid intermontane canyons that are physical, ecological, and climatic barriers to dispersal.

[…]As part of a comprehensive study of the systematics and evolution of the G. rufula complex, focusing primarily on investigations of genetics and vocalizations, we obtained DNA sequence data for 80 individuals from across the range of the complex, to assess the extent of genetic differentiation among morphologically differentiated populations (recognized species and subspecies), the extent of cryptic genetic differentiation, and the extent to which vocal differentiation in this complex matches genetic differentiation.»

Read more in Conservative plumage masks extraordinary phylogenetic diversity in the Grallaria rufula (Rufous Antpitta) complex of the humid Andes

R Terry Chesser, Morton L Isler, Andrés M Cuervo, C Daniel Cadena, Spencer C Galen, Laura M Bergner, Robert C Fleischer, Gustavo A Bravo, Daniel F Lane, Peter A Hosner, Conservative plumage masks extraordinary phylogenetic diversity in the Grallaria rufula (Rufous Antpitta) complex of the humid Andes, The Auk, ukaa009, https://doi.org/10.1093/auk/ukaa009