Vicariant events in the montane hummingbird genera Augastes and Schistes in South America

Abstract

We assessed the evolutionary histories of two hummingbirds, Augastes scutatus and Augastes lumachella, endemic to the highlands of the Espinhaço Range in Brazil. These hummingbirds are considered relictual taxa with phylogenetic affinities to members of the genus Schistes from the Andean region. We reconstructed phylogenetic relationships of Augastes through the use of mitochondrial DNA and nuclear sequences within the Polytminae hummingbird clade, and found that the inferred phylogenetic reconstructions placed A. scutatus as the sister species of A. lumachella and Augastes as sister to Schistes geoffroyi from the northern Andes, as previously suggested by similarities found in plumage and morphology. Our results are consistent with an initial divergence of Augastes and Schistes lineages in the Late Miocene, associated with geological and climatic changes across the South American landscape. A Late Pliocene vicariant event between A. scutatus and A. lumachella may be associated with climatically distinct environmental conditions influencing the local differentiation and adaptation of ancestral Augastes populations. Our findings represent additional important evidence of vicariant events between east and west in southern South America, and between north and south within the Espinhaço Range of Brazil.

First record of Augastes lumachella (Lesson, 1838) (Trochilidae) from the highest peak in northeastern Brazil

“…Augastes lumachella and A. scutatus are believed to be allo-species (Vasconcelos 2008;Chaves et al 2019). The divergence time of 2-4 mya estimated by Chaves et al (2019) using DNA sequence data suggests that these two species originated from Late Pliocene to Early Pleistocene.…”

“…Augastes lumachella and A. scutatus are believed to be allo-species (Vasconcelos 2008;Chaves et al 2019). The divergence time of 2-4 mya estimated by Chaves et al (2019) using DNA sequence data suggests that these two species originated from Late Pliocene to Early Pleistocene. Their origin could be associated with an epeirogenic uplift of the Brazilian Plateau that occurred in the eastern half of Brazil, while Pleistocene climatic fluctuations probably have favored their temporal ecological specialization and population structuring (Chaves et al 2019).…”

“…The divergence time of 2-4 mya estimated by Chaves et al (2019) using DNA sequence data suggests that these two species originated from Late Pliocene to Early Pleistocene. Their origin could be associated with an epeirogenic uplift of the Brazilian Plateau that occurred in the eastern half of Brazil, while Pleistocene climatic fluctuations probably have favored their temporal ecological specialization and population structuring (Chaves et al 2019). Pleistocene climatic fluctuations would have forced populations of A. lumachella and A. scutatus to take refuge at higher elevations during interglacial periods (Vasconcelos et al 2012).…”

“…Five bird species are currently recognized as campo rupestre endemics in the Cadeia do Espinhaço, i.e, Asthenes luizae (Vielliard, 1990), Cinclodes espinhacensis (Freitas, Chaves, Costa, Santos & Rodrigues, 2012), Formicivora grantsaui (Gonzaga, Carvalhaes & Buzzetti, 2007), A. scutatus, and A. lumachella (Vasconcelos 2008;Vasconcelos et al 2008;Freitas et al 2012). The genus Augastes is remarkable because it consists of two allo-species with a unique evolutionary history (Vasconcelos et al 2012;Chaves et al 2015Chaves et al , 2019. Distributional data on Augastes have been employed to infer speciation events on eastern Brazilian mountaintops (Vasconcelos et al 2012;Chaves et al 2015Chaves et al , 2019 and may contribute to an understanding of South American biogeography.…”

“…The genus Augastes is remarkable because it consists of two allo-species with a unique evolutionary history (Vasconcelos et al 2012;Chaves et al 2015Chaves et al , 2019. Distributional data on Augastes have been employed to infer speciation events on eastern Brazilian mountaintops (Vasconcelos et al 2012;Chaves et al 2015Chaves et al , 2019 and may contribute to an understanding of South American biogeography.…”