In new research, ornithologists from Drexel University, the Delaware Museum of Nature & Science, and Burke Museum of Natural History and Culture conducted a taxonomic revision of the Catharus fuscater complex, a group of songbirds with a broad montane distribution in Central and South America. They split Catharus fuscater into seven different species — including a newly-described species from eastern Panamá — and four subspecies.
“Genetic data have repeatedly confirmed the primary role of geographic barriers in the speciation process,” said lead author Matthew Halley and his colleagues.
“However, there is little consensus about where on the ‘speciation continuum’ to draw the line, between species and subspecies, when dealing with closely related taxa distributed on opposite sides of potential gene-flow barriers.”
“In the Neotropical highlands, hundreds of polytypic bird species have populations distributed across multiple mountain chains, which are isolated by deep river valleys, and adjacent populations may have divergent phenotypes and/or may not be phylogenetic sisters.”
“Describing and classifying this extraordinary diversity is necessary for conservation efforts, and to inform studies of the evolutionary origins and maintenance of avian biodiversity.”
“However, the process of integrntive taxonomy is not straightforward because of ideological conflicts related to species concepts and their application, and the need for broad geographic sampling of multiple traits.”
In their research, the researchers focused on the slaty-backed nightingale-thrush Catharus fuscater complex.
“The Catharus fuscater complex is composed of several disjunct populations that inhabit cloudy mountain rainforests, ranging from Costa Rica to Bolivia,” they explained.
“These birds are shy and more often heard than seen. Their song is a series of sweet, musical whistles.”
To document their differences, the scientists sequenced DNA from multiple…
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