title: The Mouse-colored Tyrannulet (Phaeomyias murina) is a species complex that includes the Cocos Flycatcher (Nesotriccus ridgwayi), an island form that underwent a population bottleneck.
abstract: Simultaneous examination of evolutionary history in island forms and closely related mainland relatives can provide reciprocal insight into the evolution of island and mainland faunas. The Cocos Flycatcher (Nesotriccus ridgwayi) is a small tyrant flycatcher (Tyrannidae) endemic to Cocos Island, an oceanic island in the eastern Pacific Ocean. We first established its close relationship to the mainland species Mouse-colored Tyrannulet (Phaeomyias murina) using a phylogeny from genome-wide ultraconserved elements and exons. We then used mitochondrial DNA to explore the relationships between Nesotriccus and Phaeomyias populations from across its distribution in Central and South America. We found that Nesotriccus is nested within the Phaeomyias evolutionary tree, and that Phaeomyias represents a complex of at least four evolutionarily distinct species that differ in plumage, voice, and habitat association. Nesotriccus underwent a population bottleneck subsequent to its divergence from Central American and northern South American Phaeomyias populations in the middle Pleistocene. The 46 UCE loci containing alleles that are fixed between the two species are widely distributed across the genome, which suggests that selective or neutral processes responsible for divergence have occurred genome-wide. Overall, our simultaneous examination of Phaeomyias and Nesotriccus revealed divergent levels of genetic diversity and evolutionary histories between island and mainland forms.
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA. Electronic address: mzucke2@lsu.edu.
authors.forename: Marc R
authors.initials: MR
authors.lastname: Zucker
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA; Museum of Natural Science, Louisiana State University, Baton Rouge, LA, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Harvey
authors.affiliation: Museum of Natural Science, Louisiana State University, Baton Rouge, LA, USA.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Oswald
authors.affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA.
authors.forename: Andrés
authors.initials: A
authors.lastname: Cuervo
authors.affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Derryberry
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA; Museum of Natural Science, Louisiana State University, Baton Rouge, LA, USA.
authors.forename: Robb T
authors.initials: RT
authors.lastname: Brumfield
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D014644:Genetic Variation; D005828:Genetics, Population; D016678:Genome; D006239:Haplotypes / Q000235:genetics; D062312:Islands; D010802:Phylogeny; D020308:Songbirds / Q000145:classification* / Q000235:genetics; D013045:Species Specificity
keywords: Coalescent methods; Cocos Island; Exons; Phylogeny; Phylogeography; Ultraconserved elements