A phylogeny of kingfishers reveals an Indomalayan origin and elevated rates of diversification on oceanic islands

Aim: Kingfishers are the most species-rich family in the avian order, Coraciiformes. Their modern distribution is largely pantropical; however, global species diversity is unevenly distributed. For example, 19 of the 114 kingfisher species occur in New Guinea, whereas only six species occur in the entire New World. This disparity in diversity suggests regions with high species richness could represent the ancestral range of the family. Furthermore, some clades of kingfishers (Ceyx, Todiramphus) are thought to be the product of rapid insular radiations. Here, we investigated the biogeographical history and speciation dynamics of the Alcedinidae using a fully sampled molecular phylogeny. Location: Global. Taxon: Kingfishers (Aves: Coraciiformes: Alcedinidae). Methods: We inferred a time-calibrated, species-level phylogeny of kingfishers from DNA sequences. Our data set comprised up to five Sanger-sequenced gene regions for all species (one mitochondrial, one nuclear exon and three nuclear introns), plus genus-level sampling of thousands of ultraconserved elements. We estimated ancestral ranges of kingfishers and explored macroevolutionary rate shifts and diversification rates across the phylogeny. Results: We recovered a well-supported phylogeny of kingfishers that includes 34 species whose phylogenetic relationships were not previously known. The pygmy-kingfishers (subfamily Alcedininae) sit on a long branch, sister to all other kingfishers: subfamilies Cerylinae and Halcyoninae. Crown-group kingfishers originated in the Indomalayan region approximately 27 Ma with subsequent colonizations into Africa (six times), the New World (twice) and Australasia (representing several major radiations). Main conclusions: Oceanic islands of Wallacea, the Philippines and Oceania promoted multiple, independent radiations in three species-rich genera: Ceyx, Actenoides and Todiramphus. In particular, Todiramphus showed patterns consistent with explosive and recent diversification relative to the background speciation rate of non-Todiramphus kingfishers, which we attribute to recent colonization of the vast archipelagos of Wallacea and the Pacific.