Rapid diversification and secondary sympatry in Australo-Pacific kingfishers (Aves: Alcedinidae:Todiramphus)

Abstract

Todiramphus chloris is the most widely distributed of the Pacific's ‘great speciators’. Its 50 subspecies constitute a species complex that is distributed over 16 000 km from the Red Sea to Polynesia. We present, to our knowledge, the first comprehensive molecular phylogeny of this enigmatic radiation of kingfishers. Ten Pacific Todiramphus species are embedded within the T. chloris complex, rendering it paraphyletic. Among these is a radiation of five species from the remote islands of Eastern Polynesian, as well as the widespread migratory taxon, Todiramphus sanctus. Our results offer strong support that Pacific Todiramphus, including T. chloris, underwent an extensive range expansion and diversification less than 1 Ma. Multiple instances of secondary sympatry have accumulated in this group, despite its recent origin, including on Australia and oceanic islands in Palau, Vanuatu and the Solomon Islands. Significant ecomorphological and behavioural differences exist between secondarily sympatric lineages, which suggest that pre-mating isolating mechanisms were achieved rapidly during diversification. We found evidence for complex biogeographic patterns, including a novel phylogeographic break in the eastern Solomon Islands that separates a Northern Melanesian clade from Polynesian taxa. In light of our results, we discuss systematic relationships of Todiramphus and propose an updated taxonomy. This paper contributes to our understanding of avian diversification and assembly on islands, and to the systematics of a classically polytypic species complex.

Notes on the natural history, taxonomy, and conservation of the endemic avifauna of the Samoan Archipelago

“…A robust molecular study by Andersen et al (2015), however, found that this species is sister to the Pohnpei and Guam "subspecies" of the Micronesian Kingfisher T. cinnamominus, a group Pratt and Etpison (2008) previously suggested actually comprises three species. Other than the fact that all have strongly rusty or ocher-tinged plumage (restricted to juveniles in reichenbachii of Pohnpei), these forms do not closely resemble each other and their relationship to the Flat-billed Kingfisher is by no means visually or behaviorally obvious.…”

Predictable evolution toward flightlessness in volant island birds

“…Therefore, we patched hypothesized relationships among island populations into a specieslevel tree from Jetz et al (46), largely derived in its major clades from Hackett et al (47). We used published phylogeographic studies (48)(49)(50)(51)(52)(53)(54) as the basis for hypothesized relationships among island populations. For taxa without published phylogeographic studies, we hypothesized relationships based on subspecies differentiation, relationships among populations of similar species on the same islands, and geographic proximity of islands (see SI Appendix, Figs.…”

An ornithological survey of Vanuatu on the islands of Éfaté, Malakula, Gaua, and Vanua Lava

“…This is one of only a few examples of sympatric Todiramphus kingfisher pairs anywhere in the Pacific (Andersen et al 2015). Prevailing wisdom suggests these sympatric species segregate by habitat, whereby one is more likely to be found in the island's interior and the other occupies edge or coastal habitat (Bregulla 1992, Pratt andEtpison 2008); however, we observed both Vanuatu Kingfisher and Pacific Kingfisher Todiramphus sacer occurring together in and around our Malakula camp.…”

“…It was recently recognized as a species separate from the polytypic Collared Kingfisher, Todiramphus chloris complex (Andersen et al 2015). Twenty-two subspecies are described, of which 5 occur in Vanuatu (Clements et al 2016).…”