The Relationships of the Hawaiian Honeycreepers (Drepaninini) as Indicated by DNA-DNA Hybridization

Abstract

Twenty-two species of Hawaiian honeycreepers (Fringillidae: Carduelinae: Drepaninini) are known. Their relationships to other groups of passerines were examined by comparing the single-copy DNA sequences of the Apapane (Himatione sanguinea) with those of 5 species of cardueline finches, 1 species of Fringilla, 15 species of New World nine-primaried oscines (Cardinalini, Emberizini, Thraupini, Parulini, Icterini), and members of 6 other families of oscines (Turdidae, Monarchidae, Dicaeidae, Sylviidae, Vireonidae, Corvidae). The DNA-DNA hybridization data support other evidence indicating that the Hawaiian honeycreepers shared a more recent common ancestor with the cardueline finches than with any of the other groups studied and indicate that this divergence occurred in the mid-Miocene, 15-20 million yr ago.The colonization of the Hawaiian Islands by the ancestral species that radiated to produce the Hawaiian honeycreepers could have occurred at any time between 20 and 5 million yr ago. Because the honeycreepers captured so many ecological niches, however, it seems likely that their ancestor was the first passerine to become established in the islands and that it arrived there at the time of, or soon after, its separation from the cardueline lineage. If so, this colonist arrived before the present islands from Hawaii to French Frigate Shoal were formed by the volcanic "hot-spot" now under the island of Hawaii. Therefore, the ancestral drepaninine may have colonized one or more of the older Hawaiian Islands and/or Emperor Seamounts, which also were formed over the "hot-spot" and which reached their present positions as the result of tectonic crustal movement. The cardueline-drepaninine lineage probably diverged from the Fringilla lineage in the late Oligocene, from the New World nine-primaried oscines in the early Oligocene, and from the other oscines in the early Eocene.During this study we also obtained evidence that the vireos (Vireonidae) are not closely related to the New World nine-primaried oscines.