‘Ō‘ōps! They did it again.

They played with appearances and got lost in the convergent evolution game. Fleischer et al. have proposed a new family for the Hawai’ian birds long believed, since the time of Captain James Cook’s last voyage, to be Australasian Honeyeaters (Meliphagidae). From museum specimens collected more than a century ago, researchers at the Smithsonian Institute sampled DNA of the five nectarivorous songbirds, formerly endemic to Hawaiʻi, but now extinct, and report that they are not Honeyeaters at all!

O‘ahu ‘Ō‘ō	Kioea	Molokaʻi ʻŌʻō	Hawaiʻi ʻŌʻō	Kaua‘i ‘Ō‘ō
Moho apicalis	Chaetoptila angustipluma	Moho bishopi	Moho nobilis	Moho braccatus

Ornithologists have long been deceived. Among the five suspects of Moho (four Ō‘ōs) and Chaetiptila (the monotypic Kioea) genera, trademarks for nectarivory and morphological similarity to true Honeyeaters is undeniable: long tarsi, long and slender, decurved bills, extendable, textured tongues with adaptations enabling capillary action, and an operculum serving to prevent pollen from entering the nares. Despite the likeness, according to DNA analysis, the Hawaiian “Honeyeaters” share a clade with Waxwings (Bombycillidae), Silky Flycatchers (Ptiligonatidae), such as Phainopepla, and the monotypic Palmchat (Dulidae), all of which are frugivorous or insectivorous, but not nectarivorous.

Fleischer et al. argue that they are deserving of their own family, Mohoidae. The so-called “Mohoids,” though long considered to originate from South Pacific ancestors, are most closely related to Holoarctic and Neotropical species. Based on nuclear DNA analysis, the Mohoids separated 14 – 17 millions of years ago, and the authors correlate this to the first appearance of bird-pollinated plantae on Hawaii.

New Phylogeny for Mohoidae

The phylogeny trees for Mohoidae have been restructured based on sequencing of A) mitochondrial DNA from th 5 Mohoidae and 43 other songbirds B) Recombination Activating Gene 1 and C) β-fibrinogen introns. Monophyly of the 5 species and New World ancestry is justified. © Fleischer et al.

The case of the Stitchbird (Notiomystis cincta), the endemic New Zealand species that was also mistakenly placed in the Melophagidae family, was not forgotten by the authors. While it qualifies as another example of convergent evolution, the Stitchbird evolved rather early in the Oscine Passerine radiation, as did true Honeyeaters. The case of the Hawaiian Mohoids is remarkable, as at least three species belong to a clade in Passerida, relatively far removed from the basal lineages and Corvida.

Evidence of the convergent evolution of traits of Old World nectarivores shared by the Honeyeaters, Sunbirds, and Flowerpeckers was presented by a New World taxon. Unfortunately, the last remaining species of the family has been extinct since 1987 before their formal acknowledgment.

Press releases for the reclassification of Avian Hawaiian Nectarivores:
1. Hawaii’s honeyeater birds tricked taxonomists
2. Smithsonian Scientists Rearrange Hawaii’s Bird Family Tree
3. Клан медососов остался без имени

~ by finchwench on Sunday, 14 December 2008.