Vicars, tramps and assembly of the New Zealand avifauna: a review of molecular phylogenetic evidence

Abstract

The avifauna of New Zealand is taxonomically and ecologically distinctive, as is typical of island biotas. However, the potential for an old geological age of New Zealand has encouraged a popular notion of a ‘Moa’s ark’ based on the idea that much of the fauna was isolated when Zealandia broke from Gondwana c. 83 million years ago. Molecular phylogenetics has proved useful for exploring the relative importance of different biogeographical processes, revealing for example that ‘tramp’ species (widely dispersing taxa) have arrived in New Zealand even in the last few hundred years, and that some avian taxa have close phylogenetic relatives overseas (predominantly Australian), indicating their recent ancestors were tramps, too. Distinctive taxa with deep phylogenetic ancestry might be ‘vicars’ that owe their presence to vicariance, but lack of close morphological, taxonomic and phylogenetic affinity provides only tenuous evidence for this. Disproving the alternative possibility that apparent vicars are descended from tramps that dispersed in earlier times remains challenging, but molecular analyses have yielded startling insights. Among New Zealand’s iconic taxa, the world’s largest eagle shared a Pleistocene ancestor with a small Australian eagle, and giant, flightless moa are phylogenetic sisters of the much smaller, flying tinamous of South America. The New Zealand avifauna is neither isolated nor stable, but demonstrative of prolonged and ongoing colonization, speciation and extinction.

Grey Gerygone hosts are not egg rejecters, but Shining Bronze-Cuckoos lay cryptic eggs

“…] in Australia and gerygones [Gerygone spp. ] in New Zealand and Melanesia), and their chicks appear quite different (Gill 1998), but morphological variation among adults is small (Gill 1983a), and there is little genetic differentiation (Sorenson and Payne 2005, Christidis and Boles 2008, Trewick and Gibb 2010. Here we study the New Zealand population and, where necessary, refer to races by their putative subspecies nomenclature.…”

Fossils reveal an early Miocene presence of the aberrant gruiform Aves: Aptornithidae in New Zealand

“…As expected, few of the original vicariant elements remain, and at least some have been lost since the Oligocene transgression. Thus, contra the views espoused by Trewick and Gibb (2010), it has long been realised that most taxa have an origin by dispersal post-dating the separation of Zealandia from the rest of Gondwana. However, this origin does not detract from the fact that the current New Zealand biota had in part a vicariant origin and is indeed now unique in its composition, as it was in the Early Miocene.…”

“…At lower taxonomic levels, the New Zealand fauna was accrued by periodic and at times repeated colonisation of taxa, mainly from Australia (Fleming 1979;Tennyson 2009;Trewick and Gibb 2010). The greatest understanding of this process is afforded by the record for Anatidae.…”

Jurassic primates, immobile ducks and other oddities: a reply to Heads’ review of The Monkey’s Voyage

“…I recognised that fact in the book, mentioning Fleming, Mildenhall and Robert McDowall in that context, but I also de-emphasised their continuing influence through the period in question. Still, the works written at the time, given above, as well as perceptions of recent developments (Winkworth et al 2002;Didham 2005;McGlone 2005;Waters and Craw 2006;Goldberg et al 2008;Giribet and Boyer 2010;Trewick and Gibb 2010) indicate that, contrary to Heads' claim, historical biogeography within New Zealand has undergone a major shift away from vicariance and towards dispersal explanations for the origins of the biota. It has not been a case of 'dispersalism' simply maintaining dominance the whole time, as Heads would have us believe.…”