Monday, July 31, 2017

[PaleoOrnithology • 2017] Ancient DNA and Morphometric Analysis Reveal Extinction and Replacement of New Zealand's Unique Black Swans, Cygnus sumnerensis



The skeleton of the poūwa, Cygnus sumnerensis (Forbes, 1890) 

 Rawlence, Kardamaki, Easton, et al. 2017.
 Ancient DNA and Morphometric Analysis Reveal Extinction and Replacement of New Zealand's Unique Black Swans.  Proceedings of the Royal Society B.  DOI:  10.1098/rspb.2017.0876 
Abstract

Prehistoric human impacts on megafaunal populations have dramatically reshaped ecosystems worldwide. However, the effects of human exploitation on smaller species, such as anatids (ducks, geese, and swans) are less clear. In this study we apply ancient DNA and osteological approaches to reassess the history of Australasia's iconic black swans (Cygnus atratus) including the palaeo-behaviour of prehistoric populations. Our study shows that at the time of human colonization, New Zealand housed a genetically, morphologically, and potentially ecologically distinct swan lineage (Cygnus sumnerensis, Poūwa), divergent from modern (Australian) C. atratus. Morphological analyses indicate C. sumnerensis exhibited classic signs of the ‘island rule’ effect, being larger, and likely flight-reduced compared to C. atratus. Our research reveals sudden extinction and replacement events within this anatid species complex, coinciding with recent human colonization of New Zealand. This research highlights the role of anthropogenic processes in rapidly reshaping island ecosystems and raises new questions for avian conservation, ecosystem re-wilding, and de-extinction.

KEYWORDS:  ancient-DNA, Australia, black swan, Chatham Islands, Cygnus atratus, Cygnus sumnerensis, Q1 extinction, island rule, New Zealand, Poūwa, recolonization

The skeleton of the extinct poūwa.
Jean-Claude Stahl / Museum of New Zealand Te Papa Tongarewa 
The mounted bones of an extinct poūwa.
Photo: Museum of New Zealand Te Papa Tongarewa




Nicolas J. Rawlence, Afroditi Kardamaki, Luke J. Easton, Alan J. D. Tennyson, R. Paul Scofield and Jonathan M. Waters. 2017. Ancient DNA and Morphometric Analysis Reveal Extinction and Replacement of New Zealand's Unique Black Swans.
 Proceedings of the Royal Society B.  DOI:  10.1098/rspb.2017.0876

  

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