澳洲鸸鹋与新西兰几维鸟并非近亲

Australia can no longer lay claim to the origins of the iconic New Zealand kiwi following University of Adelaide research published in the journal Science today showing the kiwi's closest relative is not the emu（鸸鹋） as was previously¹ thought. Instead, the diminutive²（小型的） kiwi is most closely related to the extinct Madagascan elephant bird -- a 2-3 metre tall, 275 kg giant. And surprisingly, the study concluded, both of these flightless birds once flew.

 

A new study by the University of Adelaide's Australian Centre for Ancient DNA³ (ACAD), has solved a 150-year-old evolutionary⁴ mystery about the origins of the giant flightless "ratite" birds, such as the emu and ostrich⁵（鸵鸟）, which are found across the southern continents. This group contains some of the world's largest birds -- such as the extinct giant moa of New Zealand and elephant birds of Madagascar.

 

The different "ratite" species were long thought to have formed as the flightless birds were isolated⁶ by the separation of the southern continents over the last 130 million years.

 

However, ancient DNA extracted from bones of two elephant birds held by the Museum of New Zealand, Te Papa Tongarewa, has revealed a close genetic⁷ connection with the kiwi, despite the striking differences in geography, morphology and ecology between the two.

 

"This result was about as unexpected as you could get," says Mr Kieren Mitchell, PhD candidate with ACAD, who performed the work. "New Zealand and Madagascar were only ever distantly physically⁸ joined via Antarctica and Australia, so this result shows the ratites must have dispersed⁹ around the world by flight."

 

The results correct previous work by ACAD Director Professor Alan Cooper conducted in the 1990s, which had shown the closest living relatives of the kiwi were the Australian emu and cassowary. "It's great to finally set the record straight, as New Zealanders were shocked and dismayed to find that the national bird appeared to be an Australian immigrant," says Professor Cooper. "I can only apologise it has taken so long!"

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