New Zealand's iconic kiwi is most closely related to the extinct elephant bird of Madagascar rather than the Australian emu as previously thought.
The findings stem from a study by the University of Adelaide that was based on ancient DNA analyses of elephant bird bones at the Museum of New Zealand, Te Papa Tongarewa.
At two to three metres tall and weighing in at 275kg, the Madagascan elephant bird was a far cry from the chicken-size kiwi.
But the DNA analyses found a close genetic link between them.
The study, published in the journal Science, found that ancestors of both of these flightless birds once took to the skies. And that has helped solve a 150-year-old mystery about the origins of flightless "ratite" birds found across the southern continents today, like emus and ostriches.
"This result was about as unexpected as you could get," said Kieren Mitchell, of the University of Adelaide's Australian Centre for Ancient DNA (ACAD).
"New Zealand and Madagascar were only ever distantly physically joined via Antarctica and Australia, so this result shows the ratites must have dispersed around the world by flight." The findings apparently correct previous research carried out in the 1990s that had pointed to the emu and cassowary as the kiwi's closest living relatives.
"It's great to finally set the record straight, as New Zealanders were shocked to find that the national bird appeared to be an Australian immigrant," ACAD Director Alan Cooper, who carried out the 1990s research.
The researchers used the elephant bird DNA to estimate that the ratite species separated from each other shortly before the dinosaurs became extinct about 65 million years ago.
"The evidence suggests flying ratite ancestors dispersed around the world right after the dinosaurs went extinct, before the mammals dramatically increased in size and became the dominant group," Cooper said.