Flightless birds' history upset by ancient DNA.
Madagascar's elephant birds--which weighed as much as four people and went extinct several hundred years ago--turn out to be the closest known relatives of New Zealand's chicken-sized kiwi birds (a skeleton shown).
This surprise is "a slap in the face" to a long-standing idea of how flightless birds evolved, says Alan Cooper of Australia's University of Adelaide. Biologists in the 1970s debated whether the kiwi and other flightless ratite birds arose when flightless common ancestors drifted apart by riding on landmasses that fragmented and separated.
In 1992 Cooper raised doubts about that idea when he extracted ancient DNA from specimens of New Zealand's hefty flightless moa, now extinct. As fellow travelers, the moa and kiwi should have been close relatives. But they aren't. The kiwi is more closely related to Australia's cassowary and emu.
Now he and colleagues have extracted DNA from elephant birds (an egg shown) and found that they are the kiwi's closest kin. These two birds' homes weren't near each other as continents fragmented, so drifting doesn't explain the close relationship. Their distant ancestors must have done some flying, the team concludes in the May 23 Science.
Please note: Illustration(s) are not available due to copyright restrictions.
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|Title Annotation:||LIFE & EVOLUTION; moas|
|Article Type:||Brief article|
|Date:||Jun 28, 2014|
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