A
previously extinct species of bird returned from the dead, reclaiming the
island it previously lived on and re-evolving itself back into existence,
scientists have said. The white-throated rail colonized the Aldabra Atoll in
the Indian Ocean and evolved to become flightless, before being completely
wiped out when the island disappeared below the sea around 136,000 years ago.
But
researchers found similar fossils from before and after that event, showing
that the chicken-sized bird re-appeared when sea levels fell again a few
thousand years later, re-colonized the island and again lost the
ability to fly.
The
flightless rail can be found on Aldabra to this day.
The
extremely rare process is known as iterative evolution -- the repeated
evolution of a species from the same ancestor at different times in history.
The
team's study, published in the Zoological Journal of the Linnean
Society, marks the first time the process has been seen in rails, and is one of
the "most significant" instances ever found in birds, according to
the authors.
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