Flightless bird reappears 1,36,000 years after its extinction
Madagascar : A bird species which is believed to have extinct about 1,36,000 years ago has reappeared on an isolated coral island.
Researchers from the United Kingdom’s Natural History Museum and the University of Portsmouth revealed how the bird has re-evolved from the same ancestral species on a group of four coral islands in the Indian Ocean. The findings have been published in the Zoological Journal of the Linnean Society this week.
The Aldabra atoll is home to the Aldabra rail, a flightless bird descended from the white-throated rail. White-throated rails ― which can fly ― are chicken-sized birds native to Madagascar, but are known to travel to other isolated islands and take up residence there, explains a news release from the University of Portsmouth.
White-throated rails evolved on the island in a way that they lost their flying skills because they had no harm even staying on the ground of the island. But, this turned out to be the biggest disadvantage when the island submerged into the water, it wiped out all of its species around 136,000 years ago.
But about 100,000 years ago, sea levels dropped again, and flightless rails ultimately appeared again on the atoll. Scientists say fossil records indicate that white-throated rails once again colonized the island, and once again evolved into a flightless subspecies.
"These unique fossils provide irrefutable evidence that a member of the rail family colonised the atoll, most likely from Madagascar, and became flightless independently on each occasion," said lead researcher Julian Hume of the Natural History Museum in a statement.
“We know of no other example in rails, or of birds in general, that demonstrates this phenomenon so evidently,” he said.