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The white – necked railway colonized the Aldabra atoll in the Indian Ocean and evolved to become unable to fly, before being completely wiped out when the island was disappeared under the sea about 136,000 years ago.
But the researchers found similar fossils from before and after this event, showing that the bird the size of a chicken had reappeared when the sea level was again lowered a few thousand of 39 years later. again lost the ability to fly.
The flightless rail can be found on Aldabra to this day.
The extremely rare process is known as the iterative evolution – the repeated evolution of a species of the same ancestor at different times in history.
"We do not know of any other example in rails, or birds in general, that demonstrates this phenomenon so obviously," said co-author David Martill, of the University of Portsmouth, in a statement. communicated.
The return of the rail to Aldabra is not the only time in his lineage that he has escaped extinction.
The mother species of the rail, native to Madagascar, frequently saw its population explode, forcing the birds to migrate in large numbers off the coast of East Africa.
Many who flew north or south drowned in the Indian Ocean, and those who went to the west landed in Africa, where they were eaten by predators.
But the lucky few who went to the east ended up on islands like Mauritius, Reunion and Aldabra, the latter having been studied by researchers.
The rails on Aldabra lost the ability to fly over time, because the lack of predators made it useless – just like Maurice's dodo.
Unfortunately, it did not give them any escape when the island was submerged and all its flora and fauna were exterminated.
But unlike the dodo, which died in the 17th century, the white-necked rail was resurrected to tell the story once the island resurfaced and the birds began to migrate back to their destination.
This means that a species of Madagascar bird gave birth to two distinct species of rails on Aldabra within a few thousand years.
"Only Aldabra, which has the oldest paleontological record of all oceanic islands in the Indian Ocean region, has fossil evidence demonstrating the effects of sea level change on extinction phenomena. and recolonization, "said Martill.
"The conditions were such in Aldabra, the most important being the absence of terrestrial predators and mammals competing, which allowed a rail to be able to evolve autonomously with each flight," he explained. .
"These unique fossils provide irrefutable evidence that a member of the railroad family colonized the atoll, probably from Madagascar, and each day lost its flight independently," added in a release the senior author of the study, Julian Hume from the Natural History Museum of London.
"The fossil evidence presented here is unique with respect to rails and illustrates the ability of these birds to successfully colonize isolated islands and avoid flying repeatedly," he said.
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