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An island half the size of Manhattan in the South Atlantic Ocean is so remote that it is called Inaccessible Island. On this island, and only on this island, live nearly 6,000 crazy feather balls called Inaccessible Island rails. But they can not fly and the island only has a few million years. How did the birds get there?
A new analysis may have solved the mystery. The DNA of the bird reveals that it has evolved relatively recently from a visitor to the island and has lost its ability to steal natural selection forces.
"It's quite dramatic that the smaller live-flying birds of this word have found themselves in one of the most remote places of all time," said Gizmodo, the author of the book. study, Martin Stervander, postdoctoral researcher from the University of Oregon. "It seems that the birds arrived on the island, and as they were not threatened by predators, there was no reason to fly."
When scientists first described this bird in the 1920s, they immediately realized that they were seeing something odd. Inaccessible Island is 3,500 km from South America and 2,800 km from Southern Africa. The bird does not occupy any of the two neighboring islands located within 32 km.
Before the theory of plate tectonics, they proposed that the bird would move one way or another to the island by some kind of land bridge below. They placed him in his own kind, Atlantisia. More recent research has suggested that the bird came from rails in Africa.
The scientists behind the new document have analytical tools other than the shape and geography of birds. They captured an inaccessible male insular rail in September 2011, took its blood, sequenced its DNA and compared the results to data from other rails.
They deduced that the ancestor of the rail was a South American bird arrived on the island about 1.5 million years ago and that it was probably a member of the Laterallus The genus, which includes today's birds such as black-winged gypsum, Galapagos gypsum and the same-looking black rattle, according to the article published in the journal Molecular Phylogenetics and Evolution.
It makes sense. It is known that rails fly everywhere and settle, with 53 existing or recently extinct species appearing only on islands and 32 species losing all or part of their flight capacity. An ancestral population of the Inaccessible Island Rail Rail has probably been flying east to the Atlantic and has finally returned to the island, which is which was a pretty sweet feat for which they no longer needed to steal.
"When the rail arrived at Inaccessible Island, all their food was found and there was nothing left to escape, there was no need to fly," said Stervander. The only threats of the bird on the inaccessible island are another species of bird that sometimes eats eggs and perhaps some seabirds.
It is unclear why the rail did not go to the other two islands – perhaps a population tried and failed.
Stervander pointed out that there was more research to be done. The dataset on the rails was incomplete, so maybe more data will reveal that the bird really belongs to a distinct kind.
And although the bird lives the good life, it is still considered a vulnerable species. Bird populations that are unable to fly can easily collapse if humans bring invasive species, such as cats or rats, with them.
This document solves perhaps the cutest mystery of the South Atlantic Ocean. But if you plan to visit the island (which is not easy), be sure to do nothing that could harm the birds.
[Molecular Phylogenetics and Evolution]Source link
