Thursday , February 25 2021

Scientists discover the mystery of the smallest bird-free bird in the world: inaccessible islands Biology



The inaccessible island, west of the three islands in the Tristan Archipelago, is about 3,650 miles (3,600 km) east of Porto Alegre, in Brazil, and about 1,750 miles (2,800 km) west of Cape Town, in South Africa. Formed from the now extinct volcano 3 to 6 million years ago, the island is the only place in the world where a rare species of birds without flying is called the Inner Island RailwayAtlantisia rogersi) living. According to new research, the ancestors of this species went to the island of South America about 1.5 million years ago, perhaps on wings or riding on remains.

Inland islands (Atlantisia rogersi). Image credit: Peter G. Ryan.

Rail for the unquestionable island (Atlantisia rogersi). Image credit: Peter G. Ryan.

The inaccessible island railroad is the smallest bird flying without flights and the second smallest rail, which measures only 5-6 inches (13-15.5 cm) and weighs 34-49 grams.

The species was first described in 1923 by the British surgeon Percy Love, a birdwatcher, who then led an ornithological collection at the British Museum.

Love set birds in line Atlantis, a reference to the Mythic Atlantic, and called it a species rogersi after Rev. H.M.C. Rogers, a chaplain on the nearby island of Tristan da Cunha, who first collected specimens.

He assumed that the birds strolled on an island on a submerged land bridge from Africa and South America, but later the discovery of the tectonic plate discouraged that idea.

"We found that birds did not walk on foot," said lead author Martin Stervander, a postdoctoral researcher at the Oregon Institute of Ecology and Evolution.

"They flew or helped them floating remains. Whether they traveled or robbed the storms, and then landed on the remains, we can not say. In any case, they managed to get from the mainland of South America to an inaccessible island."

Using modern sequencing of mitochondrial and nuclear DNA and phylogenetic methods, dr. Stervander and coauthors linked the island's railways with the South American crown (Porzana spiloptera).

The split came about 1.5 million years ago, and the railway colonized an inaccessible island in one migration.

Their genetics also make them black cousins ​​(Laterallus jamaicensis) found in the Americas and probably Galapagos crake (Laterallus spilonota), which also has reduced ability to fly.

"It turned out that the railroad for an unforgettable island needs a change of name," said Dr. Stervander.

Scientists recommend that the species be processed in the genus Laterallus as well as related species.

"We are sorry we suggested that we take this wonderful name, Atlantis, which is something we can all love, but now we can say that the closest relatives of this type of American bird that had their name before the Iron Island, "said Dr. Stervander.

"When birds arrived on the island, they found three habitats without predators – pastures, trees of goddesses and forests – and rich sources of food, including worms, moths, berries and seeds."

"Shortly thereafter, birds that were enlarged no longer needed strong survival wings and developed into a non-functional species."

"Our discovery focuses on the importance of continuing to prevent railroad enemies from entering an imprecise island to enter the island. If this happens, it may disappear," said Professor Lund University Bengt Hansson, co-author of the study.

Findings are published in the journal Molecular phylogenetics and evolution.

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Martin Stervander et al. 2019. Origin of the smallest bird of the world without birds, Inland Iron Island Atlantisia rogersi (Aves: Rallidae). Molecular phylogenetics and evolution 130: 92-98; doi: 10.1016 / j.impev.2018.10.007


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