It's a mystery that scientists have been trying to solve for nearly a century. How did the world's smallest flightless bird end up on a remote island in the middle of the South
Atlantic?
The Inaccessible Island rail (Atlantisia rogersi) is a tiny, flightless bird - 15 to 17 centimetres long - that is only found on Inaccessible Island, making its evolutionary origins difficult to trace.
When scientists first discovered the bird, they thought its ancestors had walked to the remote island, which is nestled between South America and Africa, on stretches of land now swallowed by the sea. So they gave the bird its own genus named Atlantisia.
But unlike Inaccessible Island, that name is a misnomer.
Given how similar this bird looks to the extinct flightless Ascension crake (from another island in the South Atlantic Ocean), researchers took it as a sign that they were related, but a modern analysis of the bird's DNA has shown that is not the case.
The ancestors of the Atlantisia genus once had wings, and they flew to Inaccessible Island 1.5 million years ago.
Today, the bird's closest living relatives are the dot-winged crake in South America and the black rail found in both South and North America
