The Aldabra white-throated rail, a flightless bird that lives on its namesake atoll in the Indian Ocean, doesn’t appear as though anything extraordinary at first look. But the little bird has big bragging rights because it has effectively evolved into existence twice after first going extinct some 136,000 years ago.
“We know of no other example in rails, or of birds in general, that demonstrates this phenomenon so evidently,” the study’s co-author, University of Portsmouth professor David Martill, said in a statement. “Only on Aldabra, which has the oldest palaeontological record of any oceanic island within the Indian Ocean region, is fossil evidence available that demonstrates the effects of changing sea levels on extinction and recolonization events.”
According to a study by Zoological Journal of the Linnean Society:
“A flightless Dryolimnas has been identified from two temporally separated Aldabran fossil localities, deposited before and after the inundation event, providing irrefutable evidence that a member of Rallidae colonized the atoll, most likely from Madagascar, and became flightless independently on each occasion,” the abstract reads. “Fossil evidence presented here is unique for Rallidae and epitomizes the ability of birds from this clade to successfully colonize isolated islands and evolve flightlessness on multiple occasions.”
According to Fox News:
So as to make the assurance that the wiped extinct bird had evolved thanks to iterative advancement, they look at fossils from 100,000 years back, after ocean began to fall off during the last Ice Age. Upon inspecting the fossils, the wing bone showed “an advanced state of flightlessness,” while the ankle bone showed properties that would suggest it was evolving towards flightlessness.
“These unique fossils provide irrefutable evidence that a member of the rail family colonized the atoll, most likely from Madagascar, and became flightless independently on each occasion,” the study’s lead researcher, Dr. Julian Hume added in the statement. “Fossil evidence presented here is unique for rails, and epitomizes the ability of these birds to successfully colonize isolated islands and evolve flightlessness on multiple occasions.”