In a genetic surprise, DNA shows an extinct bird known as the Haitian cave-rail are not in the Americas, but Africa and the South Pacific.
In a genetic surprise, ancient DNA shows the closest family members of an extinct bird known as the Haitian cave-rail are not in the Americas, but Africa and the South Pacific, uncovering an unexpected link between Caribbean bird life and the Old World.
Like many animals unique to the Caribbean, cave-rails became extinct soon after people settled the islands. The last of three known West Indian species of cave-rails – flightless, chicken-sized birds – vanished within the past 1,000 years. Florida Museum of Natural History researchers sought to resolve the group’s long-debated ancestry by analyzing DNA from a fossil toe bone of the Haitian cave-rail, Nesotrochis steganinos. But they were unprepared for the results: The genus Nesotrochis is most closely related to the flufftails, flying birds that live in sub-Saharan Africa, Madagascar and New Guinea, and the adzebills, large, extinct, flightless birds native to New Zealand.
The study presents the first example of a Caribbean bird whose closest relatives live in the Old World, showcasing the power of ancient DNA to reveal a history erased by humans.
The discovery was “just mind-blowing,” said study lead author Jessica Oswald, who began the project as a postdoctoral researcher at the Florida Museum.
“If this study had not happened, we might still be under the assumption that the closest relatives of most things in the Caribbean are on the mainland in the Americas,” said Oswald, now a postdoctoral researcher at the University of Nevada, Reno and a Florida Museum research affiliate. “This gives us an understanding of the region’s biodiversity that would otherwise be obscured.”
Many animals evolved unusual forms on islands, often making it difficult to classify extinct species based on their physical characteristics alone. But advancements in extracting viable DNA from fossils now enables scientists like Oswald to answer longstanding questions with ancient genetic evidence. Oswald described her work as similar to a forensic investigation, tracing the evolutionary backstory of extinct animals by piecing together fragmented, degraded genetic material.
“Understanding where all of these extinct species fit into a larger family tree or evolutionary history gives us insight into what a place looked like before people arrived,” she said. “That’s why my job is so fun. It’s always this whodunit.”
Oswald was just starting her ancient DNA work at the Florida Museum when David Steadman, curator of ornithology and study co-author, suggested the Haitian cave-rail as a good candidate for analysis.
Cave-rails share physical characteristics with several types of modern birds, and scientists have conjectured for decades whether they are most closely related to wood rails, coots or swamphens – birds that all belong to the rail family, part of a larger group known as the Gruiformes. Oswald and Steadman hoped that studying cave-rail DNA would clarify “what the heck this thing is,” Oswald said.
Originally published at Eurek Alert