A new species of fossil bird with tail feathers twice as long as its body has been described by researchers in a study published in the journal PLOS One, according to a May 29 announcement from the Field Museum. The species, named Plumadraco bankoorum, lived about 121 million years ago during the Cretaceous Period and is notable for having some of the proportionally longest tail feathers ever found on a fossil bird.
“Plumadraco was the size of an American robin, but its tail feathers were about a foot long, twice the length of its body,” said Alex Clark, a PhD candidate at the Field Museum and the University of Chicago and lead author of the paper. “They’re some of the proportionally longest tail feathers ever found in a fossil bird.”
Clark discovered the fossil during a research trip to China’s Shandong Tianyu Museum with his advisor and co-author Jingmai O’Connor. He said, “I saw this little guy, and I did a double-take when I saw the tail feathers. I’m really interested in the way birds do displays to attract mates, and I thought that these tail feathers were so crazy, they had to be used for something like that.”
Analysis showed that Plumadraco belonged to enantiornithines—a group of prehistoric birds that died out alongside non-bird dinosaurs after an asteroid struck Earth 66 million years ago. Clark said it is likely that only males had such elongated tails: “There are many examples of both male and female modern birds with long, showy feathers, but there seems to be this certain threshold where… it tends to be a trait that males have developed in order to attract females.” He also noted similarities between Plumadraco’s courtship behavior and those seen in modern birds.
Using chemical analysis tools on preserved feather material from Plumadraco fossils, researchers determined that its plumage was probably dark brown or black. Clark suggested there may have been additional coloration at feather tips: “It’s possible that there was some sort of eye-catching color at the tips… maybe something iridescent or blue.”
“This fossil… shows that birds have been evolving costly, elongate, specialized features to attract mates for a long time,” said Clark. The discovery contributes further insight into how sexual selection has influenced avian evolution over millions of years.
The Field Museum operates as a natural and cultural history museum situated in Chicago; it offers permanent exhibitions such as Griffin Halls of Evolving Planet featuring SUE the T. rex; interactive spaces like McDonald’s Fossil Preparation Lab; educational events; free admission days for Illinois residents; and aims to connect visitors with nature through immersive exhibitions, according to the official website.
