A remarkably preserved 121-million-year-old fossil has revealed a new species of ancient bird, named Plumadraco bankoorum, belonging to the extinct enantiornithines—a diverse group of Cretaceous birds. Found in China and analyzed by researchers from the Field Museum and the University of Chicago, the specimen measures just 15 centimeters from beak to rump but sports tail feathers nearly a foot long, twice its body length. These ornamental feathers were not used for flight but likely for courtship displays, similar to modern peacocks.

The fossil, stored at the Shandong Tianyu Museum, was identified during a research visit by lead author Alex Clark. Using mass spectrometry, the team determined the feathers were likely dark brown or black with iridescent blue tips—a structural color caused by feather proteins, not pigments. The feather structure shows variation along its length, allowing for flickering or swaying motions, and the central rachis ends partway through the feather, a trait seen in modern display feathers.

Sex could not be definitively determined, but researchers believe the specimen is male, given the exaggerated tail features common in male birds for attracting mates. The discovery provides rare direct evidence of sexual selection in Mesozoic birds and highlights the deep evolutionary roots of mating displays. The study was published in PLOS One.