Fossil Bird Reveals Its Diet

As laid out in a new study in Current Biology, Jingmai and colleagues found fossilized seeds in its stomach, indicating that the species was eating fruits, despite a long-standing hypothesis that this species used its incredibly strong teeth (enamel 50 microns thick, the same as large predatory dinosaurs) to eat fish, or, according to later hypotheses, insects. About the size of a blue jay, Longipteryx was discovered in 2000, but no specimens with fossilized stomach contents had ever been found—until Jingmai visited the Shandong Tianyu Museum of Nature a few years back, and noticed two Longipteryx specimens that appeared to have something in their stomachs. She consulted with paleobotanist and Negaunee Associate Curator of Fossil Plants Fabiany Herrera, who was able to determine that the tiny, round structures in the birds’ stomachs were seeds from the fruits of an ancient tree. Since Longipteryx lived in a temperate climate, the team suspects that it probably wasn’t eating fruits year-round, but also ate insects when fruits weren’t available. Still unknown is the function of the long, pointy beak and incredibly strong teeth. “The thick enamel is overpowered, it seems to be weaponized,” says co-author and Resident Grad Student Alex Clark (University of Chicago). “One of the most common parts of the skeleton that birds use for aggressive displays is the rostrum, the beak.” Adds Jingmai, “there are cool little hummingbirds that have keratinous projections near the tip of the rostrum that resemble what you see in Longipteryx, and they use them as weapons to fight each other.” Thus, Longipteryx’s teeth and beak may have served as a weapon, perhaps evolving under social or sexual selection. Overall, the research helps illuminate broader questions in paleontology about the scope and limits of the information revealed by skeletal traits. Read more in the press release, and in coverage from Newsweek, Discover mag, BBC Wildlife, and The Daily Mail, to name just a few. * Other co-authors with Jingmai, Alex Clark, and Fabiany: Xin Yang (Field Museum, University of Chicago), Xiaoli Wang (Shandong Tianyu Museum of Nature, Linyi University, Shandong University of Science and Technology), Xiaoting Zheng (Shandong Tianyu Museum of Nature), Han Hu (Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences), and Zhonghe Zhou (Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences).