The ancient flying reptiles called pterosaurs lived from about 220 million years ago until becoming extinct 66 million years ago, after the same event that wiped out non-avian dinosaurs.
But unlike the fossilized bones of dinosaurs, those of pterosaurs have remained elusive, in part because their hollow bones were so fragile.
About 90 percent of all specimens are found in just five fossil locales—in Brazil, China, Germany, the USA, and England—explains Alexander Kellner, the co-curator of the upcoming exhibition Pterosaurs: Flight in the Age of Dinosaurs.
In other locations, notes Curator Mark Norell, “a lot of pterosaur discovery is just serendipity.” Working in the Gobi Desert for the past 25 summers, he and his colleagues have found thousands of dinosaur bones—but only one belonging to a pterosaur.
A video explains more about why pterosaur fossils are so rare.