A quarter of a century ago, feathered non-avian theropods provided important evidence that dinosaurs were the ancestors of birds. A sample of Sinosauropteryx Prima dinosaurs discovered in 122-124 million-year-old lake deposits in China has made global headlines due to an “aura” of short membrane structures and fine threads.
Although often described as “primary blades” or non-branched monofilament, Sinosauropteryx blades are likely made up of multiple strands bonded into a common base. More feathered dinosaur fossils began to emerge after the discovery of the Sinosauropteryx fossil, and today about 40 feathered dinosaur species are known, ranging from the Middle Jurassic to the late Cretaceous. The majority of these fossils come from China, with fewer discovered in Mongolia, Siberia, Germany and North America.