“The Dinosaur Birds of China” (Asianometry, 5 November 2021)
In a most unexpected departure from the usual economics or IT topics covered, the Asianometry channel devoted an entire episode to the discovery of a series of Early Cretaceous-era fossils found in Liaoning in northern China that definitively demonstrated birds to be direct descendants of dinosaurs. On the other hand, not so unexpected is Asianometry’s thorough investigation of the controversy behind the relationship between birds and dinosaurs that had existed for much of the 20th century and the history of Liaoning province itself, right from when it was conquered by the Mongols and the Ming, to set the stage for the discovery of the Jehol fossils and the reactions engendered by the discoveries.
The view that birds might be descended from dinosaurs was raised very early, in the 19th century, but the view fell out of favour in the early 20th century after Danish palaeontologist Gerhard Heilmann published “The Origin of Birds” in 1926, in which he ruled out the possibility of birds being descended from dinosaurs on the basis of theropod dinosaurs apparently lacking clavicles despite the two groups of animals otherwise having much else in common. Heilmann’s view eventually fell out of favour after the work of John Ostrom in the 1970s in describing Deinonychus brought the possibility of the dinosaur-bird link back, along with a new system of biological classification known as cladistics in which organisms are grouped on the basis of shared characteristics. While these changes were going on, the area that became the Liaoning province itself was undergoing name and administrative changes, and even changes of ownership during the 1930s when the Japanese overran northeast China.
The narrator explains how atmospheric and other physical conditions existing in the Early Cretaceous era in what is now Liaoning province led to apparently large numbers of animals of different species dying and being preserved without being eaten or scavenged. These animals came from all known classes of land vertebrates living at the time: mammals that dined on baby dinosaurs, early birds such as Confuciusornis and feathered non-avian dinosaurs. From this point on, the narrator describes the various creatures like Confuciusornis and Sinosauropteryx (a small non-avian dinosaur first described by two Chinese scientists in a paper published in 1996) in considerable detail. There is even discussion of the dispute over Sinosauropteryx with some influential scientists objecting to the implications of the little dinosaur’s discovery that dinosaurs really were the direct ancestors of birds and that Heilmann’s theory had been incorrect all along.
Since then, the general scientific consensus has shifted to the view that birds are descended from dinosaurs and species like Sinosauropteryx help demonstrate the close connections between birds and dinosaurs. In addition, the Liaoning area has yielded more fossils of early birds and feathered dinosaurs which together have changed how scientists view dinosaurs and birds, so much so that dinosaurs are now finally being acknowledged as the complex animals they were, physically and psychologically, and their evolution far more dynamic and varied.
While this episode has been informative in ways we would usually expect on the topic of dinosaurs and birds, its real significance lies in how its investigation shows how significant scientific discoveries, especially when all grouped together, can change an entire paradigm about the phenomena they address – but often only after much difficulty in being accepted as genuine or noteworthy. It highlights a controversy that has long existed in dinosaur research and discoveries – the relationship between dinosaurs and birds – and which was only very recently put to rest.