An article published in the journal “Nature” reports the identification of a new primitive bird that lived near the end of the Cretaceous period, almost 67 million years ago, near the border between today’s Belgium and Holland. A team of researchers led by the University of Cambridge subjected the fossil bones of what was named Asteriornis maastrichtensis to a high resolution CT-scan to create 3D reconstructions. In particular, the skull is one of the best preserved among bird fossils. Its characteristics bring together those of modern chickens and ducks, suggesting that it’s a species very close to their last common ancestor.
The fossils of primitive birds and feathered dinosaurs discovered in recent decades show that birds are dinosaurs, the only group of these animals that survived the mass extinction that occurred at the end of the Cretaceous period. Reconstructing the evolution of modern birds from dinosaurs is problematic because fossils are limited and there are several species of feathered dinosaurs with different characteristics similar to those of modern birds. Each new species identified could lead to leaps forward in this task and Asteriornis maastrichtensis could make an important contribution to this type of research as well.
The specimen of Asteriornis maastrichtensis was discovered about twenty years ago in a quarry, and the fact that it was discovered in Europe and not in China or in the southern hemisphere, like many other fossils of feathered dinosaurs and primitive birds, is interesting. The skull is very well preserved, and for this reason Dr. Daniel Field of Cambridge stated that the moment he saw it was the most exciting in his scientific career.
The fossil skeleton was dated around 66.7 million years ago, which means it lived less than a million years before the mass extinction of the end of the Cretaceous period, side by side with dinosaurs. A high resolution CT-scan made it possible to create a 3D reconstructions of its bones to carry out in-depth examinations that provided interesting information on its likely relationships with modern birds and in particular with chickens and ducks.
Because of its importance, this specimen was nicknamed wonderchicken. It had long legs and probably could fly. At the end of the Cretaceous the climate was warm in Europe and Asteriornis maastrichtensis lived near the beaches on the banks of the shallow waters around the islands that existed at the time.
Fossils of primitive birds that lived shortly after the mass extinction of the end of Cretaceous were discovered in today’s New Zealand and Antarctica. This suggested that the first birds might have evolved in the southern hemisphere, in the then Gondwana. The discovery of wonderchicken could change things, but adding questions without giving answers yet. More than ever, the search for the oldest ancestors of birds continues all over the world.