It is easy to forget that dinosaurs never roamed the later countries where their fossilized remains have been found, but an unnamed and shifting landmass that was transformed over millions of years by environmental change. Each discovery is a small miracle.
120 million years ago, in the middle of what is known as the Mesozoic Era or Age of Reptiles, Liaoning Province in northeast China was a region of dense forest and lakes heaving with wildlife. Sea-levels were much higher and active volcanoes nearby periodically erupted, sending clouds of ash and toxic gasses into the air killing anything in the way.
In the early 1990s the first dinosaur remains were discovered there. Since then thousands of fossil plants and animals – including insects, fish, dinosaurs, birds, amphibians and mammals – have been found in Liaoning. Some of the fossils are the earliest known birds. Others are feathered dinosaurs, the group that spawned birds. The discoveries are amazingly well preserved – delicate features like skin texture and feathers are clearly visible in many of the specimens. The discovery of numerous feathered dinosaurs in Liaoning reveals important information about the origin of feathers and flight, as well as the evolution of birds. Together, they constitute some of the most important finds in dinosaur palaeontology in the past century.
The most famous of Liaoning’s numerous fossil sites is located near the small village of Sihetun. Today, local farmers find fossils and bring them to the attention of scientists. At most sites elsewhere in the world only bone can be found, but at Liaoning the fine particles of ash and mud that covered animals preserved soft body parts and prevented decomposition by sealing off oxygen. Paleontologists have found dinosaur fossils with stomach contents identifiable as the bones of lizards and mammals, and bird fossils containing plant seeds.
Hans-Dieter Sues of the Smithsonian Institution has said that, “The site preserved not just bones but often whole skeletons and some birds were preserved so well you can distinguish between male and female. Liaoning is unique.”
Now, what may be the earliest creature yet discovered on the evolutionary line to birds has been unearthed from Liaoning’s famous fossil beds. The animal, which retains impressions of feathers, lived some 160 million years ago. Scientists have named it Aurornis xui, meaning “dawn bird”. Just fifty centimetres from tail to beak, the animal has primitive skeletal features that place it at the base of the Aves – the group that includes birds and their close relatives after their divergence from other dinosaur lineages.
We live and learn. Unlike the dinosaurs.