Dinosaurs with feathers lived long before birds flew

Dinosaurs had feathers long before their descendants, including birds, learned to fly. The latest fossil find from China provides a striking view of what one of these feathered dinosaurs looked like and shows the complexity of its feathers.

The fossil comes from the Yixian Formation at Lingyuan, Liaoning in China, a rich source of remarkable new fossil specimens. The find is described this morning in the journal Nature, by researchers from the Chinese Academy of Geological Sciences, Beijing, and the American Museum of Natural History, New York.

The fossil is small, about 65cm long and 35cm across, about as large as a medium-sized dog. It is startlingly well preserved, its finders say, and gives an unprecedented view of its feathers and their structure and placement.

The team is working to identify the animal to see if it matches other finds, so its name remains a mystery. Its features however place it amongst the Maniraptora, the small, predatory theropod group that includes birds and the dromaeosaurid dinosaurs. The dromaeosaurs include Velociraptor, the dino-villains made famous in the film, Jurassic Park.

Dating of the sediment in which the dinosaur was found places it in the Late Jurassic age, between 124.6 million years and 147 million years ago. Its shape and size led the research team to describe it as a "sub-adult".

The animal was fully covered with feathers except for parts of its hind limbs. Its feathers or "integumentary filaments" covered the head in a "thick mat", the researchers write. "The most interesting integumentary areas are those on the arms and tail. In these areas the filaments are complex, bunched and tightly organised."

The find provided yet more evidence that modern birds evolved from the theropods, according to Dr Hans-Dieter Sues of the Royal Ontario Museum, who wrote an accompanying article on the fossil. It also showed that feathers evolved before flight.

"Feathers are the most distinctive attribute of living birds. Traditionally their evolution has been linked to the origin of flight, but there have always been a few dissenting opinions," he writes.

This and an earlier fossil find reported last month "now confirm that true feathers already existed in the non-flying dinosaurian relatives of birds and thus pre-dated the origin of birds and avian flight".

The question that now must be answered is what their purpose might have been, he said. "They clearly evolved for some purpose other than flight, perhaps thermal insulation or behavioural display (or both) - functions they retain in present-day birds."