An analysis of a dinosaur fossil found in China has revealed a primitive form of feather that may have evolved much earlier than was previously thought, as it dates back to 100 million years.
The dinosaur fossil was discovered by Xiao-Ting Zheng at the Shandong Tianyu Museum of Nature and colleagues in China.
According to a report in Nature News, they found the fossil in Liaoning that has long feather-like structures sticking up from its body. Based on the bones present, it looks like it was small, active, agile, and probably eating a mix of insects, small vertebrates and plants.
The team has identified the species as a heterodontosaurid from the Early Cretaceous period, which began about 144 million years ago.
“Heterodontosaurids are exceptionally rare, and previously unknown from Asia,” said Richard Butler at the Natural History Museum in London. This fossil “confirms that heterodontosaurids, one of the oldest groups of dinosaurs, survived into the Cretaceous”, he added.
Dinosaurs are divided into two main orders: saurischians, which have forward-pointing pubic bones, and ornithischians, which have backward-pointing pubic bones.
All previous feathered theropods belong to the saurischian order, whereas the new fossil belongs to the ornithischian.
The find “pulls the origin of feathers down into the Triassic, when the saurischian and ornithischian lineages of dinosaurs split”, said Philip Currie at the University of Alberta in Canada.
The feathery structures found on this heterodontosaurid, dubbed Tianyulong confuciusi, are not like those found on modern birds or even on some of the smaller, more bird-like theropods.
Whereas modern feathers are flexible and have a central shaft with vanes that run off either side at angles, the feathers on T. confuciusi are all relatively stiff and lack vanes.
Hai-Lu You, one of the palaeontologists who identified T. confuciusi, believes that the fossil supports the idea of a single evolution of feathers.
“We still have some missing data between T. confuciusi and feathered theropod dinosaurs, but I think further discovery will fill these gaps,” he said.
If this proves to be true, then many dinosaurs may once have sported feather-like structures, with descendant species losing the characteristic later on.
The specimen supports arguments that dinosaurs may have used feathers for display.
“If these are protofeathers, then they were not related in any way to flight,” explained Butler. “The fact that the filaments over the tail are so long and stiff suggests a possible display function,” he added.