Evolution Diary

Illustration courtesy Li-Da Xing

A newfound dinosaur fossil with feathers suggests that plumage may have begun to appear with the rise of all dinosaurs more than 200 million years ago.

The 130-million-year-old Tianyulong confuciusi from China is probably a young adult, researchers say. Its 2.3-foot-long (0.7-meter-long) body displays three distinct patches of featherlike structures.

The creature is the first known example of a feathered dinosaur belonging to Ornithischia, one of two main dinosaur groups.

Ornithischia includes armored herbivores such as Triceratops and Stegosaurus.

Until now, feathered species had been found only among the Saurischia group, which includes the two-legged meat-eaters known as theropods, thought to be the ancestors of modern birds.

The filaments or ‘protofeathers’ are clearly visible on the fossil

“So this discovery expanded the distribution of feathers into the other half of dinosaurs,” study co-author Hai-Lu You, of the Chinese Academy of Geological Sciences in Beijing, said in an email.

Tiny Tianyulong is considered particularly close to the ancient evolutionary split between the two dinosaur lineages.

As dinosaurs in the two groups diversified, feathers probably evolved to serve different purposes, from display to insulation to flight, You said.

“This will also ask us to search the origin of feathers further back beyond dinosaurs,” he added.

Hans-Dieter Sues, associate director for research and collections at the Smithsonian Institution’s National Museum of Natural History, called the find a “remarkable discovery.”

According to Sues, Tianyulong suggests that some form of filamentous body insulation existed early in dinosaur evolution.

Experts have referred to such coatings as protofeathers, or sometimes dinofuzz.

“Later,” Sues said, “these simple filaments could have developed into the true feathers found in many theropod dinosaurs and their descendants: birds.”

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