Baby dinosaur's tail — with feathers — found in 99 million-year-old amber

December 9, 2016, 2:15 p.m.
dinosaur tail in amber
Photo: Ryan C. McKellar/Royal Saskatchewan Museum

The photo above shows a piece of fossilized tree resin, or amber, from the Cretaceous Period. Aside from insects and plant debris, it contains the preserved tail of a young dinosaur, according to a groundbreaking new study in the journal Current Biology.

That alone is big news, since it's the first time skeletal material from a dinosaur has been found in amber. But this tail is also still covered in feathers, the researchers discovered, offering an unprecedented glimpse 99 million years back in time.

Amber is prized as a gemstone, and this specimen was discovered in 2015 at an amber market in Myanmar. It caught the eye of Lida Xing, a paleontologist at the China University of Geosciences, who was told the big, fuzzy object among the insects is a plant. Xing knew better, though. "I realized that the content was a vertebrate, probably theropod, rather than any plant," Xing tells CNN. "I was not sure that [the trader] really understood how important this specimen was, but he did not raise the price."

Over the past two decades, scientists have found evidence of dinosaur feathers in fossil impressions, but the actual feathers are more elusive. And feathers from unidentified animals have been found in previous pieces of amber, Xing notes, but no other recognizable body parts were preserved with them, preventing anyone from knowing for sure if they came from dinosaurs.

barbules on preserved dinosaur tail feather A view of microscopic barbules with weak pigmentation from the preserved dorsal plumage. (Photo: Ryan C. McKellar/Royal Saskatchewan Museum)

This amber, however, reveals apparent dinosaur feathers with unusual clarity. Xing and his colleagues know these feathers didn't come from a bird, they explain, because of clues in the associated tail. Modern and ancient birds have a distinctive plate of fused vertebrae in their tails, but this newfound tail is flexible enough to bend in multiple places at once. It most likely belonged to a juvenile coelurosaur, the researchers write, a broad group of two-legged dinosaurs known to have feathers.

This dinosaur probably couldn't fly, they add, since the "open, flexible structure" of its feathers resemble modern ornamental feathers more than flight feathers. Its plumage might have served other purposes, like signaling to fellow dinosaurs — although "it may have been a glider," co-author and Royal Saskatchewan Museum paleontologist Ryan McKellar tells Science Magazine.

Traces of pigment were even found in the amber, offering clues about the dinosaur's coloring. "Preserved coloration suggests a chestnut brown dorsal surface," the study's authors write, "contrasting against pale or almost white ventral plumage."

illustration of a small dinosaur in the Cretaceous Period An artist's impression of a small coelurosaur approaching a resin-coated branch on the forest floor. (Image: Cheung Chung-tat and Liu Yi)

"I have studied paleontology for more than 10 years, and have been interested in dinosaurs for more than 30 years," Xing tells NPR. "But I never expected we could find a dinosaur in amber. This may be the coolest find in my life."

That doesn't mean he'll rest on his laurels, though. As Xing tells National Geographic, he's hoping this foreshadows even bigger discoveries in Myanmar's amber deposits. "Maybe we can find a complete dinosaur," he suggests.