Scientists have discovered a feathered dinosaur tail preserved in 99-million-year-old amber in a market in Myanmar, Burma.

Up until this discovery, feather patterns and structures of dinosaurs have not been correctly assessed due to a lack of identifiable skeletal material. This tail represents the first non-avialan theropod fragments preserved in amber to ever be discovered. The study was published in Current Biology, where researchers explain what they have learned so far about the preserved dinosaur tail.

Dinosaur tail in amber
Dorsolateral overview of the feathered dinosaur tail. mage credit: Cell.

Going on an undercover mission for science

Lida Xing, from the China Academy of Geosciences in Beijing, found the piece of amber in the markets of Kachin in Myanmar, known for its amber stones. Amber is fossilized tree resin, which is often used as a material for jewelry. It is a fantastic preservation medium. The oldest samples of amber with trapped insects in them date from 150 million years ago. Organisms that become preserved in amber have much of their bodies intact, allowing scientists to understand more about ecosystems that got lost with the passing of time.

Xing had previously found baby bird-dinosaur wings in the same region in Myanmar, which led them to believe that there could be significant fossilized remains in the area’s amber market stalls and traders. The amber mines and the markets in Burma are controlled by the insurgent Kachin Independence Army, which is currently in armed conflict with the government.

According to Motherboard, to enter the marketplace, Xing disguised himself as a Burmese man with his face painted with a typical yellow-colored cosmetic paste from Myanmar, coincidentally just like amber, the paste comes from trees. Xing sported a fake ID and managed to have the person who found the tail to guide him to the mines. Then, he persuaded the Dexu Institute of Palaeontology in Chaozhou to provide the funds for acquiring the invaluable fossil remain.

A perfectly preserved part of a feathered dinosaur

The fossilized tail consists of eight vertebrae from a young theropod species, which are known to be mostly bipedal and eventually evolving into modern large birds, such as the ostrich.

The tail was analyzed using synchrotron x-ray technology to map it into a 3D model with full detail. This allowed researchers to take a look at the soft tissue, bones, and feathers of a dinosaur, all at the same time. It was also possible to understand how the feathers distributed themselves along the dinosaur’s skin, seeing that previous feathered fossils have been found lying flat, while the amber allowed the tail to remain basically intact, only losing some of its tissue due to dehydration.

They also discovered that the feathers had barbs set in uniform patterns, which may imply that the feathers evolved from these structures. The tail measures 36.73 mm or 1.3 inches, being densely covered in feathers, although its muscles, ligaments, and skin were able to be seen with X-ray scans.

Dinosaur Tail
Reconstructions focusing on dorsolateral and detailed dorsal aspects of the tail. Image credit: Cell.

By analyzing its vertebrae, researchers suggest that the fossil is a non-avialan coelurosaur’s tail, as the length of the vertebrae limit the possibilities of known bird species that were alive during that time and setting. Some pigments remain in the feathers, the dorsal plumage being darker than ventral plumage. The specimen appears to have been chestnut colored, with its ventral feathers being pale brown or white.

“The theropod tail reported here is an astonishing fossil, highlighting the unique preservation potential of amber. Importantly, in the context of bird origins, feathers and flight are key elements contributing to the success of the clade,” reads the study. “With preservation in amber, the finest details of feathers are visible in three dimensions, providing concrete evidence for feather morphologies and arrangement upon the tail, as well as supporting an important role for barbs and barbules in feather evolution.”

It is theorized that the specimen’s feathers served as a protection mechanism, allowing the dinosaur to blend in with the environment to avoid being easily spotted by predators.

Dinosaurs at first were thought to be fully related to reptiles. It was not until the 1990’s that researchers realized that they bore a closer resemblance to birds. Theropods are believed to be the most direct ancestors of birds, which has led birds to be called the modern descendants of dinosaurs, due to almost all birds possessing feathers.

The first discoveries of feathered dinosaurs occurred in Asia, where many of the specimens were trapped in volcanic ash due to eruptions about 124 million years ago. In the Liaoning province in China, researchers have found feathered remains of the velociraptor, a discovery that radically changed the perspective of how dinosaurs are depicted in movies compared to how they were in real life.

“The more we see these feathered dinosaurs and how widespread the feathers are, things like a scaly velociraptor seem less and less likely and they’ve become a lot more bird like in the overall view. They’re not quite the Godzilla-style scaly monsters we once thought,” stated Ryan McKellar, who co-authored the study.

Source: Cell