Rare Feathered Dinosaur Tail Trapped in Amber

Rare feathered dinosaur tail was discovered in amber in Myanmar (Burma).

This significant find originated in Myanmar, where a specimen of amber from the mid-Cretaceous period—approximately 99 million years ago—was obtained at a local market. Originally mistaken for plant material at a local market, the piece drew the attention of paleontologist Lida Xing from the China University of Geosciences. Detailed analysis revealed that the preserved structure was a segment of a dinosaur tail, including feathers.

The preserved tail belonged to a juvenile dinosaur, no larger than a sparrow, measuring only about 6 inches (15 cm) long. Within the amber, scientists identified a 1.4-inch (36 mm) section of tail complete with bones, skin, soft tissue, and delicate feathers. This accident of preservation—when the young dinosaur became trapped in sticky tree resin—provides one of the most detailed fossilized examples of feathered dinosaurs ever found.

The tail is described in the journal Current Biology. The specimen offers valuable insights into the morphology and evolutionary adaptations of feathered dinosaurs during the Cretaceous Period, supporting hypotheses about feather development in non-avian theropods.

Dinosaur tail fragment with integument and vertebrae preserved in mid-Cretaceous amber.

"This is the first of its kind," said paleontologist Ryan McKellar of the Royal Saskatchewan Museum in Canada, one of the researchers involved in the study published in the journal Current Biology. "I'm blown away."

A detailed examination of the tail segment revealed exceptionally well-preserved bones, soft tissue, and feathers. The feathers, not adapted for flight, were likely used for display or sensory functions.

Microscopic analysis uncovered intricate feather structures, pigmentation, and arrangement, while CT scanning enabled a non-destructive 3D reconstruction of the tail. The feathers were preserved in remarkable three-dimensional detail, showcasing both their structural and microscopic features. This discovery provides direct evidence that many dinosaurs, including those not directly ancestral to modern birds, possessed feathers.

The scientists suspect the tail belonged to a type of two-legged, bird-like dinosaur called a maniraptoran, one of several groups of dinosaurs that possessed feathers. Birds, which first appeared about 150 million years ago during the Jurassic Period, evolved from small, feathered dinosaurs.

The researchers used sophisticated scanning and microscopic observations to study the tail. They determined it boasted a chestnut-brown upper surface, with a pale or white underside, a pattern known as countershading.

"We're seeing feathers still attached to the tail, and we can see how they attach, the shapes that they have down to the micrometer scale, and things like pigment patterns within the feathers," McKellar said.

The tail consisted of eight vertebrae, soft tissue and feathers exquisitely preserved in three dimensions. McKellar said getting its tail stuck in resin "would have been a game-ender for that particular animal. They don't drop their tails like some lizards."

The tail's anatomy enabled the scientists to rule out that it belonged to a bird because it was long and flexible and lacked a pygostyle, fused vertebrae that in birds support the tail feathers.

Artist's impression of a sparrow-sized theropod dinosaur based on its feathered caudal vertebrae, preserved in Cretaceous amber with soft tissue detail. Courtesy R.C. McKellar/Royal Saskatchewan Museum

The discovery also sheds light on the evolution of feathers. The ones trapped in the amber were more primitive than those of birds, lacking much of the central shaft seen in bird feathers.

Significance: This discovery supports the theory that feathers were not exclusive to bird ancestors but were more widespread among dinosaurs, potentially serving various functions beyond flight, like insulation or display.

The feathered tail was preserved in amber from north-eastern Myanmar

Amber has long been a boon to paleontologists. Numerous creatures have been found entombed in amber, including insects, lizards, amphibians, mammals and birds, as well as plants including flowers.