​Nay Pyi Taw, Dec 9 (IANS) In one-of-a-kind discovery, a tail of a feathered dinosaur has been found perfectly preserved in amber in Myanmar, opening a new window on the biology of a group that dominated earth for more than 160 million years, a media reported on Friday.

Described in the journal Current Biology, the examination of the specimen suggests the tail was chestnut brown on top and white on its underside.

"This is the first time we've found dinosaur material preserved in amber," co-author Ryan McKellar, of the Royal Saskatchewan Museum in Canada, told the BBC news.

The study's first author, Lida Xing from the China University of Geosciences in Beijing, discovered the remarkable fossil at an amber market in Myitkina, Myanmar.

The 99-million-year-old amber had already been polished for jewellery and the seller had thought it was plant material. On closer inspection, however, it turned out to be the tail of a feathered dinosaur about the size of a sparrow.

McKellar said examination of the tail's anatomy showed it definitely belonged to a feathered dinosaur and not an ancient bird.

"We can be sure of the source because the vertebrae are not fused into a rod or pygostyle as in modern birds and their closest relatives," he explained.

"Instead, the tail is long and flexible, with keels of feathers running down each side."

McKellar said there are signs the dinosaur still contained fluids when it was incorporated into the tree resin that eventually formed the amber. This indicates that it could even have become trapped in the sticky substance while it was still alive.

Co-author Prof Mike Benton, from the University of Bristol, added: "It's amazing to see all the details of a dinosaur tail - the bones, flesh, skin, and feathers - and to imagine how this little fellow got his tail caught in the resin, and then presumably died because he could not wrestle free."

The findings also shed light on how feathers were arranged on these dinosaurs, because 3D features are often lost due to the compression that occurs when corpses become fossils in sedimentary rocks.

The feathers lack the well-developed central shaft - a rachis - known from modern birds. Their structure suggests that the two finest tiers of branching in modern feathers, known as barbs and barbules, arose before the rachis formed.

Paul Barrett, from London's Natural History Museum, called the specimen a "beautiful fossil", describing it as a "really rare occurrence of vertebrate material in amber".

He told BBC news: "Feathers have been recovered in amber before, so that aspect isn't new, but what this new specimen shows is the 3D arrangement of feathers in a Mesozoic dinosaur/bird for the first time, as almost all of the other feathered dinosaur fossils and Mesozoic bird skeletons that we have are flattened and 2D only, which has obscured some important features of their anatomy."