WASHINGTON // About 99 million years ago, a juvenile dinosaur got its feathery tail stuck in tree resin, a death trap for the small creature.
But its misfortune is now giving scientists unique insights into feathered dinosaurs that prospered during the Cretaceous Period.
Researchers said this week that a chunk of amber found by a Chinese scientist in a market in Myitkyina, Myanmar, last year contained 3.5 centimetres of the tail of the dinosaur, complete with bones, flesh, skin and feathers.
The dinosaur was no more than 15cm long, about the size of a sparrow.
“This is the first of its kind,” said palaeontologist 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.”
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 had 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 that it had 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 micrometre scale, and things like pigment patterns within the feathers,” Dr McKellar said.
The tail consisted of eight vertebrae, soft tissue and feathers exquisitely preserved in three dimensions.
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.
The discovery also sheds light on the evolution of feathers.
The ones that were trapped in the amber were more primitive than those of birds, lacking much of the central shaft holding the strands together.