Scientists occasionally find parts of animals trapped in solidified tree saps called amber, but when a group of researchers found a pair of bird-like wings encased inside an amber mined in Myanmar, they knew that they found something special.
Canada's Royal Saskatchewan Museum curator of invertebrate paleontology Ryan McKellar explained that one of the biggest challenges researchers face with feathers in amber is that they are often small fragments or isolated feathers.
Feathers do not always survive the fossilization process, and most of the information that scientists learn about prehistoric feathers were from amber fossils that often contain only single feathers, which do not provide much information about the creature they belonged to.
The newly found wings, however, were different. At about 99 million years old, they are among the most pristine fossilized feathers to be found. Researchers said that this pair of tiny wings are the first Cretaceous plumage samples to be analyzed that are not isolated feathers.
McKellar explained that the fossilized remains is the next best thing to holding the animal in the hand. The amber preserved every detail of the tiny wings, which makes it possible to see the traces of feathers, hair and bones and how these were arranged. The color of the feathers also survived and can still be seen.
With these wings, McKellar and colleagues were able to reconstruct what the bird may have looked like when it roamed the Earth alongside dinosaurs during the Cretaceous Period.
The wings belonged to members of a now-extinct group of hummingbird-size creatures known as Enantiornithes. Based on results of X-ray micro-CT analysis, the samples belong to juveniles as hinted by the bone size.
"The extremely small size and osteological development of the wings, combined with their digit proportions, strongly suggests that the remains represent precocial hatchlings of enantiornithine birds," the researchers wrote in their study, which was published in the journal Nature Communications on June 28.
These ancient birds have teeth and clawed wings, but they look similar to their modern-day relatives. Unlike most modern bird hatchlings, however, these ancient birds were born almost fully developed.
Study researcher Xing Lida, from China University of Geosciences in Beijing, said that the fact that the birds were clambering about in the trees show they had advanced development at their age, which means that they were already ready for action when they were hatched.
"These birds did not hang about in the nest waiting to be fed, but set off looking for food, and sadly died perhaps because of their small size and lack of experience," Xing Lida said. "Isolated feathers in other amber samples show that adult birds might have avoided the sticky sap, or pulled themselves free."
