Most intact bird fossil in 99-million-year-old amber

The new bird is also special because researchers were able to get a closer look at the young prehistoric creature's internal anatomy, according to study co-author Ryan McKellar of the Royal Saskatchewan Museum in Regina, Canada.

“The amber is opaque and contains many small splinters of wood. It appears to have been created on or near the forest floor,” McKellar said. This means the bird’s exterior is unremarkable, but its interior is much more interesting. “When they prepared it for research in Myanmar, they polished the front half of the specimen, allowing us to see the chest cavity and skull,” McKellar said.

The find adds to an extraordinary collection of Cretaceous fossils from amber deposits in Myanmar’s northern Hukawng Valley. In recent years, the site has yielded some spectacular bird wing fossils, the fully feathered tail of a small carnivorous dinosaur, and the skeleton of a bird hatchling. Last December, researchers even found the remains of dinosaur blood-sucking mites in amber.

Lida Xing, lead author of a study detailing the specimen in the journal Science Bulletin, said his heart was racing when he first saw the bird being sold as jewelry in Myanmar in 2015. The team was lucky enough to be able to buy the bird for the Dexu Institute of Paleontology in Chaozhou, China. Amber-encased birds can sometimes sell for as much as $500,000, putting them beyond the reach of scientists, said Xing, a paleontologist at the China University of Geosciences in Beijing.

Based on the analysis, the team concluded that the young bird was caught in the resin while alive or dead. The moisture caused the resin to bubble slightly, creating a cloudy amber mass. Some bones and soft tissue were missing, and sediments were trapped inside the spaces.

The bird is about 6cm long. Its feathers and bone structure suggest it is an enantiornithine, a primitive bird that went extinct along with the flightless dinosaurs 66 million years ago. “Even when they hatch, they have full feathers on their wings and tail. They have weak spines, so they may not have been great fliers,” McKellar speculates.

In life, the bird had a toothed beak and a chestnut-brown or walnut-colored body, with ruffled feathers on its head and neck. Unfortunately, the fossil lacks two identifying features: a toothy beak and claws on its wings. Researchers believe the fledgling may have been attacked by a predator and fallen from its nest into sap oozing from the same tree. Some plant matter and a cockroach trapped in the amber may have come from the nest.