Most intact bird fossil in 99 million year old amber
The 99-million-year-old baby bird is the most complete bird fossil ever found in an amber mine in Myanmar that scientists know of.
The newly discovered bird is also special because researchers were able to get a better 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, with lots of 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.
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Reconstruction of a bird trapped in a block of tree resin that later turned into amber. Photo:National Geographic. |
The discovery 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 hatchling bird. 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, which is 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 block of amber. Some bones and soft tissue were lost, and sediments were trapped in the spaces.
The bird is about 6 centimeters 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 chick may have been attacked by a predator and fallen from its nest into sap that seeped from the same tree. Some plant matter and a cockroach trapped in the amber may have come from the nest.
