Update: On July 22, the authors moved to retract their paper, which had suggested that an amber specimen from 99 million years ago contained the smallest dinosaur ever discovered. The paper had sparked backlash after it was published in March, with many in the scientific community doubting whether there was sufficient evidence to call the specimen a “dinosaur.”
Meet O. khaungraae, the smallest dinosaur ever found.
Scientists discovered a skull preserved in amber that may belong to a bird-like dinosaur that lived 99 million years ago. Despite its fierce-looking face, the creature is estimated to be smaller than any known species of bird.
An international research team led by Chinese paleontologist Xing Lida determined that, based on its bone structure and long beak, the animal is a previously unknown ancient bird species, which are considered dinosaurs. They named it Oculudentavis khaungraae — meaning “eye-teeth bird” — and described the fossil in a paper published Wednesday in the scientific journal Nature.
The amber was found in northern Myanmar in 2016. When Xing, a researcher from China University of Geosciences in Beijing, first laid eyes on the fossil, he couldn’t tell what it was because of the detritus trapped in the amber. To study the specimen, Xing and his colleagues scanned the amber with computed tomography and created a 3D reconstruction of the skull.
The piece of amber containing the preserved skull of Oculudentavis khaungraae. Courtesy of Xing Lida
“When I saw the CT scans, I was blown away by how weird it looked,” Xing told Sixth Tone.
The skull measures about 1.4 centimeters from the tip of the beak to the back of the head — slightly longer than a pea and shorter than a shelled peanut. Given its head, the researchers estimate that the full-sized animal would be smaller than a bee hummingbird, the world’s smallest living bird.
Despite its diminutive size, the ancient animal had a fearsome face.
While other known ancient birds tended to have teeth only at the front of their beaks, O. khaungraae had teeth all around its elongated mouth, not unlike a crocodile. Moreover, the team estimated that it had around 100 teeth — more than any other known bird. Because of this and its jaw shape, Xing said the tiny bird was likely a carnivore.
“It probably enjoyed insects like mosquitoes and lacewings,” he said. “Its teeth could kill them instantly.”
Left: An image of the skull of Oculudentavis khaungraae generated by 3D computed tomography reconstruction technology; right: A visual rendering of the ancient bird based on its skull. Courtesy of Xing Lida
Among O. khaungraae’s other distinctive features are a pair of disproportionately large eyes, an anatomical characteristic that’s more commonly seen in lizards. Mysteriously, the bird’s eyes only look out from the sides, meaning it wouldn’t have been able to see straight ahead without turning its neck.
“All modern birds have front vision, so it’s very strange to me why it developed an eye structure like that,” Xing said. “Not being able to look straight ahead sounds like a disadvantageous trait, but maybe there is something about the fossil or the animal’s habitat that we don’t understand.”
Although the current evidence suggests that O. khaungraae was an ancient bird, with just a skull to go on, this is only the team’s best guess.
“But we could be wrong and it’s actually a lizard or some other reptile,” Xing said, adding that the team is hoping to find a full O. khaungraae fossil to better understand the species.
Editor: David Paulk.
(Header image: A visual reconstruction of Oculudentavis khaungraae, the newly discovered smallest known dinosaur. Courtesy of Xing Lida)