Madrid, 15 years old (Europe Press)
The fossil remains of an animal first identified as a flying dinosaur the size of a hummingbird are consistent with a lizard, according to new evidence presented in Current Biology.
The new species, named Oculudentavis naga after the Naga people of Myanmar and India, is represented by a partial skeleton that includes a complete skull, exquisitely preserved in amber with visible scales and soft tissue. The specimen belongs to the same genus as Oculudentavis khaungraae, whose original description as the smallest known bird was withdrawn last year. The two fossils were found in the same area and are about 99 million years old.
The team, led by Arnau Polit of the Instituto Catala de Paleontology Miquel Crossfonte in Barcelona, used computed tomography to digitally separate, analyze and compare each bone of the two species, discovering a series of physical characteristics that identify the young animals as lizards. Politt said Oculudentavis is very strange, yet it was difficult to classify it without careful examination of its properties.
“The specimen baffled us all at first because if it was a lizard, that is very unusual,” he said in a statement.
Pollitt and his colleagues, lizard experts around the world, first observed the specimen while studying a collection of amber fossils obtained in Myanmar by gemologist Adolph Peretti.
Herpetologist Juan Diego Daza examined a small and unusual skull, preserved with a small part of the bones of the spine and shoulders. He was also confused by its strange set of features – could it be some kind of pterodactyl or perhaps an ancient relative of monitor lizards?
“From the moment we uploaded our first CT scan, everyone was thinking about what it could be,” said Daza, assistant professor of biological sciences at Sam Houston State University. “Ultimately, a closer look and our analyzes help us clarify their position.”
The main clues that the mysterious animal was a lizard included the presence of scales. Teeth attach directly to their jaws, rather than being embedded in cavities, like dinosaur teeth; Lizard-shaped eye structures and shoulder bones. A hockey stick-shaped skull bone is universally shared among scaly reptiles, also known as scales.
The team also determined that the skulls of both species had been deformed during preservation. The snout of Oculudentavis khaungraae is compressed into a narrower shape, like a beak, while the skull of O. naga, the part of the skull that surrounds the brain, is compressed. Study co-author Edward Stanley, director of the Digital Publishing and Discovery Laboratory at the Florida Museum of Natural History, said the deformations highlighted bird features on one skull and lizard characteristics on the other.
“Imagine you take a lizard and pinch its nose into a triangular shape,” Stanley said. “It would be more like a bird.”
However, the Oculudentavis bird skull lineage does not indicate that it is related to birds, said study co-author Susan Evans, professor of vertebrate morphology and palaeontology at University College London.
“Although it has a domed skull and a long, pointed snout, it does not have important physical properties that can be used to maintain a close relationship with birds, and all of its characteristics indicate that it is a lizard,” he said.