Working with samples that have been preserved in amber for millions of years can make securing a confident identification quite the challenge. It’s easy to miss tell-tale species indicators among the quirks of the preservation process. This was certainly the case for one critter described in a recent study which had been – until recently – thought to be a hummingbird-like dinosaur. The research, published in the journal Current Biology, describes a new species of the genus Oculudentavis which is now believed to contain ancient lizards.
Named Oculudentavis naga, the new species pays tribute to the Naga people of Myanmar (where the specimen was found) and India. The Kinder Surprise prize of a specimen is made up of a partial skeleton, including the entire skull complete with visible scales and soft tissue. It hails from the same genus as another specimen found in the same area, Oculudentavis khaungraae, which alongside O. naga is thought to be around 99 million years old.
Last year, a separate piece of research announced a new genus and species of the “early bird” O. khaungraae based on its fossilized skull. Shortly after its publication, the study was challenged by experts who thought its features better reflected those of a lizard, and the research was later retracted.
While all of this was going on, the researchers on this latest study were busy describing O. naga, the fossilized remains of which were better preserved compared to that used in the O. khaungraae study. However, despite its optimal preservation O. naga was still found to be such an unusual specimen that it proved quite the puzzle to work out exactly what it was.
Arnau Bolet of Barcelona's Institut Català de Paleontologia Miquel Crusafont led the research, using CT scans of both Oculudentavis species to compare their physical characteristics and earmark those which leaned towards the small animals being lizards.
"The specimen puzzled all of us at first because if it was a lizard, it was a highly unusual one," said Bolet in a statement.
The signs that swayed the researchers’ minds towards O. naga being a lizard included the presence of scales, teeth that were fused to its jawbone (not nestled into sockets like those of a dinosaur), and lizard-like eyes and shoulder bones. The soft tissue remains of O. naga also seemed to indicate the presence of a crest on top of the snout and a flap of loose skin, which could potentially have been used for display like the fancy dewlaps of anoles. There was also a hockey stick-shaped skull bone in O. naga which is shared among a group of reptiles known as the squamates, leading the researchers to believe that this could well be where O. naga sits.
"It's a really weird animal. It's unlike any other lizard we have today. We think it represents a group of squamates we were not aware of,” said herpetologist Juan Diego Daza in a statement. "We estimate that many lizards originated during this time, but they still hadn't evolved their modern appearance. That's why they can trick us. They may have characteristics of this group or that one, but in reality, they don't match perfectly."