Ancient bird turns out to be a lizard

A bizarre, extinct animal that puzzled researchers and was previously misidentified as bird has now been classified as a new species of lizard, according to an international team of researchers.

The new species, Oculudentavis naga (named in honour of the Naga people of Myanmar and India), has been described in a new paper in Current Biology. The specimen used to describe the new species – the holotype – is a partial skeleton including a complete skull, preserved in amber with visible scales and soft tissue. The authors say the specimen was ethically acquired from Myanmar prior to the 2017 crisis, by gemologist Adolf Peretti.

839 lizard bird
Oculudentavis naga, top, is in the same genus as Oculudentavis khaungraae, bottom, a specimen whose controversial identification as an early bird was retracted last year. Both specimens’ skulls deformed during preservation, emphasizing lizardlike features in one and birdlike features in the other. Credit: Edward Stanley of the Florida Museum of Natural History/Peretti Museum Foundation/Current Biology

The team of researchers, led by Arnau Bolet of Barcelona’s Institut Catalá de Paleontologia Miquel Crusafont, Spain, used CT scans to analyse and compare each bone in the specimen against another lizard, Oculudentavis khaungraae, which was found in the same area and hails from the same time period (about 99 million years ago).

Both species have suffered misidentifications: O. khaungraae was originally described last year as the smallest known bird, and O. naga was also thought to be a bird until recently. 

“The specimen puzzled all of us at first because if it was a lizard, it was a highly unusual one,” Bolet says. The two species had skull proportions akin to that of a bird, including a vaulted cranium and long, tapering snout. Compounding the problem, the team determined that both species’ skulls had deformed during preservation, as the amber thickened around them.

“Imagine taking a lizard and pinching its nose into a triangular shape,” says co-author Edward Stanley, director of the Florida Museum of Natural History’s Digital Discovery and Dissemination Laboratory. “It would look a lot more like a bird.”

The two tiny lizards lived during the Cretacious period (145.5 to 66 million years ago), at a time when the authors say many of today’s lizard and snake groups evolved. But tracing modern species to their ancestor can be difficult, according to Juan Diego Daza, co-author and herpetologist at Sam Houston State University, Texas US. 

“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.”

A blue-green lizard between two branches with an orange liquid dripping on it
Oculudentavis naga, as depicted in this artist’s reconstruction, was a bizarre lizard that researchers initially struggled to categorize. They are still unsure of its exact position in the lizard family tree. Credit: Stephanie Abramowicz/Peretti Museum Foundation/Current Biology

The team has made a 3D digitized specimen of O. naga available online via MorphoSource, an online 3D inventory of global natural history specimens, so that anyone with an internet connection can analyse and reassess the creature. 

“With palaeontology, you often have one specimen of a species to work with, which makes that individual very important. Researchers can therefore be quite protective of it, but our mindset is ‘Let’s put it out there’,” says Stanley. “The important thing is that the research gets done, not necessarily that we do the research. We feel that’s the way it should be.”

The specimen is particularly important because Myanmar’s rich amber deposits are no longer ethically accessible, since a coup in February plunged the country into a military dictatorship. 

“As scientists we feel it is our job to unveil these priceless traces of life, so the whole world can know more about the past. But we have to be extremely careful that during the process, we don’t benefit a group of people committing crimes against humanity,” says Daza. “In the end, the credit should go to the miners who risk their lives to recover these amazing amber fossils.”

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