Mistaken Bird Fossils Is Actually a Mysterious Small Lizard; Is This the World's Smallest Dinosaur?

In March 2020, an amber-encased fossil was touted as the world's smallest dinosaur ever found. Although little is known about this peculiar skull, scientists presented it as a hummingbird-sized toothed bird, a flying dinosaur that lived 100 years ago in Myanmar.

However, a reanalysis of the fossils described in the journal of Nature created a controversy that it is not what it was previously thought.

The findings of the reanalysis, entitled "Unusual morphology in the mid-Cretaceous lizard Oculudentavis" published in the journal Current Biology, confirm that the fossils belonged to a small lizard and not a bird.

Is It a bird or a Lizard?

Study lead author and University of Bristol paleontologist Arnau Bolet said that there are several factors why scientists got confused about which species do the fossils truly belong to, Smithsonian Magazine reported.

Bolet said that the long and tapering snout and the vaulted skull roof gave an impression that it was a bird. However, a closer examination of the fossil showed the lizard-like appearance of the fossil that cannot be seen in birds.

For instance, the teeth of the Oculudentavis are fused to the jaw, which is a characteristic commonly seen in lizards and snakes. More so, the shape and connections of the skull of the fossils are from a lizard and not a bird. The analysis of the second fossil confirms this observation.

The team used CT scans of reptiles inside the second specimen and reanalyzed them from the first specimen. Bolet and his colleagues named the second species as Oculudentavis naga in honor of the Naga people.

"It's a really weird animal. It's unlike any other lizard we have today," herpetologist Juan Diego Daza from Sam Houston State University said in a statement in Florida Museum news release. "We think it represents a group of squamates we were not aware of."

On the other hand, some experts not part of the study, like Michael Caldwell of the University of Alberta, said that the Oculudentavis might not be a lizard. He suggests that it might be much more ancient and unusual.

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Lizard Snout Might Have Been Squeezed During Fossilization

Analyzing fossils preserved in amber is not easy, as proven by the two fossils found in Myanmar. With the unusual features of the lizards, they have proven to be more challenging to be placed in the animal kingdom and also the fact that the original skull of Oculudentavis had been squashed.

According to ScienceAlert, reconstruction of the two specimens showed that O. khaungraae's snout had been squeezed during fossilization. But without the compression, the snout would resemble the long snout of the O. naga instead of a bird's beak.

Reanalysis of the O. naga specimen shed light on the controversial species because it was well-preserved that scientists can even make out some of its tissue, like what appears to be loose flaps of skin that are common for other lizards.

Despite this, scientists remain unsure where Oculudentavis exactly fit in with the family tree of lizards.

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