Scientists have identified a new species of the ‘really weird’ creature previously misclassified as the world’s smallest dinosaur, reinforcing the belief it was actually a lizard.
The 99-million-year-old specimen — which is stunningly preserved in amber — is in the same genus as ‘Oculudentavis khaungraae’, whose original description as a hummingbird-sized dinosaur was retracted last year.
Both fossils were discovered in the same area of Myanmar.
Discovery: Scientists have identified a new species of the ‘really weird’ creature previously misclassified as the world’s smallest dinosaur, reinforcing the belief it was actually a lizard. Oculudentavis naga is pictured in an artist’s reconstruction following the analysis
HOW IS A DINOSAUR DISTINGUISHED FROM OTHER REPTILES?
Dinosaurs had an upright stance which allowed them to run faster and for longer than other reptiles the same size.
This was because of their straight back legs which were positioned directly under their bodies.
By comparison, other reptiles had legs that sprawl out to the side like today’s lizards and crocodiles.
Their thigh bones are almost parallel to the ground, meaning they walk and run with a side-to-side motion.
Dinosaur skulls also had distinctive openings behind the eyes and in the snout and lower jaw.
Meanwhile, their teeth fitted into sockets in the jaw in a peg-like fashion, whereas in lizards they are attached directly to the jawbone by ligaments.
Source: Natural History Museum
‘The specimen puzzled all of us at first because if it was a lizard, it was a highly unusual one,’ said Arnau Bolet, of Barcelona’s Institut Català de Paleontologia Miquel Crusafont.
‘We concluded that both specimens are similar enough to belong to the same genus, Oculudentavis, but a number of differences suggest that they represent separate species.’
The new species has been named ‘Oculudentavis naga’ in honour of the Naga people of India and Myanmar. Its confirmation as a lizard followed the use of CT scans to analyse the fossil skull and partial skeleton.
Major clues included the presence of scales, teeth attached directly to its jawbone — rather than nestled in sockets, as dinosaur teeth were — lizard-like eye structures and shoulder bones, and a hockey stick-shaped skull bone universally shared among scaled reptiles, also known as squamates.
Researchers also determined both species’ skulls had deformed during preservation.
Oculudentavis khaungraae’s snout was squeezed into a narrower, more beak-like profile while naga’s braincase — the part of the skull that encloses the brain — was compressed.
The distortions highlighted bird-like features in one skull and lizard-like features in the other, said study co-author Edward Stanley, director of the Florida Museum of Natural History’s Digital Discovery and Dissemination Laboratory.
‘Imagine taking a lizard and pinching its nose into a triangular shape,’ Stanley said. ‘It would look a lot more like a bird.’
Stuck in time: The 99-million-year-old specimen — which is stunningly preserved in amber (pictured) — is in the same genus as ‘Oculudentavis khaungraae’, whose original description as a hummingbird-sized dinosaur was retracted last year
Comparison: The animal’s confirmation as a lizard followed the use of CT scans to analyse the fossils. Oculudentavis naga (top) is in the same genus as Oculudentavis khaungraae (bottom)
Oculudentavis’ bird-like skull proportions, however, do not indicate that it was related to birds, according to fellow co-author Susan Evans, professor of vertebrate morphology and paleontology at University College London.
‘Despite presenting a vaulted cranium and a long and tapering snout, it does not present meaningful physical characters that can be used to sustain a close relationship to birds, and all of its features indicate that it is a lizard,’ she said.
While the two species’ skulls do not closely resemble one another at first glance, their shared characteristics became clearer as the researchers digitally isolated each bone and compared them with each other.
‘We concluded that both specimens are similar enough to belong to the same genus, Oculudentavis, but a number of differences suggest that they represent separate species,’ Bolet said.
However, the researchers came up short in their attempts to find Oculudentavis’ exact position in the lizard family tree.
‘It’s a really weird animal. It’s unlike any other lizard we have today,’ said herpetologist Juan Diego Daza. ‘We think it represents a group of squamates we were not aware of.’
The Cretaceous period, 145 to 66 million years ago, gave rise to many lizard and snake groups on the planet today, but tracing fossils from this era to their closest living relatives can be difficult, Daza added.
‘We estimate that many lizards originated during this time, but they still hadn’t evolved their modern appearance,’ he said.
‘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.’
The study is published in the journal Current Biology.
FOSSILS IN BURMESE AMBER
Amber, often used in jewellery, is fossilised tree resin, and the oldest dates back more than 300 million years.
In the past few years the Hukawng Valley in northern Myanmar, formerly Burma, has yielded numerous finds.
In January 2017, researchers discovered a 100-million-year-old insect preserved in amber which bore a passing resemblance to ET.
Its features were so odd and unique that researchers placed in into a new scientific order of insects.
The creature had a triangular head and bulging eyes, which is different from any other known species of insect.
The eyes on the side of its head would have given it the ability to see at almost 180 degrees by simply turning its head to the side.
Because of its uniqueness, the insect was assigned its own brand new scientific classification order – called Aethiocarenodea.
In June 2017, researchers revealed a stunning hatchling trapped in amber, which they believe was just a few days old when it fell into a pool of sap oozing from a conifer tree in Myanmar.
The incredible find showed the head, neck, wing, tail and feet of a now extinct bird which lived at the time of the dinosaurs, 100 million years ago, in unprecedented detail.
Researchers nicknamed the young enantiornithine ‘Belone’, after a Burmese name for the amber-hued Oriental skylark.
The hatchling belonged to a group of birds known as the ‘opposite birds’ that lived alongside the ancestors of modern bird.
Archaeologists say they were actually more diverse and successful – until they died out with the dinosaurs 66 million years ago.
They had major differences from today’s birds, and their shoulders and feet had grown quite differently to those of modern birds.
In December 2017, experts discovered incredible ancient fossils of a tick grasping a dinosaur feather and another – dubbed ‘Dracula’s terrible tick’ – swollen after gorging on blood.
The first evidence that dinosaurs had bloodsucking parasites living on them was found preserved in 99 million-year-old Burmese amber.
The newly-discovered tick dates from the Cretaceous period of 145 to 66 million years ago.