This Little Guy Trapped in Amber Is the Smallest Dinosaur Ever Discovered

Scientists are marveling over the exquisitely preserved skull of what appears to be the smallest bird known to mankind – even tinier than the smallest hummingbird – encased in 99-million-year-old amber.

It is the smallest dinosaur on record, not ‘just’ the smallest bird on record. The fossil – the skull of a dinosaur that resembled a bird – was found recently in northern Myanmar, in a piece of amber that is about 99 million years old. Apparently, the creature was even smaller than a bee hummingbird, the smallest known bird currently living.

The research on the specimen was conducted by a team of Chinese, American and Canadian scientists and led by Xing Lida, a paleontologist and associate professor at China University of Geosciences in Beijing. Their findings were published in the journal Nature.

The Oculudentavis weighed about 28 grams and measured 5 cm in length, including a hypothetical bony tail. The specimen discovered is perrfectly preserved, offering researchers a startlingly clear view of its features, as demonstrated by the high resolution photographs below.

Hi-res photo of the specimen found (click to enlarge):

A handout photo provided on March 10, 2020 by China University of Geosciences shows the skull of Oculudentavis khaungraae, a bird-like dinosaur discovered in 99-million-year-old amber from northern Myanmar. The skull is only 7.1 mm in length and indicates the dinosaur could have been even smaller than a bee hummingbird, the smallest living bird. XING Lida / China University of Geosciences / AFP

“I was totally blown away,” said paleontologist Jingmai O’Connor of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, describing her feelings upon seeing the fossil. “It’s probably the most beautifully preserved Mesozoic bird skull I’ve ever seen, and it’s so weird.”

The Mesozoic Era, the age of dinosaurs, lasted from about 252 to 66 million years ago.

Here’s another high resolution image of the discovery (click to enlarge):

Amber – fossilized tree sap – has preserved numerous small organisms including insects, lizards and frogs. Unlike fossils encased in rock, amber specimens still retain their soft tissue, showing scientists their original color and morphology. XING Lida / China University of Geosciences / AFP

Previously, the smallest dinosaur on record was the bee hummingbird, which lives in Cuba. It’s also the world’s smallest living bird, with males measuring up to 57 millimetres in length, and weigh 1.6 grams, while females are larger.

“The smallest non-avian dinosaur of the Mesozoic was probably a scansoriopterygid,” said O’Connor. “There were Mesozoic birds that are smaller than these non-avian dinosaurs though, things sparrow sized. But nothing hummingbird sized!”

A restoration image of Oculudentavis khaungraae and the habitat it used to live in. /Xing Lida

Even though most of the body is missing, the team of scientists from the U.S., Canada, and China are fairly confident in labelling Oculudentavis a bird, as its pointed beak and large eye socket have previously only been seen in birds. Also, They are also confident that the fossil is an adult, despite its minuscule size.

Of course, there’s nothing more you can tell from a single skull. Though it certainly has the smallest head on record, it’s theoretically possible Oculudentavis isn’t the smallest dinosaur since there’s no body to examine.

A CT scan of the skull of Oculudentavis by Li Gang. Oculudentavis means eye-tooth-bird, so named for its distinctive features.

Birds evolved from small feathered dinosaurs roughly 150 million years ago. Oculudentavis illustrates the huge size difference among members of the dinosaur lineage, contrasting to contemporaneous South American long-necked, pillar-legged dinosaur Argentinosaurus at perhaps 90 tons and 35 meters.

“The size diversity hints at the amazing biology of dinosaurs, capable of sustaining such a diversity of forms,” said O’Connor.

The mine in northern Myanmar where the amber was found. /Xing Lida

Despite its minuscule size, researchers believe the Oculudentavis hunted insects using its sharp teeth and large eyes to home in on prey. With the eye bones forming a cone, its eyes were similar to those of owls, indicating acute vision, O’Connor added. Unlike birds of prey with forward-facing eyes and binocular vision enabling good depth perception, the eyes of Oculudentavis faced to the sides and bulged out of its head.

Considering how small an adult Oculudentavis was, the babies must have been practically microscopic.

An artistic rendering of Oculudentavis by Han Zhixin, imagining what it looked like while alive 99 million years ago.

Sources: 1, 2, 3


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