Tiny, Bird-Like Skull Found in Amber Could Belong to the Mesozoic Era's Smallest Known Dinosaur

Scientists recently discovered the skull of an extremely tiny, bird-like dinosaur that could be the smallest known species of the Mesozoic era—the period in which giant dinos like brachiosaurus, stegosaurus, and allosaurus evolved.

The specimen is preserved in a lump of 99-million-year-old amber from northern Myanmar and measures just 7.1 millimeters long, suggesting that the entire animal might have been even smaller than the bee hummingbird, which, at about 2.25 inches, is the smallest bird in existence. Very small fossils like this one are rarely found because layers of silt and rock usually destroy the delicate tissues. Amber preserves them intact.

Jingmai O’Connor, the paleontologist at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing who discovered the skull within the amber, and her colleagues found that the jaws contained more than 100 teeth—implying that, despite its size, the creature was a predator, possibly feasting on insects. However, since its eye sockets face the side, it probably didn’t have binocular vision, which gives many other predators the depth perception needed to catch prey. The conical shape of the bones in those eye sockets indicates that the animal had rather small pupils and was likely active during the day. The findings were published in the journal Nature.

Because of its defining eyes and teeth, the researchers named the new species Oculudentavis khaungraae. Oculudentavis comes from the Latin words for eye (oculus), teeth (dentes), and bird (avis), and khaungraae derives from Khuang Ra, who had originally donated the amber to China’s Hupoge Amber Museum.

While scientists have unearthed quite a few fossils of large dinosaurs from the Mesozoic era—and pop culture like the Jurassic Park franchise likes to capitalize upon the public’s endless obsession with enormous animals—not as much is known about the era’s most diminutive dinosaurs.

“People focus on how big dinosaurs were,” O’Connor tells Mental Floss. “Now we know they were also really tiny.”

Amber, tree resin that has hardened over millions of years, might be our best hope for learning more.

“When you have an animal preserved in amber, it looks like it just died yesterday. All the soft tissue in place, trapped in this little window into an ancient time,” O’Connor explains in the video above.

The researchers are publishing their full study in the science journal Nature, but there are still plenty of questions to answer.

“This paper is just scratching the surface of the information preserved. Is the skull petrified or is it the original material unaltered, preserved in the amber? Mummified, if you will? What color was it, and can we use isotopes to figure out exactly what it ate; can we reconstruct the brain better?” O’Connor says. “We need the young, tech-savvy generation to develop new methods for extracting data from amber specimens in a non-destructive manner to get at these questions.”

In the meantime, dig into these 26 fascinating facts about fossils.