Smallest Dinosaur Discovered in Amber

Scientists discovered the smallest dinosaur that may be as small as the bee hummingbird, the tiniest living bird. The specimen was from a skull trapped in 99-million year old amber from Northern Myanmar. The discovery may explain how small birds evolved from much bigger dinosaur.

The new species is now named as Oculudentavis khaungraae. The genus meant "tooth eyed bird", while the species name was in honor of the fossil collector Khaung Ra, who gave the specimen for study. It is not yet clear where the newly discovered species figure in the bird family tree.

Compared to Microraptors, the small four-winged dinosaur which weighed hundreds of grams, this newly discovered dinosaur had the size of a hummingbird, which weighed 2 g. It is the tiniest Mesozoic dinosaur yet discovered. Scientists say the new species appears to be a stem bird, the point where avians and its dinosaur ancestors split. How Oculudentavis khaungraae is related to birds is yet unclear, as the specimen consists of only a skull. There are features of the skull that are similar to dinosaurs, while there are characteristics like the advanced birds.

The stature of the new species is striking, but scientists also note of its other unusual features. One feature is that the skull is notably strong, as there appears to be a pattern of fusion in the bones. Antorbital fenestra, the tiny hole often located in front of the eye is lacking. While this feature is found in birds, it is lost in modern crocodilians.

The eyes are spoon-shaped, a characteristic found in some living lizards. The bones of the eye have conical shape with small pupils, similar to owl's eye bones, a feature suggesting an exceptional vision. The eyes are located sideways. The opening of the pupil was narrow, providing strong evidence that the newly discovered species was active in the daytime. The shape of the ossicles is different from other dinosaurs and resembles that of the modern-day lizards.

The newly discovered species has 23 teeth that are found in the dinosaur's upper jaw, indicating that Oculudentavis was a predator that consumes insects.

Dr Luis Chiappe, from the Natural History Museum of Los Angeles County said that it is fortunate that the tiny creature was preserved in the amber for 99 million years. He added that finding the new species is exciting because it give provides a picture of how the small animals lived in a tropical forest during the age of dinosaurs.

The evolutionary transition from gigantic, bipedaled and mostly carnivorous dinosaurs to small, insectivorous and frugivorous modern birds is one of the most astonishing transformation in the evolution of life. The relic Archeopteryx and recent fossils from the JeholBiota in China has given scientists some fragments on how this process evolved. Paleontologists admit that they are far from having a complete picture of the evolution of birds, much more than a complete understanding of the earth's ecosystem in the age of dinosaurs. The recent discovery of the Oculudentavis provides valuable information to explaining when, and the extent of how much the dinosaurs have evolved in terms of size.