In northern Myanmar (formerly Burma), Lida Xing (of the China University of Geosciences, Beijing) documents the discovery of the skull of a tiny bird-like dinosaur (Oculidentavis khaungraae), weighing just 2 grams. The skull is well-preserved in amber, with various soft tissues. It is very rare to find well-preserved fossils of such small animals, but amber helps preserve not only the bones but also the soft tissues of the tiny animals trapped within. The amber in question was formed from conifer resin flow approximately 99 million years ago. The name Oculidentavis khaungraae highlights the salient features of this skull: its eyes and teeth. The two enormous eyes dominate the skull, and the details of the small aperture suggest that it hunted during the day (when light was abundant). The teeth are numerous and tiny. Today, birds do not have teeth in their beaks, but teeth (several dozen) were common in early avian species. However, Oculidentavis khaungraae had many more teeth than other bird-like dinosaurs, extending far back, right under the eyes. Based on this, and other features such as its fossilized tongue, Xing concludes that this predator ate mainly invertebrates, not nectar, which is the diet of modern birds of this size. The teeth and tongue therefore indicate that its prey were small insects or other invertebrates, while the eyes, which protrude from both sides of the skull, indicate that, unlike modern predators, it did not have binocular vision. The main surprising aspect is that just after the end of the Jurassic (which spans from 201 to 145 million years ago), certain dinosaur species had already evolved to very small sizes to occupy a well-defined niche. It is the smallest bird-like dinosaur of the entire Mesozoic era (250–65 million years ago). And it therefore demonstrates that miniaturization occurred much earlier than scientists previously thought.
