In 2016, Lida Xing of China University of Geosciences first examined a piece of amber — or fossil tree resin — that came from a mine in northern Myanmar.... O’Connor said. The piece of amber — about 99 million years old — is smaller than a fingertip, Dr.... O’Connor and a team of researchers report on Wednesday in the journal Nature, and suspended inside of it is the skull of the smallest known bird, and, therefore, dinosaur, ever discovered....