The oldest amber recov-ered, dates to the Upper Carboniferous (320 Ma). Its chemical composition makes it difficult to match the amber to its producers - it is most similar to the resins produced by flowering plants, which did not evolve until the Jurassic, around 180 Ma. Amber becomes abundant soon afterwards, in the Early Cretaceous, 150 Ma, when it is found in assoc. w/insects.
The researchers discovered the creatures while doing a survey of the lifeforms encased in 70,000 droplets, each just a few millimeters in diameter. The amber comes from the Heiligkreuz Formation in northeastern Italy, and it contains plenty of microorganisms, such as bacteria and algae, that make it clear that the droplets formed during the Triassic era, 250 to 200 million years ago.