The fungus among us is a key player in the ecosystem — and was part of the world hundreds of millions of years before we were. Hold on, make that potentially a billion years before we came along. Fungi microfossils from the Canadian Arctic are 900 million-1 billion years old, pushing back the fossil record for these organisms by at least 450 million years.

This discovery is about more than the very distant evolutionary kin of mushrooms, however. The microfossils include the earliest docum