The first gardeners of dry land: a 410-million-year-old fossil shows lichens prepared Earth for life

Long before trees, flowers or animals walked the land, something small had to make the bare rock liveable — and a fossil from Brazil now points to the gardener. An international team led by Harvard researcher Bruno Becker-Kerber, reporting in Science Advances, used powerful X-ray imaging and chemical tests on the Devonian fossil Spongiophyton and found the twin signature of a lichen: fungi woven together with algae, plus chitin — the tough material in insect shells — where a simple plant would have cellulose. The fossil shows lichens were already common more than 410 million years ago, likely starting in the cold edges of the ancient supercontinent Gondwana, in what is now South America and Africa. More than 20 research centres across five countries shared the work.