At first glance, they do not look like much: tiny fragments of a primordial fungus shorter than a single hair's width. But these fungal remnants possess the unique distinction of being the oldest-known fossils of any land-dwelling organism on Earth.
A study published on Wednesday described microfossils of a subterranean fungus called Tortotubus that was an early landlubber at a time when life was largely confined to the seas, including samples from Libya and Chad that were 440 to 445 million years old.
The fossils represented the root-like filaments that fungi use to extract nutrients from soil. Tortotubus possessed a cordlike structure similar to some modern fungi. It was unclear whether it produced mushrooms.