LIFE × EVOLUTION

The First Fungi

~1 billion to 715 million years ago

Proterozoic · Neoproterozoic · Tonian

Fungi leave almost nothing behind: no shell, no wood, only threads. Two finds push them deep into the Proterozoic anyway. Microfossils from Arctic Canada, 1,010 to 890 million years old, have the shape and the wall chemistry of fungi, and are argued over on exactly that basis. Filaments from the Congo, 810 to 715 million years old, branch at wide angles into dense networks and still hold traces of chitin, the characteristic material of a fungal wall. They grew on ground that the air uncovered from time to time.

Why it matters

Fungi may well have been central to the colonisation of land: they take dead matter apart, and they would later feed roots minerals in exchange for sugar. These fossils put them at the water's edge hundreds of millions of years before the first plant, so when plants finally came ashore the decomposers were already there.

Dating & uncertainty

Microfossils from Arctic Canada dated 1,010 to 890 Ma are read as fungi on the strength of their shape and chemistry, and the assignment is debated. Filaments from the Congo dated 810 to 715 Ma carry traces of chitin, which is a firmer argument. Without the Canadian microfossils, the fossil record of fungi begins at 810 Ma.

Sources

1. Loron et al. (2019), Nature · Early fungi from the Proterozoic era in Arctic Canada
2. Bonneville et al. (2020), Science Advances · Molecular identification of fungi microfossils in a Neoproterozoic shale rock
3. Berbee & Taylor (2010), Fungal Biology Reviews · Dating the molecular clock in fungi: how close are we?

Earth history as one day

18:42:495 h 17 min before midnight

if Earth’s 4.54 billion years were compressed into a single day