An article published in the journal “Nature Communications” reports the discovery in the Doushantuo Formation in China of microfossils dating back to about 635 million years ago attributed to a fungus-like organism. A team of researchers led by Professor Shuhai Xiao of Virginia Tech University examined these microfossils that could belong to the fungi that colonized the mainland in the Ediacaran period. They might also have contributed to the Earth’s recovery after a so-called snowball Earth period, an ice age that covered the entire planet.

The snowball Earth theory describes various glaciations which, in different periods, perhaps caused the ice to completely cover the planet’s surface. There are various controversies about this theory because of the interpretation of what its supporters consider geological evidence.

According to the supporters of the snowball Earth theory, at the beginning of the Ediacaran period the planet was recovering from the last of those events. If this reconstruction is correct, the living conditions were very harsh, allowing life only to microorganisms that could rely on energy sources such as hydrothermal springs. In the Ediacaran, conditions improved considerably, allowing, among other things, the colonization of the mainland by eukaryotic organisms, therefore plants, animals, and fungi.

The microfossils discovered in the Doushantuo Formation came as a surprise to the researchers due to their age. That fossil deposit in China contains the remains of many organisms but early fungi had never been found. Their examination showed characteristics that are typical of fungi, so they could be early fungi, although there are many discussions about the period in which they emerged.

The microfossils underwent a series of examinations with various types of microscopy and spectroscopy to examine their details. The conclusion is that these are probably fungi that were colonizing the mainland. A confirmation of this interpretation would be important for the implications why these humble organisms may have played an important role in the planet’s recovery after the last snowball Earth event.

If the nature of these microfossils gets confirmed, they will be by far the oldest remains of fungi on the mainland. The ability of the fungi to break up rocks might have created the conditions for plants to later arrive on the mainland, indicating that the fungi arrived earlier.

Along with the microfossils examined in this study, others were found attributed to other types of organisms. Tian Gan, one of the authors of this study, stated that he intends to study them too to understand their nature and possible relationships with the fungi in that ancient ecosystem. Discoveries of this type are sometimes at the center of controversy regarding the identification of fossils, so there may be discussions on this one as well.