Meet Tortotubus: the oldest example of fossilized terrestrial life on the planet. You can actually thank the little fungus for your very existence. More than 440 million years ago, Tortotubus was part of the early cycle of decomposition and soil formation that allowed for more complex plant life to be established on land, and for critters to start crawling out of the ocean.

Research from the University of Cambridge describes the ancient fungus in a recent article, published in the Botanical Journal of the Linnean Society. “During the period when this organism existed, life was almost entirely restricted to the oceans: nothing more complex than simple mossy and lichen-like plants had yet evolved on the land,” author Martin Smith said in a news release. “But before there could be flowering plants or trees, or the animals that depend on them, the processes of rot and soil formation needed to be established.”

Tortotubus is a network of branding microscopic tubes, just 5-12 micrometers in diameter. It is constructed in a similar way to some modern fungi, suggesting that it is a type of mycelium and was involved in breaking down nutrients and cycling them through the ecosystem. While scientists have no fossil evidence of any earlier terrestrial organism, Tortotubus likely was not alone on that primitive Earth. In fact, it very likely played an important role in digesting simple life forms like algae and bacteria.

The fungus' cord-like structure allowed it to move nutrients from where they were plenty to where they were scarce.

Tortotubus (like modern fungi) conceivably contributed to nutrient cycling, encouraging the growth and diversification of plant communities; it may also have been a nutrient source for pioneering land animals,” writes Smith in the paper. “In contrast to early plants, which lacked roots and thus had limited interactions with the subsurface, mycelial fungi play an important role in stabilizing sediment, encouraging weathering, and forming soils.”

To this day fungus plays an incredibly important role in the planet’s ecosystems. And really, they never seem to get enough credit. This research suggests that mushrooms (the fruiting body of a fungus) may have evolved on earth before animals crawled out from the sea to snack on them.