Natural history sometimes changes direction when someone simply decides to take a closer look at what everyone thought they knew. It often happens with mushrooms, discreet, inconspicuous organisms, yet silent protagonists of the balance of ecosystems.
It also happened with Psilocybe cubensis, the most famous and cultivated psychedelic mushroom in the world. For years scientists thought they knew its history quite well. Then, among the prairies of southern Africa, something familiar and at the same time completely new arose.
A group of researchers has identified a species never described before: Psilocybe ochraceocentra. At first glance it looks a lot like the famous Psilocybe cubensis. Same shape, same habitat, same preference for soils rich in herbivore dung. Except it’s not him.
Genetic analyzes tell a much older and more fascinating story: these two mushrooms share a common ancestor that lived about 1.5 million years ago. A discovery that changes the way scientists reconstruct the origin and global diffusion of one of the most studied species of recent decades.
The discovery comes from the prairies of South Africa and Zimbabwe, environments where the landscape is dominated by tall grass, grazing animals and soils rich in organic matter. It is precisely here that mycologists have collected some specimens of mushrooms which, for years, had been considered simply a local variant of Psilocybe cubensis.
It happens often in science. An organism is attributed to an already known species because it closely resembles it. Then someone comes along who decides to look deeper. Mycologist Breyten van der Merwe, of the University of Stellenbosch, compared these African specimens with the so-called type specimens, the reference specimens preserved in scientific herbaria that establish the official identity of a species. The result was surprising.
The DNA clearly showed that those mushrooms belonged to a distinct evolutionary lineage, separated from Psilocybe cubensis by more than a million years. Hence the decision to describe a new species: Psilocybe ochraceocentra. On a visual level the similarity remains strong. The caps, the structure of the stem, the general color are very reminiscent of their more famous “cousin”. But genetics leaves no doubt: these are two different species that share a distant past.
From the African prairies to the Americas
©Cathy Sharp – Clark University
For decades many scholars have supported a rather simple theory. According to this hypothesis, Psilocybe cubensis arrived in the Americas after 1493, when Europeans introduced cattle and other domesticated animals to the Caribbean. The idea seemed plausible because these mushrooms often grow right on herbivore manure, which provides ideal nutrients for their development.
The new research makes this reconstruction much less convincing. If Psilocybe cubensis and its African relative diverged about 1.5 million years ago, it means their history is much older than the domestication of livestock and human trade routes. Scientists then look at another protagonist of this story: the great migrations of prehistoric herbivores.
During some climatic phases of the Pleistocene, tropical and subtropical grasslands expanded rapidly. Large herds of animals moved from Africa to Eurasia and other regions of the planet. For a fungus specialized in colonizing animal dung, following these natural routes meant having a perfect ecological corridor to expand. The discovery also solved a little puzzle that had long been circulating among mushroom growers.
In fact, many enthusiasts know of a strain called Natal super strength, sometimes also referred to by the name Transkei. It is considered one of the most popular, because it grows easily and is known for its potency. For years it was classified as a simple variant of Psilocybe cubensis. The study demonstrated that that mushroom actually belongs to the new African species Psilocybe ochraceocentra.
A correction that might seem like a technical detail, but actually has important implications. In scientific research, medicine and legal regulations, the name of a species represents the starting point for understanding its chemical, ecological and biological properties.
The great void in African mushroom research
The story of this discovery also highlights another interesting aspect: in many regions of Africa fungal biodiversity is still little explored. Mycologists have long known that the number of documented species is probably only a small fraction of those actually present in African ecosystems.
When scientific collections are sporadic and few specimens are available, it is easy for similar organisms to be attributed to the wrong species. So it can happen that a close relative of one of the world’s best-known fungi remains invisible to science for decades.
To try to reconstruct the geographical history of Psilocybe cubensis, the researchers also analyzed the available data on the distribution of the species. After filtering scientific databases, they worked with 1,001 reliable reports, of which only twelve came from Africa.
By crossing this information with climate models that reconstruct the environments of the last three million years, scholars have identified several regions potentially suitable for the growth of the fungus: some areas of Africa, parts of Asia and vast areas of the Americas. This suggests that the historical range of the species may have been much larger than that documented today.
The origin of Psilocybe cubensis remains a mystery
The discovery of the new African relative adds an important piece to the evolutionary history of these fungi, but does not yet solve the puzzle. Scientists cannot establish with certainty where Psilocybe cubensis actually originated. The new analyzes revise the theory of recent diffusion linked to European livestock, but leave several possibilities open: ancient movements through Asia, an early presence in the Americas or a much wider distribution in the past.
To arrive at a definitive answer, many more samples from regions that are still little studied will be needed. It is the perfect reminder of how fungal biodiversity remains, even today, one of nature’s most mysterious territories. Sometimes we just need to look more carefully at something we thought we knew to discover that its story begins much earlier than we imagined.
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