A discovery in Scotland reveals that Prototaxites were not giant fungi as previously believed

A recent analysis of fossils discovered in northeastern Scotland has revolutionized scientific understanding of Prototaxites, mysterious organisms that dominated the land hundreds of millions of years ago. The research, published in Science Advances, provides crucial evidence challenging over a century of belief about the nature of these extinct life forms that have intrigued specialists since the mid-19th century. The findings in Scotland suggest that these organisms represent a completely different chapter in Earth’s evolutionary history.

The mystery of the largest organisms of the Devonian

During the Devonian period, often called the “Age of Fishes,” Earth underwent profound ecological transformations. It was a time when complex organisms began their decisive colonization of the terrestrial environment. In that primitive context, only low plants and small animals sustained a lifestyle on land.

Prototaxites represented a fascinating anomaly in that landscape. They stood as cylindrical structures without branches, leaves, flowers, or true roots, reaching heights of up to eight meters. For decades, researchers favored the hypothesis that they were colossal fungi, leading scientists to imagine a primitive world where giant fungi replaced trees in the ecological landscape.

New evidence from the Rhynie Chert site in Scotland

The scientific debate took a crucial turn with the detailed analysis of a smaller species called Prototaxites taiti. Researchers focused their attention on fossils recovered from the Rhynie Chert paleontological site, located in northeastern Scotland. This site, approximately 407 million years old, is notable for the exceptional preservation of ancient plants, fungi, and fauna.

The extraordinary quality of these fossils allowed for microscopic and chemical analyses rarely possible in such ancient samples. The scientific team employed advanced technology including lasers, 3D reconstruction, and confocal microscopy to examine the interior of the organisms. The data revealed that the specimen contained three distinct types of interconnected conduits, linked by dense branching regions, forming a sophisticated three-dimensional structure very different from the simple filament networks of contemporary fungi.

The chemical analysis that changed classification

The “chemical signature” of the fossil was examined using artificial intelligence, an innovative approach in paleontology. Scientists searched for the presence of key compounds found in all known fungi: chitin, chitosan, and beta-glucan, essential polymers for fungal cell walls.

The results were conclusive: these compounds were completely absent. No fungal biomarkers such as perilene, substances that do appear visible in other fungi preserved in the same rock block, were detected. This finding ruled out any chemical degradation over geological time, reinforcing the conclusion that the group does not belong to the Fungi kingdom.

A completely different evolutionary lineage

The study’s authors concluded that Prototaxites does not belong to any current living group. The integrated approach combining structural, chemical, and computational evidence “undermines the traditional hypothesis that Prototaxites taiti was a fungus.” According to the researchers, these organisms were part of “an extinct eukaryotic lineage, not previously described.”

This discovery broadens our perspective on the evolutionary experiments that occurred on primitive Earth. It suggests that the history of life includes biological solutions very different from those classified in contemporary groups, reinforcing the possibility that evolution explored entirely different pathways during the early chapters of terrestrial colonization.