Prototaxites Was Not a Fungus, New Research Reveals

The skyline was dominated by a unique lifeform in the late Silurian era, long before woods formed the topography. Among the low mats of liverworts and moss, Prototaxites seemed like a lone chimney, towering over anything else that was living at the moment. Researchers were confused not only by its height but also by its outright refusal to be classified.

Early interpretations viewed it as a primeval tree, especially in the 19th century. Paleobotanists, who made an early comparison to coniferous species, were greatly aided by the appearance of layered trunks. But that story was constantly upended by more thorough research.

Interestingly, Prototaxites have no roots, leaves, or vascular tissue. An altogether different structure was suggested by the interior structure, which was filamentous and isotropically knotted. In the early 2000s, it was reclassified as a gigantic terrestrial fungus as a result. This looked especially novel at the time, enabling scientists to envision the Devonian Earth with massive fungal spires instead of trees.

Scientists discovered different signals in the fossilized remnants by examining carbon isotopes, which are suggestive of a heterotrophic life. That information greatly diminished the possibility that it was photosynthetic. A consistent photosynthesizer is desirable. It didn’t. This discrepancy strengthened the theory since it aligned well with fungal feeding habits.

Recent research, however, has called into question even this fungal theory. Researchers discovered that Prototaxites lacked important fungal molecules like chitin utilizing sophisticated imaging and spectrometry techniques. This absence was a warning sign rather than just a footnote. Without chitin, it is much less likely to be classified as a fungal species.

Instead, a completely different picture emerged. A plant, not. No fungus. It might have been a branch of life that grew tall, thrived, and then vanished, leaving only a trail of questions and stone impressions.

I recall standing in a fossil lab in Scotland one really wet summer, looking through Prototaxite cross-sections under a microscope. It was a rather moving experience. The specimen was beautiful in its own right, but not because it was beautiful in the sense that it sounded like a voice from a time no one could recall, structurally perplexing and stubbornly silent.

The ability of paleontologists to use digital simulation to mimic ancient ecosystems has significantly increased during the last ten years. These tools have made it easier to see the potential appearance and functionality of prototaxites. They may have given smaller organisms cover or a scaffolding of nutrients, as towering cylinders projected shadows across shallow soils. If so, they played an unexpectedly important ecological role—especially for an organism that was so poorly understood.

The most recent study teams were able to evaluate Prototaxites against thousands of known plant, algal, and fungal samples by combining microstructural analysis with machine learning. And the outcome? It was not easily categorized into any of the preexisting ones. One researcher referred to it as a “molecular no-man’s land,” where it was neither entirely fungal nor entirely plant-like—an organism too complicated to be a lichen and too foreign to be readily categorized.

Additionally, its height begs any explanation. Why, in an era without trees, without blooming plants, and with little herbivory on land, did an organism grow twenty feet taller than its neighbors? According to one explanation, its height aided in its ability to collect moisture or airborne spores. Another suggests it was merely an evolutionary experiment, outperformed by the vascular plant revolution after a period of remarkable success.

Strategic comparisons with early vascular flora have revealed that after ferns and seed-bearing species took over, Prototaxites lost its advantage. Their leaf structures, photosynthetic efficiency, and flexibility gave these immigrants a major advantage.

AI-powered fossil reconstruction may eventually enable researchers to create digital representations of extinct species at an anatomical level never previously possible in the upcoming years. With sufficient preserved data, scientists may model chemical metabolism, internal function, and even likely reproduction tactics. In order to better comprehend extinct animals like prototaxites, whose biology leaves no living relatives to study, these models may prove especially helpful.

The fossil’s distribution over several continents suggests that it may be widespread. This was neither an anomaly nor a local quirk. After thriving for millions of years, the genus was gradually phased out as ecosystems shifted around it. That story of early supremacy followed by silent extinction is not new, but it is a sobering one.

The true nature of Prototaxites may still be discovered by scientists using increasingly accurate geochemical methods. Regardless of whether it is a biochemically twisted cousin of fungi or a lost eukaryotic lineage, its story has already changed our perception of ancient land ecosystems. It reminds us that life on Earth was far more varied and unusual in the beginning than we usually think.

Prototaxites is a compelling case study in the context of evolutionary history—an organism that was incredibly adept at being itself but may not have been designed to adapt. Longevity is not a promise of evolution. Niche-finding, flexibility, and occasionally mishaps are rewarded. Even though it didn’t pass one of those exams, this enormous creature managed to make a lasting impression.

And that might be the most important thing. That something so timeless, so subtly extinct, nevertheless challenges our comprehension.