Giant, fungus-like organism may be a completely unknown branch of life
Prototaxites and its biology
- Commenters note the new preprint’s claim: Prototaxites lacks fungal chitin and instead shows lignin‑like compounds, suggesting an entirely extinct eukaryotic lineage rather than fungus or plant.
- Historical misclassification (as rotten conifers, then “stringy plants”) is used as an example of how radically interpretations can change with new microstructural data.
Why grow tall?
- One puzzle: if Prototaxites fed on decaying matter via mycelia and did not photosynthesize, what selective pressure drove tree‑trunk‑scale vertical growth?
- Proposed ideas include:
- Hosting burrowing arthropods as nutrient‑importing “partners” (their waste enriches the substrate).
- Escaping high‑CO₂ boundary layers near the ground, analogous to mushroom fruiting bodies seeking better gas exchange.
- An earlier hypothesis (now considered weakly supported) that they were giant lichens with photosynthetic symbionts, making height advantageous for light capture.
Was there ever a “fungus planet”?
- A detailed reply argues “no”: cyanobacteria and heterotrophic bacteria colonized moist land long before fungi and plants, forming mats and crusts.
- Fungi likely appeared only once there was abundant terrestrial biomass and may have co‑evolved closely with early land plants.
Domains, kingdoms, and how to classify life
- Strong criticism of the familiar four‑kingdom model (plants, animals, fungi, protists) as genetically inaccurate; modern groupings like Archaeplastida, SAR, Amoebozoa, and Opisthokonta are mentioned.
- Counter‑arguments emphasize stability, communicative usefulness, and the need for simplified models in education.
- Long sub‑thread on pedagogy: when simplification becomes harmful, how to flag models as provisional, and analogies (Newton vs relativity, Bohr vs Schrödinger, “fruit vs vegetable”).
- Another extensive comment contrasts cladistic classification (common ancestry) with ecological “lifestyle” categories (ingesters, decomposers, phototrophs, etc.), arguing both are useful and sometimes conflict.
Viruses and borderline life
- Debate over whether viruses are “alive”: they lack independent metabolism and reproduction, yet resemble extreme parasites.
- Some compare their dependency on cells to animals’ dependency on planetary ecosystems, framing them as a higher‑abstraction “sub‑cellular life.”
Extinct domains or deep lineages
- The article’s suggestion of a “new domain” prompts discussion of whether entire top‑level lineages may have gone extinct.
- Responses stress that “domain” boundaries are human constructs over a continuous, graph‑like evolutionary history; it is “probably yes” that many major clades vanished, especially among microbes and enigmatic Ediacaran organisms.
Science communication and preprints
- Some argue non–peer‑reviewed claims shouldn’t be popularized, calling this a pathway to “fake science.”
- Others note the demand for immediate, entertaining science news and see outlets like LiveScience as serving that role rather than acting as primary scientific arbiters.
Tone, awe, and humor
- Many express amazement that chemical and structural analyses can still be done on 400‑million‑year‑old fossils.
- Paleo‑biology is likened to exobiology: each deep‑time ecosystem is like studying life on a different planet.
- Running jokes reference Groot/Ents, game plots, fridge molds, the “wood‑wide web,” and “series of tubes,” blending genuine curiosity with lighthearted banter.