Giant, fungus-like organism may be a completely unknown branch of life

Prototaxites, an ancient treetrunk-mushroom-like organism that preceded land plants about 400M yr ago. Its fossils contained plantlike lignin instead of funguslike chitin or chitosan.<p><a href="https:&#x2F;&#x2F;www.biorxiv.org&#x2F;content&#x2F;10.1101&#x2F;2025.03.14.643340v1" rel="nofollow">https:&#x2F;&#x2F;www.biorxiv.org&#x2F;content&#x2F;10.1101&#x2F;2025.03.14.643340v1</a><p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Prototaxites" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Prototaxites</a>

&gt; Upon examining the internal structure of the fossilized Prototaxites, the researchers found that its interior was made up of a series of tubes<p>Who knew the internet evolved millions of years ago?

&gt; with eukarya containing all multicellular organisms within the four kingdoms of fungi, animals, plants and protists.<p>This bugs me so much. The four-kingdom system should have died out decades ago, it&#x27;s absurdly wrong. For one thing, fungi and animals should be together (opisthokonts) if you&#x27;re dividing eukaryotes into the major groups. If you consider genetics, there&#x27;s no such thing as &quot;protists&quot;, they&#x27;re just a whole bunch of small things that were grouped together because we didn&#x27;t know otherwise.<p>It&#x27;s more like, Archaeplastida, Excavata, SAR supergroup, Amoebozoa, and Opisthokonta at the moment. The exact list is up for debate, and currently undergoing change. There&#x27;s plenty of weird things like Hemimastigophora and we&#x27;re not really sure where they fit yet.

I saw this on bsky a few days ago and was fascinated, so glad to see it made its way here! I had this question that went unanswered, so hopefully there&#x27;s some experts&#x2F;fellow musers here:<p><i>Why grow up if you don&#x27;t need photosynthesis?</i><p>From my perusal of The Literature (AKA an amazing Wikipedia article + the paper discussed in this link), we have a few strong theories about the prototaxites:<p>1. They fed off decaying matter in the soil through a vast network of mycelia&#x2F;roots, and didn&#x27;t photosynthesize.<p>2. They grew large, trunk-like protrusions, but without any branches or leaves (that were fossilized, at least). Like, way, <i>way</i> taller than the bugs, moss, and short weird proto-grass around at the time.<p>3. These protrusions were regularly burrowed into by aforementioned bugs, which surely was a major health risk.<p>4. Even before this analysis, they&#x27;ve always been something of an oddball compared to contemporary life -- so everything&#x27;s on the table, so to speak.<p>Given those facts, I&#x27;m pretty stumped as to what evolutionary pressures might have driven them to grow upwards. At first I considered spore (seed?) dispersal, but mushrooms seem to get along just fine without towering above everything else, and I don&#x27;t think wind speeds were way lower or anything. Anyone here have any better guesses?

&gt; Prototaxites did not contain chitin, a major building block of fungal cell walls and a hallmark of the fungal kingdom. The Prototaxites fossils instead appeared to contain chemicals similar to lignin, which is found in the wood and bark of plants. ... best considered a member of a previously undescribed, entirely extinct group of eukaryotes<p>So these are the ancestors of Groot? or Ents? and all manner of &quot;animated trees&quot;?

Acknowledging this is a pre-print, but it is _wild_ that we can do this kind of analysis on a species that went extinct nearly a third of a billion years before the first hominids emerged. Every now and again I&#x27;m reminded of just how far we&#x27;ve extended our sensorium as a species.

Oh, that? That’s just Bob. He helps out around the busy season sometimes. Didn’t know this much about his family, though—neat!

The article about the study writes: `The study has not yet been peer-reviewed.`<p>We should just stop reading the article then and there. This is a major method of how a single study can perpetuate fake science and fake news.

Perhaps its a Ediacaran biota remnant, that had very diverse groups some of which could be misclassified because the consensus is against Ediacaran relics existing past their period.

This was an interesting read, and reminded me how paleo-biology is the closest thing to exobiology we&#x27;ve got. Looking at the different biomes that emerged on planet earth over a billion years feels equivalent to looking at a thousand different planets at the same time. Basically a thousand chance to see what that &#x27;megayear&#x27; produced, life wise.

&gt; All life on Earth is classified within three domains — bacteria, archaea and eukarya — with eukarya containing all multicellular organisms<p>Single cell eukaryotes also exist. Is it strictly true that there are no multicellular prokaryotes (what they call bacteria) or archaea? No exceptions at all?

Is there a point in Earth’s history where if you were to visit you’d find it was just a fungus planet, with no other form of life? Could there have been fungal type creatures that lived, died, and left no trace?

Discussions about classifying the domains of life aside, this article implies that there was, or could have been entire domains that are now extinct. Is this the case?

It&#x27;s likely simply a fungus that used lignin instead of chitin. It went instinct when fungus learned to attack lignin.

You never did like my mother.

I wonder what it tastes like

I&#x27;m still trying to wrap my head around nitroplasts, another newfound plastid.

Common Side Effects, here we come.

There’s one of them at the back of my fridge.

Pretty sure this was a major plot point of the latest resident evil game.