iiinova — where your digital self keeps evolving

Laura Cooper @transitionalform.bsky.social · 11/09/2026

Strange things found looking up fossil localities this week.

A screenshot from Wikipedia of Megaliths in Kazakhstan

A screenshot of a google review of the Kuznetsk Alatau reading "While ventricular may not be the correct word, neither should citrus fruit be given nose trimmers. Those are my thoughts. But please do visit and judge for yourself"

A screenshot of a google review reading "Samantha was attacked by a polar bear, but i dont really care. but they didn't let me bring my tractor. 2 star"

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Laura Cooper @transitionalform.bsky.social · 23/06/2026

Because the Rhynie chert plants include plants with xylem but without true phloem, this suggests that xylem and phloem did not have a common origin within the land plants, but rather both tissues evolved gradually and independently, occurring in their modern form in at different times. 10.

Schematic showing the gradual evolution of phloem and xylem from food conducting cells and water conducting cells, respectively, with the phloem evolving sepately in the euphyllophytes and extant lycophytes.

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Laura Cooper @transitionalform.bsky.social · 23/06/2026

But we found that the FCCs of Asteroxylon did have (submicron!) sieve pores, which in extant plants is involved in the movement of sugars through the phloem, suggesting this tissue did have a sugar conduction specialisation. This is the earliest example of sieve pores in the fossil record. 8/

Sieve pores imaged using CLSM and SEM in Asteroxylon mackiei

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Laura Cooper @transitionalform.bsky.social · 23/06/2026

These FCCs had some, but not all, of the features of phloem of extant vascular plants. The Rhynie chert plants didn't have a distinction between FCCs and cortical cells, or a boundary between these tissues, and the FCCs are very large in diameter compared to phloem cells. 7/

Cladogram showing that the Rhynie chert plants lacked a pericycle, and had a grading of tissue between FCCs and cortex.

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Laura Cooper @transitionalform.bsky.social · 23/06/2026

The Rhynie chert plants had a tissue called FCCs (food conducting cells) around the central strand of xylem (or water conducting cells), in the position that phloem is in extant plants. 6/

Asteroxylon mackiei in a thin section from the University of Manchester

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Laura Cooper @transitionalform.bsky.social · 23/06/2026

I also compared these plants with the extant lycophytes, the earliest diverging group of living vascular plants, and the group to which one of the Rhynie chert species (Asteroxylon mackiei) belongs. Illustration by @palaeojules.bsky.social 5/

Lycopodium annotinum, illustrated by Julianne Kiely.

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Laura Cooper @transitionalform.bsky.social · 23/06/2026

I imaged the Rhynie chert plants using confocal laser scanning microscopy and scanning electron microscopy, two very high resolution imaging techniques that can be used to identify sub-micron features in these fossil plants. 4/

A CLSM image of Rhynia from the Rhynie chert, thin section from the University of Manchester.

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Laura Cooper @transitionalform.bsky.social · 23/06/2026

To understand these sort of fundamental questions in plant evolution, we can examine the exceptionally preserved plants of the Rhynie chert, a 407 million year old fossil deposit where some of the earliest land plants are preserved through the activity of a hot spring. Art by Victor Leshyk. 2/

The Rhynie chert ecosystem by Victor Leshyk

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Laura Cooper @transitionalform.bsky.social · 03/06/2026

We had a great time at the Deep Time Gala organised by @scottishgeology.bsky.social ! I'm glad people enjoyed learning about the Rhynie chert and it's strange organisms!

Laura talking on a stage holding up a model of Prototaxites

Laura and Sophie Burne talking to the public behind a stall

A poster board asking "what is one thing you've learnt tonight?" Where someone had replied "More about the Rhynie chert :)"

A model of Prototaxites in a jar, surrounded by two 3d printed models of Asteroxylon

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Laura Cooper @transitionalform.bsky.social · 27/01/2026

Here's the top view of the hat, with baby hippos and Prototaxites!

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Laura Cooper @transitionalform.bsky.social · 21/01/2026

22 / 23 This project was a large collaboration between research groups at Edinburgh and other institutions, with Corentin Loron and I as co-first authors (and as part of my PhD thesis!) and @sandyheth.bsky.social as corresponding author.

Sandy Hetherington, Corentin Loron and Laura Cooper standing in a museum collection next to a large slab of Rhynie chert. Laura is holding the Prototaxites fossil and Corentin is holding a slide.

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Laura Cooper @transitionalform.bsky.social · 21/01/2026

21 / 23 This means that the first giant organisms on the Earth’s surface were not closely related to anything alive today. But despite its strangeness, in its time Prototaxites would have had an important role, being eaten by arthropods and having impacts on the ecosystem that we don’t yet know.

The Prototaxites specimen resting on a mossy floor

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Laura Cooper @transitionalform.bsky.social · 21/01/2026

13 / 23 Another distinctive feature of Prototaxites is tubes with internal thickenings or bands, found throughout the organism. These banded tubes are also not found in fungi, and as they resemble the xylem of land plants, they could have had a similar function in Prototaxites.

A microscopy photo of tubes with internal banding

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Laura Cooper @transitionalform.bsky.social · 21/01/2026

12 / 23 Below shows us imaging through the medullary spots of Prototaxites, revealing the dense and interconnected branching of tubes that go down to one micron in diameter!

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Laura Cooper @transitionalform.bsky.social · 21/01/2026

10 / 23 Prototaxites has spherical features called medullary spots. We imaged through these spots and found them to be made of many densely packed small tubes that were heavily interconnected.

A confocal image of a medullary spot of Prototaxites

A 3D model showing the interconnections of tubes in the medullary spot of Prototaxites

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Laura Cooper @transitionalform.bsky.social · 21/01/2026

9 / 23 My contribution to this paper was to use confocal laser scanning microscopy, a high-resolution form of microscopy, to look at the micro-structure of our specimen.

Confocal microscope image of the small and large tubes of Prototaxites

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Laura Cooper @transitionalform.bsky.social · 21/01/2026

8 / 23 But NSC.36 was extremely well preserved, as was a range of other organism in the chert surrounding it, including fungi and plants, making this specimen uniquely suited for our analyses.

The NSC.36 block containing Prototaxites, plants and soil

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Laura Cooper @transitionalform.bsky.social · 21/01/2026

7 / 23 Our new specimen, called NSC.36, is the largest Prototaxites known from the Rhynie chert and would have been the largest organism in this ecosystem, but it is still a lot smaller than the 8m+ Prototaxites from other fossil sites. Photo by Neil Hanna (hand modelling by me).

A block containing Prototaxites being held by me between the thumb and forefinger

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Laura Cooper @transitionalform.bsky.social · 21/01/2026

6 / 23 A new specimen of Prototaxites from the Rhynie chert provided both of these things! The Rhynie chert is an early Devonian (410 million years old) from Aberdeenshire, Scotland, and it is famous for the exquisite quality of its preservation.

A thin section of the plant Asteroxylon mackiei from the Rhynie chert, showing cellular preservation.

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Laura Cooper @transitionalform.bsky.social · 21/01/2026

1 / 23 Prototaxites is known from some very large fossils, including columns over 8m tall. These fossils date from the end of the Silurian to the Late Devonian (425–365 million years ago). This makes Prototaxites the largest organism on the Earth’s surface before the appearance of tall trees.

Palaeoart of a giant Prototaxites by Mary Parrish, from Hueber (2001).

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Laura Cooper @transitionalform.bsky.social · 21/01/2026

Our paper on the mysterious Devonian organism Prototaxites has now finally been published! See the paper here (www.science.org/doi/10.1126/...) and our explainer thread below! Prototaxites reconstruction by Matt Humpage

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Laura Cooper @transitionalform.bsky.social · 15/12/2025

I had a great time at #palass25 catching up with some and meeting others, and spreading the word on Prototaxites! Thanks to all the organisers!

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Laura Cooper @transitionalform.bsky.social · 15/09/2025

My institute has a pet snail called Go-Taq so I've been periodically wandering over to them to check they are sufficiently misted.

A close up photo of a snail climbing a glass wall, you can see the antennae and mouth.

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Laura Cooper @transitionalform.bsky.social · 05/08/2025

Saw the (old) Stigmaria and the (new) caecilian (video below) at Manchester Museum this weekend.

Laura standing next to a large fossilised stigmaria rooting system

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Laura Cooper @transitionalform.bsky.social · 23/06/2025

Won @matt-humpage.bsky.social 's prize winning Prototaxites reconstruction in the @progpal2025.bsky.social auction last week, I think everyone knew better than to try to bid against me for it!

A photo of a desk with computer monitor, mug, books and a print of Prototaxites resting on it

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Laura Cooper @transitionalform.bsky.social · 18/03/2025

And also some exclusive behind the scenes photos of me and @jeremywyman.bsky.social beautifying a patch of moss (hiding the tracheophytes) for our Prototaxites photo shoot

Two people moving plants out of the way of a patch of moss

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Laura Cooper @transitionalform.bsky.social · 18/03/2025

🎊We are very pleased to announce that our paper investigating what we think Prototaxites, the mysterious giant of the Devonian landscape, actually was is now available as a pre-print on @biorxivpreprint.bsky.social. www.biorxiv.org/content/10.1...

A block of Prototaxites fossil on a mossy surface, resembling the landscape of the early Devonian

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