Prototaxites: Scientists rethink ancient 'rock-hard' tree-like mystery
It somewhat looked like a tree, stood like a tree and had bark like a tree — but it wasn’t a tree at all.
And according to scientists, it may not have been a fungus either, but something far stranger that disappeared from the face of the Earth hundreds of millions of years ago.
That’s the conclusion of a new study published in the journal Science Advances.
It revisited one of the most puzzling fossils ever discovered, known as Prototaxites.
Prototaxites was a huge, pillar-shaped living organism that grew on land about 400 million years ago, long before trees existed.
“Prototaxites was the first giant organism to live on the terrestrial surface, represented by columnar fossils of up to eight meters from the Early Devonian,” the study said.
In the new research, scientists of the University of Edinburgh and National Museums Scotland examined fossils of Prototaxites taiti from the exceptionally well-preserved Rhynie Chert rocks in Scotland and compared them with fossil fungi found in the same ancient ecosystem.
“They are life, but not as we now know it, displaying anatomical and chemical characteristics distinct from fungal or plant life, and therefore belonging to an entirely extinct evolutionary branch of life,” Sandy Hetherington, lead co-author and research associate at National Museums Scotland said.
The study itself said: “Our study, combining analysing the chemistry and anatomy of this fossil, demonstrates that Prototaxites cannot be placed within the fungal group.”
The fossil’s internal structure and chemistry did not match known fungi.
Fungi are living organisms such as mushrooms, mould, mildew and yeast.
They are not plants or animals and usually feed by breaking down other material rather than making their own food as plants do.
The researchers found that Prototaxites lacked chemical features typical of fungal cell walls but instead had patterns more similar to plant-like compounds such as lignin — a feature not expected in fungi.
The paper states plainly: “We report that fossils of Prototaxites taiti from the 407-million-year-old Rhynie chert were chemically distinct from contemporaneous Fungi and structurally distinct from all known Fungi.”
“This finding casts doubt upon the fungal affinity of Prototaxites,” the researchers wrote, “instead suggesting that this enigmatic organism is best assigned to an entirely extinct eukaryotic lineage.”
Put simply, Prototaxites does not fit into any group of life that exists today.
Its shape and tubes are unlike those of classic fungi, and the chemicals preserved in its fossil do not match what scientists would expect from known fungi or plants.
Because of these differences, the researchers said Prototaxites most likely belonged to a “previously undescribed extinct eukaryotic lineage” — a complex form of life that no longer survives on Earth.
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