The Possibility of Alternative Forms of Human Life 370 Million Years Ago

A 370 million-year-old fossil found in Scotland is an entirely new form of life which towered 26ft tall, scientists have confirmed.

The genus – called Prototaxites – resembled a woody giant tree trunk without a leafy canopy and was originally thought to be a form of fungus.

But new research from the University of Edinburgh and National Museums Scotland has shown the fossil is neither fungus nor plant, but a new lifeform that became extinct around 370 million years ago.

Sandy Hetherington, the lead co-author and research associate at National Museums Scotland, said: “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.”

For the new study, researchers looked at the molecular composition of fossils from 407-million-year-old Rhynie chert, a sedimentary deposit near Rhynie, Aberdeenshire.

Prototaxites fossils were first collected in 1843, but it was not until 14 years later that J W Dawson, a Canadian scientist, studied the fossils and thought they were partially rotten giant conifers.

Since then, there has been an ongoing debate about where the organism sits in the tree of life.

Studies showed that it did not seem to get its energy solely through photosynthesis like a plant, nor did it appear to be in a symbiotic relationship with any organism, as lichens support fungi.

It also appeared not to have the extensive network of subterranean mycelia – the vast roots of fungus – to obtain enough organic carbon to sustain its giant size.

New analysis found the specimens were chemically and structurally distinct from contemporaneous fungi, and that it is “best assigned to an entirely extinct eukaryotic lineage”.

Laura Cooper, the study’s co-author and doctoral student from the University of Edinburgh’s institute of molecular plant sciences, said: “Our study, combining analysing the chemistry and anatomy of this fossil, demonstrates that Prototaxites cannot be placed within the fungal group.

“As previous researchers have excluded Prototaxites from other groups of large complex life, we concluded that Prototaxites belonged to a separate and now entirely extinct lineage of complex life.

“Prototaxites therefore represents an independent experiment that life made in building large, complex organisms, which we can only know about through exceptionally preserved fossils.”

Prototaxites dates from the late Silurian to the Late Devonian – 420 to 370 million years ago – a time of remarkable change on Earth’s surface in which plants and animals were starting to gain a foothold and spread.

It was the first giant organism to live on the land, dwarfing other plants and animals from the period.

The new research was published in the journal Science Advances.