| Thuchomyces Temporal range:Archean,2800 Ma | |
|---|---|
 | |
| Reconstruction of Thuchomyces in an Archean soil. | |
Scientific classification | |
| (unranked): | incertae sedis |
| Genus: | †Thuchomyces Hallbauer & Jahns, 1977 |
| Species: | †T. lichenoides |
| Binomial name | |
| †Thuchomyces lichenoides Hallbauer & Jahns, 1977 | |
Thuchomyces (sometimes mistakenly called “Thucomyces”) is a genus ofArchean fossils from theWitwatersrand ofSouth Africa, and is the earliest macroscopic land life known.[1] The generic name derives fromthucholite, the carbonaceous material whichThuchomyces is preserved in, and the Ancient Greek word "myces", meaning "fungus". The specific name,lichenoides, derives from its similarity to some modern lichens.[1]
Thuchomyces resembles modern columnar biomats, alongside certainlichens, however the latter are far more recent, only having appearedat most 300 million years ago, and therefore it almost certainly is not a lichen, or even a eukaryote at all.[2] Some fossils have a round structure at their tip, interpreted as adiaspore, and these structures can also be observed in the rock surrounding the fossils.[1] The internal structure ofThuchomyces consists of a network ofhyphae, made of intensely branching cells possibly connected viaanastomoses. The outer layer of the organism consists of highly agglutinated hyphae with a layer of loose tissue inside it, alongside a "central cord" observed in immature specimens which disappears with age.Thuchomyces columns are roughly 200–500 micrometers across, and reach a height of roughly 1 mm.[1]Thuchomyces shares many similarities with thePaleoproterozoicDiskagma, having a similar size and shape, alongside both forming dense palisades onpaleosols. However it lacks the spines ofDiskagma and has complex vertical partitions, alongside having rounded terminations instead of the cup-like tips ofDiskagma.[3]
Taking into account various features such asventifacts, the concentration of carbon-13 in the rock and other geological features, the sedimentsThuchomyces is known from are interpreted as being a wind-blasted desert environment crossed by ephemeral streams, which was occasionally flooded. In addition another organism namedWitwateromyces conidiophorus, a possibleactinomycete bacterium, was found associated withThuchomyces, possibly as adecomposer.[1]