Opisthokonta microfossils with 1,010–890 million years discovered in Canada

Grassy Bay Formation where shown to be the oldest Arctic fungal fossils on Earth

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Corentin and colleagues have recently published an exciting letter in which they report that multicellular organic-walled microfossils were located in Grassy Bay Formation, Arctic Canada. After performing several analyses, the researchers indicated that the group Opisthokonta was discovered preserved in shale of dates, with around 1,010–890 million years ago. The microorganisms were determined has having a fungal affinity and with younger age than previously described!

It's been really exciting times for bioarcheology!

Did you know?
- Opisthokonts come from the Greek: ὀπίσθιος (opísthios) = "rear, posterior" + κοντός (kontós) = "pole" i.e. "flagellum" and were previously called the "Fungi/Metazoa group
- This group of eukaryotes included both the animal and fungus kingdoms and are commonly recognized as a clade
- The close relationship between Animals and Fungi was proposed only in 1987, by Thomas Cavalier-Smith. His suspicions were supported by later genetic studies

(doi:10.1371/journal.pone.0002098; doi:10.1093/molbev/msj011; ISBN 0-521-33050-5; doi:10.1126/science.8469985)

Fungi are crucial components of modern ecosystems. They may have had an important role in the colonization of land by eukaryotes, and in the appearance and success of land plants and metazoans. Nevertheless, fossils that can unambiguously be identified as fungi are absent from the fossil record until the middle of the Palaeozoic era. Here we show, using morphological, ultrastructural and spectroscopic analyses, that multicellular organic-walled microfossils preserved in shale of the Grassy Bay Formation (Shaler Supergroup, Arctic Canada), which dates to approximately 1,010–890 million years ago, have a fungal affinity. These microfossils are more than half a billion years older than previously reported unambiguous occurrences of fungi, a date which is consistent with data from molecular clocks for the emergence of this clade6,7. In extending the fossil record of the fungi, this finding also pushes back the minimum date for the appearance of eukaryotic crown group Opisthokonta, which comprises metazoans, fungi and their protist relatives.

Reference: Corentin C. Loron et al. Letter | Published: May 2019 Early fungi from the Proterozoic era in Arctic Canada. May 2019.

Celia Fortuna Rodrigues

PharmD, PhD , University of Porto