First Report of Fungi and Fungus-Like Organisms From Mesozoic Hot Springs

Abstract

Herein we provide the first report of the diversity of fungi and fungus-like organisms within a Mesozoic hot spring ecosystem. The Jurassic San Agustín hot spring deposit (Patagonia, Argentina), represents only the second known Phanerozoic hot spring ecosystem with an associated microflora and contains diverse, exceptionally preserved microorganisms. Preserved propagules include flask-shaped pycnidia produced by extant coelomycetes, shield-like and nearly round thyriothecia of extant Microthyriales in the ascomycetes, variously shaped spore-like bodies representing chytrid and chytrid-like zoosporangia and other life cycle forms, and additional fungal and fungus-like remains (spores, hyphal fragments, reproductive structures) of uncertain affinity. Many of these microorganisms are associated with variously decayed organic remains, most commonly of horsetails. This expands the fungal fossil record and provides a unique opportunity to learn about the biology of Mesozoic microorganisms.

Biota and palaeoenvironment of a high middle-latitude Late Triassic peat-forming ecosystem from Hopen, Svalbard archipelago

“…Several chytrid fossils have also been found in Carboniferous deposits (see references in Taylor et al 2015) and there are some records from younger strata (e.g. Daugherty 1941;Bradley 1967;García-Massini et al 2012). The new discoveries add to the sparse fossil record of chytrid fungi and are significant in revealing their infestation of bennettitalean roots.…”

Peronosporomycetes (Oomycota) from a Middle Permian Permineralised Peat within the Bainmedart Coal Measures, Prince Charles Mountains, Antarctica

“…These are also interpreted to be terminally inserted on the hyphae and but are typically oblong and longer than the oogonia described herein. Possible oogonia have also been reported from the Jurassic San Augustín hot spring deposit from Patagonia, Argentina [25] although they lack the forked spines seen in the Prince Charles Mountains examples.…”

“…Similar unpublished spinose spore-like bodies are also known from the Upper Triassic of Hopen, Svalbard Archipelago, but are attributed to Ascomycetes (C. Strullu and S. McLoughlin unpublished data). Multilayered oogonium-like structures possibly attributable to Peronosporomycetes have also been reported from a Jurassic hot spring deposit in Patagonia, Argentina [25]. Other possible examples of Peronosporomycetes have been documented from amber [26]–[29].…”

Filamentous cyanobacteria preserved in masses of fungal hyphae from the Triassic of Antarctica

“…Finally, the lack of evidence for these organisms from permineralized peat elsewhere, (e.g., DiMichele & Phillips, 1994;Galtier, 2008;McLoughlin & Strullu-Derrien, 2015;Slater, McLoughlin & Hilton, 2015), could mean that peat-forming paleoenvironments were perhaps generally not conducive to the preservation of cyanobacteria. The scarcity of cyanobacterial fossils in peat deposits stands in stark contrast to silicified geothermal hot spring (sinter) deposits, which often yield diverse assemblages of structurally preserved cyanobacteria (e.g., Guido et al, 2010;García Massini et al, 2012;Hamilton et al, 2019;Krings, 2019;Krings & Harper, 2019;Krings & Sergeev, 2019). Nothing is known to date about the possible influence of a hydrothermal system on the silicification process at Fremouw Peak (Taylor, Taylor & Collinson, 1989).…”