Fungi diverged from other life around 1.5 billion years ago,[1][2] with theglomaleans branching from the "higher fungi" (dikaryans) at ~570 million years ago, according to DNA analysis. (Schüssler et al., 2001; Tehler et al., 2000)[2] Fungi probably colonized the land during theCambrian, over500 million years ago, (Taylor & Osborn, 1996),[2] and possibly 635 million years ago during theEdiacaran,[3][4] but terrestrial fossils only become uncontroversial and common during theDevonian,400 million years ago.[2]
Evidence from DNA analysis suggests that all fungi are descended from amost recent common ancestor that lived at least 1.2 to 1.5 billion years ago. It is probable that these earliest fungi lived in water, and hadflagella.[5]
However, a 2.4-billion-year-old basalt from thePalaeoproterozoicOngeluk Formation in South Africa containing filamentous fossils in vesicles and fractures, that form mycelium-like structures may push back the origin of the Kingdom over one billion years before.[6]
The earliest terrestrial fungus fossils, or at least fungus-like fossils, have been found in South China from around 635 million years ago. The researchers who reported on these fossils suggested that these fungus-like organisms may have played a role in oxygenating Earth's atmosphere in the aftermath of theCryogenian glaciations.[3]
About 250 million years ago fungi became abundant in many areas, based on the fossil record, and could even have been the dominant form of life on the earth at that time.[5]
A rich diversity of fungi is known from the lowerDevonianRhynie chert; an earlier record is absent. Since fungi do notbiomineralise, they do not readily enter the fossil record; there are only three claims of early fungi. One from theOrdovician[7] has been dismissed on the grounds that it lacks any distinctly fungal features, and is held by many to be contamination;[8] the position of a "probable" Proterozoic fungus is still not established,[8] and it may represent astem group fungus. There is also a case for a fungal affinity for the enigmatic microfossilOrnatifilum. Since the fungi form a sister group to the animals, the two lineages must have diverged before the first animal lineages, which are known from fossils as early as theEdiacaran.[9]
In contrast toplants andanimals, the early fossil record of the fungi is meager. Factors that likely contribute to the under-representation of fungal species among fossils include the nature of fungalfruiting bodies, which are soft, fleshy, and easily degradable tissues and the microscopic dimensions of most fungal structures, which therefore are not readily evident. Fungal fossils are difficult to distinguish from those of other microbes, and are most easily identified when they resembleextant fungi.[10] Often recovered from apermineralized plant or animal host, these samples are typically studied by making thin-section preparations that can be examined withlight microscopy ortransmission electron microscopy.[11]Compression fossils are studied by dissolving the surrounding matrix with acid and then using light orscanning electron microscopy to examine surface details.[12]
The earliest fossils possessing features typical of fungi date to thePaleoproterozoic era, some2,400 million years ago (Ma); these multicellularbenthic organisms had filamentous structures capable ofanastomosis, in which hyphal branches recombine.[6] Other recent studies (2009) estimate the arrival of fungal organisms at about 760–1060 Ma on the basis of comparisons of the rate of evolution in closely related groups.[13] For much of thePaleozoic Era (542–251 Ma), the fungi appear to have been aquatic and consisted of organisms similar to the extantChytrids in having flagellum-bearingspores.[14]Phylogenetic analyses suggest that the flagellum was lost early in the evolutionary history of the fungi, and consequently, the majority of fungal species lack a flagellum.[15] The evolutionary adaptation from an aquatic to a terrestrial lifestyle necessitated a diversification of ecological strategies for obtaining nutrients, includingparasitism,saprobism, and the development ofmutualistic relationships such asmycorrhiza and lichenization.[16] Recent (2009) studies suggest that the ancestral ecological state of theAscomycota was saprobism, and that independentlichenization events have occurred multiple times.[17]
In May 2019, scientists reported the discovery of afossilized fungus, namedOurasphaira giraldae, in theCanadian Arctic, that may have grown on land a billion years ago, well beforeplants were living on land.[18][19][20] Earlier, it had been presumed that the fungi colonized the land during theCambrian (542–488.3 Ma), also long before land plants.[2] Fossilized hyphae and spores recovered from theOrdovician of Wisconsin (460 Ma) resemble modern-dayGlomerales, and existed at a time when the land flora likely consisted of only non-vascularbryophyte-like plants;[21] but these have been dismissed as contamination.[8][22]Prototaxites, which was probably a fungus or lichen, would have been the tallest organism of the lateSilurian. Fungal fossils do not become common and uncontroversial until the earlyDevonian (416–359.2 Ma), when they are abundant in theRhynie chert, mostly asZygomycota andChytridiomycota.[2][23][24] At about this same time, approximately 400 Ma, the Ascomycota and Basidiomycota diverged,[25] and all modernclasses of fungi were present by the LateCarboniferous (Pennsylvanian, 318.1–299 Ma).[26]
Lichen-like fossils have been found in theDoushantuo Formation in southern China dating back to 635–551 Ma.[27] Lichens were a component of the early terrestrial ecosystems, and the estimated age of the oldest terrestrial lichen fossil is 400 Ma;[28] this date corresponds to the age of the oldest knownsporocarp fossil, aPaleopyrenomycites species found in the Rhynie Chert.[29] The oldest fossil with microscopic features resembling modern-day basidiomycetes isPalaeoancistrus, found permineralized with afern from the Pennsylvanian.[30] Rare in the fossil record are the homobasidiomycetes (ataxon roughly equivalent to the mushroom-producing species of theagaricomycetes). Twoamber-preserved specimens provide evidence that the earliest known mushroom-forming fungi (the extinct speciesArchaeomarasmius legletti) appeared during the mid-Cretaceous, 90 Ma.[31][32]
Some time after thePermian-Triassic extinction event (251.4 Ma), a fungal spike (originally thought to be an extraordinary abundance of fungal spores insediments) formed, suggesting that fungi were the dominant life form at this time, representing nearly 100% of the availablefossil record for this period.[33] However, the proportion of fungal spores relative to spores formed byalgal species is difficult to assess,[34] the spike did not appear worldwide,[35][36] and in many places it did not fall on the Permian-Triassic boundary.[37]
Approximately 66 million years ago, immediately after theCretaceous-Tertiary (K-T) extinction, there was a dramatic increase in evidence of fungi. Fungi appear to have had the chance to flourish due to the extinction of most plant and animal species, and the resultant fungal bloom has been described as like "a massive compost heap".[38] The lack of K-T extinction in fungal evolution is also supported by molecular data. Phylogenetic comparative analyses of a tree consisting of 5,284agaricomycete species do not show signal for a mass extinction event around the Cretaceous-Tertiary boundary.[39]
^Taylor TN, Taylor EL (1996). "The distribution and interactions of some Paleozoic fungi".Review of Palaeobotany and Palynology.95 (1–4):83–94.doi:10.1016/S0034-6667(96)00029-2.
^Taylor TN, Hass H, Kerp H, Krings M, Hanlin RT (2005). "Perithecial Ascomycetes from the 400 million year old Rhynie chert: an example of ancestral polymorphism".Mycologia.97 (1):269–85.doi:10.3852/mycologia.97.1.269.hdl:1808/16786.PMID16389979.
^Dennis RL. (1970). "A Middle Pennsylvanian basidiomycete mycelium with clamp connections".Mycologia.62 (3):578–84.doi:10.2307/3757529.JSTOR3757529.
^Foster CB, Stephenson MH, Marshall C, Logan GA, Greenwood PF (2002). "A revision of Reduviasporonites Wilson 1962: description, illustration, comparison and biological affinities".Palynology.26 (1):35–58.Bibcode:2002Paly...26...35F.doi:10.2113/0260035.
^López-Gómez J, Taylor EL (2005). "Permian-Triassic transition in Spain: a multidisciplinary approach".Palaeogeography, Palaeoclimatology, Palaeoecology.229 (1–2):1–2.doi:10.1016/j.palaeo.2005.06.028.
^Fungi and the Rise of Mammals That ecological calamity was accompanied by massive deforestation, an event followed by a fungal bloom, as the earth became a massive compost.
^Varga, Torda; Krizsán, Krisztina; Földi, Csenge; Dima, Bálint; Sánchez-García, Marisol; Sánchez-Ramírez, Santiago; Szöllősi, Gergely J.; Szarkándi, János G.; Papp, Viktor; Albert, László; Andreopoulos, William; Angelini, Claudio; Antonín, Vladimír; Barry, Kerrie W.; Bougher, Neale L.; Buchanan, Peter; Buyck, Bart; Bense, Viktória; Catcheside, Pam; Chovatia, Mansi; Cooper, Jerry; Dämon, Wolfgang; Desjardin, Dennis; Finy, Péter; Geml, József; Haridas, Sajeet; Hughes, Karen; Justo, Alfredo; Karasiński, Dariusz; Kautmanova, Ivona; Kiss, Brigitta; Kocsubé, Sándor; Kotiranta, Heikki; LaButti, Kurt M.; Lechner, Bernardo E.; Liimatainen, Kare; Lipzen, Anna; Lukács, Zoltán; Mihaltcheva, Sirma; Morgado, Louis N.; Niskanen, Tuula; Noordeloos, Machiel E.; Ohm, Robin A.; Ortiz-Santana, Beatriz; Ovrebo, Clark; Rácz, Nikolett; Riley, Robert; Savchenko, Anton; Shiryaev, Anton; Soop, Karl; Spirin, Viacheslav; Szebenyi, Csilla; Tomšovský, Michal; Tulloss, Rodham E.; Uehling, Jessie; Grigoriev, Igor V.; Vágvölgyi, Csaba; Papp, Tamás; Martin, Francis M.; Miettinen, Otto; Hibbett, David S.; Nagy, László G. (April 2019)."Megaphylogeny resolves global patterns of mushroom evolution".Nature Ecology & Evolution.3 (4):668–678.Bibcode:2019NatEE...3..668V.doi:10.1038/s41559-019-0834-1.PMC6443077.PMID30886374.
