Editing Lichen (section)

=== Evolution and paleontology ===
The fossil record for lichens is poor.<ref name=UCMPLFR>[http://www.ucmp.berkeley.edu/fungi/lichens/lichenfr.html "Lichens: Fossil Record"] {{Webarchive|url=https://web.archive.org/web/20100125101841/http://www.ucmp.berkeley.edu/fungi/lichens/lichenfr.html |date=25 January 2010 }}, University of California Museum of Paleontology.</ref> The extreme habitats that lichens dominate, such as tundra, mountains, and deserts, are not ordinarily conducive to producing fossils.<ref name=UCMPLFR/><ref name="urlFossil Record of Lichens"/> There are fossilized lichens embedded in amber. The fossilized ''Anzia'' is found in pieces of amber in northern Europe and dates back approximately 40 million years.<ref name=Poinar1992/> Lichen fragments are also found in fossil leaf beds, such as ''[[Lobaria]]''  from Trinity County in northern California, US, dating back to the early to middle [[Miocene]].<ref name=Peterson2000/>

The oldest fossil lichen in which both symbiotic partners have been recovered is ''[[Winfrenatia]]'', an early zygomycetous ([[Glomeromycota]]n) lichen symbiosis that may have involved controlled parasitism,{{citation needed|date=March 2016}} is permineralized in the [[Rhynie Chert]] of Scotland, dating from early [[Devonian|Early Devonian]], about 400 million years ago.<ref name=Taylor1995/> The slightly older fossil ''[[Spongiophyton]]'' has also been interpreted as a lichen on morphological<ref name=Taylor2004/> and isotopic<ref name=Jahren2003/> grounds, although the isotopic basis is decidedly shaky.<ref name=Fletcher2004/> It has been demonstrated that [[Silurian]]-[[Devonian]] fossils ''[[Nematothallus]]''<ref>{{cite journal |author1=Edwards D |author2=Axe L |year= 2012|title=Evidence for a fungal affinity for Nematasketum, a close ally of Prototaxites|journal=Botanical Journal of the Linnean Society|volume=168|pages=1–18|doi=10.1111/j.1095-8339.2011.01195.x|doi-access=free}}</ref> and ''[[Prototaxites]]''<ref>{{cite journal |author1=Retallack G.J. |author2=Landing, E.|year= 2014|title=Affinities and architecture of Devonian trunks of ''Prototaxites loganii''|journal=Mycologia|volume=106|issue=6|pages=1143–1156|doi=10.3852/13-390|pmid=24990121|s2cid=20013625}}</ref> were lichenized. Thus lichenized [[Ascomycota]] and [[Basidiomycota]] were a component of [[Llandovery epoch|Early Silurian]]-[[Devonian]] terrestrial ecosystems.<ref name=Karatygin2009/><ref name=Karatygin2007/> Newer research suggests that lichen evolved after the evolution of land plants.<ref>{{Cite web |url=https://scitechdaily.com/lichens-are-way-younger-than-scientists-thought-likely-evolved-millions-of-years-after-plants/ |title=Lichens Are Way Younger Than Scientists Thought – Likely Evolved Millions of Years After Plants |access-date=18 November 2019 |archive-url=https://web.archive.org/web/20191218121324/https://scitechdaily.com/lichens-are-way-younger-than-scientists-thought-likely-evolved-millions-of-years-after-plants/ |archive-date=18 December 2019 |url-status=live |date=15 November 2019 }}</ref>

The ancestral ecological state of both [[Ascomycota]] and [[Basidiomycota]] was probably [[saprobe|saprobism]], and independent lichenization events may have occurred multiple times.<ref>{{Cite journal|last1=Hansen|first1=Karen|last2=Perry|first2=Brian A.|last3=Dranginis|first3=Andrew W.|last4=Pfister|first4=Donald H.|date=May 2013|title=A phylogeny of the highly diverse cup-fungus family Pyronemataceae (Pezizomycetes, Ascomycota) clarifies relationships and evolution of selected life history traits|url=http://dx.doi.org/10.1016/j.ympev.2013.01.014|journal=Molecular Phylogenetics and Evolution|volume=67|issue=2|pages=311–335|doi=10.1016/j.ympev.2013.01.014|pmid=23403226|bibcode=2013MolPE..67..311H |issn=1055-7903}}</ref><ref name=Schoch2009/> In 1995, Gargas and colleagues proposed that there were at least five independent origins of lichenization; three in the basidiomycetes and at least two in the Ascomycetes.<ref name=Gargas1995/> Lutzoni et al. (2001) suggest lichenization probably evolved earlier and was followed by multiple independent losses. Some non-lichen-forming fungi may have secondarily lost the ability to form a lichen association. As a result, lichenization has been viewed as a highly successful nutritional strategy.<ref name=Honegger1998/><ref name=Wedin2004/>

Lichenized [[Glomeromycota]] may extend well back into the Precambrian. Lichen-like fossils consisting of coccoid cells ([[cyanobacteria]]?) and thin filaments (mucoromycotinan [[Glomeromycota]]?) are permineralized in marine [[phosphorite]] of the [[Doushantuo Formation]] in southern China. These fossils are thought to be 551 to 635 million years old or [[Ediacaran]].<ref name=Yuan2005/> Ediacaran [[acritarchs]] also have many similarities with [[Glomeromycota]]n vesicles and spores.<ref>{{cite journal |author=Retallack G.J. |year=2015 |title=Acritarch evidence of a late Precambrian adaptive radiation of Fungi. |journal=Botanica Pacifica |volume=4 |issue=2 |doi=10.17581/bp.2015.04203 |url=http://botsad.ru/media/aux/bp/BP_2015_4_2_retallack.pdf |pages=19–33 |access-date=22 December 2016 |archive-url=https://web.archive.org/web/20161222222005/http://botsad.ru/media/aux/bp/BP_2015_4_2_retallack.pdf |archive-date=22 December 2016 |url-status=live |doi-access=free }}</ref> It has also been claimed that [[Ediacaran biota|Ediacaran fossils]] including ''[[Dickinsonia]]'',<ref name=Retallack2007/> were lichens,<ref name=Retallack1994/> although this claim is controversial.<ref name=Switek2012/> Endosymbiotic [[Glomeromycota]] comparable with living ''[[Geosiphon]]'' may extend back into the [[Proterozoic]] in the form of 1500 million year old ''[[Horodyskia]]''<ref>{{cite journal |author1=Retallack, G.J. |author2=Dunn, K.L. |author3=Saxby, J. |year=2015 |title=Problematic Mesoproterozoic fossil Horodyskia from Glacier National Park, Montana, USA. |journal=Precambrian Research |volume=226 |pages=125–142 |doi=10.1016/j.precamres.2012.12.005|bibcode=2013PreR..226..125R }}</ref> and 2200 million year old ''[[Diskagma]]''.<ref name="Retallack-2013">{{cite journal |author1=Retallack, G.J. |author2=Krull, E.S. |author3=Thackray, G.D. |author4=Parkinson, D.|year= 2013|title=Problematic urn-shaped fossils from a Paleoproterozoic (2.2 Ga) paleosol in South Africa. |journal=Precambrian Research|volume= 235 |pages=71–87|doi=10.1016/j.precamres.2013.05.015|bibcode=2013PreR..235...71R}}</ref> Discovery of these fossils suggest that fungi developed symbiotic partnerships with photoautotrophs long before the evolution of vascular plants, though the Ediacaran lichen hypothesis is largely rejected due to an inappropriate definition of lichens based on taphonomy and substrate ecology.<ref>{{Citation|last1=Lücking|first1=Robert|title=Ediacarans, Protolichens, and Lichen-Derived Penicillium|date=2018|url=http://dx.doi.org/10.1016/b978-0-12-813012-4.00023-1|work=Transformative Paleobotany|pages=551–590|publisher=Elsevier|isbn=978-0-12-813012-4|access-date=2020-11-14|last2=Nelsen|first2=Matthew P.|doi=10.1016/b978-0-12-813012-4.00023-1}}</ref> However, a 2019 study by the same scientist who rejected the Ediacaran lichen hypothesis, Nelsen, used new time-calibrated phylogenies to conclude that there is no evidence of lichen before the existence of vascular plants.<ref>{{Cite journal |last1=Nelsen |first1=Matthew P. |last2=Lücking |first2=Robert |last3=Boyce |first3=C. Kevin |last4=Lumbsch |first4=H. Thorsten |last5=Ree |first5=Richard H. |date=January 2020 |title=No support for the emergence of lichens prior to the evolution of vascular plants |url=https://onlinelibrary.wiley.com/doi/10.1111/gbi.12369 |journal=Geobiology |language=en |volume=18 |issue=1 |pages=3–13 |doi=10.1111/gbi.12369 |pmid=31729136 |bibcode=2020Gbio...18....3N |s2cid=208034624 |issn=1472-4677}}</ref>

Lecanoromycetes, one of the most common classes of lichen-forming fungi, diverged from its ancestor, which may have also been lichen forming, around 258 million years ago, during the late Paleozoic period. However, the closely related clade Euritiomycetes appears to have become lichen-forming only 52 million years ago, during the early Cenozoic period.<ref>{{Cite journal |last1=Song |first1=Hyeunjeong |last2=Kim |first2=Ki-Tae |last3=Park |first3=Sook-Young |last4=Lee |first4=Gir-Won |last5=Choi |first5=Jaeyoung |last6=Jeon |first6=Jongbum |last7=Cheong |first7=Kyeongchae |last8=Choi |first8=Gobong |last9=Hur |first9=Jae-Seoun |last10=Lee |first10=Yong-Hwan |date=2022-06-24 |title=A comparative genomic analysis of lichen-forming fungi reveals new insights into fungal lifestyles |journal=Scientific Reports |language=en |volume=12 |issue=1 |pages=10724 |doi=10.1038/s41598-022-14340-5 |pmid=35750715 |pmc=9232553 |bibcode=2022NatSR..1210724S |issn=2045-2322}}</ref>