Editing Permian–Triassic extinction event (section)

=== Terrestrial vertebrates ===
Land vertebrates took an unusually long time to recover from the P–Tr extinction; paleontologist [[Michael Benton]] estimated the recovery was not complete until {{val|30|u=million years}} after the extinction, i.e. not until the Late Triassic, when the first [[dinosaurs]] had risen from bipedal [[panaves|archosaurian ancestors]] and the first mammals from small [[probainognathia|cynodont ancestors]].<ref name="Benton" /> A tetrapod gap may have existed from the Induan until the early Spathian between ~30 °N and ~ 40 °S due to extreme heat making these low latitudes uninhabitable for these animals. During the hottest phases of this interval, the gap would have spanned an even greater latitudinal range.<ref>{{cite journal |last1=Liu |first1=Jun |last2=Abdala |first2=Fernando |last3=Angielczyk |first3=Kenneth D. |last4=Sidor |first4=Christian A. |date=January 2022 |title=Tetrapod turnover during the Permo-Triassic transition explained by temperature change |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825221003871 |journal=[[Earth-Science Reviews]] |volume=224 |page=103886 |doi=10.1016/j.earscirev.2021.103886 |bibcode=2022ESRv..22403886L |s2cid=244900399 |access-date=31 May 2023|url-access=subscription }}</ref> East-central Pangaea, with its relatively wet climate, served as a dispersal corridor for PTME survivors during their Early Triassic recolonization of the supercontinent.<ref>{{cite journal |last1=Liu |first1=Jun |last2=Angielczyk |first2=Kenneth D. |last3=Abdala |first3=Fernando |date=October 2021 |title=Permo-Triassic tetrapods and their climate implications |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818121002034 |journal=[[Global and Planetary Change]] |volume=205 |page=103618 |doi=10.1016/j.gloplacha.2021.103618 |bibcode=2021GPC...20503618L |access-date=10 August 2023|url-access=subscription }}</ref> In North China, tetrapod body and [[ichnofossil]]s are extremely rare in Induan facies, but become more abundant in the Olenekian and Anisian, showing a biotic recovery of tetrapods synchronous with the decreasing aridity during the Olenekian and Anisian.<ref name="ZhuEtAl2022" /><ref name="YuEtAl2022" /> In Russia, even after 15 Myr of recovery, during which ecosystems were rebuilt and remodeled, many terrestrial vertebrate guilds were absent, including small insectivores, small piscivores, large herbivores, and apex predators.<ref>{{cite journal |last1=Benton |first1=Michael James |last2=Tverdokhlebov |first2=V. P. |last3=Surkov |first3=M. V. |date=4 November 2004 |title=Ecosystem remodelling among vertebrates at the Permian–Triassic boundary in Russia |url=https://www.nature.com/articles/nature02950 |journal=[[Nature (journal)|Nature]] |volume=432 |issue=7013 |pages=97–100 |doi=10.1038/nature02950 |pmid=15525988 |bibcode=2004Natur.432...97B |s2cid=4388173 |access-date=31 May 2023|url-access=subscription }}</ref> [[Coprolite|Coprolitic]] evidence indicates that freshwater food webs had recovered by the early Ladinian, with a lacustrine coprolite assemblage from the [[Ordos Basin]] of China providing evidence of a trophically multileveled ecosystem containing at least six different trophic levels. The highest trophic levels were filled by vertebrate predators.<ref>{{cite journal |last1=Yao |first1=Mingtao |last2=Sun |first2=Zuoyu |last3=Meng |first3=Qingqiang |last4=Li |first4=Jiachun |last5=Jiang |first5=Dayong |date=15 August 2022 |title=Vertebrate coprolites from Middle Triassic Chang 7 Member in Ordos Basin, China: Palaeobiological and palaeoecological implications |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018222002541 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=600 |page=111084 |doi=10.1016/j.palaeo.2022.111084 |bibcode=2022PPP...60011084M |s2cid=249186414 |access-date=8 January 2023|url-access=subscription }}</ref> Overall, terrestrial faunas after the extinction event tended to be more variable and heterogeneous across space than those of the Late Permian, which exhibited less provincialism, being much more geographically homogeneous.<ref>{{cite journal |last1=Sidor |first1=Christian A. |last2=Vilhena |first2=Daril A. |last3=Angielczyk |first3=Kenneth D. |last4=Huttenlocker |first4=Adam K. |last5=Nisbett |first5=Sterling J. |last6=Peecook |first6=Brandon R. |last7=Steyer |first7=J. Sébastien |last8=Smith |first8=Roger M. H. |last9=Tsuji |first9=Linda A. |date=29 April 2013 |title=Provincialization of terrestrial faunas following the end-Permian mass extinction |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=110 |issue=20 |pages=8129–8133 |doi=10.1073/pnas.1302323110 |pmid=23630295 |pmc=3657826 |bibcode=2013PNAS..110.8129S |doi-access=free }}</ref>

====Synapsids====
[[File:Lystrosaurus hedini.JPG|thumb|upright=1.25|right|''[[Lystrosaurus]]'' was by far the most abundant early Triassic land vertebrate.]]
''[[Lystrosaurus]]'', a pig-sized herbivorous [[dicynodont]] [[therapsid]], constituted as much as 90% of some earliest Triassic land vertebrate fauna, although some recent evidence has called into question its status as a post-PTME [[disaster taxon]].<ref>{{cite journal |last1=Modesto |first1=Sean P. |date=16 December 2020 |title=The Disaster Taxon Lystrosaurus: A Paleontological Myth |journal=[[Frontiers in Earth Science]] |volume=8 |page=617 |doi=10.3389/feart.2020.610463 |bibcode=2020FrEaS...8..617M |doi-access=free }}</ref> The dicynodont genus is often used as a biostratigraphic marker for the PTME.<ref>{{Cite journal |last1=Angielczyk |first1=Kenneth D. |last2=Liu |first2=Jun |last3=Sidor |first3=Christian A. |last4=Yang |first4=Wan |date=November 2022 |title=The stratigraphic and geographic occurrences of Permo-Triassic tetrapods in the Bogda Mountains, NW China — Implications of a new cyclostratigraphic framework and Bayesian age model |journal=[[Journal of African Earth Sciences]] |language=en |volume=195 |pages=104655 |doi=10.1016/j.jafrearsci.2022.104655 |doi-access=free |bibcode=2022JAfES.19504655A }}</ref> The evolutionary success of ''Lystrosaurus'' in the aftermath of the PTME is believed to be attributable to the dicynodont taxon's grouping behaviour and tolerance for extreme and highly variable climatic conditions.<ref>{{cite journal |last1=Viglietti |first1=Pia A. |last2=Smith |first2=Roger M. H. |last3=Compton |first3=John S. |date=15 December 2013 |title=Origin and palaeoenvironmental significance of Lystrosaurus bonebeds in the earliest Triassic Karoo Basin, South Africa |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018213003787 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=392 |pages=9–21 |doi=10.1016/j.palaeo.2013.08.015 |bibcode=2013PPP...392....9V |access-date=31 May 2023|url-access=subscription }}</ref> Other likely factors behind the success of ''Lystrosaurus'' included extremely fast growth rate exhibited by the dicynodont genus,<ref>{{cite journal |last1=Botha-Brink |first1=Jennifer |last2=Angielczyk |first2=Kenneth D. |date=26 July 2010 |title=Do extraordinarily high growth rates in Permo-Triassic dicynodonts (Therapsida, Anomodontia) explain their success before and after the end-Permian extinction? |journal=[[Zoological Journal of the Linnean Society]] |volume=160 |issue=2 |pages=341–365 |doi=10.1111/j.1096-3642.2009.00601.x |doi-access=free }}</ref> along with its early onset of sexual maturity.<ref name="BreedingYoung">{{cite journal |last1=Botha-Brink |first1=Jennifer |last2=Codron |first2=Daryl |last3=Huttenlocker |first3=Adam K. |last4=Angielczyk |first4=Kenneth D. |last5=Ruta |first5=Marcello |date=5 April 2016 |title=Breeding Young as a Survival Strategy during Earth's Greatest Mass Extinction |journal=[[Scientific Reports]] |volume=6 |issue=1 |page=24053 |doi=10.1038/srep24053 |pmid=27044713 |pmc=4820772 |bibcode=2016NatSR...624053B }}</ref> Antarctica may have served as a refuge for dicynodonts during the PTME from which surviving dicynodonts spread out of in its aftermath.<ref name="AntarcticRefuge">{{cite journal |last1=Fröbisch |first1=Jörg |last2=Angielczyk |first2=Kenneth D. |last3=Sidor |first3=Christian A. |date=3 December 2009 |title=The Triassic dicynodont Kombuisia (Synapsida, Anomodontia) from Antarctica, a refuge from the terrestrial Permian-Triassic mass extinction |url=https://link.springer.com/article/10.1007/s00114-009-0626-6 |journal=[[Naturwissenschaften]] |volume=97 |issue=2 |pages=187–196 |doi=10.1007/s00114-009-0626-6 |pmid=19956920 |s2cid=20557454 |access-date=31 May 2023|url-access=subscription }}</ref> Ichnological evidence from the earliest Triassic of the Karoo Basin shows dicynodonts were abundant in the immediate aftermath of the biotic crisis.<ref>{{cite journal |last1=Marchetti |first1=Lorenzo |last2=Klein |first2=Hendrik |last3=Buchwitz |first3=Michael |last4=Ronchi |first4=Ausonio |last5=Smith |first5=Roger M. H. |last6=De Klerk |first6=William J. |last7=Sciscio |first7=Lara |last8=Groenewald |first8=Gideon H. |date=August 2019 |title=Permian-Triassic vertebrate footprints from South Africa: Ichnotaxonomy, producers and biostratigraphy through two major faunal crises |journal=[[Gondwana Research]] |volume=72 |pages=139–168 |doi=10.1016/j.gr.2019.03.009 |bibcode=2019GondR..72..139M |s2cid=133781923 |doi-access=free }}</ref> Smaller carnivorous [[cynodont]] [[therapsids]] also survived, a group that included the ancestors of mammals.<ref name="BodySizeReductions" /> As with dicynodonts, selective pressures favoured endothermic [[Epicynodontia|epicynodonts]].<ref>{{cite journal |last1=Rey |first1=Kévin |last2=Amiot |first2=Romain |last3=Fourel |first3=François |last4=Abdala |first4=Fernando |last5=Fluteau |first5=Frédéric |last6=Jalil |first6=Nour-Eddine |last7=Liu |first7=Jun |last8=Rubidge |first8=Bruce S. |last9=Smith |first9=Roger M. H. |last10=Steyer |first10=J. Sébastien |last11=Viglietti |first11=Pia A. |last12=Wang |first12=Xu |last13=Lécuyer |first13=Christophe |date=18 July 2017 |title=Oxygen isotopes suggest elevated thermometabolism within multiple Permo-Triassic therapsid clades |journal=[[eLife]] |volume=6 |pages=e28589 |doi=10.7554/eLife.28589 |pmid=28716184 |pmc=5515572 |doi-access=free }}</ref> [[Therocephalia]]ns likewise survived; burrowing may have been a key adaptation that helped them make it through the PTME.<ref>{{cite journal |last1=Fontanarrosa |first1=Gabriela |last2=Abdala |first2=Fernando |last3=Kümmell |first3=Susanna |last4=Gess |first4=Robert |date=26 March 2019 |title=The manus of Tetracynodon (Therapsida: Therocephalia) provides evidence for survival strategies following the Permo-Triassic extinction |url=https://www.tandfonline.com/doi/abs/10.1080/02724634.2018.1491404 |journal=[[Journal of Vertebrate Paleontology]] |volume=38 |issue=4 |pages=(1)-(13) |doi=10.1080/02724634.2018.1491404 |hdl=11336/91246 |s2cid=109228166 |access-date=31 May 2023|hdl-access=free }}</ref> In the [[Karoo]] region of southern [[Africa]], the [[therocephalia]]ns ''[[Tetracynodon]]'', ''[[Moschorhinus]]'' and ''[[Ictidosuchoides]]'' survived, but do not appear to have been abundant in the Triassic.<ref name="BothaSmith2007LystrosaurusSpeciesComposition">{{cite journal |author1=Botha, J. |author2=Smith, R.M.H. |name-list-style=amp | year=2007 | title=Lystrosaurus species composition across the Permo–Triassic boundary in the Karoo Basin of South Africa | journal=[[Lethaia]] | volume=40 | pages=125–137 |url=http://www.nasmus.co.za/PALAEO/jbotha/pdfs/Botha%20and%20Smith%202007.pdf |archive-url=https://web.archive.org/web/20080910214110/http://www.nasmus.co.za/PALAEO/jbotha/pdfs/Botha%20and%20Smith%202007.pdf |url-status=dead |archive-date=2008-09-10 | access-date=2008-07-02 | doi=10.1111/j.1502-3931.2007.00011.x | issue=2 |bibcode=2007Letha..40..125B }}</ref> Early Triassic therocephalians were mostly survivors of the PTME rather than newly evolved taxa that originated during the evolutionary radiation in its aftermath.<ref>{{cite journal |last1=Huttenlocker |first1=Adam K. |last2=Sidor |first2=Christian A. |last3=Smith |first3=Roger M. H. |date=21 March 2011 |title=A new specimen of Promoschorhynchus (Therapsida: Therocephalia: Akidnognathidae) from the Lower Triassic of South Africa and its implications for theriodont survivorship across the Permo-Triassic boundary |url=https://www.tandfonline.com/doi/abs/10.1080/02724634.2011.546720 |journal=[[Journal of Vertebrate Paleontology]] |volume=31 |issue=2 |pages=405–421 |doi=10.1080/02724634.2011.546720 |bibcode=2011JVPal..31..405H |s2cid=129242450 |access-date=31 May 2023|url-access=subscription }}</ref> Both therocephalians and cynodonts, known collectively as [[Eutheriodontia|eutheriodonts]], decreased in body size from the Late Permian to the Early Triassic.<ref name="BodySizeReductions">{{cite journal |last1=Huttenlocker |first1=Adam K. |date=3 February 2014 |title=Body Size Reductions in Nonmammalian Eutheriodont Therapsids (Synapsida) during the End-Permian Mass Extinction |journal=[[PLOS ONE]] |volume=9 |issue=2 |pages=e87553 |doi=10.1371/journal.pone.0087553 |pmid=24498335 |pmc=3911975 |bibcode=2014PLoSO...987553H |doi-access=free }}</ref> This decrease in body size has been interpreted as an example of the Lilliput effect.<ref>{{cite journal |last1=Huttenlocker |first1=Adam K. |last2=Botha-Brink |first2=Jennifer |date=8 April 2014 |title=Bone microstructure and the evolution of growth patterns in Permo-Triassic therocephalians (Amniota, Therapsida) of South Africa |journal=[[PeerJ]] |volume=2 |pages=e325 |doi=10.7717/peerj.325 |pmid=24765566 |pmc=3994631 |doi-access=free }}</ref>

====Sauropsids====
[[Archosaurs]] (which included the ancestors of dinosaurs and [[crocodilia]]ns) were initially rarer than therapsids, but they began to displace therapsids in the mid-Triassic. Olenekian tooth fossil assemblages from the Karoo Basin indicate that archosauromorphs were already highly diverse by this point in time, though not very ecologically specialised.<ref>{{cite journal |last1=Hoffmann |first1=Devin K. |last2=Hancox |first2=John P. |last3=Nesbitt |first3=Sterling J. |date=1 May 2023 |title=A diverse diapsid tooth assemblage from the Early Triassic (Driefontein locality, South Africa) records the recovery of diapsids following the end-Permian mass extinction |journal=[[PLOS ONE]] |volume=18 |issue=5 |pages=e0285111 |doi=10.1371/journal.pone.0285111 |pmid=37126508 |pmc=10150976 |bibcode=2023PLoSO..1885111H |doi-access=free }}</ref> In the mid to late Triassic, the [[dinosaur]]s evolved from one group of archosaurs, and went on to dominate terrestrial ecosystems during the [[Jurassic]] and [[Cretaceous]].<ref name="BentonVertebratePaleontology">{{cite book|author=Benton, M.J.|author-link = Michael Benton| year=2004|title=Vertebrate Paleontology|publisher=Blackwell Publishers|pages=xii–452|isbn=978-0-632-05614-9|no-pp=true|title-link = Vertebrate Palaeontology (Benton)}}</ref> This "Triassic Takeover" may have contributed to the [[evolution of mammals]] by forcing the surviving therapsids and their [[mammaliformes|mammaliform]] successors to live as small, mainly [[Nocturnality|nocturnal]] [[insectivore]]s; nocturnal life probably forced at least the mammaliforms to develop fur, better [[hearing]] and higher [[metabolic rate]]s,<ref name="RubenJones2000FurAndFeathers">{{cite journal |author1=Ruben, J.A. |author2=Jones, T.D. |name-list-style=amp | title=Selective Factors Associated with the Origin of Fur and Feathers | journal=[[American Zoologist]] | year=2000 | volume=40 | issue=4 | pages=585–596 |doi=10.1093/icb/40.4.585 | doi-access=free }}</ref> while losing part of the differential color-sensitive retinal receptors reptilians and birds preserved. Archosaurs also experienced an increase in metabolic rates over time during the Early Triassic.<ref>{{cite journal |last1=Benton |first1=Michael James |date=December 2021 |title=The origin of endothermy in synapsids and archosaurs and arms races in the Triassic |journal=[[Gondwana Research]] |volume=100 |pages=261–289 |doi=10.1016/j.gr.2020.08.003 |bibcode=2021GondR.100..261B |s2cid=222247711 |doi-access=free }}</ref> The archosaur dominance would end again due to the [[Cretaceous–Paleogene extinction event]], after which both [[birds]] (only extant dinosaurs) and mammals (only extant synapsids) would diversify and share the world.

====Temnospondyls====
[[Temnospondyl]] [[amphibian]]s made a quick recovery; the appearance in the fossil record of so many temnospondyl clades suggests they may have been ideally suited as pioneer species that recolonised decimated ecosystems.<ref>{{cite thesis |last=McHugh |first=Julia Beth |date=May 2012 |title=Temnospondyl ontogeny and phylogeny, a window into terrestrial ecosystems during the Permian-Triassic mass extinction |url=https://www.proquest.com/docview/1030963218 |type=PhD |chapter=ASSESSING TEMNOSPONDYL EVOLUTION AND ITS IMPLICATIONS FOR THE TERRESTRIAL PERMO-TRIASSIC MASS EXTINCTION |publisher=[[University of Iowa]] |access-date=20 September 2023|id={{ProQuest|1030963218}} }}</ref> During the Induan, [[Tupilakosauridae|tupilakosaurids]] in particular thrived as disaster taxa,<ref name="TheLessonOfTemnospondyls" /> including ''[[Tupilakosaurus]]'' itself,<ref>{{Cite journal |last1=Scholze |first1=Frank |last2=Golubev |first2=Valeriy K. |last3=Niedźwiedzki |first3=Grzegorz |last4=Sennikov |first4=Andrey G. |last5=Schneider |first5=Jörg W. |last6=Silantiev |first6=Vladimir V. |date=1 July 2015 |title=Early Triassic Conchostracans (Crustacea: Branchiopoda) from the terrestrial Permian–Triassic boundary sections in the Moscow syncline |url=https://www.sciencedirect.com/science/article/pii/S003101821500187X |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=429 |pages=22–40 |doi=10.1016/j.palaeo.2015.04.002 |bibcode=2015PPP...429...22S |issn=0031-0182 |access-date=24 November 2023|url-access=subscription }}</ref> though they gave way to other temnospondyls as ecosystems recovered.<ref name="TheLessonOfTemnospondyls">{{Cite journal |last1=Ruta |first1=Marcello |last2=Benton |first2=Michael J. |title=Calibrated Diversity, Tree Topology and the Mother of Mass Extinctions: The Lesson of Temnospondyls |date=19 November 2011 |journal=[[Palaeontology (journal)|Palaeontology]] |language=en |volume=51 |issue=6 |pages=1261–1288 |doi=10.1111/j.1475-4983.2008.00808.x |s2cid=85411546 |doi-access=free |bibcode=2008Palgy..51.1261R }}</ref> Temnospondyls were reduced in size during the Induan, but their body size rebounded to pre-PTME levels during the Olenekian.<ref>{{cite journal |last1=Tarailo |first1=David A. |date=5 November 2018 |title=Taxonomic and ecomorphological diversity of temnospondyl amphibians across the Permian–Triassic boundary in the Karoo Basin (South Africa) |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/jmor.20906 |journal=[[Journal of Morphology]] |volume=279 |issue=12 |pages=1840–1848 |doi=10.1002/jmor.20906 |pmid=30397933 |s2cid=53234826 |access-date=31 May 2023|url-access=subscription }}</ref> ''[[Mastodonsaurus]]'' and [[trematosauria]]ns were the main aquatic and semiaquatic predators during most of the Triassic, some preying on [[tetrapod]]s and others on fish.<ref>{{cite journal |author1=Yates, A. M. |author2=Warren, A. A. |year=2000 |title=The phylogeny of the 'higher' temnospondyls (Vertebrata: Choanata) and its implications for the monophyly and origins of the Stereospondyli|journal=[[Zoological Journal of the Linnean Society]] |volume=128|issue=1|pages=77–121|doi=10.1111/j.1096-3642.2000.tb00650.x
|doi-access=free}}</ref>