Editing Permian (section)

=== Fish ===
The diversity of fish during the Permian is relatively low compared to the following Triassic. The dominant group of [[Osteichthyes|bony fishes]] during the Permian were the "[[Palaeonisciformes|Paleopterygii]]" a [[paraphyletic]] grouping of [[Actinopterygii]] that lie outside of [[Neopterygii]].<ref name="Romano-2016" /> The earliest unequivocal members of Neopterygii appear during the Early Triassic, but a Permian origin is suspected.<ref>{{Cite journal|last=Romano|first=Carlo|date=2021|title=A Hiatus Obscures the Early Evolution of Modern Lineages of Bony Fishes|journal=Frontiers in Earth Science|volume=8|language=English|doi=10.3389/feart.2020.618853|issn=2296-6463|doi-access=free|bibcode=2021FrEaS...8.8853R }}</ref> The diversity of [[coelacanth]]s is relatively low throughout the Permian in comparison to other marine fishes, though there is an increase in diversity during the terminal Permian (Changhsingian), corresponding with the highest diversity in their evolutionary history during the Early Triassic.<ref name="Romano-2016" /> Diversity of freshwater fish faunas was generally low and dominated by [[lungfish]] and "Paleopterygians".<ref name="Romano-2016">{{Cite journal|last1=Romano|first1=Carlo|last2=Koot|first2=Martha B.|last3=Kogan|first3=Ilja|last4=Brayard|first4=Arnaud|last5=Minikh|first5=Alla V.|last6=Brinkmann|first6=Winand|last7=Bucher|first7=Hugo|last8=Kriwet|first8=Jürgen|date=February 2016|title=Permian-Triassic Osteichthyes (bony fishes): diversity dynamics and body size evolution: Diversity and size of Permian-Triassic bony fishes|url=https://onlinelibrary.wiley.com/doi/10.1111/brv.12161|journal=Biological Reviews|language=en|volume=91|issue=1|pages=106–147|doi=10.1111/brv.12161|pmid=25431138|s2cid=5332637|access-date=2021-07-23|archive-date=2021-07-23|archive-url=https://web.archive.org/web/20210723083954/https://onlinelibrary.wiley.com/doi/10.1111/brv.12161|url-status=live}}</ref> The last common ancestor of all living lungfish is thought to have existed during the Early Permian. Though the fossil record is fragmentary, lungfish appear to have undergone an evolutionary diversification and size increase in freshwater habitats during the Early Permian, but subsequently declined during the middle and late Permian.<ref>{{Cite journal|last1=Kemp|first1=Anne|last2=Cavin|first2=Lionel|last3=Guinot|first3=Guillaume|date=April 2017|title=Evolutionary history of lungfishes with a new phylogeny of post-Devonian genera|journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]]|language=en|volume=471|pages=209–219|doi=10.1016/j.palaeo.2016.12.051|bibcode=2017PPP...471..209K|doi-access=free}}</ref> Conodonts experienced their lowest diversity of their entire evolutionary history during the Permian.<ref>{{Cite journal |last1=Ginot |first1=Samuel |last2=Goudemand |first2=Nicolas |date=December 2020 |title=Global climate changes account for the main trends of conodont diversity but not for their final demise |url=https://www.researchgate.net/publication/344363357 |journal=[[Global and Planetary Change]] |language=en |volume=195 |pages=103325 |bibcode=2020GPC...19503325G |doi=10.1016/j.gloplacha.2020.103325 |s2cid=225005180 |access-date=4 April 2023 |doi-access=free}}</ref> Permian chondrichthyan faunas are poorly known.<ref name="Koot-2013">{{Cite journal|last1=Koot|first1=Martha B.|last2=Cuny|first2=Gilles|last3=Tintori|first3=Andrea|last4=Twitchett|first4=Richard J.|date=March 2013|title=A new diverse shark fauna from the Wordian (Middle Permian) Khuff Formation in the interior Haushi-Huqf area, Sultanate of Oman: CHONDRICHTHYANS FROM THE WORDIAN KHUFF FORMATION OF OMAN|journal=[[Palaeontology (journal)|Palaeontology]]|language=en|volume=56|issue=2|pages=303–343|doi=10.1111/j.1475-4983.2012.01199.x|s2cid=86428264 |doi-access=}}</ref> Members of the chondrichthyan clade [[Holocephali]], which contains living [[chimaera]]s, reached their apex of diversity during the Carboniferous-Permian, the most famous Permian representative being the "buzz-saw shark" ''[[Helicoprion]],'' known for its unusual spiral shaped spiral tooth whorl in the lower jaw.<ref>{{Cite journal|last1=Tapanila|first1=Leif|last2=Pruitt|first2=Jesse|last3=Wilga|first3=Cheryl D.|last4=Pradel|first4=Alan|date=2020|title=Saws, Scissors, and Sharks: Late Paleozoic Experimentation with Symphyseal Dentition|journal=The Anatomical Record|language=en|volume=303|issue=2|pages=363–376|doi=10.1002/ar.24046|pmid=30536888|s2cid=54478736|issn=1932-8494|doi-access=free}}</ref> [[Hybodontiformes|Hybodonts]], a group of shark-like chondrichthyans, were widespread and abundant members of marine and freshwater faunas throughout the Permian.<ref name="Koot-2013" /><ref>{{Cite journal|last1=Peecook|first1=Brandon R.|last2=Bronson|first2=Allison W.|last3=Otoo|first3=Benjamin K.A.|last4=Sidor|first4=Christian A.|date=November 2021|title=Freshwater fish faunas from two Permian rift valleys of Zambia, novel additions to the ichthyofauna of southern Pangea|journal=Journal of African Earth Sciences|language=en|volume=183|pages=104325|doi=10.1016/j.jafrearsci.2021.104325|bibcode=2021JAfES.18304325P|doi-access=free}}</ref>  [[Xenacanthiformes]], another extinct group of shark-like chondrichthyans, were common in freshwater habitats, and represented the [[apex predator]]s of freshwater ecosystems.<ref>{{Cite journal |last1=Kriwet |first1=Jürgen |last2=Witzmann |first2=Florian |last3=Klug |first3=Stefanie |last4=Heidtke |first4=Ulrich H.J |date=2008-01-22 |title=First direct evidence of a vertebrate three-level trophic chain in the fossil record |journal=Proceedings of the Royal Society B: Biological Sciences |language=en |volume=275 |issue=1631 |pages=181–186 |doi=10.1098/rspb.2007.1170 |issn=0962-8452 |pmc=2596183 |pmid=17971323}}</ref>