Editing Vertebrate (section)

=== Paleozoic: from fish to amphibians ===

{{see also|Evolution of fish|Evolution of tetrapods}}

[[File:Acanthostega BW.jpg|thumb|upright=0.9|''[[Acanthostega]]'', a [[Devonian]] [[Labyrinthodontia|labyrinthodont]], {{circa}} 365 mya<ref>{{cite book |last=Benton |first=Michael J. |title=Vertebrate Palaeontology |date=2019 |publisher=[[Wiley (publisher)|Wiley]] |section=Acanthostega |page=90 |edition=Kindle}}</ref> ]]

The first [[Gnathostomata|jawed vertebrates]] may have appeared in the late [[Ordovician]] (~445 mya) and became common in the [[Devonian|Devonian period]], often known as the "Age of Fishes".<ref name=britannica1954>{{cite book |title=Encyclopædia Britannica |volume=17 |year=1954 |publisher=Encyclopædia Britannica |page=107}}</ref> The two groups of [[bony fishes]], [[Actinopterygii]] and [[Sarcopterygii]], evolved and became common.<ref>{{cite book |last1=Berg |first1=L. R. |last2=Solomon |first2=E. P. |last3=Martin |first3=D. W. |title=Biology |year=2004 |publisher=Cengage Learning |isbn=978-0-534-49276-2 |page=599}}</ref> By the middle of the Devonian, a lineage of sarcopterygii with both gills and air-breathing lungs adapted to life in swampy pools used their muscular paired fins to propel themselves on land.<ref name="Carroll 1977">{{cite book |title=Patterns of Evolution, as Illustrated by the Fossil Record |last=Carroll |first=Robert L. |editor-last=Hallam |editor-first=Anthony |editor-link=Anthony Hallam |year=1977 |publisher=[[Elsevier]] |isbn=978-0-444-41142-6 |pages=405–420 |url=https://books.google.com/books?id=q7GjDIyyWegC&q=Amphibian+evolution&pg=PA405 |access-date=October 15, 2020 |archive-date=April 14, 2021 |archive-url=https://web.archive.org/web/20210414082736/https://books.google.com/books?id=q7GjDIyyWegC&q=Amphibian+evolution&pg=PA405 |url-status=live }}</ref> The fins, already possessing bones and joints, evolved into two pairs of walking legs.<ref name="NarkiewiczNarkiewicz2015">{{cite journal |last1=Narkiewicz |first1=Katarzyna |last2=Narkiewicz |first2=Marek |title=The age of the oldest tetrapod tracks from Zachełmie, Poland |journal=[[Lethaia]] |volume=48 |issue=1 |date=January 2015 |pages=10–12 |doi=10.1111/let.12083 |bibcode=2015Letha..48...10N }}</ref> These established themselves as [[amphibian]]s, terrestrial [[tetrapod]]s, in the next geological period, the [[Carboniferous]].<ref>{{cite book |url=https://books.google.com/books?id=Z0YWn5F9sWkC&pg=PA209 |title=Fins into Limbs: Evolution, Development, and Transformation |isbn=9780226313405 |access-date=2020-04-25 |archive-date=2020-08-09 |archive-url=https://web.archive.org/web/20200809023449/https://books.google.no/books?id=Z0YWn5F9sWkC&pg=PA209 |url-status=live |last=Hall |first=Brian K. |date=15 September 2008 |publisher=[[University of Chicago Press]] |page=209}}</ref> A group of vertebrates, the [[amniote]]s, with membranes around the [[embryo]] allowing it to survive on dry land, branched from amphibious tetrapods in the Carboniferous.<ref name="benton2014">{{Cite book| edition = 4th| publisher = John Wiley & Sons| isbn = 978-1-118-40764-6| last = Benton| first = Michael| title = Vertebrate Palaeontology| date = 2014 |pages=119, 148}}</ref>