Editing Tetrapod (section)

=== Crown group ===
Crown tetrapods are defined as the nearest common ancestor of all living tetrapods (amphibians, reptiles, birds, and mammals) along with all of the descendants of that ancestor.

The inclusion of certain extinct groups in the crown Tetrapoda depends on the relationships of modern amphibians, or [[lissamphibia]]ns. There are currently three major hypotheses on the origins of lissamphibians. In the temnospondyl hypothesis (TH), lissamphibians are most closely related to dissorophoid [[temnospondyl]]s, which would make temnospondyls tetrapods. In the lepospondyl hypothesis (LH), lissamphibians are the sister taxon of lysorophian [[lepospondyl]]s, making lepospondyls tetrapods and temnospondyls stem-tetrapods. In the polyphyletic hypothesis (PH), frogs and salamanders evolved from dissorophoid temnospondyls while caecilians come out of microsaur lepospondyls, making both lepospondyls and temnospondyls true tetrapods.<ref name="SigurdsenGreen2011">{{cite journal|last1=Sigurdsen|first1=Trond|last2=Green|first2=David M.|title=The origin of modern amphibians: a re-evaluation|journal=Zoological Journal of the Linnean Society|volume=162|issue=2|date=June 2011|pages=457–469|issn=0024-4082|doi=10.1111/j.1096-3642.2010.00683.x|doi-access=free}}</ref><ref name="Benton2014">{{cite book|last=Benton|first=Michael|author-link=Michael Benton|title=Vertebrate Palaeontology|url=https://books.google.com/books?id=qak-BAAAQBAJ&pg=PT398|access-date=2 July 2015|date=4 August 2014|publisher=Wiley|isbn=978-1-118-40764-6|page=398|archive-date=19 August 2020|archive-url=https://web.archive.org/web/20200819201052/https://books.google.com/books?id=qak-BAAAQBAJ&pg=PT398|url-status=live}}</ref>