Editing Gill (section)

===Amphibians===
[[File:Smooth Newt larva (aka).jpg|thumb|right|An [[alpine newt]] larva showing the [[external gills]], which flare just behind the head]]

[[Tadpole]]s of [[amphibian]]s have from three to five gill slits that do not contain actual gills. Usually no spiracle or true operculum is present, though many species have operculum-like structures. Instead of internal gills, they develop three feathery external gills that grow from the outer surface of the gill arches. Sometimes, adults retain these, but they usually disappear at [[metamorphosis]]. Examples of salamanders that retain their external gills upon reaching adulthood are the [[olm]] and the [[mudpuppy]].

Still, some extinct tetrapod groups did retain true gills. A study on ''[[Archegosaurus]]'' demonstrates that it had internal gills like true fish.<ref>Florian Witzmann; Elizabeth Brainerd (2017). "Modeling the physiology of the aquatic temnospondyl Archegosaurus decheni from the [[Cisuralian|early Permian]] of Germany". Fossil Record. 20 (2): 105–127. doi:10.5194/fr-20-105-2017.</ref>