Editing Louse (section)

===Internal classification===
Phthiraptera is clearly a [[monophyletic]] grouping, united as the members are by a number of derived features, including their parasitism on [[warm-blooded]] vertebrates and the combination of their [[Metathorax|metathoracic]] [[ganglia]] with their [[abdominal]] ganglia to form a single ventral nerve junction.<ref name=Ax>{{cite book| vauthors = Ax P |title=Multicellular Animals: Volume II: The Phylogenetic System of the Metazoa |url=https://books.google.com/books?id=x7vtCAAAQBAJ&pg=PA303 |year=2013|publisher=Springer Science & Business Media |isbn=978-3-662-10396-8 |pages=303–307 }}</ref>

The order has traditionally been divided into two suborders, the sucking lice ([[Anoplura]]) and the chewing lice ([[Mallophaga]]). However, subsequent classifications indicated that the Mallophaga are [[paraphyletic]], and four suborders were then recognized.<ref name=info>{{cite web |url=http://phthiraptera.info/ |title=Phthiraptera.info | vauthors = Smith V |publisher=International Society of Phthirapterists |access-date=25 October 2015}}</ref>

Upon finding that Phthiraptera was nested within [[Psocoptera]] in 2021, de Moya ''et al.'' reduced the rank of Phthiraptera to [[infraorder]], and the [[suborder]]s were reduced down to [[parvorder]].<ref name="deMoya2021"/><ref name="PsocodeaSpeciesFile"/> Also, based on the [[paraphyletic]] nature of one of the parvorders -  [[Ischnocera]] - they proposed creation of a fifth parvorder [[Trichodectera]] to be created and split off from Ischnocera. Here are the five proposed parvorders within Phthiraptera:<ref name="deMoya2021"/>
* [[Amblycera]]: primitive chewing lice, widespread on birds, and also occurring on South American and Australian mammals
* [[Anoplura]]: sucking lice, occurring on mammals exclusively
* [[Rhynchophthirina]]: parasites of elephants and [[warthog]]s
* [[Ischnocera]]: avian chewing lice, and contains the large family [[Philopteridae]]
* [[Trichodectera]]: parasitizing mammals, split off from Ischnocera, and contains the family [[Trichodectidae]]