{{Short description|Subclass of annelid worms}} {{Automatic taxobox | fossil_range = {{Geological range|Cambrian Stage 4|Recent}}<ref>{{cite journal |last1=Yang |first1=Xiaoyu |last2=Aguado |first2=M. Teresa |last3=Helm |first3=Conrad |last4=Zhang |first4=Zhiqian |last5=Bleidorn |first5=Christoph |title=New fossil of Gaoloufangchaeta advances the origin of Errantia (Annelida) to the early Cambrian |journal=Royal Society Open Science |date=April 2024 |volume=11 |issue=4 |doi=10.1098/rsos.231580 |doi-access=free|pmid=38601033 |language=en |issn=2054-5703|pmc=11004674 }}</ref> | image = Nereis virens.jpg | image_caption = ''[[Alitta virens]]'' | taxon = Errantia | authority = Audouin & H Milne Edwards 1832 | subdivision_ranks = Orders | subdivision_ref = <ref name="Handbook Zoology Annelida 1"/><ref name="AnnelidCurrent"/> | subdivision = *[[Aciculata]] **[[Eunicida]] **[[Phyllodocida]] *[[Protodriliformia]] **[[Polygordiidae]] **[[Protodrilida]] }}
'''Errantia''' is a diverse group of [[marine life|marine]] [[polychaete]] worms in the phylum [[Annelida]]. Traditionally a [[subclass (biology)|subclass]] of the [[paraphyletic]] class [[Polychaeta]],<ref>{{Cite web |url=http://www.eol.org/pages/85 |title=Encyclopedia of Life |access-date=2011-06-25 |archive-url=https://web.archive.org/web/20101115153944/http://www.eol.org/pages/85 |archive-date=2010-11-15 |url-status=dead }}</ref> it is currently regarded as a [[monophyletic]] group within the larger [[Pleistoannelida]], composed of Errantia and [[Sedentaria]].<ref name="Handbook Zoology Annelida 1"/> These worms are found worldwide in marine environments and brackish water.
==Phylogeny== The [[phylogeny]] of [[polychaete]]s is slowly being resolved. Errantia and [[Sedentaria]] are the two biggest [[clade]]s of polychaetes, and together they compose clade [[Pleistoannelida]].<ref name="Two adaptive routes Annelida"/> Two groups are nested within Errantia: [[Aciculata]] ([[Eunicida]] + [[Phyllodocida]]) and [[Protodriliformia]] ([[progenesis|small]] meiofaunal worms such as the [[Protodrilida]]).<ref name="Articulating Archiannelids"/><ref name="AnnelidCurrent"/><ref name="Handbook Zoology Annelida 1"/>
Historically, the order [[Amphinomida]] was part of this subclass. However, [[phylogenetic analyses]] place [[Amphinomida]] inside a basal clade with [[Sipunculida]] and ''[[Lobatocerebrum]]'', and this clade is the [[sister group]] to [[Pleistoannelida]].<ref name="AnnelidCurrent"/> {{clade|style=font-size:90%;|1={{clade|1=[[Amphinomida]]|2={{clade|1=''[[Lobatocerebrum]]''|2=[[Sipunculida]]}}}}|label2=[[Pleistoannelida]]|2={{clade|label1='''Errantia'''|1={{clade|label1=[[Aciculata]]|1={{clade|1=[[Eunicida]]|2=[[Phyllodocida]]}}|label2=[[Protodriliformia]]|2={{clade|1=[[Protodrilida]]|2=[[Polygordiidae]]}}}}|2=[[Sedentaria]]}}}} Some [[taxon|taxa]], such as [[Spintheridae]] and [[Myzostomida]], are still difficult to place due to their long branching, but they likely belong to either Errantia or [[Sedentaria]].<ref name="AnnelidCurrent"/>
==Classification== ===Historical=== Errantia is, along with [[Sedentaria]], one of the two old orders of the [[paraphyletic]] class "[[Polychaeta]]". In 1977 the zoologist Kristian Fauchald split Errantia into three orders: [[Phyllodocida]], [[Amphinomida]] and [[Eunicida]], giving way to this classification.<ref name="Fauchald Polychaetes"/> *Order [[Amphinomida]] – 2 families ([[Amphinomidae]], [[Euphrosinidae]]) *Order [[Eunicida]] **Superfamily Eunicea – 7 families ([[Onuphidae]], [[Eunicidae]], [[Lumbrineridae]], [[Iphitimidae]], [[Arabellidae]], [[Lysaretidae]], [[Dorvilleidae]]) **Superfamily incertae sedis – 2 families ([[Histriobdellidae]], [[Ichthytomidae]]) *Order [[Phyllodocida]] **Suborder [[Phyllodociformia]] – 4 families ([[Phyllodocidae]], [[Alciopidae]], [[Lopadorrhynchidae]], [[Pontodoridae]]) **Suborder [[Aphroditiformia]] ***Superfamily [[Aphroditacea]] – 6 families ([[Aphroditidae]], [[Polynoidae]], [[Polyodontidae]], [[Pholoididae]], [[Eulepethidae]], [[Sigalionidae]]) ***Superfamily [[Chrysopetalacea]] – 2 families ([[Chrysopetalidae]], [[Palmyridae]]) ***Superfamily [[Pisionacea]] – 1 family ([[Pisionidae]]) **Suborder [[Nereidiformia]] – 6 families ([[Hesionidae]], [[Pilargiidae]], [[Syllidae]], [[Calamyzidae]], [[Nereididae]], [[Antonbmunidae]]) **Suborder [[Glyceriformia]] – 3 families ([[Glyceridae]], [[Goniadidae]], [[Lacydoniidae]]) **Suborder incertae sedis – 5 families ([[Iospilidae]], [[Nephtyidae]], [[Sphaerodoridae]], [[Tomopteridae]], [[Typhloscolecidae]])
==References== {{Reflist|refs=
<ref name="Two adaptive routes Annelida">{{cite journal|vauthors=Struck TH, Golombek A, Weigert A, Franke FA, Westheide W, Purschke G, Bleidorn C, Halanych KM|title=The evolution of annelids reveals two adaptive routes to the interstitial realm|journal=Curr Biol|date=3 August 2015|volume=25|issue=15|pages=1993–1999|doi=10.1016/j.cub.2015.06.007|pmid=26212885|doi-access=free|bibcode=2015CBio...25.1993S }}</ref>
<ref name="Articulating Archiannelids">{{cite journal|first1=Sónia C.S.|last1=Andrade|first2=Marta|last2=Novo|first3=Gisele Y.|last3=Kawauchi|first4=Katrine|last4=Worsaae|first5=Fredrik|last5=Pleijel|first6=Gonzalo|last6=Giribet|first7=Greg W.|last7=Rouse|title=Articulating "Archiannelids": Phylogenomics and Annelid Relationships, with Emphasis on Meiofaunal Taxa|journal=Molecular Biology and Evolution|volume=32|issue=11|date=November 2015|pages=2860–2875|doi=10.1093/molbev/msv157|doi-access=free|pmid=26205969 }}</ref>
<ref name="Handbook Zoology Annelida 1">{{cite book|chapter=Phylogeny|vauthors=Struck TH|doi=10.1515/9783110291582-002|title=Handbook of Zoology: Annelida|volume=1: Annelida Basal Groups and Pleistoannelida, Sedentaria I|veditors=Purschke G, Böggemann M, Westheide W|isbn=9783110291469|publisher=De Gruyter|date=2019|pages=37–68 }}</ref>
<ref name="AnnelidCurrent">{{cite journal|vauthors=Weigert A, Bleidorn C|title=Current status of annelid phylogeny|journal=Org Divers Evol|volume=16|pages=345–362|date=2016|issue=2 |doi=10.1007/s13127-016-0265-7}}</ref>
<ref name="Fauchald Polychaetes">{{citation|last1=Fauchald|first1=Kristian|date=3 February 1977|title=The polychaete worms, definitions and keys to the orders, families and genera|publisher=Natural History Museum of Los Angeles County: Los Angeles, CA (USA)|series=Science Series|volume=28|pages=1–188|url=http://www.vliz.be/imisdocs/publications/123110.pdf}}</ref>
}}
{{Taxonbar|from1=Q6759542|from2=Q2823177}}
[[Category:Errantia| ]] [[Category:Protostome subclasses]]