Editing Octopus (section)

===Fossil history and phylogeny===
[[File:Muensterella_scutellaris_348.jpg|thumb|The octopuses evolved from the [[Muensterelloidea]] (fossil pictured) in the [[Jurassic]] period.<ref name="Fuchs Iba 2019"/>|alt=Fossil of crown group coleoid on a slab of Jurassic rock from Germany]]

The Cephalopoda descended from a mollusc resembling the [[Monoplacophora]] in the [[Cambrian]] some 530 million years ago. The Coleoidea, which brought their shells inside the body, diverged from the [[Nautiloid|nautiloids]] in the [[Devonian]] some 416 million years ago. Around 276 million years ago, during the [[Permian]], the coleoids split into two groups, the [[Octopodiformes|Vampyropoda]] and the [[Squid|Decabrachia]].<ref name="Kröger 2011">{{cite journal |last1=Kröger |first1=Björn |last2=Vinther |first2=Jakob |last3=Fuchs |first3=Dirk |title=Cephalopod origin and evolution: A congruent picture emerging from fossils, development and molecules |journal=BioEssays |volume=33 |issue=8 |year=2011 |pages=602–613 |issn=0265-9247 |doi=10.1002/bies.201100001|pmid=21681989 |s2cid=2767810 }}</ref> The octopuses arose from the [[Muensterelloidea]] within the Vampyropoda in the [[Jurassic]]. The earliest octopus likely lived near the sea floor ([[Benthic zone|benthic]] to [[Demersal zone|demersal]]) in shallow marine environments.<ref name="Kröger 2011"/><ref name="Fuchs Schweigert 2018">{{Cite journal |last1=Fuchs |first1=Dirk |last2=Schweigert |first2=Günter |year=2018 |title=First Middle–Late Jurassic gladius vestiges provide new evidence on the detailed origin of incirrate and cirrate octopuses (Coleoidea) |journal=PalZ |volume=92 |issue=2 |pages=203–217 |doi=10.1007/s12542-017-0399-8 |bibcode=2018PalZ...92..203F |s2cid=135245479 |issn=0031-0220}}</ref><ref name="Fuchs Iba 2019">{{cite journal |last1=Fuchs |first1=Dirk |last2=Iba |first2=Yasuhiro |last3=Heyng |first3=Alexander |last4=Iijima |first4=Masaya |last5=Klug |first5=Christian |last6=Larson |first6=Neal L. |last7=Schweigert |first7=Günter |last8=Brayard |first8=Arnaud |title=The Muensterelloidea: phylogeny and character evolution of Mesozoic stem octopods |journal=Papers in Palaeontology |volume=6 |issue=1 |year=2019 |pages=31–92 |issn=2056-2802 |doi=10.1002/spp2.1254|s2cid=198256507 }}</ref> Octopuses consist mostly of soft tissue, and so fossils are relatively rare. As soft-bodied cephalopods, they lack the external shell of most molluscs, including other cephalopods like the nautiloids and the (extinct) [[Ammonoidea]].<ref name="CephGroup">{{cite web |title=A Broad Brush History of the Cephalopoda |url=http://www.thecephalopodpage.org/evolution.php |publisher=The Cephalopod Group |access-date=27 March 2017 |archive-date=16 July 2018 |archive-url=https://web.archive.org/web/20180716165558/http://www.thecephalopodpage.org/evolution.php |url-status=dead }}</ref> They have eight limbs like other [[Coleoidea]], but lack the extra specialised feeding appendages known as [[tentacle]]s which are longer and thinner with suckers only at their club-like ends.<ref>{{cite web |last1=Young |first1=R. E. |first2=M. |last2=Vecchione |first3=K. M. |last3=Mangold |year=1999 |url=http://tolweb.org/accessory/Cephalopoda_Glossary?acc_id=587 |title=Cephalopoda Glossary |publisher=Tree of Life web project |access-date=30 May 2017}}</ref><ref>{{cite journal|last1=Nödl|first1=M-T|last2=Fossati|first2=S. M.|last3=Domingues|first3=P|last4=Sánchez|first4=F. J.|last5=Zullo|first5=L|year=2015|title=The making of an octopus arm|journal=EvoDevo|volume=6|page=19|doi=10.1186/s13227-015-0012-8|doi-access=free |pmid=26052417 |pmc=4458049 }}</ref> The vampire squid (''[[Vampyroteuthis]]'') also lacks tentacles but has sensory filaments.<ref>{{cite web |last=Seibel |first=B. |title=''Vampyroteuthis infernalis'', Deep-sea Vampire squid |publisher=The Cephalopod Page |url=http://www.thecephalopodpage.org/vampy.php |access-date=31 May 2017 |archive-date=16 July 2018 |archive-url=https://web.archive.org/web/20180716165547/http://www.thecephalopodpage.org/vampy.php |url-status=dead }}</ref>

The [[cladogram]]s are based on Sanchez et al., 2018, who created a [[molecular phylogeny]] based on [[mitochondria]]l and [[nuclear DNA]] marker sequences.<ref name="Sanchez et al, 2018">{{cite journal |last1=Sanchez |first1=Gustavo |last2=Setiamarga |first2=Davin H. E. |last3=Tuanapaya |first3=Surangkana |last4=Tongtherm |first4=Kittichai |last5=Winkelmann |first5=Inger E. |last6=Schmidbaur |first6=Hannah |last7=Umino |first7=Tetsuya |last8=Albertin |first8=Caroline |last9=Allcock |first9=Louise |last10=Perales-Raya |first10=Catalina |last11=Gleadall |first11=Ian |last12=Strugnell |first12=Jan M. |last13=Simakov |first13=Oleg |last14=Nabhitabhata |first14=Jaruwat |title=Genus-level phylogeny of cephalopods using molecular markers: current status and problematic areas |journal=PeerJ  |volume=6 |year=2018 |doi=10.7717/peerj.4331 |pmid=29456885 |pmc=5813590 |page=e4331 |doi-access=free }}</ref> The position of the Eledonidae is from Ibáñez et al., 2020, with a similar methodology.<ref name="Ibáñez Fenwick 2020">{{cite journal |last1=Ibáñez |first1=Christian M. |last2=Fenwick |first2=Mark |last3=Ritchie |first3=Peter A. |last4=Carrasco |first4=Sergio A. |last5=Pardo-Gandarillas |first5=M. Cecilia |title=Systematics and Phylogenetic Relationships of New Zealand Benthic Octopuses (Cephalopoda: Octopodoidea) |journal=Frontiers in Marine Science |volume=7 |year=2020 |page=182 |issn=2296-7745 |doi=10.3389/fmars.2020.00182|doi-access=free |bibcode=2020FrMaS...7..182I }}</ref> Divergence dates are from Kröger et al., 2011 and Fuchs et al., 2019.<ref name="Kröger 2011"/><ref name="Fuchs Iba 2019"/>

{{clade
|label1=[[Cephalopods]]|sublabel1=530 mya<!--<ref name="Kröger 2011"/>-->
|1={{clade
   |label1=[[Nautiloid]]s
   |1=''[[Nautilus (genus)|Nautilus]]'' [[File:Nautilus belauensis profile (white background).jpg|70px|alt=A spiral nautilus in a blue sea]]
   |label2=[[Coleoidea|Coleoids]]|sublabel2=416 mya<!--<ref name="Kröger 2011"/>-->
   |2={{clade
      |label1=[[Decabrachia]] 
      |1=[[Squid|Squids and cuttlefish]] [[File:Berryteuthis_magister.jpg|70px|alt=A squid]]
      |label2=Vampyropoda|sublabel2=276 mya<!--<ref name="Kröger 2011"/>--> 
      |2={{clade
         |label1=[[Vampyromorphida]] 
         |1=[[File:Vampyroteuthis_infernalis.jpg|90px|alt=A strange blood-red octopus, its arms joined by a web]]
         |label2='''Octopods'''|sublabel2=155 mya
         |2=[[File:Octopus vulgaris Merculiano.jpg|70px|alt=A brown octopus with wriggly arms]]
         }}
      }}
   }}
}}

The molecular analysis of the octopods shows that the suborder Cirrina (Cirromorphida) and the superfamily Argonautoidea are [[paraphyletic]] and are broken up; these names are shown in quotation marks and italics on the cladogram.

{{clade
|label1='''Octopoda'''
|1={{clade
   |label1="''[[Cirrina|Cirromorphida]]''" part
   |1={{clade
      |1=[[Cirroteuthidae]] [[File:CirrothaumaMurDraw2.jpg|40px]]
      |2=[[Stauroteuthidae]] [[File:Stauroteuthis syrtensis (main).jpg|65px]]
      }}
   |2={{clade
      |label1="''[[Cirrina|Cirromorphida]]''" part
      |1={{clade
         |1=[[Opisthoteuthidae]] [[File:Opisthoteuthis californiana (white background).jpg|45px]]
         |2=[[Cirroctopodidae]] [[File:Cirroctopus mawsoni Vent.jpg|45px]]
         }}
      |label2=[[Octopoda|Octopodida]]
      |2={{clade
         |label1="''[[Argonautoidea]]''" part
         |1={{clade
            |1=[[Tremoctopodidae]] [[File:Pelagic octopus Tremoctopus.jpg|45px]]
            |2=[[Alloposidae]] [[File:Haliphron atlanticus (70 mm ML).jpg|60px]]
            }}
         |2={{clade
            |1={{clade
               |label1="''[[Argonautoidea]]''" part
               |1={{clade
                  |1=[[Argonautidae]] [[File:Argonauta_argo_Merculiano.jpg|55px]]
                  |2=[[Ocythoidae]] [[File:Ocythoe tuberculata (Merculiano).jpg|50px]]
                  }}
               |label2=[[Octopodoidea]]
               |2={{clade
                  |1=[[Eledonidae]] [[File:Eledone cirrhosa1.jpg|75px]]
                  |2={{clade
                     |1=[[Bathypolypodidae]] [[File:Bathypolypus valdiviae.jpg|75px]]
                     |2={{clade
                        |1=[[Enteroctopodidae]] [[File:E zealandicus (white background).jpg|55px]]
                        |2={{clade
                           |1=[[Octopodidae]] [[File:Octopus vulgaris Merculiano.jpg|55px]]
                           |2=[[Megaleledonidae]] [[File:Graneledone boreopacifica (white background).jpg|55px]]
                           }}
                        }}
                     }}
                  }}
               }}
            |2={{clade
               |1=[[Bolitaenidae]] [[File:Eledonella pygmaea.jpg|75px]]
               |2={{clade
                  |1=[[Amphitretidae]] [[File:Amphitretus pelagicus.jpg|70px]]
                  |2=[[Vitreledonellidae]] [[File:Vitreledonella richardi (white background).jpg|50px]]
                  }}
               }}
            }}
         }}
      }}
   }}
}}