Editing Eared seal (section)

==Evolution and taxonomy==

{{Cladogram|align=left|title=
|clade=
{{clade
|style=font-size:75%;line-height:75%;width:500px;
|label1=[[Pinnipedia]]
|1={{clade
   |1=[[Phocidae]]|sublabel1=(earless seals)
   |2={{clade
      |label1='''Otariidae'''|sublabel1=(eared seals)
      |1={{clade
         |1=[[Northern fur seal]]<!-- Callorhinus ursinus -->
         |2={{clade
            |label1=Otariinae
            |1={{clade
               |1=[[Steller sea lion]]<!-- Eumetopias jubatus -->
               |label2=''[[Zalophus]]''
               |2={{clade
                  |1=[[California sea lion]]<!-- Zalophus californianus -->
                  |2=[[Galápagos sea lion]]<!-- Zalophus wollebaeki -->
                  }}
               }}
            |2={{clade
               |1=[[South American sea lion]]<!-- Otaria flavescens (= O. byronia) -->
               |2={{clade
                  |1=[[Australian sea lion]]<!-- Neophoca cinerea -->
                  |2=[[New Zealand sea lion]]<!-- Phocarctos hookeri -->
                  }}
               |label3=''[[Arctocephalus]]''|sublabel3=(fur seals)
               |3={{clade<!--yes, tree in Fig. 5 is not fully resolved-->
                  |1={{clade
                     |1=[[Brown fur seal]]<!-- Arctocephalus pusillus -->
                     |2=[[Subantarctic fur seal]]<!-- Arctocephalus tropicalis -->
                     }}
                  |2={{clade
                     |1=[[Antarctic fur seal]]<!-- Arctocephalus gazella -->
                     |2={{clade
                        |1=[[Guadalupe fur seal]]<!-- Arctocephalus townsendi -->
                        |2=[[Juan Fernández fur seal]]<!-- Arctocephalus philippii -->
                        }}
                     |3={{clade<!--yes, tree in Fig. 5 is not fully resolved here either-->
                        |1=[[Arctophoca forsteri|Antipodean fur seal]]<!--Arctocephalus forsteri-->
                        |2={{clade
                           |1=[[Galápagos fur seal]]<!-- Arctocephalus galapagoensis -->
                           |2=[[South American fur seal]]<!--Arctocephalus australis-->
                           }}
                        }}
                     }}
                  }}
               }}
            }}
         }}
      |label2=[[Odobenidae]]
      |2=&nbsp;[[Walrus]]
      }}
   }}
}}
|caption=[[Cladogram]] showing relationships among the otarids, combining several phylogenetic analyses. The fur seal tree is not fully resolved.<ref name="Berta Churchill Boessenecker 2018">{{cite journal | last1=Berta | first1=Annalisa | last2=Churchill | first2=Morgan | last3=Boessenecker | first3=Robert W. | title=The Origin and Evolutionary Biology of Pinnipeds: Seals, Sea Lions, and Walruses | journal=Annual Review of Earth and Planetary Sciences | publisher=Annual Reviews | volume=46 | issue=1 | date=2018-05-30 | issn=0084-6597 | doi=10.1146/annurev-earth-082517-010009 | pages=203–228| bibcode=2018AREPS..46..203B | s2cid=135439365 | doi-access=free }}</ref>
}}

Morphological and molecular evidence supports a [[Monophyly|monophyletic]] origin of pinnipeds, sharing a common ancestor with [[Musteloidea]],<ref>{{Cite journal |last1=Hassanin |first1=Alexandre |last2=Veron |first2=Géraldine |last3=Ropiquet |first3=Anne |last4=Vuuren |first4=Bettine Jansen van |last5=Lécu |first5=Alexis |last6=Goodman |first6=Steven M. |last7=Haider |first7=Jibran |last8=Nguyen |first8=Trung Thanh |date=2021-02-16 |title=Evolutionary history of Carnivora (Mammalia, Laurasiatheria) inferred from mitochondrial genomes |journal=PLOS ONE |language=en |volume=16 |issue=2 |pages=e0240770 |doi=10.1371/journal.pone.0240770 |issn=1932-6203 |pmc=7886153 |pmid=33591975|doi-access=free |bibcode=2021PLoSO..1640770H }}</ref><ref>{{Citation |last=Berta |first=Annalisa |title=Pinniped Evolution |date=2009 |url=http://dx.doi.org/10.1016/b978-0-12-373553-9.00199-1 |encyclopedia=Encyclopedia of Marine Mammals |pages=861–868 |publisher=Elsevier |doi=10.1016/b978-0-12-373553-9.00199-1 |isbn=9780123735539 |access-date=2022-07-04}}</ref> though an earlier hypothesis suggested that Otаriidae are descended from a [[Enaliarctos|common ancestor]] most closely related to modern [[bear]]s.<ref>{{cite journal |author1=Lento, G.M. |author2=Hickson, R.E. |author3=Chambers, G.K. |author4=Penny, D. | date=1 January 1995| title = Use of spectral analysis to test hypotheses on the origin of pinnipeds | journal = Molecular Biology and Evolution | volume = 12 | issue = 1 | pages = 28–52 | pmid = 7877495 | doi=10.1093/oxfordjournals.molbev.a040189| doi-access =  }}</ref> Debate remains as to whether the phocids diverged from the otariids before or after the walrus.

Otariids arose in the [[Miocene]] (15–17 million years ago) in the North Pacific, diversifying rapidly into the Southern Hemisphere, where most species now live. The earliest known fossil otariid is ''[[Eotaria crypta]]'' from southern California,<ref name=eotaria>{{Cite journal | doi = 10.1098/rsbl.2014.0835| pmid = 25672999| title = The oldest known fur seal| journal = Biology Letters| volume = 11| issue = 2| pages = 20140835| year = 2015| last1 = Boessenecker | first1 = R. W.| last2 = Churchill | first2 = M.| pmc = 4360102}}</ref> while the genus ''Callorhinus'' ([[northern fur seal]]) has the oldest fossil record of any living otariid, extending to the middle Pliocene. It probably arose from the extinct fur seal genus ''[[Thalassoleon]]''.

Traditionally, otariids had been subdivided into the fur seal (Arctocephalinae) and sea lion (Otariinae) subfamilies, with the major distinction between them being the presence of a thick underfur layer in the former. Under this categorization, the fur seals comprised two genera: ''Callorhinus'' in the North Pacific with a single representative, the northern fur seal (''C. ursinus''), and eight species in the Southern Hemisphere under the genus ''Arctocephalus''; while the sea lions comprise five species under five genera.<ref>{{cite book | author = J.E. King | year = 1983 | title = Seals of the World
| url = https://archive.org/details/sealsofworld0000king_b3o0 | url-access = registration | edition = 2nd | publisher = Cornell University Press | location = New York | isbn = 978-0-7022-1694-7}}</ref> Recent analyses of the [[molecular phylogeny|genetic evidence]] suggests that ''Callorhinus ursinus'' is in fact more closely related to several sea lion species.<ref>{{cite journal | year = 2001 | doi = 10.1006/mpev.2001.1012 | title = Phylogenetic relationships within the eared seals (Otariidae: Carnivora): implications for the historical biogeography of the family | journal = Mol. Phylogenet. Evol. | volume = 21 | pages = 270–284 | author = Wynen, L | pmid = 11697921 | last2 = Goldsworthy | first2 = SD | last3 = Insley | first3 = SJ | last4 = Adams | first4 = M | last5 = Bickham | first5 = JW | last6 = Francis | first6 = J | last7 = Gallo | first7 = JP | last8 = Hoelzel | first8 = AR | last9 = Majluf | first9 = P | last10 = White | first10 = Robert W.G. | last11 = Slade | first11 = Rob | issue = 2 | bibcode = 2001MolPE..21..270W | display-authors = 8 }}</ref> Furthermore, many of the Otariinae appear to be more [[phylogeny|phylogenetically]] distinct than previously assumed; for example, the [[Japanese sea lion]] (''Zalophus japonicus'') is now considered a separate species, rather than a subspecies of the [[California sea lion]] (''Zalophus californius'').

In light of this evidence, the subfamily separation has been removed entirely and the family Otariidae has been organized into seven genera with 16 species and two subspecies.<ref>{{cite journal | author = Brunner, S. | year = 2003 | url = http://journals.cambridge.org/action/displayAbstract?aid=198243 | title = Fur seals and sea lions (Otariidae): identification of species and taxonomic review | journal = Systematics and Biodiversity | volume = 1 | issue = 3 | pages = 339–439 | doi = 10.1017/S147720000300121X| s2cid = 86375627 }}</ref><ref>{{ITIS |id=180615 |taxon=Otariidae |access-date= }}</ref>
Nonetheless, because of morphological and behavioral similarities among the "fur seals" and "sea lions", these remain useful categories when discussing differences between groups of species. Compared to sea lions, fur seals are generally smaller, exhibit greater [[sexual dimorphism]], eat smaller prey and go on longer foraging trips; and, of course, there is the contrast between the coarse short sea lion hair and the fur seal's fur.