Editing Steller's sea cow (section)

===Phylogeny===
{{Multiple image|image1=Dugong dugon.jpg|image2=Dugong Marsa Alam PLW edit.jpg|alt1=A gray dugong swimming in the water: The underside is visible, and it has large limbs behind the head, pointed down. They are triangular in shape, similar to a dolphin fin. It has a thin body compared to the head, and a forked tail fluke like that of a dolphin. It has a small eye.|alt2=A gray dugong bottom feeding, with plumes of sand trailing from it mouth. It is resting its hands on the ground. Small sprouts of seagrasses litter on the ground, and yellow fish with black stripes are hovering around its snout. The snout has two large nostrils, and the mouth is on the ground.|direction=vertical|align=left|footer=The closely related [[dugong]]}}

Steller's sea cow was a member of the [[genus (biology)|genus]] ''[[Hydrodamalis]]'', a group of large sirenians, whose sister taxon was ''[[Dusisiren]]''. Like those of Steller's sea cow, the ancestors of ''Dusisiren'' lived in tropical [[mangrove]]s before adapting to the cold climates of the [[Pacific Ocean|North Pacific]].<ref>{{cite book |last=Domning |first=D. P. |year=1978 |title=Sirenian evolution in the North Pacific Ocean |publisher=University of California Publications in Geological Sciences |location=Berkeley, California |isbn=978-0-520-09581-6 |oclc=895212825 |volume=118 |pages=1–176}}</ref> ''Hydrodamalis'' and ''Dusisiren'' are classified together in the [[family (biology)|subfamily]] [[Hydrodamalinae]],<ref>{{fossilworks|id=53133|title=Hydrodamalinae|date=12 March 2017}}</ref> which diverged from other sirenians around 4 to 8 [[mya (unit)|mya]].<ref>{{cite journal |last1=Rainey |first1=W. E. |last2=Lowenstein |first2=J. M. |last3=Sarich |first3=V. M. |last4=Magor |first4=D. M. |year=1984 |title=Sirenian molecular systematics—including the extinct Steller's sea cow (''Hydrodamalis gigas'') |journal=[[Naturwissenschaften]] |doi=10.1007/BF01189187 |pmid=6521758 |volume=71 |issue=11 |pages=586–588|bibcode=1984NW.....71..586R |s2cid=28213762 }}</ref> Steller's sea cow is a member of the family [[Dugongidae]], the sole surviving member of which, and thus Steller's sea cow's closest living relative is the [[dugong]] (''Dugong dugon'').<ref>{{cite book |last=Marsh |first=Helene |title=Fauna of Australia |chapter=Chapter 57: Dugongidae |publisher=[[CSIRO]] |location=Canberra, Australia |isbn=978-0-644-06056-1 |oclc=27492815 |volume=1B |chapter-url=http://www.environment.gov.au/biodiversity/abrs/publications/fauna-of-australia/pubs/volume1b/57-ind.pdf  |archive-url=https://web.archive.org/web/20130511221756/http://www.environment.gov.au/biodiversity/abrs/publications/fauna-of-australia/pubs/volume1b/57-ind.pdf |archive-date=2013-05-11 |year=1989 }}</ref>

Steller's sea cow was a direct descendant of the [[Cuesta sea cow]] (''H. cuestae''),<ref name=marsh2011/> an extinct tropical sea cow that lived off the coast of western North America, particularly California. The Cuesta sea cow is thought to have become extinct due to the onset of the [[Quaternary glaciation]] and the subsequent cooling of the oceans. Many populations died out, but the lineage of Steller's sea cow was able to adapt to the colder temperatures.<ref name=domning>{{cite journal |last=Domning |first=Daryl P. |year=1978 |title=An Ecological Model for Late Tertiary Sirenian Evolution in the North Pacific Ocean |journal=[[Systematic Biology|Systematic Zoology]] |jstor=2412510 |volume=25 |number=4 |pages=352–362 |doi=10.2307/2412510 }}</ref> The [[Takikawa sea cow]] (''H. spissa'') of Japan is thought of by some researchers to be a [[taxonomic synonym]] of the Cuesta sea cow, but based on a comparison of [[endocast]]s, the Takikawa and Steller's sea cows are more [[synapomorphy|derived]] than the Cuesta sea cow. This has led some to believe that the Takikawa sea cow is its own species.<ref name=furusawa2004/> The evolution of the genus ''Hydrodamalis'' was characterized by increased size, and a loss of teeth and [[phalanx bone|phalanges]], as a response to the onset of the Quaternary glaciation.<ref name=domning/><ref name=forsten/>

{{align|left|
Based on a 2015 study by Mark Springer:<ref>{{cite journal |last1=Springer |first1=M. |last2=Signore |first2=A. V. |last3=Paijmans |first3=J. L. A. |last4=Vélez-Juarbe |first4=J. |last5=Domning |first5=D. P. |last6=Bauer |first6=C. E. |last7=He |first7=K. |last8=Crerar |first8=L. |last9=Campos |first9=P. F. |last10=Murphy |first10=W. J. |last11=Meredith |first11=R. W. |last12=Gatesy |first12=J. |last13=Willerslev |first13=E. |last14=MacPhee |first14=R. D. |last15=Hofreiter |first15=M. |last16=Campbell |first16=K. L. |year=2015 |title=Interordinal gene capture, the phylogenetic position of Steller's sea cow based on molecular and morphological data, and the macroevolutionary history of Sirenia |journal=[[Molecular Phylogenetics and Evolution]] |doi=10.1016/j.ympev.2015.05.022 |pmid=26050523 |volume=91 |issue=10 |pages=178–193|doi-access=free |bibcode=2015MolPE..91..178S }}</ref>
{{clade|style=font-size:90%;line-height:100%;width:100%
|label1=[[Sirenia]]
|1={{clade
|1={{clade
|1={{clade
|1=†''[[Anomotherium|Anomotherium langewieschei]]''
|2=†''[[Miosiren|Miosiren kocki]]''
}}
|2={{clade
|1=[[Amazonian manatee|''Trichechus inunguis'']]
|2={{clade
|1=[[West Indian manatee|''Trichechus manatus'']]
|2=[[African manatee|''Trichechus senegalensis'']]
}}
}}
}}
|2={{clade
|1=†''[[Eotheroides|Eotheroides aegyptiacum]]''
|2={{clade
|1=†''[[Halitherium|Halitherium schinzii]]''
|2={{clade
|1=†''[[Priscosiren atlantica]]''
|2={{clade
|1=[[Dugong|''Dugong dugon'']]
}}
|3={{clade
|1=†''[[Metaxytherium|Metaxytherium krahuletzi]]''
|2={{clade
|1=†''[[Metaxytherium|Metaxytherium serresii]]''
|2=†''[[Metaxytherium|Metaxytherium medium]]''
|3=†''[[Metaxytherium|Metaxytherium floridanum]]''
|4=†''[[Metaxytherium|Metaxytherium crataegense]]''
|5={{clade
|1=†''[[Metaxytherium|Metaxytherium arctodites]]''
|2={{clade
|1=†''[[Dusisiren|Dusisiren jordani]]''
|2={{clade
|1=†''[[Cuesta sea cow|Hydrodamalis cuestae]]''
|2='''†''Hydrodamalis gigas'''''
}}
}}
}}
}}
}}
}}
}}
}}
}}
}}
}}
{{align|right|
Based on a 2004 study by Hitoshi Furusawa:<ref name=furusawa2004>{{cite journal |last=Furusawa |first=Hitoshi |year=2004 |title=A phylogeny of the North Pacific Sirenia (Dugongidae: Hydrodamalinae) based on a comparative study of endocranial casts |journal=Paleontological Research |doi=10.2517/prpsj.8.91 |volume=8 |issue=2 |pages=91–98 |s2cid=83992432 |doi-access=free |bibcode=2004PalRe...8...91F }}</ref>
{{clade|style=font-size:90%;line-height:75%
|label1=[[Sirenia]]
|1={{clade
|1=†''[[Dusisiren|Dusisiren reinharti]]''
|2={{clade
|1=†''[[Dusisiren|Dusisiren jordani]]''
|2={{clade
|1=†''[[Dusisiren|Dusisiren dewana]]''
|2={{clade
|1=†''[[Dusisiren|Dusisiren takasatensis]]''
|2={{clade
|1=†''[[Cuesta sea cow|Hydrodamalis cuestae]]''
|2={{clade
|1=†''[[Takikawa sea cow|Hydrodamalis spissa]]''
|2={{clade
|1='''†''Hydrodamalis gigas'''''
}}
}}
}}
}}
}}
}}
}}
}}
}}
{{clear}}