Hydrodamalis

{{Short description|Extinct family of mammals}}

{{Automatic taxobox

| fossil_range = late Pliocene to Holocene, {{Fossil range|3.6|0.000257}}

| image = Hydrodamalis gigas skeleton - Finnish Museum of Natural History - DSC04529.JPG

| image_caption = Skeleton of Steller's sea cow (Hydrodamalis gigas) at the Finnish Museum of Natural History

| taxon = Hydrodamalis

| authority = Retzius, 1794

| type_species = {{extinct}}Hydrodamalis stelleri

| type_species_authority = Retzius, 1794

| synonyms = {{collapsible list|

• †Dystomus von Waldheim, 1813
• †Haligyna Billberg, 1827
• †Manati Steller, 1774
• †Nepus von Waldheim, 1814
• †Rhytina Berthold, 1827
• †Rhytine Burmeister, 1837
• †Rytina Illiger, 1811
• †Sirene Link, 1794
• †Stellerus Desmarest, 1822

}}

| synonyms_ref = {{cite web|url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=36885|title=Hydrodamalis|publisher=Fossilwork.org|access-date=17 December 2021|archive-date=12 December 2021|archive-url=https://web.archive.org/web/20211212191129/http://www.fossilworks.org/cgi-bin/bridge.pl?a=taxonInfo&taxon_no=36885|url-status=live}}

| subdivision_ranks = Species

| subdivision = †Hydrodamalis gigas
(Zimmermann, 1780)

†Hydrodamalis cuestae
Domning, 1978

†?Hydrodamalis spissa
Furusawa, 1988

}}

Hydrodamalis is a genus of extinct herbivorous sirenian marine mammals. It included the Steller's sea cow (Hydrodamalis gigas), the Cuesta sea cow (Hydrodamalis cuestae), and the Takikawa sea cow (Hydrodamalis spissa). The fossil genus Dusisiren is regarded as the sister taxon of Hydrodamalis: together, the two genera form the dugong subfamily Hydrodamalinae. They were the largest member of the order Sirenia, whose only extant members are the dugong (Dugong dugon) and the manatees (Trichechus spp.). They reached up to {{convert|9|m|ft}} in length, making the Steller's sea cow among the largest mammals other than whales to have existed in the Holocene epoch.{{cite book|chapter-url={{Google books|plainurl=yes|id=7pQgAwAAQBAJ|page=front}}|first1=Helene|last1=Marsh|first2=Thomas J.|last2=O'Shea|first3=John E. |last3=Reynolds III|year=2011|title=Ecology and Conservation of the Sirenia: Dugongs and Manatees|chapter=Steller's sea cow: discovery, biology and exploitation of a relict giant sirenian|publisher=Cambridge University Press |location=New York|pages=18–35|isbn=978-0-521-88828-8}} Steller's sea cow was first described by Georg Wilhelm Steller,{{Cite book| last=Steller| first=Georg W.| author-link=Georg Wilhelm Steller|editor-first=Paul|editor-last=Royster| title =De Bestiis Marinis|year=2011|orig-year=1751| publisher = University of Nebraska|location=Lincoln|isbn=978-1-295-08525-5|pages=13–43|chapter=The Manatee|chapter-url={{Google books|plainurl=yes|id=r0NTAgAAQBAJ|page=13}}}}

Cuesta by Daryl Domning,{{cite journal| first=Daryl P.|last=Domning|year=1978|title=An Ecological Model for Late Tertiary Sirenian Evolution in the North Pacific Ocean|journal=Systematic Zoology|volume=25|number=4|pages=352–362|jstor=2412510|doi=10.2307/2412510|s2cid=88362556 }} and Takikawa by Hitoshi Furusawa.{{cite book|last=Furusawa|first=H.|year=1988|title=A new species of hydrodamaline Sirenia from Hokkaido, Japan|publisher= Takikawa Museum of Art and Natural History|pages=1–73}} The Steller's sea cow was the only member of the genus to survive into modern times, and, although had formerly been abundant throughout the North Pacific, by the mid 1700s, its range had been limited to a single, isolated population surrounding the uninhabited Commander Islands. It was hunted for its meat, skin, and fat by fur traders, and was also hunted by aboriginals of the North Pacific coast, leading to its and the genus' extinction 27 years after discovery.{{cite journal |last=Jones|first=Ryan T. |title=A 'Havock Made among Them': Animals, Empire, and Extinction in the Russian North Pacific, 1741–1810 |journal=Environmental History |volume=16 |issue=4 |date=September 2011 |pages=585–609 |doi=10.1093/envhis/emr091 |jstor=23049853}} The Cuesta sea cow along with the Takikawa sea cow were probably extinct at the end of the Pliocene due to the onset of the Ice Ages and the subsequent recession of seagrasses—their main food source.

{{clade|style=font-size:100%;line-height:100%

|label1=Sirenia

|1={{clade

|1={{clade

|label1={{font color|white|......}}Dugongidae

|1={{clade

|1={{clade

|label1=†Halitherium

|1={{clade

|1=†H. schinzii

|2=†H. alleni

}}

|2={{clade

|1={{clade

|label1=†Dusisiren

|1={{clade

|1=†D. jordani

|2=†D. reinharti

|3=†D. dewana

|4=†D. takasatensis

}}

}}

|3={{clade

|label1=†Hydrodamalis

|1={{clade

|1=†H. gigas

|2={{clade

|1=†H. cuestae

|2=†H. spissa

}}

}}

}}

}}

}}

|2={{clade

|label1=Dugong

|1={{clade

|1=Dugong dugon

}}

}}

}}

}}

|2={{clade

|1={{clade

|label1=Trichechidae

|1={{clade

|label1={{font color|white|.....}}Trichechus

|1={{clade

|1=Trichechus inunguis

|2=Trichechus manatus

|3=Trichechus senegalensis

}}

}}

}}

}}

}}

}}

Cladogram on the relations of the hydrodamalines based on a 2004 study by Hitoshi Furuwasha {{cite journal|first=Hitoshi|last=Furusawa|year=2004|title=A phylogeny of the North Pacific Sirenia (Dugongidae: Hydrodamalinae) based on a comparative study of endocranial casts|journal=Paleontological Research|volume=8|number=2|pages=91–98|doi=10.2517/prpsj.8.91|doi-access=free}}