''Hydrodamalis'' is a genus of extinct

herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

sirenia The Sirenia (), commonly referred to as sea-cows or sirenians, are an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters. The Sirenia currently comprise two distinct f ...

marine mammal Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They are an informal group, unified only by their reli ...

s, and included the

Steller's sea cow Steller's sea cow (''Hydrodamalis gigas'') is an extinct sirenian described by Georg Wilhelm Steller in 1741. At that time, it was found only around the Commander Islands in the Bering Sea between Alaska and Russia; its range extended across ...

(''Hydrodamalis gigas''), the

Cuesta sea cow The Cuesta sea cow (''Hydrodamalis cuestae'') is an extinct herbivorous marine mammal and is the direct ancestor of the Steller's sea cow (''Hydrodamalis gigas''). They reached up to in length, making them among the biggest sirenians to have ev ...

(''Hydrodamalis cuestae''), and the Takikawa sea cow (''Hydrodamalis spissa''). The fossil genus ''

Dusisiren ''Dusisiren'' is an extinct genus of dugong related to the Steller's sea cow that lived in the North Pacific during the Neogene. Paleobiology ''Dusisiren'' is a sirenian exemplar of the evolutionary theory of punctuated equilibrium. It evolved ...

'' is regarded as the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

of ''Hydrodamalis'': together, the two genera form the

dugong The dugong (; ''Dugong dugon'') is a marine mammal. It is one of four living species of the order Sirenia, which also includes three species of manatees. It is the only living representative of the once-diverse family Dugongidae; its closest m ...

subfamily

Hydrodamalinae Hydrodamalinae is a recently extinct subfamily of the sirenian family Dugongidae. The Steller's sea cow (''Hydrodamalis gigas'') was hunted to extinction by 1768, while the genus ''Dusisiren'' is known from fossils dating from the middle Miocen ...

. They were the largest member of the order Sirenia, whose only

extant Extant is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Extant taxon, a taxon which is not extinct, ...

members are the

(''Dugong dugon'') and the

manatee Manatees (family Trichechidae, genus ''Trichechus'') are large, fully aquatic, mostly herbivorous marine mammals sometimes known as sea cows. There are three accepted living species of Trichechidae, representing three of the four living species ...

s (''Trichechus'' spp.). They reached up to in length, making the Steller's sea cow among the largest mammals other than

whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

s to have existed in the

Holocene epoch The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

. Steller's sea cow was first described by

Georg Wilhelm Steller Georg Wilhelm Steller (10 March 1709 – 14 November 1746) was a German botanist, zoologist, physician and explorer, who worked in Russia and is considered a pioneer of Alaskan natural history.Evans, Howard Ensign. Edward Osborne Wilson (col.) ...

, Cuesta by

Daryl Domning Darryl is an English name, a variant spelling of Darell (disambiguation), Darell. Male variations of this name include: Darlin, Daryl, Darrell, Darryl, Daryll, Darryll, Darrell, Darrel. Female and unisex variations of this name include: Daryl ...

, and Takikawa by Hitoshi Furusawa. 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 The Commander Islands, Komandorski Islands, or Komandorskie Islands (russian: Командо́рские острова́, ''Komandorskiye ostrova'') are a series of treeless, sparsely populated Russian islands in the Bering Sea located about ea ...

. 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. The Cuesta sea cow along with the Takikawa sea cow were probably extinct at the end of the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Ice Ages An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

and the subsequent recession of seagrasses—their main food source. Cladogram on the relations of the hydrodamalines based on a 2004 study by Hitoshi Furuwasha

References

{{Taxonbar, from=Q1056723 Mammal genera Taxa named by Anders Jahan Retzius Holocene extinctions