A viperfish is any species of marine fish in the genus ''Chauliodus''. Viperfishes are mostly found in the

mesopelagic zone The mesopelagic zone (Greek μέσον, middle), also known as the middle pelagic or twilight zone, is the part of the pelagic zone that lies between the photic epipelagic and the aphotic bathypelagic zones. It is defined by light, and begins ...

and are characterized by long, needle-like teeth and hinged lower jaws. A typical viperfish grows to lengths of . Viperfishes undergo

diel vertical migration Diel vertical migration (DVM), also known as diurnal vertical migration, is a pattern of movement used by some organisms, such as copepods, living in the ocean and in lakes. The word ''diel'' comes from the Latin ''dies'' day, and means a 24-h ...

and are found all around the world in tropical and temperate oceans. Viperfishes possess photophores along the ventral side of their body, likely used to camouflage them by blending in with the less than 1% of light that reaches to below 200 meters depth. Although it may appear to be covered in scales, viperfishes do not possess scales. Rather, they are covered by a thick, transparent coating of unknown substance. Extremely large, fang-like teeth give the fish a slightly protruded lower jaw.

Habitat

Viperfishes live in meso- and

bathypelagic The bathypelagic zone or bathyal zone (from Greek βαθύς (bathýs), deep) is the part of the open ocean that extends from a depth of below the ocean surface. It lies between the mesopelagic above, and the abyssopelagic below. The bathypelagic ...

environments where humans cannot easily make direct observations. Viperfishes engage in diel vertical migration, meaning they migrate up into more productive waters during the night to feed. However, it is likely that only part of the total population of viperfishes engages in diel vertical migration in any given night, which could be due to their slow metabolism, i.e. they likely do not have to feed every night.

Feeding

Viperfishes, depending on the species, prey on other pelagic fishes and crustaceans. Stomach contents of captured individuals have contained lanternfishes,

bristlemouth The Gonostomatidae are a family of mesopelagic marine fish, commonly named bristlemouths, lightfishes, or anglemouths. It is a relatively small family, containing only eight known genera and 32 species. However, bristlemouths make up for their l ...

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

s and krill.

Species

There are currently nine extant recognized species in this genus: * '' Chauliodus barbatus'' Garman, 1899 * ''

Chauliodus danae ''Chauliodus danae'', or dana viperfish, is a species of viperfish in the family Stomiidae. The Dana Viperfish is mostly found in the bathyal zone The bathypelagic zone or bathyal zone (from Greek βαθύς (bathýs), deep) is the part of the ...

Regan The family name Regan, along with its cognates O'Regan, O Regan, Reagan, and O'Reagan, is an Anglicized form of the Irish surname Ó Riagáin or Ó Ríogáin, from Ua Riagáin. The meaning is likely to have originated in ancient Gaelic ''ri'' ...

& Trewavas, 1929 (Dana viperfish) * '' Chauliodus dentatus'' Garman, 1899 * '' Chauliodus macouni'' T. H. Bean, 1890 (pacific viperfish) * '' Chauliodus minimus'' Parin & Novikova, 1974 * '' Chauliodus pammelas''

Alcock Alcock is a surname. Notable people with the surname include: Notable people with the surname Alcock * Alfred William Alcock, British naturalist * C. W. Alcock, British sports administrator and creator of the FA Cup * Charles R. Alcock, American ...

, 1892 * '' Chauliodus schmidti'' Ege, 1948 * ''

Chauliodus sloani Sloane's viperfish, ''Chauliodus sloani'', is a predatory mesopelagic dragonfish found in waters across the world. The species was first described by German scientists Marcus Elieser Bloch and Johann Gottlob Schneider in their 1801 book ''Systema ...

Bloch Bloch is a surname of German origin. Notable people with this surname include: A–F * (1859-1914), French rabbi *Adele Bloch-Bauer (1881-1925), Austrian entrepreneur *Albert Bloch (1882–1961), American painter * (born 1972), German motor journal ...

& J. G. Schneider, 1801 (Sloane's viperfish) * ''

Chauliodus vasnetzovi ''Chauliodus vasnetzovi'' is a species of viperfish in the family Stomiidae, first discovered in 1972. It is generally found in the Bathypelagic zone in the Southeast Pacific near Chile and can grow to be up to long. See also * Viperfish ...

'' Novikova, 1972 At least two more species are recognized from

Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million ye ...

-aged fossils: * '' Chauliodus eximus'', (Jordan, 1925), originally ''Eostomias eximus'', from Late Miocene California * '' Chauliodus testa'', Nazarkin, 2014, from the Late Miocene of Western

Sakhalin Island Sakhalin ( rus, Сахали́н, r=Sakhalín, p=səxɐˈlʲin; ja, 樺太 ''Karafuto''; zh, c=, p=Kùyèdǎo, s=库页岛, t=庫頁島; Manchu: ᠰᠠᡥᠠᠯᡳᠶᠠᠨ, ''Sahaliyan''; Orok: Бугата на̄, ''Bugata nā''; Nivkh: ...

References

{{Taxonbar, from=Q860394 Chauliodus Extant Miocene first appearances Taxa named by Marcus Elieser Bloch