Ophidiiformes is an order of

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

that includes the

cusk-eel The cusk-eel family, Ophidiidae, is a group of marine bony fishes in the Ophidiiformes order. The scientific name is from the Greek ''ophis'' meaning "snake", and refers to their eel-like appearance. True eels, however, diverged from other ray- ...

s (family

Ophidiidae The cusk-eel family, Ophidiidae, is a group of marine bony fishes in the Ophidiiformes order. The scientific name is from the Greek ''ophis'' meaning "snake", and refers to their eel-like appearance. True eels, however, diverged from other ray ...

pearlfish Pearlfish are marine fish in the ray-finned fish family Carapidae. Pearlfishes inhabit the tropical waters of the Atlantic, Indian, and Pacific Oceans at depths to , along oceanic shelves and slopes. They are slender, elongated fish with no ...

es (family

Carapidae Pearlfish are marine fish in the ray-finned fish family Carapidae. Pearlfishes inhabit the tropical waters of the Atlantic, Indian, and Pacific Oceans at depths to , along oceanic shelves and slopes. They are slender, elongated fish with no sca ...

viviparous brotula The viviparous brotulas form a family, the Bythitidae, of ophidiiform fishes. They are known as viviparous brotulas as they generally bear live young, although there are indications that some species (at least '' Didymothallus criniceps'') do no ...

s (family Bythitidae), and others. Members of this order have small heads and long slender bodies. They have either smooth scales or no scales, a long dorsal fin and an anal fin that typically runs into the caudal fin. They mostly come from the tropics and subtropics, and live in both freshwater and marine habitats, including abyssal depths. They have adopted a range of feeding methods and lifestyles, including

parasitism Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of lif ...

. The majority are egg-laying, but some are

viviparous Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the m ...

Distribution

This order includes a variety of deep-sea species, including the deepest known, ''

Abyssobrotula galatheae ''Abyssobrotula galatheae'' is a species of cusk eel in the family Ophidiidae. It is the deepest-living fish known; one specimen, trawled from a depth of in the Puerto Rico Trench in 1970, holds the record for the deepest fish ever captured. Alt ...

'', found at in the

Puerto Rico Trench The Puerto Rico Trench is located on the boundary between the Caribbean Sea and the Atlantic Ocean. The oceanic trench, the deepest in the Atlantic, is associated with a complex transition between the Lesser Antilles subduction zone to the sou ...

. Many other species, however, live in shallow water, especially near coral reefs, while a few inhabit freshwater. Most species live in tropical or subtropical habitats, but some species are known from as far north as the coast of Greenland, and as far south as the

Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha ...

Characteristics

Ophidiiform fish typically have slender bodies with small heads, and either smooth scales, or none at all. They have long

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

s, and an

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

that is typically united with the

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

. The group includes

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

, and even

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...

species, although all have a similar body form. Some species are

, giving birth to live young, rather than laying eggs. They range in size from '' Grammanoides opisthodon'' which measures just in length, to ''

Lamprogrammus shcherbachevi ''Lamprogrammus shcherbachevi'', the scaleline cusk, is a species of marine ray-finned fish in the family Ophidiidae. Description Attaining a maximum length of in males, this species is the largest among the cusk-eels. This species is character ...

'' at in length. The families

Ranicipitidae The Gadidae are a family of marine fish, included in the order Gadiformes, known as the cods, codfishes, or true cods. It contains several commercially important fishes, including the cod, haddock, whiting, and pollock. Most gadid species are ...

(

tadpole cod ''Guttigadus globosus'', the tadpole cod, is a deepwater fish found in the oceanic islands off New Zealand and in the mid South Atlantic at depths ranging from 1200 to 1600 m. The tadpole cod is a member of the family Moridae, the morid cods, re ...

s) and

Euclichthyidae The Eucla cod (''Euclichthys polynemus'') is a deepwater marine fish belonging to the cod order ( Gadiformes). It is the only species currently classified in the family Euclichthyidae. It is named after the town of Eucla, Western Australia, in ...

( eucla cods) were formerly classified in this order, but are now preferred in

Gadiformes Gadiformes are an order of ray-finned fish, also called the Anacanthini, that includes the cod. Many major food fish are in this order. They are found in marine waters throughout the world and the vast majority of the species are found in tempe ...

; Ranicipitidae has been absorbed within the family

Gadidae The Gadidae are a family of marine fish, included in the order Gadiformes, known as the cods, codfishes, or true cods. It contains several commercially important fishes, including the cod, haddock, whiting, and pollock. Most gadid species are ...

Timeline of genera

ImageSize = width:1000px height:auto barincrement:15px PlotArea = left:10px bottom:50px top:10px right:10px Period = from:-65.5 till:15 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:5 start:-65.5 ScaleMinor = unit:year increment:1 start:-65.5 TimeAxis = orientation:hor AlignBars = justify Colors = #legends id:CAR value:claret id:ANK value:rgb(0.4,0.3,0.196) id:HER value:teal id:HAD value:green id:OMN value:blue id:black value:black id:white value:white id:cenozoic value:rgb(0.54,0.54,0.258) id:paleogene value:rgb(0.99,0.6,0.32) id:paleocene value:rgb(0.99,0.65,0.37) id:eocene value:rgb(0.99,0.71,0.42) id:oligocene value:rgb(0.99,0.75,0.48) id:neogene value:rgb(0.999999,0.9,0.1) id:miocene value:rgb(0.999999,0.999999,0) id:pliocene value:rgb(0.97,0.98,0.68) id:quaternary value:rgb(0.98,0.98,0.5) id:pleistocene value:rgb(0.999999,0.95,0.68) id:holocene value:rgb(0.999,0.95,0.88) BarData= bar:eratop bar:space bar:periodtop bar:space bar:NAM1 bar:NAM2 bar:NAM3 bar:NAM4 bar:NAM5 bar:NAM6 bar:NAM7 bar:NAM8 bar:NAM9 bar:NAM10 bar:NAM11 bar:NAM12 bar:NAM13 bar:NAM14 bar:NAM15 bar:NAM16 bar:NAM17 bar:NAM18 bar:NAM19 bar:NAM20 bar:NAM21 bar:NAM22 bar:NAM23 bar:NAM24 bar:NAM25 bar:NAM26 bar:NAM27 bar:space bar:period bar:space bar:era PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 shift:(7,-4) bar:periodtop from: -65.5 till: -55.8 color:paleocene text:

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), E ...

from: -55.8 till: -33.9 color:eocene text:

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

from: -33.9 till: -23.03 color:oligocene text:

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

from: -23.03 till: -5.332 color:miocene text:

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

from: -5.332 till: -2.588 color:pliocene text: Plio. from: -2.588 till: -0.0117 color:pleistocene text:

Pleist. The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...

from: -0.0117 till: 0 color:holocene text: H. bar:eratop from: -65.5 till: -23.03 color:paleogene text:

Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...

from: -23.03 till: -2.588 color:neogene text:

Neogene The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...

from: -2.588 till: 0 color:quaternary text: Q. PlotData= align:left fontsize:M mark:(line,white) width:5 anchor:till align:left color:paleocene bar:NAM1 from: -65.5 till: -61.7 text:

Eolamprogrammus ''Eolamprogrammus'' is an extinct genus of prehistoric bony fish that lived during the Danian stage of the Paleocene epoch. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may ...

color:paleocene bar:NAM2 from: -65.5 till: -33.9 text: Ampheristus color:eocene bar:NAM3 from: -55.8 till: 0 text: Ophidion color:eocene bar:NAM4 from: -55.8 till: 0 text:

Onuxodon ''Onuxodon'' is an Indo-Pacific genus of pearlfishes from the family Carapidae. The generic name is derived from the Greek ''onyx'' meaning "claw" and ''odon'' meaning "tooth", referring to the sharp fang like teeth of ''Onuxodon parvibrachium ...

color:eocene bar:NAM5 from: -55.8 till: 0 text: Oligopus color:eocene bar:NAM6 from: -55.8 till: 0 text: Ogilbia color:eocene bar:NAM7 from: -55.8 till: 0 text:

Glyptophidium ''Glyptophidium'' is a genus of cusk-eels. Species There are currently seven recognized species in this genus: * ''Glyptophidium argenteum'' Alcock, 1889 * ''Glyptophidium effulgens'' J. G. Nielsen & Machida, 1988 * ''Glyptophidium japonicum' ...

color:eocene bar:NAM8 from: -55.8 till: 0 text: Brotula color:eocene bar:NAM9 from: -48.6 till: -15.97 text: Nolfophidion color:eocene bar:NAM10 from: -48.6 till: 0 text: Neobythites color:eocene bar:NAM11 from: -48.6 till: 0 text: Monomitopus color:eocene bar:NAM12 from: -48.6 till: 0 text: Hoplobrotula color:eocene bar:NAM13 from: -48.6 till: 0 text: Dannevigia color:eocene bar:NAM14 from: -48.6 till: 0 text:

Carapus ''Carapus'' is a genus of pearlfishes, with these currently recognized species: * ''Carapus acus'' ( Brünnich, 1768) (pearlfish) * ''Carapus bermudensis'' ( J. M. Jones, 1874) (Atlantic pearlfish) * ''Carapus dubius'' ( Putnam, 1874) (Pacific pe ...

color:eocene bar:NAM15 from: -48.6 till: 0 text: Benthocomectes color:eocene bar:NAM16 from: -37.2 till: 0 text: Saccogaster color:eocene bar:NAM17 from: -37.2 till: 0 text:

Dipulus ''Dipulus'' is a genus of viviparous brotulas. Species There are currently four recognized species in this genus: * '' Dipulus caecus'' Waite, 1905 (Orange eelpout) * '' Dipulus hutchinsi'' Møller & Schwarzhans, 2006 (Hutchin's mudbrotula) * ...

color:oligocene bar:NAM18 from: -33.9 till: -28.4 text: Protobrotula color:oligocene bar:NAM19 from: -33.9 till: -28.4 text: Propteridium color:oligocene bar:NAM20 from: -33.9 till: 0 text:

Genypterus ''Genypterus'' is a genus of cusk-eels. Etymology ''Genypterus'' is derived from the Greek words ''genyos'' = face, jaw and ''pteron'' = wing, fin. Species There are currently five recognized species in this genus: * ''Genypterus blacodes'' ( ...

color:oligocene bar:NAM21 from: -33.9 till: 0 text:

Diplacanthopoma ''Diplacanthopoma'' is a genus of viviparous brotulas. Species There are currently nine recognized species in this genus: * ''Diplacanthopoma alcockii'' George Brown Goode, Goode & Tarleton Hoffman Bean, T. H. Bean, 1896 * ''Diplacanthopoma brac ...

color:oligocene bar:NAM22 from: -28.4 till: 0 text: Sirembo color:oligocene bar:NAM23 from: -28.4 till: 0 text:

Echiodon ''Echiodon'' is a genus of pearlfishes, with these currently recognized species: * ''Echiodon anchipterus'' J. T. Williams, 1984 (closefin pearlfish) * '' Echiodon atopus'' M. E. Anderson, 2005 * '' Echiodon coheni'' J. T. Williams, 1984 * '' ...

color:miocene bar:NAM24 from: -23.03 till: 0 text: Lepophidium color:miocene bar:NAM25 from: -15.97 till: 0 text:

Dermatopsis ''Dermatopsis'' is a genus of viviparous brotula The viviparous brotulas form a family, the Bythitidae, of ophidiiform fishes. They are known as viviparous brotulas as they generally bear live young, although there are indications that some s ...

color:miocene bar:NAM26 from: -11.608 till: 0 text:

Bassozetus ''Bassozetus'' is a genus of cusk-eels found in Atlantic, Indian and Pacific Ocean. Species There are currently 13 recognized species in this genus: * '' Bassozetus compressus'' ( Günther, 1878) (Abyssal assfish) Tomiyama, S., Takami, M. & Fuku ...

color:pliocene bar:NAM27 from: -5.332 till: 0 text: Chilara PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 bar:period from: -65.5 till: -55.8 color:paleocene text:

from: -55.8 till: -33.9 color:eocene text:

from: -33.9 till: -23.03 color:oligocene text:

from: -23.03 till: -5.332 color:miocene text:

from: -5.332 till: -2.588 color:pliocene text: Plio. from: -2.588 till: -0.0117 color:pleistocene text:

from: -0.0117 till: 0 color:holocene text: H. bar:era from: -65.5 till: -23.03 color:paleogene text:

from: -23.03 till: -2.588 color:neogene text:

from: -2.588 till: 0 color:quaternary text: Q.

Classification

The order Ophidiiformes is subdivided into suborders and families as follows: * Suborder Ophidioidei ** Family

Poey, 1867 — pearlfishes ** Family

Rafinesque Constantine Samuel Rafinesque-Schmaltz (; October 22, 1783September 18, 1840) was a French 19th-century polymath born near Constantinople in the Ottoman Empire and self-educated in France. He traveled as a young man in the United States, ultimat ...

, 1810— cusk-eels *Suborder Bythitoidei ** Family Bythitidae

Gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

, 1861 — viviparous brotulas ** Family Aphyonidae

Jordan Jordan ( ar, الأردن; tr. ' ), officially the Hashemite Kingdom of Jordan,; tr. ' is a country in Western Asia. It is situated at the crossroads of Asia, Africa, and Europe, within the Levant region, on the East Bank of the Jordan Rive ...

& Evermann, 1898 — aphyonids, blind cusk-eel ** Family

Parabrotulidae The Parabrotulidae, the false brotulas, are a small family of bathypelagic cusk eels that currently contains two genera. The species in this family are known from the northwest Pacific Ocean and the northeast Atlantic Ocean The Atlantic ...

Nielsen, 1968 — false brotulas The suborder Ophidioidei may be a

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

grouping but the suborder Bythitoidei are

and seem to make up a

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

, while the Ophidioidei are

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and ...

References

* * * {{Taxonbar, from=Q574457 Ray-finned fish orders Taxa named by Lev Berg