The Myctophiformes are an

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

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 ...

es consisting of two

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...

deep-sea The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of 200 metres (656 feet) or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combin ...

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

fish, most notably the highly abundant

lanternfish Lanternfishes (or myctophids, from the Greek μυκτήρ ''myktḗr'', "nose" and ''ophis'', "serpent") are small mesopelagic fish of the large family Myctophidae. One of two families in the order Myctophiformes, the Myctophidae are represente ...

es (Myctophidae). The

blackchin The Neoscopelidae (blackchins or neoscopelids) are a small family of deep-sea fish closely related to the lanternfish. They are found in tropical and subtropical marine waters worldwide. They can be distinguished from the lanternfish only by a f ...

s (Neoscopelidae) contain six species in three genera, while the bulk of the family belongs to the Myctophidae, with over 30 genera and some 252 species.Nelson (2006): p.223 The

scientific name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

ultimately derives from

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

''myktér'' (μυκτήρ, "nose") + ''óphis'' (ὄφῖς, "serpent") +

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''forma'' ("external form"), the Greek part in reference to the long, slender, and heavy-headed shape of these fishes.

Description and ecology

These smallish fishes inhabit the

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 ...

and

benthopelagic The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

zones of the

deep sea The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of 200 metres (656 feet) or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combin ...

. They are laterally compressed and usually have

photophore A photophore is a glandular organ that appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors, ...

s (light organs). The eyes are large, in some decidedly huge, and generally directed straight sideways. The mouth also quite large and located at the tip of the snout; its gape extends to below the eyes or even beyond. They have an

adipose 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 s ...

. The

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

has eight

ray Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (g ...

s in most myctophiforms, and the number of

branchiostegal ray This glossary of ichthyology is a list of definitions of terms and concepts used in ichthyology, the study of fishes. A B C ...

s is usually higher than six and lower than 12.

Systematics

The two

of the Myctophiformes are: * Myctophidae – lanternfishes *

Neoscopelidae The Neoscopelidae (blackchins or neoscopelids) are a small family of deep-sea fish closely related to the lanternfish. They are found in tropical and subtropical marine waters worldwide. They can be distinguished from the lanternfish only by a f ...

– blackchins The

Myctophiformes is

anatomical Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having it ...

ly similar to the grinners (Aulopiformes), but their

pharyngobranchial Branchial arches, or gill arches, are a series of bony "loops" present in fish, which support the gills. As gills are the primitive condition of vertebrates, all vertebrate embryos develop pharyngeal arches, though the eventual fate of these arc ...

s and retractor muscles are more

plesiomorph In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, and ...

ic. It was also allied with the more advanced spiny- rayed

Teleostei Teleostei (; Ancient Greek, Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts ), is, by far, the largest class (biology), infraclass in the class Actinopterygii, the ray-finned fishes, containing 96% of a ...

(e.g.

Paracanthopterygii Paracanthopterygii is a superorder of fishes. Members of this group are called paracanthopterygians. It includes five orders: * † Sphenocephaliformes * Percopsiformes ( trout-perches & allies) * Zeiformes (dories) * Stylephoriformes ( Tube ...

) as " Ctenosquamata". These

apomorph In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...

ically have a fifth upper pharyngeal toothplate and a third internal levator muscle to move it, and

molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

data also support the long-held view that these two lineages are at least closely related. Other sources ally them with the

Lampriformes Lampriformes is an order of ray-finned fish. Members are collectively called lamprids (which is more properly used for the Lampridae) or lampriforms, and unite such open-ocean and partially deep-sea Teleostei as the crestfishes, oarfish, opah ...

, which are often placed in a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

superorder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

"Lampridiomorpha". In a similar fashion, separation of the Myctophiformes in superorder "Scopelomorpha" has been proposed. The Aulopiformes, though, are usually considered to be closer or even among the

Protacanthopterygii Protacanthopterygii is a ray-finned fish taxon ranked as a superorder of the infraclass Teleostei. They inhabit both marine and freshwater habitats. They appear to have evolved in the Cretaceous or perhaps late Jurassic, originating probably rou ...

, one of the core groups of moderately advanced teleosts. As modern

taxonomy Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

tries to avoid a profusion of small

taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

, and the delimitation of the Euteleostei (Protacanthopterygii ''

sensu stricto ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular co ...

'' and their allies) versus "Ctenosquamata" such as the

remains uncertain, the

systematics Biological systematics is the study of the diversification of living forms, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees (synonyms: cladograms, phylogenetic tre ...

and taxonomy of the Myctophiformes among the teleosts are in need of further study.Nelson (2006): p.223, Diogo (2008)

Timeline of genera

ImageSize = width:1500px height:auto barincrement:15px PlotArea = left:10px bottom:50px top:10px right:10px Period = from:-145.5 till:15 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:10 start:-145.5 ScaleMinor = unit:year increment:1 start:-145.5 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:cretaceous value:rgb(0.5,0.78,0.31) id:earlycretaceous value:rgb(0.63,0.78,0.65) id:latecretaceous value:rgb(0.74,0.82,0.37) 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: -145.5 till: -99.6 color:earlycretaceous text:

Early Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early ...

from: -99.6 till: -65.5 color:latecretaceous text:

Late Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

from: -65.5 till: -55.8 color:paleocene text: Paleo. from: -55.8 till: -33.9 color:eocene text: Eo. from: -33.9 till: -23.03 color:oligocene text: Oligo. from: -23.03 till: -5.332 color:miocene text: Mio. from: -5.332 till: -2.588 color:pliocene text: Pl. from: -2.588 till: -0.0117 color:pleistocene text: Pl. from: -0.0117 till: 0 color:holocene text: H. bar:eratop from: -145.5 till: -65.5 color:cretaceous text:

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

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:latecretaceous bar:NAM1 from: -99.6 till: -70.6 text:

Sardinoides ''Sardinioides'' is an extinct genus of prehistoric ray-finned fish from the Campanian. It is a member of the Myctophiformes order, and considered a sister group to Paleogene and modern neoscopelids and myctophids Lanternfishes (or myctophid ...

color:latecretaceous bar:NAM2 from: -85.8 till: -83.5 text:

Chirothrix ''Cheirothrix'' (meaning "hand hair") is an extinct genus of ray-finned fish. One of the species in this genus is '' Cheirothrix lewisii'', known from the Late Cretaceous of Lebanon Lebanon ( , ar, لُبْنَان, translit=lubnān, ), o ...

color:latecretaceous bar:NAM3 from: -83.5 till: -70.6 text: Sardinius color:paleocene bar:NAM4 from: -65.5 till: -55.8 text: Neocassandra color:paleocene bar:NAM5 from: -65.5 till: -55.8 text:

Eokrefftia ''Eokrefftia'' is an extinct genus of prehistoric ray-finned fish that lived during the Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the P ...

color:eocene bar:NAM6 from: -55.8 till: 0 text:

Diaphus ''Diaphus'' is a genus of lanternfish Lanternfishes (or myctophids, from the Greek μυκτήρ ''myktḗr'', "nose" and ''ophis'', "serpent") are small mesopelagic fish of the large family Myctophidae. One of two families in the order Myct ...

color:eocene bar:NAM7 from: -48.6 till: -23.03 text:

Eomyctophum ''Eomyctophum'' is an extinct genus of prehistoric 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 ...

color:oligocene bar:NAM8 from: -28.4 till: 0 text:

Lobianchia ''Lobianchia'' is a genus of lanternfishes found in the Atlantic Ocean. The generic name was derived from Latin ''lobus'' ("lobe") and Greek αγχόνη (''anchonē'', "noose"). Species There are currently two recognized species in this genus: ...

color:oligocene bar:NAM9 from: -28.4 till: 0 text:

Hygophum ''Hygophum'' is a genus of lanternfishes. Species There are currently nine recognized species in this genus: * ''Hygophum atratum'' (Samuel Garman, Garman, 1899) (Thickhead lanternfish) * ''Benoit's lanternfish, Hygophum benoiti'' (Anastasio Coc ...

color:miocene bar:NAM10 from: -23.03 till: 0 text:

Symbolophorus ''Symbolophorus'' is a genus of lanternfishes. It feeds on various small forms of sea life, in particular fish. Some species in this genus are known to exhibit the Stylophthalmine trait in their larval form Species There are currently eight re ...

color:miocene bar:NAM11 from: -23.03 till: 0 text:

Lampanyctus ''Lampanyctus'' is a genus of lanternfishes. Species There are currently 39 recognized species in this genus: * '' Lampanyctus acanthurus'' Wisner, 1974 (Spinytail lampfish) * '' Lampanyctus achirus'' Andriashev, 1962 (Cripplefin Lanternfish ...

color:miocene bar:NAM12 from: -23.03 till: 0 text: Bolinichthyes color:miocene bar:NAM13 from: -15.97 till: 0 text:

Notoscopelus ''Notoscopelus'' is a genus of lanternfishes. Species There are currently six recognized species in this genus: * ''Notoscopelus bolini'' Basil George Nafpaktitis, B. G. Nafpaktitis, 1975 * ''Notoscopelus caudispinosus'' (James Yate Johnson, J. ...

color:miocene bar:NAM14 from: -15.97 till: 0 text:

Benthosema ''Benthosema'' is a genus of lanternfishes. Species The currently recognized species in this genus are: * ''Benthosema fibulatum'' (Charles Henry Gilbert, C. H. Gilbert & Frank Cramer, Cramer, 1897) (spinycheek lanternfish) * ''Benthosema glacia ...

color:miocene bar:NAM15 from: -11.608 till: 0 text:

Myctophum ''Myctophum'' is a genus of lanternfishes, some species of which, such as ''M. punctatum'' are noted for having the Stylophthalmine trait in their larval form. Species There are currently 16 recognized species in this genus: * '' Myctophum af ...

color:miocene bar:NAM16 from: -11.608 till: 0 text: Lampichthyes color:miocene bar:NAM17 from: -11.608 till: 0 text:

Lampanyctodes Hector's lanternfish (''Lampanyctodes hectoris'') is a lanternfish in the family Myctophidae, the only species in the genus ''Lampanyctodes''. It is named after James Hector. It is a widespread marine fish, known from shallow tropical waters i ...

color:miocene bar:NAM18 from: -11.608 till: 0 text:

Electrona Electrona may refer to: * ''Electrona'' (fish), a genus of lanternfishes in the family Myctophidae * Electrona, Tasmania, a town in Tasmania, Australia {{disambig ...

color:pliocene bar:NAM19 from: -5.332 till: 0 text: Triphoturus color:pliocene bar:NAM20 from: -5.332 till: 0 text:

Tarletonbeania ''Tarletonbeania'' is a genus of lanternfishes found in the Pacific Ocean. Etymology The genus is named after ichthyologist Tarleton H. Bean (1846-1916), of the U.S. National Museum. Species There are currently two recognized species in this ge ...

color:pliocene bar:NAM21 from: -5.332 till: 0 text:

Stenobrachius ''Stenobrachius'' is a genus of lanternfish Lanternfishes (or myctophids, from the Greek μυκτήρ ''myktḗr'', "nose" and ''ophis'', "serpent") are small mesopelagic fish of the large family Myctophidae. One of two families in the order ...

color:pliocene bar:NAM22 from: -5.332 till: 0 text:

Scopelopsis ''Scopelopsis multipunctatus'', the multispotted lanternfish, is a species of lanternfish. This species grows to a length of 9.5 cm (3.7 in). Description Scopelopsis multipunctatus has round eyes, a long and slender body, and a forked homocerc ...

color:pliocene bar:NAM23 from: -5.332 till: 0 text:

Protomyctophum ''Protomyctophum'' is a genus of lanternfishes. Species There are currently 16 recognized species in this genus: * '' Protomyctophum andriashevi'' Becker, 1963 * '' Protomyctophum arcticum'' ( Lütken, 1892) (Arctic telescope) * '' Protomycto ...

color:pliocene bar:NAM24 from: -5.332 till: 0 text: Parvilux color:pliocene bar:NAM25 from: -5.332 till: 0 text:

Lampadena ''Lampadena'' is a genus of lanternfishes. Species There are currently nine recognized species in this genus: * '' Lampadena anomala'' A. E. Parr, 1928 * '' Lampadena chavesi'' Collett, 1905 (Chaves' lanternfish) * '' Lampadena dea'' Fraser-B ...

color:pliocene bar:NAM26 from: -5.332 till: 0 text: Gymnoscopelus color:pliocene bar:NAM27 from: -5.332 till: 0 text:

Ceratoscopelus ''Ceratoscopelus'' is a genus of lanternfish Lanternfishes (or myctophids, from the Greek μυκτήρ ''myktḗr'', "nose" and ''ophis'', "serpent") are small mesopelagic fish of the large family Myctophidae. One of two families in the orde ...

PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 bar:period from: -145.5 till: -99.6 color:earlycretaceous text:

from: -99.6 till: -65.5 color:latecretaceous text:

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.

Footnotes

References

* (2008): On the cephalic and pectoral girdle muscles of the deep sea fish ''Alepocephalus rostratus'', with comments on the functional morphology and phylogenetic relationships of the Alepocephaloidei (Teleostei). '' Anim. Biol.'' 58(1): 23-29. * (2006)
Order Myctophiformes
Version of 2006-OCT-09. Retrieved 2009-SEP-28. * (1968–1982): ''

Oxford Latin Dictionary The ''Oxford Latin Dictionary'' (or ''OLD'') is the standard English lexicon of Classical Latin, compiled from sources written before AD 200. Begun in 1933, it was published in fascicles between 1968 and 1982; a lightly revised second edition ...

'' (1st ed.). Oxford University Press, Oxford. * (2006): ''

Fishes of the World ''Fishes of the World'' by the American ichthyologist Joseph S. Nelson (1937–2011) is a standard reference for fish systematics. Now in its fifth edition (2016), the work is a comprehensive overview of the diversity and classification of the ...

'' (4th ed.). John Wiley & Sons, Inc. * (1910): ''English-Greek Dictionary - A Vocabulary of the Attic Language''. George Routledge & Sons Ltd., Broadway House, Ludgate Hill, E.C
Searchable JPEG fulltext
* {{Authority control Deep sea fish Ray-finned fish orders