The Atheriniformes, also known as the silversides, 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 h ...

es that includes the Old World silversides and several less-familiar families, including the unusual

Phallostethidae Phallostethidae, also known as the priapium fish, is a family of atheriniform fish native to freshwater and brackish habitats in southeast Asia. They are small, no more than in length, with partially translucent bodies. They are found in fre ...

. The order includes at least 354 species. They are found worldwide in tropical and temperate marine and freshwater environments.

Description

Atheriniformes are generally elongated and silvery in colour, although exceptions do exist. They are typically small fish, with the largest being the Argentinian silverside, with a head-body length of , and the smallest species, such as the

Bangkok minnow Bangkok, officially known in Thai as Krung Thep Maha Nakhon and colloquially as Krung Thep, is the capital and most populous city of Thailand. The city occupies in the Chao Phraya River delta in central Thailand and has an estimated population ...

, being only in adult length. Members of the order usually have two

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 c ...

s, the first with flexible spines, 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 s ...

with one spine at the front. The lateral line is typically weak or absent. Atheriniform larvae share several characteristics; the gut is unusually short, a single row of

melanophore Chromatophores are cells that produce color, of which many types are pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals and birds, in contra ...

s occurs along the back, and the fin rays do not become evident until some time after hatching. They scatter their eggs widely, with most species attaching them to aquatic plants.

Taxonomy

Classification of the Atheriniformes is uncertain, with the best evidence for

monophyly 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 gr ...

in the larval characteristics mentioned below. Their closest relatives are thought to be the

Cyprinodontiformes Cyprinodontiformes is an order of ray-finned fish, comprising mostly small, freshwater fish. Many popular aquarium fish, such as killifish and live-bearers, are included. They are closely related to the Atheriniformes and are occasionally in ...

. Nelson 2016 recognizes the infraseries Atherinomorpha, part of the sub series Ovalentaria which includes the orders Atheriniformes, Beloniformes, and Cyprinodontiformes, citing the larval characteristics and supporting molecular studies of these taxa as support for monophyly of this grouping. The sister taxon to the Atherinomorpha appears to be the Mugiliformes. Following Nelson (2006), the family Melanotaeniidae includes the subfamilies Bedotiinae, Melanotaeniinae, Pseudomugilinae, and Telmatherininae, to demonstrate their

. However, in a 2004 study, a different classification scheme classifies the families Bedotiidae, Melanotaeniidae, and Pseudomugilidae (also include Telmatherinine genera) in a suborder Melanotaenioidei. Thus, the number of families in Atheriniformes varies from author to author. Nelson 2016 classifies the families as follows: * Order Atheriniformes ** Suborder

Atherinopsoidei Atherinopsoidei is a suborder of the order Atheriniformes comprising two families, both of which are restricted to the Americas. Families The suborder contains the following families: * Family Atherinopsidae Fitzinger, 1873 (New World silver ...

*** Family Atherinopsidae (New World silversides) *** Family

Notocheiridae The surf silverside (''Notocheirus hubbsi'') is a species of silverside from the order Atheriniformes found along the Pacific coast of Argentina and Chile. It is the only known member of its family and molecular evidence points to this species ...

(Surf silversides) ** Suborder Atherinoidei *** Family Isonidae (Surf sardines) *** Family Melanotaeniidae (Rainbowfishes and blue eyes) *** Family

Atherion ''Atherion'' is a small genus of silversides, known as the pricklenose silversides. It is the only genus in the family Atherionidae. Other authorities classify this as a monogeneric subfamily, Atherioninae, of the Atherinidae, while others inclu ...

idae (Pricklenose silversides) *** Family Dentatherinidae (Mercer's tusked silverside) *** Family

(Priapiumfishes) *** Family Atherinidae (Old World silversides)

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: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 that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pal ...

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

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

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 ...

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 recent" ...

from: -5.332 till: -2.588 color:pliocene text: Plio. from: -2.588 till: -0.0117 color:pleistocene text: Pleist. from: -0.0117 till: 0 color:holocene text: H. bar:eratop from: -65.5 till: -23.03 color:paleogene text:

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

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:eocene bar:NAM1 from:-55.8 till:0 text: Atherina color:eocene bar:NAM2 from:-37.2 till:-5.332 text:

Palaeoatherina ''Palaeoatherina'' is an extinct genus of prehistoric bony fish. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: People * List (surname) Organizati ...

color:eocene bar:NAM3 from:-37.2 till:0 text:

Pranesus ''Pranesus'' is an extinct genus of prehistoric bony fish. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: People * List (surname) Organizations * ...

color:miocene bar:NAM4 from:-23.03 till:0 text: Stenatherina color:miocene bar:NAM5 from:-11.608 till:0 text:

Atherinopsis ''Atherinopsis californiensis'', the jack silverside or jacksmelt,Leo PinkasCalifornia Marine Fish Landings For 1972 and Designated Common Names of Certain Marine Organisms of California fish bulletin 161, Marine Resources Region, 1974 is a speci ...

color:pliocene bar:NAM6 from:-5.332 till:0 text: Chirostoma color:pliocene bar:NAM7 from:-5.332 till:0 text: Colpichthys color:pliocene bar:NAM8 from:-5.332 till:0 text: Menidia color:pleistocene bar:NAM9 from:-2.588 till:0 text:

Leuresthes Grunion are two fish species of the genus ''Leuresthes'': the California grunion, ''L. tenuis'', and the Gulf grunion, ''L. sardinas''. They are sardine-sized teleost fishes of the New World silverside family Atherinopsidae, found only off the ...

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: Pleist. 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.

References

* {{taxonbar, from=Q254606 Ray-finned fish orders Articles which contain graphical timelines