The beardfishes consist of a single extant

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

, '' Polymixia'', of deep-sea marine

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 ...

named for their pair of long

hyoid The hyoid bone (lingual bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies between the base of the mandible and the third cervical vertebra. ...

barbel Barbel may refer to: *Barbel (anatomy), a whisker-like organ near the mouth found in some fish (notably catfish, loaches and cyprinids) and turtles *Barbel (fish), a common name for certain species of fish **''Barbus barbus'', a species of cyprinid ...

s. They are classified in their own order Polymixiiformes . But as Nelson says, "few groups have been shifted back and forth as frequently as this one, and they were recently added to Paracanthoptergii". For instance, they have previously been classified as belonging to the

Beryciformes The Beryciformes are a poorly-understood order of carnivorous ray-finned fishes consisting of 7 families, 30 genera, and 161 species. They feed on small fish and invertebrates. Beyond this, little is known about the biology of most member specie ...

. They are of little economic importance. They are found in tropical and subtropical waters of the

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

Indian Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asia ...

and western

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

. They are bottom-dwelling fish, found down to about depth. Most are relatively small fish, although one species, '' Polymixia berndti'', is over in length.

Classification

* Order Polymixiiformes Rosen & Patterson, 1969 ** Genus †'' Cumbaaichthys'' Murray 2016 *** †'' Cumbaaichthys oxyrhynchus'' Murray 2016 ** Family † Boreiohydriidae Murray & Cumbaa 2013 *** Genus †'' Boreiohydrias'' Murray & Cumbaa 2013 **** †'' Boreiohydrias dayi'' Murray & Cumbaa 2013 ** Family † Digoriidae Bannikov 1985 *** Genus †''

Digoria Digoria (Ossetic: Дигорæ (Digoræ); russian: Дигория (Digoria)) is a mostly mountainous region of the North Caucasus in the western part of the Republic of North Ossetia–Alania, Russia. The inhabitants speak the archaic Digor dialect ...

'' Jordan 1923 **** †'' Digoria ambigua'' Jordan 1923 ** Family Polymixiidae Gill 1862 erycopsidae Regan 1911; Dalmatichthyidae Radovčić 1975; Omosomopsidae Gaudant 1978; Homonotichthyidae Whitley 1933*** Genus †'' Apricenaichthys'' Taverne 2011 **** †'' Apricenaichthys italicus'' *** Genus †'' Berycopsia'' Radovčić 1975 **** †'' Berycopsia inopinnata'' Radovčić 1975 *** Genus †'' Berycopsis'' Dixon 1850 'Platycormus''_von_der_Marck_1900.html" ;"title="Platycormus.html" ;"title="' 'Platycormus''_von_der_Marck_1900">Platycormus.html"_;"title="'Platycormus">'Platycormus''_von_der_Marck_1900****_†''Berycopsis_elegans.html" ;"title="Platycormus">'Platycormus'' von der Marck 1900">Platycormus.html" ;"title="'Platycormus">'Platycormus'' von der Marck 1900**** †''Berycopsis elegans">B. elegans'' Dixon 1850 [''Platycormus elegans'' (Dixon 1850)] **** †''Berycopsis germana, B. germana'' (Agassiz 1839) [''Beryx germanus'' Agassiz 1839; ''Platycormus germanus'' (Agassiz 1839)] **** †''Berycopsis pulcher, B. pulcher'' Bannikov & Bacchia 2004 *** Genus †'' Dalmatichthys'' Radovčić 1975 **** †'' Dalmatichthys malezi'' Radovčić 1975 *** Genus †'' Homonotichthys'' Whitley 1933 **** †'' H. dorsalis'' (Dixon 1850) 'Homonotus dorsalis'' Dixon 1850**** †'' H. elegans'' (Dixon 1850) 'Homonotus elegans'' Dixon 1850**** †'' H. rotundus'' (Woodward 1902) 'Homonotus rotundus'' Woodward 1902*** Genus †'' Magrebichthys'' Murray & Wilson 2014 **** †'' Magrebichthys nelsoni'' Murray & Wilson 2014 *** Genus †'' Omosoma'' Costa 1857 **** †'' O. garretti'' Bardack 1976 **** †'' O. pulchellum'' Davis 1887 **** †'' O. sahelaimae'' Costa 1857 **** †'' O. tselfatense'' Gaudant 1978 *** Genus †'' Omosomopsis'' Gaudant 1978 **** †'' Omosomopsis sima'' (Arambourg 1954) Gaudant 1978 *** Genus †'' Parapolymyxia'' David 1946 *** Genus †'' Pycnosterinx'' Heckel 1849 'Imogaster''_Costa_1857.html" ;"title="Imogaster.html" ;"title="' 'Imogaster''_Costa_1857">Imogaster.html"_;"title="'Imogaster">'Imogaster''_Costa_1857 ****_†'' 'Imogaster''_Costa_1857">Imogaster.html"_;"title="'Imogaster">'Imogaster''_Costa_1857 ****_†''Pycnosterinx_discoides">P._discoides''_Heckel_1849 ****_†'' 'Imogaster''_Costa_1857">Imogaster.html"_;"title="'Imogaster">'Imogaster''_Costa_1857 ****_†''Pycnosterinx_discoides">P._discoides''_Heckel_1849 ****_†''Pycnosterinx_dorsalis">P._dorsalis''_Pictet_1850 ****_†'' 'Imogaster''_Costa_1857">Imogaster.html"_;"title="'Imogaster">'Imogaster''_Costa_1857 ****_†''Pycnosterinx_discoides">P._discoides''_Heckel_1849 ****_†''Pycnosterinx_dorsalis">P._dorsalis''_Pictet_1850 ****_†''Pycnosterinx_heckelii">P._heckelii''_Pictet_1850 ****_†'' 'Imogaster''_Costa_1857">Imogaster.html"_;"title="'Imogaster">'Imogaster''_Costa_1857 ****_†''Pycnosterinx_discoides">P._discoides''_Heckel_1849 ****_†''Pycnosterinx_dorsalis">P._dorsalis''_Pictet_1850 ****_†''Pycnosterinx_heckelii">P._heckelii''_Pictet_1850 ****_†''Pycnosterinx_latus">P._latus''_Davis_1887 ****_†''Pycnosterinx_russeggeri.html" ;"title="Pycnosterinx_latus.html" ;"title="Pycnosterinx_heckelii.html" ;"title="Pycnosterinx_dorsalis.html" ;"title="Pycnosterinx_discoides.html" ;"title="Imogaster">'Imogaster'' Costa 1857">Imogaster.html" ;"title="'Imogaster">'Imogaster'' Costa 1857 **** †''Pycnosterinx discoides">P. discoides'' Heckel 1849 **** †''Pycnosterinx dorsalis">P. dorsalis'' Pictet 1850 **** †''Pycnosterinx heckelii">P. heckelii'' Pictet 1850 **** †''Pycnosterinx latus">P. latus'' Davis 1887 **** †''Pycnosterinx russeggeri">P. russeggeri'' Heckel 1849 [''Homonotus pulcher'' Davis 1886] *** Genus '' Polymixia'' Lowe 1836 [''Dinemus'' Poey 1860; ''Nemobrama'' Valenciennes 1860 non Jordan, Evermann & Clark 1930] **** '' Polymixia berndti, P. berndti'' Gilbert 1905 (Pacific beardfish) **** '' P. busakhini'' Kotlyar 1993 (Busakhin's beardfish) **** '' P. fusca'' Kotthaus 1970 **** '' P. japonica'' Günther 1877 (Silver eye) **** '' P. longispina'' Deng, Xiong & Zhan 1983 'Polymixia kawadae'' Okamura & Ema 1985**** '' P. lowei'' Günther 1859 (Beardfish) **** '' P. nobilis'' Lowe 1838 'Nemobrama webbii'' Valenciennes 1837; ''Dinemus venustus'' Poey 1860; ''Polymixia nobilis virginica'' Nichols & Firth 1936(Stout beardfish) **** †'' P. polita'' Schwarzhans 2012 **** '' P. salagomeziensis'' Kotlyar 1991 **** '' P. sazonovi'' Kotlyar 1992 **** '' P. yuri'' Kotlyar 1982

Timeline of genera

ImageSize = width:1000px height:auto barincrement:15px PlotArea = left:10px bottom:50px top:10px right:10px Period = from:-145.5 till:10 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: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 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:-97.6 text: Aipichthyoides color:latecretaceous bar:NAM2 from:-99.6 till:-97.6 text: Aipichthys color:latecretaceous bar:NAM3 from:-99.6 till:-97.6 text: Paraipichthys color:latecretaceous bar:NAM4 from:-99.6 till:-93.5 text: Homonotichthys color:latecretaceous bar:NAM5 from:-99.6 till:-70.6 text: Omosoma color:latecretaceous bar:NAM6 from:-99.6 till:-70.6 text: Berycopsis color:latecretaceous bar:NAM7 from:-93.5 till:-89.3 text: Berycopsia color:latecretaceous bar:NAM8 from:-89.3 till:-65.5 text: Dalmatichthys color:latecretaceous bar:NAM9 from:-85.8 till:-83.5 text: Pycnosterinx color:eocene bar:NAM10 from:-37.2 till:0 text: Polymixia PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 bar:period from: -145.5 till: -99.6 color:earlycretaceous text: Early 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.

References

* {{Taxonbar, from1=Q1922429, from2=Q3907757 Fish of Hawaii Extant Late Cretaceous first appearances