Beardfish

The beardfishes consist of a single extant genus, Polymixia, of deep-sea marine ray-finned fish named for their pair of long hyoid barbels. 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, and are presently considered either paracanthopterygians or the sister group to acanthopterygians. They are of little economic importance.

They are found in tropical and subtropical waters of the Atlantic, Indian and western Pacific Ocean. They are bottom-dwelling fish, found down to about depth. Most are relatively small fish, although one species, Polymixia berndti, is over in length.

The earliest body fossils are from the Late Cenomanian of Lebanon, of the genus Pycnosteroides. However, tentative earlier records are known from distinctive fossil otoliths from the Early Cretaceous (Albian) of Texas, USA. Many different fossil families and genera are known from the Late Cretaceous and early Cenozoic, in contrast to the relatively few surviving species in a single genus. Extant beardfish can thus be considered "living fossils".

Classification

• Order Polymixiiformes <small>Rosen & Patterson, 1969</small>
• Genus ?†Allocyclostoma <small>Schwarzhans, Stringer & Welton, 2022</small> <nowiki/>[<nowiki/>otolith]
• †A. alienus <small>Schwarzhans, Stringer & Welton, 2022</small>
• Genus †Cumbaaichthys <small>Murray 2016</small>
• †Cumbaaichthys oxyrhynchus <small>Murray 2016</small>
• Genus †Severnichthys <small>Stringer & Schwarzhans, 2021</small> [<nowiki/>otolith]
• †S. beauryi <small>(Schwarzhans, 2010)</small>
• †S. bourdoni <small>Stringer & Schwarzhans, 2021</small>
• Genus ?†Texoma <small>Schwarzhans, Stringer & Welton, 2022</small> [otolith]
• †T. cyclogaster <small>Schwarzhans, Stringer & Welton, 2022</small>
• Family †Boreiohydriidae <small>Murray & Cumbaa 2013</small>
• Genus †Boreiohydrias <small>Murray & Cumbaa 2013</small>
• †Boreiohydrias dayi <small>Murray & Cumbaa 2013</small>
• Family †Dalmatichthyidae <small>Radovčić 1975</small>
• Genus †Dalmatichthys <small>Radovčić 1975</small>
• †Dalmatichthys malezi <small>Radovčić 1975</small>
• Family †Digoriidae <small>Bannikov 1985</small>
• Genus †Digoria <small>Daniltshenko, 1980</small>
• †Digoria ambigua <small>Daniltshenko, 1980</small>
• Family †Dinopterygidae <small>Jordan, 1923</small>
• Genus †Dinopteryx <small>Woodward, 1901</small>
• †Dinopteryx spinosus <small>(Davis, 1887)</small>
• Family Polymixiidae <small>Gill 1862</small> [Berycopsidae <small>Regan 1911</small>; Dalmatichthyidae <small>Radovčić 1975</small>; Omosomopsidae <small>Gaudant 1978</small>; Homonotichthyidae <small>Whitley 1933</small>]
• Genus †Apricenaichthys <small>Taverne 2011</small>
• †Apricenaichthys italicus
• Genus †Berycopsia <small>Radovčić 1975</small>
• †Berycopsia inopinnata <small>Radovčić 1975</small>
• Genus †Berycopsis <small>Dixon 1850</small> [Platycormus <small>von der Marck 1900</small>]
• †B. elegans <small>Dixon 1850</small> [Platycormus elegans <small>(Dixon 1850)</small>]
• †B. germana <small>(Agassiz 1839)</small> [Beryx germanus <small>Agassiz 1839</small>; Platycormus germanus <small>(Agassiz 1839)</small>]
• †B. pulcher <small>Bannikov & Bacchia 2004</small>
• Genus †Cowetaichthys <small>Schwarzhans, Huddleston & Takeuchi, 2018</small> [otolith]
• †C. alabamae <small>Schwarzhans, Huddleston & Takeuchi, 2018</small>
• †C. beauryi <small>(Schwarzhans, 2010)</small>
• †C. carnevalei <small>Schwarzhans & Stringer, 2020</small>
• †C. groenlandicus <small>(Schwarzhans, 2004)</small>
• †C. harderi <small>(Schwarzhans, 2003)</small>
• †C. lamberi <small>Schwarzhans, Huddleston & Takeuchi, 2018</small>
• Genus †Homonotichthys <small>Whitley 1933</small>
• †H. dorsalis <small>(Dixon 1850)</small> [Homonotus dorsalis <small>Dixon 1850</small>]
• †H. elegans <small>(Dixon 1850)</small> [Homonotus elegans <small>Dixon 1850</small>]
• †H. rotundus <small>(Woodward 1902)</small> [Homonotus rotundus <small>Woodward 1902</small>]
• Genus †Namicauda <small>Schwarzhans, Ohe & Ando, 2017</small> [otolith]
• †Namicauda pulvinata <small>Schwarzhans, Ohe & Ando, 2017</small>
• Genus †Omosoma <small>Costa 1857</small>
• †O. garretti <small>Bardack 1976</small>
• †O. pulchellum <small>Davis 1887</small>
• †O. sahelalmae <small>Costa 1857</small>
• †O. tselfatense <small>Gaudant 1978</small>
• Genus †Omosomopsis <small>Gaudant 1978</small>
• †Omosomopsis sima <small>(Arambourg 1954) Gaudant 1978</small>
• Genus †Parapolymixia <small>David 1946</small>
• †Parapolymixia californica <small>David 1946</small>
• Genus †Pycnosterinx <small>Heckel 1849</small> [Imogaster <small>Costa 1857</small>]
• †P. discoides <small>Heckel 1849</small>
• †P. dorsalis <small>Pictet 1850</small>
• †P. heckelii <small>Pictet 1850</small>
• †P. latus <small>Davis 1887</small>
• †P. russeggeri <small>Heckel 1849</small> [Homonotus pulcher <small>Davis 1886</small>]
• Genus Polymixia <small>Lowe 1836</small> [Dinemus <small>Poey 1860</small>; Nemobrama <small>Valenciennes 1860 non Jordan, Evermann & Clark 1930</small>]
• P. berndti <small>Gilbert 1905</small> (Pacific beardfish)
• P. busakhini <small>Kotlyar 1993</small> (Busakhin's beardfish)
• P. carmenae <small>Caixeta, Oliveira & de Melo, 2024</small> (Brazilian beardfish)
• P. fusca <small>Kotthaus 1970</small>
• †?P. harderi <small>(Schwarzhans 2003)</small> [otolith]
• P. hollisterae <small>Grande & Wilson, 2021</small> (Bermuda beardfish)
• P. japonica <small>Günther 1877</small> (Silver eye)
• P. longispina <small>Deng, Xiong & Zhan 1983</small> [Polymixia kawadae <small>Okamura & Ema 1985</small>]
• P. lowei <small>Günther 1859</small> (Beardfish)
• P. nobilis <small>Lowe 1838</small> [Nemobrama webbii <small>Valenciennes 1837</small>; Dinemus venustus <small>Poey 1860</small>; Polymixia nobilis virginica <small>Nichols & Firth 1936</small>] (Stout beardfish)
• †P. polita <small>Schwarzhans 2012</small> [otolith]
• P. salagomeziensis <small>Kotlyar 1991</small>
• P. sazonovi <small>Kotlyar 1992</small>
• P. yuri <small>Kotlyar 1982</small>
• Genus †Polyspinatus <small>Schrøder, Rasmussen, Møller & Carnevale, 2022</small>
• †Polyspinatus fluere <small>Schrøder, Rasmussen, Møller & Carnevale, 2022</small>
• Family †Pycnosteroididae <small>Patterson, 1964</small>
• Genus †Magrebichthys <small>Murray & Wilson 2014</small>
• †Magrebichthys nelsoni <small>Murray & Wilson 2014</small>
• Genus †Pycnosteroides <small>Woodward, 1942</small>
• †Pycnosteroides levispinosus <small>(Hay, 1903)</small>

References