Beardfish Explained

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".[1] 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.[2]

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 800m (2,600feet) depth. Most are relatively small fish, although one species, Polymixia berndti, is over 40cm (20inches) in length.[2]

The earliest body fossils are from the Late Cenomanian of Lebanon, of the genus Pycnosteroides.[3] However, tentative earlier records are known from distinctive fossil otoliths from the Early Cretaceous (Albian) of Texas, USA.[4] 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.[5] Extant beardfish can thus be considered "living fossils".[6]

Classification

Timeline of genera

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References

Notes and References

  1. Book: Joseph S. Nelson . . 29 April 1994 . John Wiley & Sons . 0-471-54713-1.
  2. Book: Paxton, J.R. . Eschmeyer, W.N. . Paxton, John R.. 1998. Encyclopedia of Fishes. Academic Press. San Diego. 161. 0-12-547665-5.
  3. Schrøder . Ane Elise . Rasmussen . Jan Audun . Møller . Peter Rask . Carnevale . Giorgio . 2022-08-31 . A new beardfish (Teleostei, Polymixiiformes) from the Eocene Fur Formation, Denmark . Journal of Vertebrate Paleontology . en . 42 . 2 . 10.1080/02724634.2022.2142914 . 0272-4634. 10037/28645 . free .
  4. Schwarzhans . Werner . Stringer . Gary L. . Welton . Bruce . 2022-12-01 . Oldest Teleostean Otolith Assemblage from North America (Pawpaw Formation, Lower Cretaceous, upper Albian, northeast Texas, USA) . Cretaceous Research . 140 . 105307 . 10.1016/j.cretres.2022.105307 . 0195-6671. free .
  5. Murray . Alison M. . 2014 . Mid-Cretaceous acanthomorph fishes with the description of a new species from the Turonian of Lac des Bois, Northwest Territories, Canada . Vertebrate Anatomy Morphology Palaeontology . en . 1 . 101–115 . 10.18435/B5CC78 . 2292-1389. free .
  6. De Cia Caixeta . Heloísa . Oliveira . Claudio . Melo . Marcelo Roberto Souto de . 2024-03-01 . Another piece of the living fossil puzzle: A new species of Polymixia Lowe, 1836 (Polymixiiformes: Polymixiidae) from the western South Atlantic . Deep Sea Research Part I: Oceanographic Research Papers . 205 . 104249 . 10.1016/j.dsr.2024.104249 . 0967-0637.
  7. Web site: Mikko's Phylogeny Archive. Haaramo. Mikko. 2007. Polymixiomorpha – beardfishes and relatives . 30 December 2016.
  8. Collection of genus-group names in a systematic arrangement. Part 7- Vertebrates. etal. 30 June 2016. https://web.archive.org/web/20161005114629/http://mave.tweakdsl.nl/tn/genera7.html. 2016-10-05. dead.
  9. Stringer . Gary . Schwarzhans . Werner . 2021 . Upper Cretaceous teleostean otoliths from the Severn Formation (Maastrichtian) of Maryland, USA, with an unusual occurrence of Siluriformes and Beryciformes and the oldest Atlantic coast Gadiformes . Cretaceous Research . 125 . 104867 . 10.1016/j.cretres.2021.104867 . 0195-6671. free .
  10. SCHWARZHANS . WERNER W. . HUDDLESTON . RICHARD W. . TAKEUCHI . GARY T. . 2018-01-22 . A LATE SANTONIAN FISH-FAUNA FROM THE EUTAW FORMATION OF ALABAMA RECONSTRUCTED FROM OTOLITHS . Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy) . en . V. 124 . N. 1 (2018) . 10.13130/2039-4942/9624.
  11. Schwarzhans . Werner . Ohe . Fumio . Ando . Yusuke . 2017 . An Early Oligocene fish-fauna from Japan reconstructed from otoliths . Zitteliana . 3–26 . 10.5282/ubm/epub.40475 . 0373-9627.
  12. Web site: 2017-02-15 . Bulletin Volume 65 – 2017 . 2024-07-28 . Dansk Geologisk Forening . da-DK . 10.37570/bgsd-2017-65-05.