Palaeoniscum Explained

Palaeoniscum (from Greek, Modern (1453-);: παλαιός, 'ancient' and Greek, Modern (1453-);: ὀνίσκος 'cod-fish' or 'woodlouse')[1] is an extinct genus of ray-finned fish from the Permian period (Guadalupian-Lopingian) of England, Germany, Turkey, North America and Greenland, and possibly other regions.[2] The genus was named Palaeoniscum in 1818 by Henri Marie Ducrotay de Blainville,[3] but was later misspelled as Palaeoniscus by Blainville and other authors (notably Louis Agassiz).[4] Palaeoniscum belongs to the family Palaeoniscidae.

The type species Palaeoniscum freieslebeni was named after Johann Carl Freiesleben (1774–1846), mining commissioner of Saxony. P. freieslebeni is the most common taxon in the Wuchiapingian aged Kupferschiefer and Marl Slate, where it constitutes 80% of all fish fossils.[5] The genus is considered to be a poorly defined wastebasket taxon.[6]

Palaeoniscum had a torpedo-shaped body 30cm (10inches) in length, with a deeply forked caudal fin and tall dorsal fin, indicating that it was a fast swimmer. It was probably an active predator, feeding on other freshwater fish. Its sharp teeth could be replaced when lost, a trait also seen in modern sharks. Like other early ray-finned fish, Palaeoniscum had air sacs connected to the mouth, which served as a primitive swim bladder.[7]

Several Palaeozoic and Mesozoic species that have been ascribed to the genus Palaeoniscum were later shown to be only distantly related with P. freieslebeni. These species were subsequently removed and transferred to other genera (e.g., Acentrophorus, Aeduella, Paramblypterus, see list below).[8] The allocation of other species to Palaeoniscum (see list below) is often doubtful and mostly based on superficial resemblance with P. freieslebeni.

Palaeoniscum is the name giving taxon of the extinct Palaeonisciformes (or Palaeoniscoidei), a polyphyletic group comprising several superficially similar looking but not closely related early actinopterygian taxa. Palaeonisciformes is considered a wastebasket taxon by modern taxonomic standards.

Species

Species moved to other genera

Notes and References

  1. Book: Roberts . George . An etymological and explanatory dictionary of the terms and language of geology . 1839 . Longman, Orme, Brown, Green, & Longmans . London . 129 . 31 December 2021 . English.
  2. Hoşgör . Izzet . Štamberg . Stanislav . A first record of late Middle Permian actinopterygian fish from Anatolia, Turkey . Acta Geologica Polonica . 2014 . 64 . 2 . 147–159 . 10.2478/agp-2014-0009. 2014AcGeP..64..147H . free .
  3. Blainville, H.-M. D. (1818). Sur les Ichthyolites, les Poisons Fossiles; Article extrait du Nouveau Dictionnaire d’Histoire Naturelle, vol. 28, Abel Lange, p. 16.
  4. Book: Agassiz, Louis . 1833–1843 . Recherches sur les poissons fossiles . Petitpierre, Neuchâtel.
  5. Schaumberg . Günther . Die Richelsdorfer Kupferschiefer und seine Fossilien, III . Aufschluss . 1977 . 28 . 297–352.
  6. Henderson . Struan . Dunne . Emma M. . Fasey . Sophie A. . Giles . Sam . February 2023 . The early diversification of ray‐finned fishes (Actinopterygii): hypotheses, challenges and future prospects . Biological Reviews . en . 98 . 1 . 284–315 . 10.1111/brv.12907 . 1464-7931 . 10091770 . 36192821.
  7. Book: Palmer, D.. 1999 . The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. Marshall Editions. London. 36. 1-84028-152-9.
  8. Romano . Carlo . Koot . Martha B. . Kogan . Ilja . Brayard . Arnaud . Minikh . Alla V. . Brinkmann . Winand . Bucher . Hugo . Kriwet . Jürgen . Permian-Triassic Osteichthyes (bony fishes): diversity dynamics and body size evolution . Biological Reviews . February 2016 . 91 . 1 . 106–147 . 10.1111/brv.12161 . 25431138 . 5332637 .

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