Palaeoniscum

{{Short description|Extinct genus of fishes}} {{Automatic taxobox | fossil_range = {{fossil range|272|252|Guadalupian-Lopingian | earliest=299 | latest= 237}} | image = Palaeoniscus freieslebeni 2.jpg | image_caption = ''Palaeoniscum freieslebeni'' fossil | taxon = Palaeoniscum | authority = Blainville, 1818 | type_species = †'''''Palaeoniscum freieslebeni''''' | type_species_authority = Blainville, 1818 | subdivision_ranks = Other species | subdivision = see list | synonyms = * {{extinct}}''Palaeoniscus'' Agassiz, 1833 non Von Meyer, 1858 * {{extinct}}''Palaeoniscas'' Rzchak, 1881 * {{extinct}}''Eupalaeoniscus'' Rzchak, 1881 * {{extinct}}''Palaeomyzon'' Weigelt, 1930 * {{extinct}}''Geomichthys'' Sauvage, 1888 }}

'''''Palaeoniscum''''' (from {{langx|el|παλαιός}} {{Transliteration|el|palaiós}}, 'ancient' and {{langx|el|ὀνίσκος}} {{Transliteration|el|onískos}} 'cod-fish' or 'woodlouse')<ref>{{cite book |last1=Roberts |first1=George |title=An etymological and explanatory dictionary of the terms and language of geology |date=1839 |publisher=Longman, Orme, Brown, Green, & Longmans |location=London |page=129 |url=https://archive.org/details/anetymologicala00robegoog |access-date=31 December 2021 |language=English}}</ref> is an extinct genus of ray-finned fish from the Middle to Late Permian period (Guadalupian-Lopingian) of England, Germany, Turkey, North America and Greenland, and possibly other regions.<ref>{{cite journal |last1=Hoşgör |first1=Izzet |last2=Štamberg |first2=Stanislav |title=A first record of late Middle Permian actinopterygian fish from Anatolia, Turkey |journal=Acta Geologica Polonica |date=2014 |volume=64 |issue=2 |pages=147–159 |url = https://geojournals.pgi.gov.pl/agp/article/view/13704 |doi = 10.2478/agp-2014-0009|bibcode=2014AcGeP..64..147H |doi-access=free }}</ref> The genus was named ''Palaeoniscum'' in 1818 by Henri Marie Ducrotay de Blainville,<ref>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.</ref> but was later misspelled as '''''Palaeoniscus''''' by Blainville and other authors (notably Louis Agassiz).<ref>{{cite book |author=Agassiz, Louis |date=1833–1843 |title=Recherches sur les poissons fossiles |url=https://www.biodiversitylibrary.org/bibliography/4275 |publisher=Petitpierre, Neuchâtel}}</ref> ''Palaeoniscum'' belongs to the family Palaeoniscidae.

200px|thumb|left|Restoration of ''Palaeoniscum'' 200px|thumb|left|''P. vratislavensis'' fossil 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.<ref>{{cite journal |last1=Schaumberg |first1=Günther |title=Die Richelsdorfer Kupferschiefer und seine Fossilien, III |journal=Aufschluss |date=1977 |volume=28 |pages=297–352}}</ref> The genus is considered to be a poorly defined wastebasket taxon.<ref>{{Cite journal |last1=Henderson |first1=Struan |last2=Dunne |first2=Emma M. |last3=Fasey |first3=Sophie A. |last4=Giles |first4=Sam |date=February 2023 |title=The early diversification of ray‐finned fishes ( Actinopterygii ): hypotheses, challenges and future prospects |journal=Biological Reviews |language=en |volume=98 |issue=1 |pages=284–315 |doi=10.1111/brv.12907 |issn=1464-7931 |pmc=10091770 |pmid=36192821}}</ref>

''Palaeoniscum'' had a torpedo-shaped body {{convert|30|cm|in|abbr=on}} 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.<ref>{{cite book |editor=Palmer, D.|year=1999 |title= The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals|publisher= Marshall Editions|location=London|page= 36|isbn= 1-84028-152-9}}</ref>

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).<ref>{{cite journal |last1=Romano |first1=Carlo |last2=Koot |first2=Martha B. |last3=Kogan |first3=Ilja |last4=Brayard |first4=Arnaud |last5=Minikh |first5=Alla V. |last6=Brinkmann |first6=Winand |last7=Bucher |first7=Hugo |last8=Kriwet |first8=Jürgen |title=Permian-Triassic Osteichthyes (bony fishes): diversity dynamics and body size evolution |journal=Biological Reviews |date=February 2016 |volume=91 |issue=1 |pages=106–147 |doi=10.1111/brv.12161 |pmid=25431138 |s2cid=5332637 }}</ref><ref>{{Cite journal|last1=Gonçalves|first1=D. |last2=Luccisano|first2=V. |title=Taxonomic status of ‘Palaeoniscum delessei’ (early Permian, Bourbon-l’Archambault Basin, Allier, France) |year=2025 |journal=Journal of Vertebrate Paleontology |doi=10.1080/02724634.2025.2523972 }}</ref> 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. {{Portal|Paleontology|Fish}}

==Species== * {{extinct}}''Palaeoniscum angustum'' (Rzehak, 1881) [{{extinct}}''Palaeoniscas angustus'' Rzehak, 1881] * {{extinct}}''Palaeoniscum antipodeum'' (Egerton, 1864) [{{extinct}}''Palaeoniscus antipodeus'' Egerton, 1864] * {{extinct}}''Palaeoniscum antiquum'' Williams, 1886 * {{extinct}}''Palaeoniscum arenaceum'' Berger, 1832 * {{extinct}}''Palaeoniscum capense'' (Bloom, 1913) [{{extinct}}''Palaeoniscus capensis'' Bloom, 1913] * {{extinct}}''Palaeoniscum comtum'' (Agassiz, 1833) [{{extinct}}''Palaeoniscus comtus'' Agassiz, 1833] * {{extinct}}''Palaeoniscum crassum'' (Woodward, 1908) [{{extinct}}''Palaeoniscus crassus'' Woodward, 1908] * {{extinct}}''Palaeoniscum daedalium'' Yankevich & Minich, 1998 * {{extinct}}''Palaeoniscum devonicum'' Clarke, 1885 * {{extinct}}''Palaeoniscum elegans'' (Sedgwick, 1829) [{{extinct}}''Palaeoniscus elegans'' Sedgwick, 1829] * {{extinct}}''Palaeoniscum freieslebeni'' de Blainville, 1818 (type species) [{{extinct}}''Eupalaeoniscus freieslebeni'' (de Brainville, 1818); {{extinct}}''Palaeoniscus freieslebeni'' (de Brainville, 1818); {{extinct}}''Palaeoniscus macropomus'' Agassiz, 1833; {{extinct}}''Palaeoniscus magnus'' Woodward, 1937] * {{extinct}}''Palaeoniscum hassiae'' (Jaekel, 1898) [{{extinct}}''Galeocerdo contortus hassiae'' Jaekel, 1898; {{extinct}}''Palaeomyzon hassiae'' (Jaekel, 1898)] * {{extinct}}''Palaeoniscum kasanense'' Geinitz & Vetter, 1880 * {{extinct}}''Palaeoniscum katholitzkianum'' (Rzehak, 1881) [{{extinct}}''Palaeoniscas katholitzkianus'' Rzehak, 1881] * {{extinct}}''Palaeoniscum landrioti'' (le Sauvage, 1890) [{{extinct}}''Palaeoniscus landrioti'' le Sauvage, 1890] * {{extinct}}''Palaeoniscum longissimum'' (Agassiz, 1833) [{{extinct}}''Palaeoniscus longissimus'' Agassiz, 1833] * {{extinct}}''Palaeoniscum macrophthalmum'' (McCoy, 1855) [{{extinct}}''Palaeoniscus macrophthalmus'' McCoy, 1855] * {{extinct}}''Palaeoniscum moravicum'' (Rzehak, 1881) [{{extinct}}''Palaeoniscas moravicus'' Rzehak, 1881] * {{extinct}}''Palaeoniscum promtus'' (Rzehak, 1881) [{{extinct}}''Palaeoniscas promtus'' Rzehak, 1881] * {{extinct}}''Palaeoniscum reticulatum'' Williams, 1886 * {{extinct}}''Palaeoniscum scutigerum'' Newberry, 1868

==Species moved to other genera== * {{extinct}}''Palaeoniscum abbsi'' Kirkby, 1862 → †''Acentrophorus varians'' (Kirkby, 1862) * {{extinct}}''Palaeoniscum glaphyrus'' (Agassiz, 1835) [{{extinct}}''Palaeoniscus glaphyrus''] Agassiz, 1835 → †''Acentrophorus glaphyrus'' (Agassiz, 1835) * {{extinct}}''Palaeoniscum blainvillei'' (Agassiz, 1833) [{{extinct}}''Palaeoniscus blainvillei'' Agassiz, 1833] → †''Aeduella blainvillei'' (Agassiz, 1833) * {{extinct}}''Palaeoniscum delessei'' (Sauvage, 1878) → †''Aeduella blainvillei'' (Agassiz, 1833) * {{extinct}}''Palaeoniscum gelberti'' Goldfuss, 1847 → †''Paramblypterus duvernoyi'' (Agassiz, 1833) * {{extinct}}''Palaeoniscum vratislaviensis'' (Agassiz, 1833) [{{extinct}}''Palaeoniscus vratislaviensis'' Agassiz, 1833] → †''Paramblypterus vratislaviensis'' (Agassiz, 1833)

==References== {{Reflist}}

Category:Prehistoric ray-finned fish genera Category:Permian bony fish Category:Palaeonisciformes Category:Permian fish of Europe Category:Permian fish of North America Category:Fossil taxa described in 1818 Category:Lopingian life Category:Wuchiapingian life