Palaeoniscum


Palaeoniscum is an extinct genus of ray-finned fish from the Middle to Late Permian period of England, Germany, Turkey, North America and Greenland, and possibly other regions. The genus was named Palaeoniscum in 1818 by Henri Marie Ducrotay de Blainville, but was later misspelled as Palaeoniscus by Blainville and other authors. Palaeoniscum belongs to the family Palaeoniscidae.
The type species Palaeoniscum freieslebeni was named after Johann Carl Freiesleben, 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. The genus is considered to be a poorly defined wastebasket taxon.
Palaeoniscum had a torpedo-shaped body 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.
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. The allocation of other species to Palaeoniscum is often doubtful and mostly based on superficial resemblance with P. freieslebeni.
Palaeoniscum is the name giving taxon of the extinct Palaeonisciformes, 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

  • Palaeoniscum angustum
  • Palaeoniscum antipodeum
  • Palaeoniscum antiquum Williams, 1886
  • Palaeoniscum arenaceum Berger, 1832
  • Palaeoniscum capense
  • Palaeoniscum comtum
  • Palaeoniscum crassum
  • Palaeoniscum daedalium Yankevich & Minich, 1998
  • Palaeoniscum devonicum Clarke, 1885
  • Palaeoniscum elegans
  • Palaeoniscum freieslebeni de Blainville, 1818
  • Palaeoniscum hassiae
  • Palaeoniscum kasanense Geinitz & Vetter, 1880
  • Palaeoniscum katholitzkianum
  • Palaeoniscum landrioti
  • Palaeoniscum longissimum
  • Palaeoniscum macrophthalmum
  • Palaeoniscum moravicum
  • Palaeoniscum promtus
  • Palaeoniscum reticulatum Williams, 1886
  • Palaeoniscum scutigerum Newberry, 1868

    Species moved to other genera

  • Palaeoniscum abbsi Kirkby, 1862 → †Acentrophorus varians
  • Palaeoniscum glaphyrus Agassiz, 1835 → †Acentrophorus glaphyrus
  • Palaeoniscum blainvillei → †Aeduella blainvillei
  • Palaeoniscum delessei → †Aeduella blainvillei
  • Palaeoniscum gelberti Goldfuss, 1847 → †Paramblypterus duvernoyi
  • Palaeoniscum vratislaviensis → †''Paramblypterus vratislaviensis''