Holoptychius

Holoptychius (from Greek: όλος holos, 'whole' and Greek: πτυχή ptyche 'fold')[1] is an extinct genus of porolepiform lobe-finned fish from the Middle Devonian to Carboniferous (Mississippian) periods. It is known from fossils worldwide. The genus was first described by Louis Agassiz in 1839.[2]

Holoptychius
Temporal range: Late Devonian-Mississippian
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Fossil of H. quebecensis in the Field Museum of Natural History, Chicago
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Order: †Porolepiformes
Family: †Holoptychiidae
Genus: †Holoptychius
Agassiz 1839
Type species
Holoptychius nobilissimus
Species
  • H. americanus
  • H. andersoni
  • H. flemingi
  • H. giganteus
  • H. halli
  • H. hopkinsii
  • H. nobilissimus
  • H. quebecensis

Description

Holoptychius was streamlined predator about 50 centimetres (20 in) long (though largest specimen could grew up to 2.5 metres (8.2 ft)), which fed on other bony fish. Its rounded scales and body form indicate that it could have swum quickly through the water to catch prey.[3][4] Similar to other rhipidistians, it had fang-like teeth on its palate in addition to smaller teeth on the jaws. Its asymmetrical tail sported a caudal fin on its lower end. To compensate for the downward push caused by this fin placement, the pectoral fins of Holoptychius were placed high on the body.

Species

Of the genus Holoptychius the following species have been described:[2]

  • H. americanus
  • H. andersoni
  • H. flemingi
  • H. giganteus
  • H. halli
  • H. hopkinsii
  • H. nobilissimus
  • H. quebecensis

Distribution

Fossils of Holoptychius have been found in the Mississippian of the United Kingdom and the Devonian of Belgium, Colombia (Cuche Formation, Boyacá),[5] Norway, the Russian Federation, and the United States (Pennsylvania).[6]

  • H. andersoni
  • Life restoration of Holoptychius sp.
  • H. nobilissimus and scale

References
  1. Roberts, George (1839). An etymological and explanatory dictionary of the terms and language of geology. London: Longman, Orme, Brown, Green, & Longmans. p. 78. Retrieved 30 December 2021.
  2. Species Holoptychius
  3. Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 43. ISBN 1-84028-152-9.
  4. Holland, Timothy (2010). "Upper Devonian osteichthyan remains from the Genoa River, Victoria, Australia" (PDF). Memoirs of Museum Victoria. 67: 35–44. Retrieved 2017-04-04.
  5. Janvier & Villarroel, 1998
  6. Holoptychius at Fossilworks.org

Bibliography

Media related to Holoptychius at Wikimedia Commons


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