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Temporal range: Late Triassic - Eocene
Gyrodus hexagonus 2.jpg
Gyrodus hexagonus
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Pycnodontiformes
Berg, 1937
(see text)

Pycnodontiformes is an extinct order of bony fish. The group evolved during the Late Triassic and disappeared during the Eocene. The group has been found in rock formations in Africa, Asia, Europe, North and South America.[1]

The pycnodontiforms were small to middle-sized fish, with laterally-compressed body and almost circular outline.[2]

Pycnodontiform fishes lived mostly in shallow-water seas. They had special jaws with round and flattened teeth,[3] well adapted to crush food items.[2] One study links the dentine tubules in pycnodont teeth to comparable structures in the dermal denticles of early Paleozoic fish.[4] Some species lived in rivers and possibly fed on molluscs and crustaceans.[5]



  1. ^ "Pycnodontiformes". Palaeos vertebrates. Archived from the original on 25 October 2008. Retrieved 27 July 2009.
  2. ^ a b "Pycnodontid fishes from the Kansas Cretaceous". Oceans of Kansas. 16 April 2009. Retrieved 29 July 2009.
  3. ^ McMenamin, M. A. S. (2009). Paleotorus: The Laws of Morphogenetic Evolution. Meanma Press. ISBN 978-1-893882-18-8.
  4. ^ Lepelstat, A. L.; McMenamin, M. A. S.; Bouse, L. A.; Fleury, D.; Marchand, G. J. (2010). "Dentine canals in Cambro-Ordovician ostracoderms and Cretaceous-Eocene pycnodont fish". Geological Society of America Abstracts with Programs. 42 (5): 94.
  5. ^ "Mosasaurs terrorized Cretaceous rivers". Planet Earth online. 29 July 2009. Archived from the original on 3 August 2009. Retrieved 30 July 2009.
  6. ^ Nelson, Joseph S.; Grande, Terry C.; Wilson, Mark V. H. (2016). Fishes of the World (5th ed.). John Wiley & Sons. ISBN 9781118342336.
  7. ^ van der Laan, Richard (2016). "Family-group names of fossil fishes". Cite journal requires |journal= (help)
  8. ^ a b L. Taverne; L. Capasso (2014). "Ostéologie et phylogénie des Coccodontidae, une famille remarquable de poissons Pycnodontiformes du Crétacé supérieur marin du Liban, avec la description de deux nouveaux genres". Palaeontos. 25.