Pycnodontiformes

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Pycnodontiformes
Temporal range: Late Triassic - Eocene
Gyrodus hexagonus 2.jpg
Gyrodus hexagonus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Pycnodontiformes
Families
(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]

Taxonomy[edit]

Timeline of genera[edit]

Paleogene Cretaceous Jurassic Triassic Oligocene Eocene Paleocene Late Cretaceous Early Cretaceous Late Jurassic Middle Jurassic Early Jurassic Late Triassic Middle Triassic Early Triassic Micropycnodon Nursallia Polygyrodus Grypodon Acrotemnus Anomoeodus Trewavasia Ichthyoceras Coccodus Stemmatodus Palaeobalistum Athrodon Coelodus Tibetodus Pycnodus Proscinetes Gyronchus Gyrodus Mesturus Eomesodon Gibbodon Brembodus Paleogene Cretaceous Jurassic Triassic Oligocene Eocene Paleocene Late Cretaceous Early Cretaceous Late Jurassic Middle Jurassic Early Jurassic Late Triassic Middle Triassic Early Triassic

References[edit]

  1. ^ "Pycnodontiformes". Palaeos vertebrates. 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. Retrieved 30 July 2009. 
  6. ^ "Pycnodontiformes". Mikko's Phylogeny Archive. 11 March 2008. Retrieved 27 July 2009. 
  7. ^ Nursall and Capasso, Mesozoic Fishes 4 – Homology and Phylogeny, G. Arratia, H.-P. Schultze & M. V. H. Wilson (eds.), Verlag Dr. Friedrich Pfeil, München, Germany 2008 – ISBN 978-3-89937-080-5"Additional specimens from Lebanon reveal more of the structure of the pycnodont fish Trewavasia carinata (DAVIS, 1887)"
  8. ^ Nursall, Ralph Mesozoic Fishes – Systematics and Paleoecology, G. Arratia & G. Viohl (eds.), Verlag Dr. Friedrich Pfeil, München, Germany, 1996 – ISBN 3-923871-90-2 "The phylogeny of pycnodont fishes"