Pycnodontiformes

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]

Pycnodontiformes
Temporal range: Late Triassic - Eocene
Gyrodus hexagonus 2
Gyrodus hexagonus
Scientific classification
Kingdom:
Phylum:
Class:
Order:
Pycnodontiformes
Families
(see text)

Taxonomy

  • Order Pycnodontiformes (Berg, 1937) [6][7][8]
    • Genus ?†Acrorhinichthys Taverne & Capasso 2015
    • Genus ?†Archaeopycnodon Sanchez & Benedetto 1980
    • Genus ?†Athrodon le Sauvage 1880 non Osborn 1887
    • Genus ?†Callodus Thurmond 1974
    • Genus ?†Cosmodus le Sauvage 1879 [Glossodus Costa 1851 non Agassiz 1828 ex Spix & Agassiz 1829 non McCoy 1848]
    • Genus ?†Ellipsodus Cornuel 1877
    • Genus ?†Grypodon Hay 1899 [Ancistrodon Dames 1883 non De Beauvois 1799 non Roemer 1852 non Wagler 1830]
    • Genus ?†Mercediella Koerber 2012 [Camposichthys Figueiredo & Silva-Santos 1991 non Travassos 1946 non Whitley 1953]
    • Genus ?†Piranhamesodon Kölbl-Ebert et al., 2018
    • Genus ?†Pseudopycnodus Taverne 2003
    • Genus ?†Tergestinia Capasso 2000
    • Genus ?†Thurmondella Thurmond 1974 non [Paramicrodon Thurmond 1974 non de Meijere 1913]
    • Genus ?†Uranoplosus le Sauvage 1879
    • Genus ?†Woodthropea Swinnerton 1925
    • Family ?†Hadrodontidae Thurmond & Jones 1981
      • Genus †Hadrodus Leidy 1858 [Propenser Applegate 1970]
    • Family ?†Gebrayelichthyidae Nursall & Capasso 2004
      • Genus †Gebrayelichthys Nursall & Capasso 2004
      • Genus †Maraldichthys Taverne & Capasso 2014
    • Family ?†Gladiopycnodontidae Taverne & Capasso 2013
      • Genus †Arduafrons Frickhinger 1991
      • Genus †Eomesodon Woodward 1918
      • Genus †Gladiopycnodus Taverne & Capasso 2013
      • Genus †Joinvillichthys Taverne & Capasso 2014
    • Genus †Micropycnodon Hibbard & Graffham 1945 [Pycnomicrodon Hibbard & Graffham 1941 non Hay 1916]
      • Genus †Monocerichthys Taverne & Capasso 2013
      • Genus †Pankowskichthys Taverne & Capasso 2014
      • Genus †Paramesturus Taverne 1981
      • Genus †Rostropycnodus Taverne & Capasso 2013
      • Genus †Stenoprotome Hay 1903
    • FamilyMesturidae Nursall 1996
    • FamilyGyrodontidae Berg 1940
    • FamilyBrembodontidae Tintori 1981 [Brembodidae; Gibbodontidae Tintori 1981]
    • FamilyCoccodontidae Berg 1940 [Trewavasiidae Nursall 1996]
    • FamilyPycnodontidae Agassiz 1833 corrig. Bonaparte 1845 [Nursalliidae Bloy 1987; Sphaerodontidae Giebel 1846; Palaeobalistidae Blot 1987; Proscinetidae Gistel 1848; Gyronchidae]
      • Genus †Abdobalistum Poyato-Ariza & Wenz 2002
      • Genus †Anomiophthalmus Costa 1856
      • Genus †Anomoedus Forir 1887
      • Genus †Acrotemnus Agassiz 1836
      • Genus †Akromystax Poyato-Ariza & Wenz 2005
      • Genus †Coelodus Heckel 1854
      • Genus †Flagellipinna Cawley & Kriwet 2019
      • Genus †Macropycnodon Shimada, Williamson & Sealey 2010
      • Genus †Macromesodon Blake 1905 non Lehman 1966 [Mesodon Wagner 1851 non Rafinesque 1821; Gyronchus Agassiz 1839; Apomesodon Poyato-Ariza & Wenz 2002]
      • Genus †Neoproseinetes De Figueiredo & Silva Santos 1990
      • Genus †Nursallia Blot 1987
      • Genus †Ocloedus Poyato-Ariza & Wenz 2002
      • Genus †Oropycnodus Poyato-Ariza & Wenz 2002
      • Genus †Palaeobalistum Taverne et al. 2015
      • Genus †Paranursallia Taverne et al. 2015
      • Genus †Phacodus Dixon 1850 [Phacodus Dixon 1850 non Cope 1869]
      • Genus †Polazzodus Poyoto-Ariza 2010
      • Genus †Polygyrodus White 1927
      • Genus †Potiguara Machado & Brito 2006
      • Genus †Proscinetes Gistl 1848 [Microdon Agassiz 1833 non Meigen 1803 non Fritsch 1876 non Conrad 1842 non Gistl 1848 non Dixon 1850; Polypsephis Hay 1899]
      • Genus †Pycnomicrodon Hay 1916 non Hibbard & Graffham 1941
      • Genus †Pycnodus Agassiz 1833
      • Genus †Rhinopycnodus Taverne & Capasso 2013
      • Genus †Sphaerodus Agassiz 1833
      • Genus †Sphaeronchus Stinton & Torrens 1967
      • Genus †Stenamara Poyato-Ariza & Wenz 2000
      • Genus †Stemmatias Hay 1899 [Stemmatodus St. John & Worthen 1875 non Heckel 1854 non]
      • Genus †Stemmatodus Heckel 1854 non St. John & Worthen 1875 non
      • Genus †Sylvienodus Poyato-Ariza & Wenz 2013
      • Genus †Tamanja Wenz 1989
      • Genus †Tepexichtys Applegate 1992
      • Genus †Tibetodus Young & Liu 1954
      • Genus †Turbomesodon Poyato-Ariza & Wenz 2004 [Macromesodon Lehman 1966 non Blake 1905]
      • Genus †Typodus Quenstedt 1858
      • Genus †Abdobalistum Poyato-Ariza & Wenz 2002

References

  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. ^ Haaramo, Mikko (2007). "†Pycnodontiformes – pycnodont fishes". Mikko's Phylogeny Archive. Retrieved 30 December 2016.
  7. ^ Nelson, Joseph S.; Grande, Terry C.; Wilson, Mark V. H. (2016). Fishes of the World (5th ed.). John Wiley & Sons. ISBN 9781118342336.
  8. ^ van der Laan, Richard (2016). "Family-group names of fossil fishes".
  9. ^ 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.
Acrotemnus

Acrotemnus is an extinct genus of prehistoric ray-finned fish that lived during the Late Cretaceous epoch.

Anomoeodus

Anomoeodus is an extinct genus of prehistoric ray-finned fish from the Albian to Maastrichtian of France, Belgium, the Netherlands, Egypt, Uzbekistan and the United States.

Coccodontidae

Coccodontidae is a family of extinct pycnodontid fish that lived during the lower Cenomanian. The various genera had massive, curved spines.

The family is composed of five genera, the type genus, Coccodus, Paracoccodus which was split off from Coccodus, the newly described Corusichthys, the sexually dimorphic Hensodon, and Trewavasia. Ichthyoceros was, at one time, placed in Coccodontidae, but then was moved with Trewavasia in "Trewavasiidae," and then, in 2014, was placed in the related pycnodontid family Gladiopycnodontidae, while Trewavasia was returned to Coccodontidae.Coccodontidae, together with Gladiopycnodontidae and the superficially shrimpfish-like Gebrayelichthyidae, make up the pycnodontid superfamily Coccodontoidea.

Coccodus

Coccodus is an extinct genus of extinct pycnodontid fish that lived during the lower Cenomanian. The various species had a pair of massive, curved spines emanating from the lower sides of the head, and one curved spine on the top of its head. Unlike most pycnodontids (which tend to have short, marine butterflyfish-like bodies), Coccodus species had a comparatively long body, giving the living animals a superficial resemblance to a scaly chimaera.

Coccodus is closely related to the similarly spined genera Trewavasia, Corusichthys, Paracoccodus, and Hensodon, which also lived during the Cenomanian of Lebanon.

Corusichthys

Corusichthys megacephalus is an extinct pycnodontid that lived during the lower Cenomanian of what is now Lebanon. C. megacephalus is known from a 34 mm long fossil. It had plates arranged like a helmet around its head, and had a massive, triangular spine on its dorsal side. C. megacephalus is closely related the genera Trewavasia and Hensodon, as well as Coccodus.

Eomesodon

Eomesodon is an extinct genus of prehistoric ray-finned fish. It lived during the Late Triassic and Jurassic.

Grypodon

Grypodon is an extinct genus of prehistoric ray-finned fish that lived during the Late Cretaceous epoch.

Gyrodus

Gyrodus is an extinct genus of pycnodontiform ray-finned fish that lived from the late Triassic (Rhaetian) to the middle Cretaceous (Cenomanian).

Gyronchus

Gyronchus is an extinct genus of prehistoric ray-finned fish from the Jurassic.

Ichthyoceros

Ichthyoceros spinosus is an extinct pycnodontid that lived during the lower Cenomanian of what is now Lebanon. I. spinosus had a triple, forward-pointing horn-like spine between its eyes, very similar to the single spine of Trewavasia, and a massive, multipointed spine emanating from the back of its head. It was originally placed in the family Coccodontidae, but then was transferred to "Trewavasiidae" with Trewavasia. Recently, it has been placed in Gladiopycnodontidae due to recent anatomical similarities with the various genera within that family, including Gladiopycnodus.

Micropycnodon

Micropycnodon is an extinct genus of prehistoric ray-finned fish that lived during the Santonian.

Nursallia

Nursallia is an extinct genus of pycnodontid ray-finned fishes, ranging from the Late Cretaceous period until its extinction during the Eocene.

Polazzodus

Polazzodus is an extinct pycnodontid from the late Cretaceous (early Santonian) of the Polazzo locality of northeastern Italy. The paleoenvironment of Polazzo was a large marine carbonate platform and shallow internal lagoons formed from rudist reefs. P. coronatus is known from a large number of specimens, many of which were very well preserved.

The new genus Polazzodus was erected based on a number of autapomorphies that distinguished it from similar pycnodontid fish. These include a second dorsal ridge scale (from which the Latin species name, coronatus, is derived), presence of olfactory fenestra on premaxilla, posterodorsal process on cleithrum, and several others. The largest measured recovered specimen was 97 mm (3.8 in), and the smallest was 30 mm (1.2 in), which represented a subadult specimen. Polazzodus, being a low-bodied pycnodont, is most similar morphologically to Pycnodus and Tergestrinia, though its body shape is more oval than these genera.

Proscinetes

Proscinetes is an extinct genus of prehistoric ray-finned fish from the Jurassic.

Pycnodontidae

Pycnodontidae is an extinct family of ray-finned fishes, ranging from the Triassic period until the Eocene.

Pycnodus

Pycnodus (from Greek for crowded teeth) is an extinct genus of ray-finned fish ranging from the Jurassic to Eocene periods. As its name suggests, it is the type genus of Pycnodontiformes.

The known whole fossils of Pycnodus are around 12 centimetres (5 in) long, and have a superficial resemblance to angelfish or butterflyfish. The animals, as typical of all other pycnodontids, had many knob-like teeth, forming pavements in the jaws with which to break and crush hard food substances, probably mollusks and echinoderms. These teeth are the most common form of fossil.

Pycnodus fossils have been found in present-day India, Northern Africa, Belgium, England, and Italy, regions corresponding with the Tethys Ocean. A specimen of the prehistoric whale, Basilosaurus isis, was found in the Eocene-aged Wadi El Hitan with stomach contents of its last meals, including a large specimen of the species P. mokattamensis along with skeletons of a smaller whale called Dorudon.

Stephanodus

Stephanodus is a genus of fossil fish that lived in the Mesozoic era. It was described by Zittel in 1883.

Tibetodus

Tibetodus is an extinct genus of prehistoric ray-finned fish that lived during the Late Jurassic epoch.

Trewavasia

Trewavasia carinata is an extinct pycnodontid that lived during the lower Cenomanian of what is now Lebanon. It had a large, forward-pointing horn-like spine between its eyes, and a massive stump-like spine emanating from the back of its head. T. carinata is closely related the genera Corusichthys and Hensodon, as well as Coccodus.

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