Eugeneodontida

Eugeneodontida; Temporal range: 407.7–247.2 Ma PreꞒ Ꞓ O S D C P T J K Pg N Early Devonian to Olenekian
	Helicoprion davisii
	Edestus heinrichi
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Holocephali
Order:	†Eugeneodontida; Zangerl, 1981
Synonyms
	Eugeneodontiformes;

The Eugeneodontida is an extinct and poorly known order of cartilaginous fishes. They possessed "tooth-whorls" on the symphysis of either the lower or both jaws and pectoral fins supported by long radials. They probably lacked pelvic fins and anal fins.^[3] The palatoquadrate was either fused to the skull or reduced. Now determined to be within the Holocephali, their closest living relatives are ratfish.^[4] The eugeneodonts are named after paleontologist Eugene S. Richardson, Jr.^[5] The Eugeneodontida disappeared in the Early Triassic.^[6]

Members of the Eugeneodontida are further classified into different families, the most well-preserved members that have been discovered are commonly placed within the families Helicoprionidae ("spiral saws"), and Edestidae ("those which devour"), the former containing the genera Helicoprion, Sarcoprion, and Parahelicoprion, and the latter containing the genera Edestus, Lestrodus, and Metaxyacanthus. All eugeneodonts are thought to have been obligate carnivores, with each genus having specialized feeding behaviors, territory ranges, and specific prey.

Taxonomy^[7]

Superfamily Caseodontoidea
- Family Caseodontidae
  - Genus Caseodus
  - Genus Erikodus
  - Genus Fadenia
  - Genus Ornithoprion
  - Genus Pirodus
  - Genus Romerodus
- Family Eugeneodontidae
  - Genus Bobbodus
  - Genus Eugeneodus
  - Genus Gilliodus
- Family incertae sedis
  - Genus Campodus
  - Genus Chiastodus
  - Genus Tiaraju
Superfamily Edestoidea
- Family Helicoprionidae
  - Genus Agassizodus
  - Genus Arpagodus
  - Genus Campyloprion
  - Genus Helicoprion
  - Genus Parahelicoprion
  - Genus Sarcoprion
  - Genus Toxoprion
- Family Edestidae
  - Genus Edestus
  - Genus Helicampodus
  - Genus Lestrodus
  - Genus Parahelicampodus
  - Genus Syntomodus
- Family incertae sedis
  - Genus Paredestus

References

^ Mutter, Raoul J., and Andrew G. Neuman. "New eugeneodontid sharks from the Lower Triassic Sulphur Mountain Formation of Western Canada." Geological Society, London, Special Publications 295.1 (2008): 9-41.
^ The Paleobiology Database - Eugeneodontiformes
^ Lebedev, O.A. (2009). "A new specimen of Helicoprion Karpinsky, 1899 from Kazakhstanian Cisurals and a new reconstruction of its tooth whorl position and function". Acta Zoologica. 90: 171–182. doi:10.1111/j.1463-6395.2008.00353.x. ISSN 0001-7272.
^ Tapanila L.; Pruitt J.; Pradel A.; Wilga C.; Ramsay J.; Schlader R.; Didier D. (2013). "Jaws for a spiral-tooth whorl: CT images reveal novel adaptation and phylogeny in fossil Helicoprion". Biology Letters. 9 (2): 20130057. doi:10.1098/rsbl.2013.0057. PMC 3639784. PMID 23445952.
^ Zangerl, R. (1981). Handbook of Paleoichthyology. Volume 3A. Chondrichthyes I. Paleozoic Elasmobranchi. Stuttgart: Gustav Fischer Verlag. ISBN 978-3-89937-045-4.
^ Scheyer, Torsten M.; Romano, Carlo; Jenks, Jim; Bucher, Hugo (19 March 2014). "Early Triassic Marine Biotic Recovery: The Predators' Perspective". PLOS ONE. 9 (3): e88987. Bibcode:2014PLoSO...988987S. doi:10.1371/journal.pone.0088987. PMC 3960099. PMID 24647136.
^ Ginter, M.; Hampe, O.; Duffin, C. (2010). Handbook of Paleoichthyology. Volume 3D. Chondrichthyes. Paleozoic Elasmobranchi: Teeth. Munich: Verlag Dr. Friedrich Pfeil. ISBN 978-3-89937-116-1.

External links

[1] Palaeos Vertebrates 70.100 Chondrichthyes: Eugnathostomata at paleos.com
JSTOR: Journal of Paleontology Vol. 70, No. 1 (Jan., 1996), pp. 162-165
More about Chondrichthyes at Devonian Times

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[mutter-1] Mutter, Raoul J., and Andrew G. Neuman. "New eugeneodontid sharks from the Lower Triassic Sulphur Mountain Formation of Western Canada." Geological Society, London, Special Publications 295.1 (2008): 9-41.

[paleodb-2] The Paleobiology Database - Eugeneodontiformes

[Lebedev2009-3] Lebedev, O.A. (2009). "A new specimen of Helicoprion Karpinsky, 1899 from Kazakhstanian Cisurals and a new reconstruction of its tooth whorl position and function". Acta Zoologica. 90: 171–182. doi:10.1111/j.1463-6395.2008.00353.x. ISSN 0001-7272.

[Tapanila_2013-4] Tapanila L.; Pruitt J.; Pradel A.; Wilga C.; Ramsay J.; Schlader R.; Didier D. (2013). "Jaws for a spiral-tooth whorl: CT images reveal novel adaptation and phylogeny in fossil Helicoprion". Biology Letters. 9 (2): 20130057. doi:10.1098/rsbl.2013.0057. PMC 3639784. PMID 23445952.

[5] Zangerl, R. (1981). Handbook of Paleoichthyology. Volume 3A. Chondrichthyes I. Paleozoic Elasmobranchi. Stuttgart: Gustav Fischer Verlag. ISBN 978-3-89937-045-4.

[Scheyer_et_al_2014-6] Scheyer, Torsten M.; Romano, Carlo; Jenks, Jim; Bucher, Hugo (19 March 2014). "Early Triassic Marine Biotic Recovery: The Predators' Perspective". PLOS ONE. 9 (3): e88987. Bibcode:2014PLoSO...988987S. doi:10.1371/journal.pone.0088987. PMC 3960099. PMID 24647136.

[7] Ginter, M.; Hampe, O.; Duffin, C. (2010). Handbook of Paleoichthyology. Volume 3D. Chondrichthyes. Paleozoic Elasmobranchi: Teeth. Munich: Verlag Dr. Friedrich Pfeil. ISBN 978-3-89937-116-1.

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Taxonomy[7]

References

External links

Taxonomy^[7]