Eugeneodontida

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

The Eugeneodontida is an extinct and poorly known order of bizarre cartilaginous fishes. They possessed a unique "tooth-whorl" on the symphysis of the lower jaw and pectoral fins supported by long radials. The palatoquadrate was either fused to the skull or reduced. Now determined to be within the Holocephali, their closest living relatives are ratfish.^[3] The meaning of the name Eugeneodont correlates to "true origin teeth", and comes from the Greek eu (good/true), geneos (race, kind, origin), and odon (tooth).

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, Listracanthus, and Metaxyacanthus. All eugeneodonts are thought to be obligate carnivores, with each genus having specialized feeding behaviors, territory ranges, and specific prey.

Taxonomy

Family Eugeneodontidae
- Genus Bobbodus
- Genus Eugeneodus
- Genus Gilliodus
Superfamily Edestoidea
- Family Helicoprionidae
  - Genus Agassizodus
  - Genus Arpagodus
  - Genus Campyloprion
  - Genus Helicoprion
  - Genus Hunanohelicoprion
  - Genus Parahelicoprion
  - Genus Sarcoprion
  - Genus Sinohelicoprion
  - Genus Toxoprion
- Family Edestidae
  - Genus Edestus
  - Genus Helicampodus
  - Genus Lestrodus
  - Genus Metaxyacanthus
  - Genus Parahelicampodus
  - Genus Physonemus
  - Genus Prospiraxis
  - Genus Syntomodus
Superfamily Caseodontoidea
- Genus Campodus
- Genus Chiastodus
- Family Caseodontidae
  - Genus Caseodus
  - Genus Erikodus
  - Genus Fadenia
  - Genus Ornithoprion
  - Genus Romerodus

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
^ 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.

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

This article about a prehistoric shark is a stub. You can help Wikipedia by expanding it.

[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

[Tapanila_2013-3] 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.

[1]

[2]

[3]