Helicoprionidae

Helicoprionidae; Temporal range: 358–252 Ma PreꞒ Ꞓ O S D C P T J K Pg N Early Carboniferous to Late Permian
	Helicoprion
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Holocephali
Order:	†Eugeneodontida
Clade:	†Edestoidea
Family:	†Helicoprionidae; Karpinsky, 1911
Type genus
	Helicoprion; Karpinsky, 1899
Type species
	Helicoprion bessonowi; Karpinsky, 1899
Genera
	Agassizodus; Arpagodus; Campyloprion; Helicoprion; Hunanohelicoprion; Karpinskiprion; Parahelicoprion; Sarcoprion; Shaktauites; Sinohelicoprion; Toxoprion;
Synonyms
	Agassizodontidae Zangerl, 1981;

Helicoprionidae (sometimes referred to as Agassizodontidae)^[2] is an extinct family of holocephalans within the order Eugeneodontida. Members of the Helicoprionidae possessed a "whorl" of tooth crowns connected by a single root along the midline of the lower jaw.^[2]^[3] While historically considered elasmobranchs related sharks and rays,^[2] the closest living relatives of the Helicoprionidae and all other eugeneodonts are now thought to be the ratfishes.^[4] The anatomy of the tooth-whorls vary between taxa, with some possessing highly specialized, coiling spirals (such as those of the namesake genus Helicoprion), while others such as Sarcoprion and Parahelicoprion possessed shorter whorls.^[2]

References

^ ^a ^b 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.
^ ^a ^b ^c ^d Zangerl, Rainer (1981). Chondrichthyes 1: Paleozoic Elasmobranchii (Handbook of Paleoichthyology). Friedrich Pfiell. pp. 74–94. ISBN 978-3899370454.
^ Cicimurri, D. J.; Fahrenbach, M. D. (2002). "Chondrichthyes from the upper part of the Minnelusa Formation (Middle Pennsylvanian: Desmoinesian), Meade County, South Dakota" (PDF). Proceedings of the South Dakota Academy of Science. 81: 81–92.
^ Nelson, Joseph S.; Grande, Terry; Wilson, Mark V. H.; Wilson, Mark V. (2016). Fishes of the world (5th ed.). Hoboken, New Jersey: John Wiley & Sons. pp. 48–50. ISBN 978-1-118-34233-6.

External links

Palaeos Vertebrates 70.100 Chondrichthyes: Eugnathostomata at paleos.com
JSTOR: Journal of PaleontologyVol. 70, No. 1 (Jan., 1996), pp. 162-165
More about Chondrichthyes Archived 2017-10-22 at the Wayback Machine at Devonian Times

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[Lebedev-1] 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.

[:0-2] Zangerl, Rainer (1981). Chondrichthyes 1: Paleozoic Elasmobranchii (Handbook of Paleoichthyology). Friedrich Pfiell. pp. 74–94. ISBN 978-3899370454.

[3] Cicimurri, D. J.; Fahrenbach, M. D. (2002). "Chondrichthyes from the upper part of the Minnelusa Formation (Middle Pennsylvanian: Desmoinesian), Meade County, South Dakota" (PDF). Proceedings of the South Dakota Academy of Science. 81: 81–92.

[4] Nelson, Joseph S.; Grande, Terry; Wilson, Mark V. H.; Wilson, Mark V. (2016). Fishes of the world (5th ed.). Hoboken, New Jersey: John Wiley & Sons. pp. 48–50. ISBN 978-1-118-34233-6.

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