| Helicoprionidae Temporal range: 358–252 Ma PreꞒ Ꞓ O S D C P T J K Pg N Early Carboniferous to Late Permian | |
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| Helicoprion | |
Scientific classification 
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| 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 | |
| Synonyms | |
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Helicoprionidae (sometimes referred to as Agassizodontidae) 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. While historically considered elasmobranchs related sharks and rays, the closest living relatives of the Helicoprionidae and all other eugeneodonts are now thought to be the ratfishes. 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.
References
- ^ 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.
- ^ 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
| Taxon identifiers | |
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| Agassizodontidae | |
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