Helicoprionidae

Helicoprionidae
Temporal range: Mississippian–Lopingian
Helicoprion
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Chondrichthyes
Subclass:
Holocephali
Order:
†Eugeneodontiformes
Family:
†Helicoprionidae
Type species
†Helicoprion bessonovi
Karpinsky, 1899

Helicoprionidae (sometimes called Agassizodontidae) is an extinct family of holocephalans within the order Eugeneodontiformes. Members of the Helicoprionidae possessed a unique structure called a tooth whorl connected by a single root along the midline of the lower jaw.

The structure of tooth whorls varies, with some having highly specialized, coiling spirals (such as those of the iconic genus Helicoprion), while others such as Sarcoprion and Parahelicoprion possessed shorter whorls.

Genera

Agassizodus in the upper right, Romerodus, and the center, and Listracanthus behind

References

  1. 1 2 3 Zangerl, Rainer (1981). Chondrichthyes 1: Paleozoic Elasmobranchii (Handbook of Paleoichthyology). Friedrich Pfeil. pp. 74–94. ISBN 978-3899370454.
  2. ↑ 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. Archived from the original (PDF) on 2018-10-15. Retrieved 2025-07-27.
  3. ↑ Itano, Wayne; Lebedev, Oleg Anatolyevich; Johanson, Zerina; Alekseev, Alexander S. (February 2023). "Tooth whorl structure, growth and function in a helicoprionid chondrichthyan Karpinskiprion (nom. nov.) (Eugeneodontiformes) with a revision of the family composition". Transactions of the Royal Society of Edinburgh Earth Sciences. doi:10.1017/s1755691022000251.

Other websites

Media related to Helicoprionidae at Wikimedia Commons