Helicoprionidae

Helicoprionidae; Temporal range: 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 (synonym Agassizodontidae) is an extinct, poorly known family of bizarre holocephalids within the poorly understood order Eugeneodontida. Members of the Helicoprionidae possessed a unique "tooth-whorl" on the symphysis of the lower jaw and pectoral fins supported by long radials. The closest living relatives of the Helicoprionidae and all other eugeneodontids are the ratfishes. The anatomy of the tooth-whorl differed amongst genus and species, some possessing complete spirals (such as those of Helicoprion), others possessing halved spirals (seen in Parahelicoprion), and some with wedged half-spirals (seen in Sarcoprion). Each tooth-whorl is thought to be adapted to a different type of prey, and a different predation strategy.

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.