Helicoprionidae
Extinct family of cartilaginous fishes
From Wikipedia, the free encyclopedia
Helicoprionidae (sometimes referred to as Agassizodontidae)[3] 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.[3][4] While historically considered elasmobranchs related to sharks and rays,[3] the closest living relatives of the Helicoprionidae and all other eugeneodonts are now thought to be the ratfishes.[5] 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.[3]
| Helicoprionidae Temporal range: Early Carboniferous to Late Permian | |
|---|---|
| |
| Helicoprion | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Holocephali |
| Order: | †Eugeneodontiformes |
| Clade: | †Edestoidea |
| Family: | †Helicoprionidae Karpinsky, 1911 |
| Type genus | |
| Helicoprion Karpinsky, 1899[1] | |
| Type species | |
| Helicoprion bessonowi Karpinsky, 1899 | |
| Genera[2] | |
| Synonyms | |
| |
