Ctenacanthiformes Temporal range: Devonian— Late Permian (Possible Valanginian record)
Life restoration of Dracopristis
Fin spine of Ctenacanthus formosus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Order:	†Ctenacanthiformes Glikman, 1964
Subtaxa
†Acandylacanthus †Arauzia †Ctenacanthoidea †Ctenacanthidae †Goodrichthys †Heslerodidae †Kaibabvenator †Moyacanthus †Nanoskalme †Neosaivodus †Pororhiza †Saivodus
Synonyms
Ctenacanthida Cappetta (1988)

Ctenacanthiformes is an extinct order of elasmobranch fish. They possessed ornamented fin spines at the front of their dorsal fins and cladodont-type dentition,^[1] that is typically of a grasping morphology, though some taxa developed cutting and gouging tooth morphologies.^[2] Some ctenacanths are thought to have reached sizes comparable to the great white shark, with body lengths of up to 7 metres (23 ft) and weights of 1,500–2,500 kilograms (3,300–5,500 lb).^[3] Ctenacanths are typically thought to have existed from the Devonian to the Late Permian, becoming extinct in the Permian-Triassic extinction event. Members of the family Ctenacanthidae may have survived into the Cretaceous based on teeth found in deep water deposits of Valanginian age in France^[4] and Austria,^[5] however, other authors contend that the similarity of these teeth to Paleozoic ctenacanths is only superficial, and they likely belong to neoselachians instead.^[6] The monophyly of the group has been questioned, with some studies recovering the group as a whole as paraphyletic or polyphyletic.^[7]

References