Ctenacanthiformes

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]

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)