Sphenacanthus

Sphenacanthus Temporal range: Late Devonian-Late Permian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Family:	†Sphenacanthidae
Genus:	†Sphenacanthus Agassiz, 1837[1]
Type species
Sphenacanthus serrulatus Agazzis, 1837
Species[2]
Sphenacanthus aequistriatus Davis, 1879 Sphenacanthus carbonarius Giebel, 1848 Sphenacanthus costellatus Traquair, 1884 Sphenacanthus gondwanus Silva Santos, 1947 Sphenacanthus hybodioides Sphenacanthus hybodoides Sphenacanthus hybodoides Newberry, 1873 Sphenacanthus ignis Figueroa & Gallo, 2017 Sphenacanthus maranhensis Silva Santos, 1946 Sphenacanthus marshi Newberry, 1873 Sphenacanthus riorastoensis Pauliv et al., 2012 Sphenacanthus sanpauloensis Chahud et al., 2010 Sphenacanthus serrulatus Agassiz, 1837

Sphenacanthus (from Greek: σφήν sphḗn, 'wedge' and Greek: ἄκανθα akantha, 'spine')^[3] is an extinct genus of a chondrichtyan xenacanthiform that belongs to the Sphenacanthidae family and lived from the Late Devonian, through Carboniferous until the Late Permian period in Scotland,^[4] Spain,^[5] Russia^[6] and Brazil.^[7] It lived 359 million years ago, and probably it was one of the first member of the elasmobranchians, the lineage that leads to the modern sharks. Sphenacanthus probably hunts small fishes and, unlike their modern-day relatives, its inhabited fresh water lagoons. Sphenacanthus had seven fins, two in the upper part and five in the underside, and it had a heterodont dentition and mandibles relatively long and deeper.^[4] Sphenacanthus serrulatus is still only known from incomplete neurocranial remains and associated dermal material. These suggest that it was a relatively large shark, probably well over one meter in length when fully grown. Its body form was probably similar to that of other phalacanthous sharks.^[8]