Artistic impression of a Orthacanthus hunting a Triodus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Euselachii
Order: Xenacanthida
Family: Orthacanthidae
Genus: Orthacanthus
Species: Orthacanthus arcuatus (Newberry, 1856)
+Orthacanthus cylindricus (Agassiz, 1843)
+Orthacanthus senckenbergianus

Orthacanthus is a genus of prehistoric freshwater shark that lived during the Paleozoic era. It was also an member of a group of ancient sharks called xenacanths, all of which were freshwater sharks with long fins down their backs and a spine at the start of the fin. It was the largest of the known xenacanths at 3 meters (10 feet) and 45 kg (100 lbs).

About 260 million years ago, Orthacanthus was the apex predator of freshwater swamps and bayous in Europe and North America. It owned a peculiar set of double-fanged teeth. They first appeared about 400 million years ago in the Devonian, and became extinct just before the Mesozoic period, about 225 million years ago.

Description and Paleobiology

Historical information and discovery



In Popular Culture

  • Orthacanthus was featured in the Shark Week special Prehistoric Sharks, where it was labelled as the terror of permian swamps.
  • A set of jaws and teeth from Orthacanthus can be seen in the American Museum of Natural History in New York.
  • Orthacanthus appears in Jurassic World: The Game, where it is a cave creature that is obtained through VIP Membership.
  • A stylized Orthacantus is seen in The Land Before Time V: The Mysterious Island during the song Big Water.
  • It appears in the River Monsters episode Prehistoric Terrors alongside several other prehistoric fish.