Phoebodontiformes

Thrinacodus is an extinct genus of basal elasmobranch, found worldwide from the Late Devonian-Lower Carboniferous. The type species is Thrinacodus nanus. Most species are only known from their tricuspid teeth. T. gracia, originally placed in the separate genus Thrinacoselache from the Serpukhovian-aged Bear Gulch Limestone, of what is now Montana, is known from full body impressions, showing a long, slender eel-like body up to a metre in length, with an elongate rostrum. Stomach contents of T. gracia include remains of crustaceans and small chondrichthyan fish (Harpagofututor and Falcatus). It

Phoebodus is an extinct genus of phoebodontiform total group elasmobranch, known from over a dozen species found worldwide spanning the middle to late Devonian, making it one of the oldest known total group elasmobranchs. Most species are only known from their isolated tricuspid teeth, but one species, Phoebodus saidselachus from the Late Devonian of Morocco, is known from a complete skeleton, estimated to have been in total length in life, which shows that it had a slender body superficially similar to that of the living frilled shark. The teeth of Phoebodus and frilled sharks are also morpho

Phoebodontiformes is an extinct group of elasmobranchs (sensu lato), known from the Devonian and Carboniferous periods. It includes the genera Phoebodus, Diademodus and Thrinacodus. Phoebodus and Thrinacodus have slender, elongate bodies. Their teeth are tricuspate (bearing three cusps). Some studies have recovered the group as paraphyletic.