Late Devonian cartilaginous fish

Cladoselache ("branch shark") is an extinct genus of shark-like chondrichthyan (cartilaginous fish) from the Late Devonian (Famennian) of North America. It was similar in body shape to modern lamnid sharks (such as mako sharks and the great white shark), but was not closely related to lamnids or to any other modern (selachian) shark. As an early chondrichthyan, it had yet to evolve traits of modern sharks such as accelerated tooth replacement, a loose jaw suspension, enameloid teeth, and possibly claspers.

Cladoselachidae is an extinct family of cartilaginous fishes closely related to, and possibly nested within, Symmoriiformes. They are characterized by having an elongated body with a spine in each of the two dorsal fins.

Sphenacanthus (from , 'wedge' and , 'spine') 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, Spain, Russia and Brazil. 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 hunted small fishes and, unlike their modern-day relatives, it inhabited fresh water lagoons. Sphenacanthus had seven fins, two in the upper part and five in the un

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

left|thumb|Tooth assigned to Symmorium Symmorium is an extinct symmoriiform cartilaginous fish from the Devonian and Carboniferous of the United States (Illinois) and Russia. The type species, Symmorium reniforme, was named by Edward Drinker Cope in 1893, with other species assigned to the genus having since been reclassified into other genera such as Petalodus. Symmorium bears close similarity in size and appearance to Stethacanthus but lacks the "spine-brush complex" in place of the first dorsal fin. Some paleontologists think that the two forms represented the males and females of related s