The Hexanchiformes are a primitive order of sharks, that numbering just seven extant species in two families. Fossil sharks that were apparently very similar to modern sevengill species are known from Jurassic specimens.
The Lamniformes are an order of sharks commonly known as mackerel sharks. It includes some of the most familiar species of sharks, such as the great white, as well as more unusual representatives, such as the goblin shark and megamouth shark.
Hybodus is an extinct genus of hybodont, a group of shark-like euselachians that lived from the Late Devonian to the end of the Cretaceous. Species closely related to the type species Hybodus reticulatus lived during the Early Jurassic epoch. Numerous species have been assigned to Hybodus spanning a large period of time, and it is currently considered a wastebasket taxon that is 'broadly polyphyletic' and requires reexamination.
Peirosauridae is a Gondwanan family of mesoeucrocodylians that lived during the Cretaceous period. It was a clade of terrestrial crocodyliforms that evolved a rather dog-like skull, and were terrestrial carnivores. It was phylogenetically defined in 2004 as the most recent common ancestor of Peirosaurus and Lomasuchinae and all of its descendants. Lomasuchinae is a subfamily of peirosaurids that includes the genus Lomasuchus.
Hybodontiformes, commonly called hybodonts, are an extinct group of shark-like cartilaginous fish (chondrichthyans) which existed from the late Devonian to the Late Cretaceous. Hybodonts share a close common ancestry with modern sharks and rays (Neoselachii) as part of the clade Euselachii. They are distinguished from other chondrichthyans by their distinctive fin spines and cephalic spines present on the heads of males. An ecologically diverse group, they were abundant in marine and freshwater environments during the late Paleozoic and early Mesozoic, but were rare in open marine environments by the end of the Jurassic, having been largely replaced by modern sharks, though they were still common in freshwater and marginal marine habitats. They survived until the end of the Cretaceous, before going extinct.
Lonchidion is a genus of extinct hybodont in the family Lonchidiidae. The genus first appears in the fossil record during the Middle Triassic (Ladinian) and was among the last surviving hybodont genera, with its youngest known fossils dating to the very end of the Cretaceous (Maastrichtian).
Cretorectolobus is an extinct carpet shark. It was described by G.R. Case in 1978, and the type species is C. olsoni, which existed during the Campanian in Canada and the United States. Another species, C. gracilis, was described by Charlie J. Underwood and Mitchell in 1999, from the Hauterivian to Barremian strata of the Speeton Clay Formation of England. The species epithet refers to the shark's teeth, which Underwood and Mitchell described as gracile and narrow in form. A new species, C. robustus, was described from the Cenomanian of Canada by Underwood and Stephen L. Cumbaa in 2010.
Orectoloboides is an extinct genus of wobbegong sharks. It was described by Cappetta in 1977. A new species, O. angulatus, was described from the Cenomanian age of Canada by Charlie J. Underwood and Stephen L. Cumbaa in 2010.
Roulletia is an extinct genus of sand sharks. It was described by Romain Vullo, Henri Cappetta, and Didier Néraudeau in 2007, and the type species is R. bureaui, which existed during the upper Cenomanian of what is now France. The genus was named after its type locality, Roullet-Saint-Estèphe, while the species epithet honours Michel Bureau, an amateur paleontologist who gathered the material for the species. Another species, R. canadensis, was described from the Cenomanian of Canada by Charlie J. Underwood and Stephen L. Cumbaa in 2010. The species epithet refers to the country in which it was discovered. It has been suggested tentatively this genus may be related to Haimirichia, which has been placed in its own family (Haimirichiidae) based on soft-tissue preservation.
Asteracanthus is an extinct genus of hybodont, known from the Middle Jurassic (Bathonian) to the Early Cretaceous (Valanginian).
Pseudocorax is an extinct genus of mackerel sharks that lived during the Late Cretaceous. It contains six valid species that have been found in Europe, the Middle East, North Africa, and North America. It was formerly assigned to the family Anacoracidae, but is now placed in its own family Pseudocoracidae along with Galeocorax. The former species "P." australis and "P." primulus have been reidentified as species of Echinorhinus and Squalicorax, respectively.
Timeline showing the development of the extinct reptilian order Pterosauria from its appearance in the late Triassic period to its demise at the end of the Cretaceous, together with an alphabetical listing of pterosaur species and their geological ages.
Paracestracion is an extinct genus of heterodontiform sharks from Early Jurassic to Early Cretaceous-aged rocks of England, France, Germany and Luxembourg. The genu was first described in 1911 by Ernst Hermann Friedrich von Koken in Karl Alfred von Zittel.
Naomichelys is an extinct genus of helochelydrid stem turtle known from the Cretaceous (Aptian-Campanian) of North America. It is the only member of the family known to be native to North America.
Tribodus is an extinct genus of hybodont. It lived during the mid Cretaceous (Albian-Cenomanian) with fossils being known from northern South America, North Africa, and southern Europe.
Protolamna is an extinct genus of mackerel shark from the Cretaceous Period. The genus is known from Europe, Asia and North America.
Acrorhizodus is an extinct genus of hybodont chondrichthyan currently containing only the species: Acrorhizodus khoratensis. It is known from the Albian to Aptian aged Khok Kruat formation of the Khok Pha Suam locality near the town of Sri Muang Mai, Thailand. It displays a mix of features which sets it apart from all hybodont families currently known.
Strophodus is an extinct genus of durophagous hybodont known from the Triassic to Cretaceous. It was formerly confused with Asteracanthus.
Egertonodus is an extinct genus of shark-like hybodont fish. It includes E. basanus from the Jurassic of Europe and North Africa and Cretaceous of North America, North Africa and Europe, and E. duffini from the Middle Jurassic of England. Indeterminate remains of the genus have been reported from the Early Cretaceous of Asia. E. basanus is known from preserved skull material, while E. duffini is only known from teeth. The genus is distinguished from Hybodussensu stricto by characters of the skull and teeth. E. basanus, the most common species, is thought to have reached 1.5 m in length. E. fraasi from the Late Jurassic of Germany, known from a poorly preserved full body fossil, was placed in Egertonodus in one study, but this has been subsequently questioned by other authors, due to strong differences in tooth morphology from the type species. Fossils have been found in freshwater and lagoonal environments.
Planohybodus is an extinct genus of hybodont, known from the Middle Jurassic-Early Cretaceous (Bathonian-Barremian) of Europe and the Indian subcontinent. Fossils have been found in marine as well as freshwater environments. The genus contains 3 confirmed species, two of which were originally assigned to the genus Hybodus. Possible records have been reported from the Late Jurassic of Mexico, the Early Cretaceous of Brazil and the Late Cretaceous (Santonian) of North America, but these are unconfirmed. Planohybodus peterboroughensis is suggested to have reached lengths of 2–3 metres (6.6–9.8 ft). A specimen of the ammonite genus Orthaspidoceras from the Late Jurassic of France has been found with an embedded tooth of Planohybodus, suggesting that while the teeth of Planohybodus were adapted to tearing soft bodied prey, it would attack hard-shelled prey at least on occasion.
