Carcharhiniformes, the ground sharks, are the largest order of sharks, with over 270 species. They include a number of common types, such as catsharks, swellsharks, and the sandbar shark.
The megamouth shark is a species of deepwater shark. Rarely seen by humans, it measures around 5.2 m (17 ft) long and is the smallest of the three extant filter-feeding sharks alongside the relatively larger whale shark and basking shark. Since its discovery in 1976, fewer than 100 specimens have been observed or caught. Like the other two planktivorous sharks, it swims with its mouth wide open, filtering water for plankton and jellyfish. It is recognizable from its large head with rubbery lips. The megamouth is so unlike any other type of shark that it is usually considered to be the sole extant species in the family Megachasmidae, though some scientists have suggested it may belong in the family Cetorhinidae.
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.
Cretoxyrhina is an extinct genus of large mackerel shark that lived about 107 to 73 million years ago during the late Albian to late Campanian of the Late Cretaceous. The type species, C. mantelli, is more commonly referred to as the Ginsu shark, first popularized in reference to the Ginsu knife, as its theoretical feeding mechanism is often compared with the "slicing and dicing" when one uses the knife. Cretoxyrhina is traditionally classified as the likely sole member of the family Cretoxyrhinidae but other taxonomic placements have been proposed, such as within the Alopiidae and Lamnidae.
Anomotodon is an extinct genus of shark related to the extant goblin shark. The distribution of Anomotodon fossils is worldwide, in formations indicating that members of the genus lived from the Early Cretaceous epoch through the Eocene epoch, and perhaps through the Oligocene as well. Described species include A. novus, A. plicatus, A. principalis, and A. multidenticula.
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.
The Toolebuc Formation is a geological formation that extends from Queensland across South Australia and the Northern Territory in Australia, whose strata date back to the Albian stage of the Early Cretaceous. Dinosaurs, pterosaurs, plesiosaurs, ichthyosaurs, protostegid turtles, sharks, chimaeroids and bony fish remains are among the fossils that have been recovered from the formation.
The Carlile Shale is a Turonian age Upper/Late Cretaceous series shale geologic formation in the central-western United States, including in the Great Plains region of Colorado, Kansas, Nebraska, New Mexico, North Dakota, South Dakota, and Wyoming.
Cardabiodon is an extinct genus of large mackerel shark that lived about 95 to 91 million years ago (Ma) during the Cenomanian to Turonian of the Late Cretaceous. It is a member of the Cardabiodontidae, a family unique among mackerel sharks due to differing dental structures, and contains the two species C. ricki and C. venator. Cardabiodon fossils have been found in Australia, North America, England, and Kazakhstan. It was likely an antitropical shark that inhabited temperate neritic and offshore oceans between 40° and 60° paleolatitude, similar to the modern porbeagle shark.
Dwardius is an extinct genus of cardabiodontid sharks which existed during the Cretaceous period in what is now Australia, England, France, and India. It was described by Mikael Siverson in 1999, as a new genus for the species Cretalamna woodwardi, which had been described by J. Hermann in 1977. Another species, D. siversoni, was described from the middle Albian of northeastern France by V.I. Zhelezko in 2000; the species epithet honours the author of the genus. A new species, D. sudindicus, was described by Charlie J. Underwood, Anjali Goswami, G.V.R. Prasad, Omkar Verma, and John J. Flynn in 2011, from the Cretaceous Karai Formation of India.
Cretalamna is a genus of extinct otodontid shark that lived from the latest Early Cretaceous to Eocene epoch. It is considered by many to be the ancestor of the largest sharks to have ever lived, such as Otodus angustidens, Otodus chubutensis, and Otodus megalodon.
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.
The Kristianstad Basin is a Cretaceous-age structural basin and geological formation in northeastern Skåne, the southernmost province of Sweden. The basin extends from Hanöbukten, a bay in the Baltic Sea, in the east to the town of Hässleholm in the west and ends with the two horsts Linderödsåsen and Nävlingeåsen in the south. The basin's northern boundary is more diffuse and there are several outlying portions of Cretaceous-age sediments. During the Cretaceous, the region was a shallow subtropical to temperate inland sea and archipelago.
Eoptolamna is an extinct genus of mackerel sharks that lived during the Cretaceous. It contains two valid species, E. eccentrolopha and E. supracretacea, which have been found in Europe and North Africa.
Johnlongia is an extinct genus of sand shark from the Cretaceous period. It contains two described species, J. parvidens and J. allocotodon, and possibly a third unnamed species from the Niobrara Chalk. It is presumed piscivorous; however, it forms a clade with an early filter-feeding shark genus, Pseudomegachasma.
Archaeolamna is an extinct genus of mackerel sharks that lived during the Cretaceous. It contains three valid species which have been found in Europe, North America, and Australia. While it is mostly known from isolated teeth, an associated set of teeth, jaws, cranial fragments, and vertebrae of A. kopingensis is known from the Pierre Shale of Kansas. Teeth of A. k. judithensis were found with a plesiosaur skeleton with bite marks from the Judith River Formation of Montana. It was a medium-sized shark with an estimated total body length of 3–4 metres (9.8–13.1 ft).
The Kristianstad Basin is a Cretaceous-age structural basin and geological formation in northeastern Skåne, the southernmost province of Sweden. The sediments in the basin preserves a wide assortment of taxa represented in its fossil record, including the only non-avian dinosaur fossils in Sweden and one of the world's most diverse mosasaur faunas.
Pseudoscapanorhynchidae is a family of extinct mackerel sharks that lived during the Cretaceous and potentially the Paleogene. It currently includes Cretodus, Eoptolamna, Leptostyrax, Protolamna, Pseudoscapanorhynchus, and possibly Lilamna.
This list of fossil fish research presented in 2021 is a list of new taxa of jawless vertebrates, placoderms, acanthodians, fossil cartilaginous fishes, bony fishes, and other fishes that were described during the year, as well as other significant discoveries and events related to paleoichthyology that occurred in 2021.
