The megamouth shark is a species of deepwater shark. Rarely seen by humans, it measures around 17 ft (5.2 m) 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.
Sand sharks, also known as sand tiger sharks, gray nurse sharks or ragged tooth sharks, are mackerel sharks of the family Odontaspididae. They are found worldwide in temperate and tropical waters. The three species are in two genera.
Carcharias is a genus of mackerel sharks belonging to the family Odontaspididae. Once bearing many prehistoric species, all have gone extinct with the exception of the critically endangered sand tiger shark.
The Aquia Formation is a geologic sandstone formation that extends from the upper Chesapeake Bay to the James River near Hopewell, Virginia. It consists of clayey, silty, very shelly, glauconitic sand. Fossil records indicate that this stratigraphic unit was created during the Paleocene.
Coupatezia is a prehistoric genus of ray in the family Dasyatidae whose fossils are found in strata dating from the Maastrichtian stage until the last species' extinction during the Middle Eocene. These rays were found shallow seas in Europe, Africa and the eastern United States.
Odontaspis and Greek: ἀσπίς aspís 'shield') is a genus of sand shark with two extant species.
Manta hynei is an extinct species of manta ray that was extant in the Pliocene. Its fossils have been found in North America, specifically North Carolina and Virginia. It was first described by Jim Bourdon in 1999, as a specimen dated to the Zanclean. The species is known from its distinctive fossilized teeth. Some authors have suggested, on the basis of tooth morphology, that this species should be classified in the genus Mobula instead.
Otodus aksuaticus is an extinct species of large shark in the family Otodontidae which may represent a transitional species between Otodus obliquus and Otodus auriculatus. They are similar in overall morphology to Otodus obliquus except they have serrations on their cusps and blade. It is sometimes placed in the genus Otodus. It is mainly found in the Ypresian stage of the Eocene epoch. They have been found in the Woodstock Member of the Nanjemoy Formation of Maryland and Virginia and Ypresian sediments in Aktulagay, Kazakhstan as well as the Ypres clay in Belgium and the London Clay in the United Kingdom.
Trigonotodus is an extinct genus of sharks, most likely belonging to the family Alopiidae. This genus includes three extinct species, which span from the early Eocene to the late Oligocene. It was originally placed in the family Otodontidae, but subsequently found to have affinities with Thresher sharks. This genus is sometimes considered part of the genus Alopias. It is currently only known from isolated teeth.
Abdounia is an extinct genus of requiem shark which lived during the Paleogene period. It is mainly known from isolated teeth. It is one of the earliest requiem sharks, and attained widespread success in North America, Europe, and Africa.
Protolamna is an extinct genus of mackerel shark from the Cretaceous Period. The genus is known from Europe, Asia and North America.
Xiphodolamia is a rare extinct genus of mackerel shark which lived during the Eocene epoch. It is only known from isolated teeth, but has been found in Europe, Africa, and Asia. It is assumed to be pelagic, occurring more frequently in deeper water deposits, most notably the London Clay and Eocene deposits in Denmark. It is distinguished by its rectangular root and twisted blade, unique among Mackerel sharks. It is unclear what niche this specialized dentition helped exploit.
Abdounia beaugei is an extinct species of requiem shark from the Paleocene and Eocene epochs of the Paleogene period. It is known from North Africa, Europe, and North America.
Abdounia recticona is an extinct species of requiem shark from the Eocene epoch. It is known from isolated teeth in Europe and North America.
Carcharoides is an extinct genus of mackerel shark which lived during the Oligocene and Miocene epochs. It is a widespread genus, known from specimens in North and South America, Europe, Africa, and Australia. It is most common in the European portion of its range, being comparatively uncommon in other places. It is only known from isolated teeth, which are relatively delicate.
Isurolamna is an extinct genus of mackerel shark from the Paleogene period. It contains at least three species and a fourth is sometimes placed in it. It is thought to be closely related to Macrorhizodus, Isurus, and Cosmopolitodus. Isurolamna arose in the Paleocene epoch during the Selandian age, and was extinct by the close of the Rupelian age of the Oligocene epoch. Some features which define this genus include a small, elliptical foramen (hole) in the middle of the lingual side of the root, triangular cusps except on lower interior teeth, and a relatively thick root with nearly vertical margins. The genus has a complicated taxonomic past.
Lethenia is an extinct genus of mackerel shark from the Rupelian age of the Oligocene epoch. It is a monotypic genus, containing only L. vandenbroeki. It is considered closely related to Isurolamna and sometimes included within it. It differs in the morphology of its teeth, which are much more gracile than Isurolamna and has larger spacing between its crown and lateral cusps. Lethenia is rare and only known from isolated teeth. It is best known from the Boom Clay Formation of Belgium and the Uzunbas Formation of Kazakhstan.
Burnhamia is an extinct genus of devil ray from the Paleogene period. Due to superficial similarities, some species were originally mistaken for Cownose rays and placed in the genus Rhinoptera. It is known exclusively from dental batteries, mostly isolated teeth. There are several species attributed to this genus but their relation to each other is still unresolved. Some have proposed the type species B. daviesi arises in the late Paleocene and persists until the middle Eocene giving rise to the similar genus Eoplinthicus with an earlier offshoot leading to smaller and less ornamented species in the lower Eocene, namely B. fetahi. B. fetahi is known from Morocco and North America. B. daviesi was described from the London Clay Formation, but is well known from Eocene deposits throughout Asia, Europe, North Africa, and North America. However, teeth from the Claiborne Group of Alabama show teeth identical to B. daviesi coexisting with Eoplinthicus in the Bartonian. A Ypresian species, B. nessovi, known from a singular site in Kazakhstan was tentatively ascribed to the genus, though more material may show it warrant its own. B. crimensis is known from the Bartonian and Priabonian of Crimea.
Cantioscyllium is an extinct genus of nurse shark from the Mesozoic era. It is known mainly from isolated teeth, but was named on a partial skeleton from the Late Cretaceous of England. It is a widespread and diverse genus, currently containing 10 species. They are uncommon but present throughout the late cretaceous of the eastern United States, including the Severn Formation of Maryland, the Tar Heel and Peedee formations of North Carolina, and Campanian of New Jersey. It is also known from the Western Interior Seaway and western Europe. C. hashimiaensis is known from the Santonian of Jordan. C. alhaulfi is from the Barremian.
