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.
Requiem sharks are sharks of the family Carcharhinidae in the order Carcharhiniformes. They are migratory, live-bearing sharks of warm seas and include such species as the bull shark, lemon shark, spinner shark, blacknose shark, blacktip shark, grey reef shark, blacktip reef shark, silky shark, dusky shark, blue shark, copper shark, oceanic whitetip shark, and whitetip reef shark.
The Priabonian is, in the ICS's geologic timescale, the latest age or the upper stage of the Eocene Epoch or Series. It spans the time between 37.71 and33.9 Ma. The Priabonian is preceded by the Bartonian and is followed by the Rupelian, the lowest stage of the Oligocene.
The Rupelian is, in the geologic timescale, the older of two ages or the lower of two stages of the Oligocene Epoch/Series. It spans the time between 33.9 and27.82 Ma. It is preceded by the Priabonian Stage and is followed by the Chattian Stage.
Palaeotherium is an extinct genus of perissodactyl ungulate known from the Mid Eocene to earliest Oligocene of Europe. First described by French naturalist Georges Cuvier in 1804, Palaeotherium was among the first Paleogene mammals to be described.
The Borneo shark is a species of requiem shark, and part of the family Carcharhinidae. Extremely rare, it is known only from inshore waters around Mukah in northwestern Borneo, though it may once have been more widely distributed. A small, gray shark reaching 65 cm (26 in) in length, this species is the only member of its genus with a row of enlarged pores above the corners of its mouth. It has a slender body with a long, pointed snout and a low second dorsal fin placed posterior to the anal fin origin.
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.
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.
The White River Formation is a geologic formation of the Paleogene Period, in the northern Great Plains and central Rocky Mountains, within the United States.
Ronzotherium is an extinct genus of perissodactyl mammal from the family Rhinocerotidae. The name derives from the hill of 'Ronzon', the French locality near Le Puy-en-Velay at which it was first discovered, and the Greek suffix 'therium' meaning 'beast'. At present 5 species have been identified from several localities in Europe and Asia, spanning the Late Eocene to Upper Oligocene.
Galeocerdo alabamensis is an extinct relative of the modern tiger shark. Nomenclature of this shark has been debated, and recent literature identified it more closely with the Physogaleus genus of prehistoric shark, rather than Galeocerdo. The classification of Physogaleus is known as tiger-like sharks while Galeocerdo refers to tiger sharks. In 2003, P. alabamensis was classified as Galeocerdo. However, in 2019 they were proclaimed to be more morphologically similar to the genus Physogaleus. This definition was based primarily on tooth shape, as the majority of information on P. alabamensis is a result of studying tooth fossils. Distinctions between Physogaleus and Galeocerdo are difficult with extinct sharks from the Oilgocene/Miocene as there is little paleobiological information allowing for hard conclusions.
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 minutissima is an extinct species of requiem shark from the Eocene Epoch. It is known from isolated teeth in England, Belgium and possibly the Chespeake Bay region of the eastern United States.
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.
Macrorhizodus is an extinct genus of Mackerel shark which lived during the early to middle Eocene epoch of the Paleogene period. It is often considered ancestral to Isurus and sometimes considered part of it. Macrorhizodus is also likely ancestral to Cosmopolitodus. It seems to be related to Isurolamna. It is known from isolated teeth and vertebral centra as well as at least two associated dentitions. It is an incredibly widespread shark, known from every continent except Australia. This includes a report from Antarctica.
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.
