Fossils of the United States

Daspletosaurus ( ; meaning "frightful lizard") is a genus of tyrannosaurid dinosaur that lived in Laramidia between about 77 and 74.4 million years ago, during the Late Cretaceous Period. The genus Daspletosaurus contains three named species. Fossils of the earlier type species, D. torosus, have been found in Alberta, while fossils of a later species, D. horneri, have been found in Montana and Alberta. D. wilsoni has been suggested as an intermediate species between D. torosus and D. horneri that evolved through anagenesis, though further research may be required to definitively support the th

Hipparion is an extinct genus of three-toed, medium-sized equine belonging to the extinct tribe Hipparionini, which lived about 10-5 million years ago. While the genus formerly included most hipparionines, the genus is now more narrowly defined as hipparionines from Eurasia spanning the Late Miocene. Hipparion was a mixed-feeder who ate mostly grass, and lived in the savannah biome. Hipparion evolved from Cormohipparion, and went extinct due to environmental changes like cooling climates and decreasing atmospheric carbon dioxide levels.

A nummulite is a large lenticular fossil, characterised by its numerous coils, subdivided by septa into chambers. They are the shells of the fossil and present-day marine protozoan Nummulites, a type of foraminiferan. Nummulites commonly vary in diameter from and are common in Eocene to Miocene marine rocks, particularly around southwest Asia and the Mediterranean in the area that once constituted the Tethys Ocean, such as Eocene limestones from Egypt or from Pakistan. Fossils up to six inches wide are found in the Middle Eocene rocks of Turkey. They are valuable as index fossils.

Helicoprion is an extinct genus of large shark-like cartilaginous fish that lived from the Early to the Middle Permian, about 290-270 million years ago. Helicoprion is a member of the Eugeneodontiformes, an extinct order of cartilaginous fish within the clade Holocephali, a group today represented only by chimaeras. It is also the type genus of the Helicoprionidae, a family of eugeneodonts characterised by distinctive tooth structures called tooth whorls. Helicoprion was first named in 1899 by Alexander Karpinsky on the basis of fossils discovered in Russia and Australia, the generic name mean

Ophthalmosaurus (Greek ὀφθάλμος ophthalmos 'eye' and σαῦρος sauros 'lizard') is a genus of ichthyosaur known from the Middle-Late Jurassic. Possible remains from the earliest Cretaceous (Berriasian stage) are also known. It was a relatively medium-sized ichthyosaur, measuring long and weighing . Named for its extremely large eyes, it had a jaw containing many small but robust teeth. Major fossil finds of this genus have been recorded in Europe with a second species possibly being found in North America.

Placerias (meaning 'broad body') is an extinct genus of dicynodonts that lived during the Carnian and Norian stages of the Triassic period (230–215 million years ago). Placerias belongs to a clade of dicynodonts called Kannemeyeriiformes, which was the last known group of dicynodonts before the taxon became extinct at the end of the Triassic.

Xiphactinus (from Latin and Greek for "sword-ray") is an extinct genus of large predatory marine ray-finned fish that lived during the late Albian to the late Maastrichtian. The genus grew up to in length, and superficially resembled a gargantuan, fanged tarpon. It is a member of the extinct order Ichthyodectiformes, which represent close relatives of modern teleosts.

Coryphodon (from Greek , "point", and , "tooth", meaning peaked tooth, referring to "the development of the angles of the ridges into points [on the molars].") is an extinct genus of pantodonts of the family Coryphodontidae.

Barylambda (Greek: "heavy" (baros), "lambda" (lambda) in a reference to larger size than that of Pantolambda) is an extinct genus of pantodont mammal from the middle to late Paleocene, well known from several finds in the Wasatchian (NALMA classification) DeBeque Formation of Colorado and the Clarkforkian Wasatch Formation to Tiffanian Fort Union Formation in Wyoming. Three species of Barylambda are currently recognized. The creature likely lived a life similar to that of a modern tapir, browsing on foliage and soft vegetation. Barylambda seems to have been quite successful for an early pantod

Eremotherium (from Greek for "steppe" or "desert" "beast": ἔρημος "steppe or desert" and θηρίον "beast") is an extinct genus of giant ground sloth in the family Megatheriidae. Eremotherium lived in southern North America, Central America, and northern South America. It was one of the largest sloths, with a body size comparable to elephants, weighing around and measuring about long, slightly larger than its close relative Megatherium.

Hyperodapedon (from , 'above' and , 'pavement') is an extinct genus of rhynchosaur reptiles which lived during Late Triassic period. Like other rhynchosaurs, it was a heavily built archosauromorph, distantly related to archosaurs such as crocodilians and dinosaurs. Hyperodapedon in particular was part of the subfamily Hyperodapedontinae, a specialized rhynchosaurian subgroup with broad skulls, beaked snouts, and crushing tooth plates on the roof of the mouth.

Megalonyx (Greek, "great-claw") is an extinct genus of ground sloths of the family Megalonychidae, native to North America. It evolved during the Pliocene Epoch and became extinct at the end of the Late Pleistocene, living from ~5 million to ~13,000 years ago. The type species, M. jeffersonii (also called '''Jefferson's ground sloth'''), the youngest and largest known species, measured about in length and weighed up to nearly .

Baculites is an extinct genus of heteromorph ammonite cephalopods with almost straight shells. The genus, which lived worldwide throughout most of the Late Cretaceous, and which briefly survived the K-Pg mass extinction event, was named by Lamarck in 1799.

Cuvieronius is an extinct New World genus of gomphothere which ranged from southern North America to northwestern South America during the Pleistocene epoch. Reaching a shoulder height of and a body mass of , it was comparable in size to an Asian elephant. Cuvieronius inhabited subtropical and tropical latitudes in environments ranging from grasslands to tropical rainforest. Among the last gomphotheres along with the South American Notiomastodon, it became extinct as part of the end Pleistocene-extinction event, approximately 12-11,000 years ago, along with most other large mammals in the Amer

Nimravus is an extinct genus of "false" saber-toothed cat that lived in North America and Eurasia during the Eocene and Oligocene epochs 35.3—27.1 mya, existing for approximately . Not closely related to true saber-toothed cats, they evolved a similar form through parallel evolution. Fossils have been uncovered from western U.S. from Oregon to Southern California and Nebraska, and also from Eurasia from France to Mongolia.

Notharctus is a genus of adapiform primate that lived in North America and Europe during the early to middle Eocene. left|thumb|N. tenebrosus (left) compared to Plesiadapis|Plesiadapis cookei (right), a plesiadapiform. Both come from [[Eocene Wyoming, though the latter is slightly geologically older (Museum of Natural Sciences, Brussels).]] The body form of Notharctus is similar to that of modern rats. Its fingers were elongated for clamping onto branches, including the development of a thumb. Its spine is flexible and the animal was about in length, excluding the long tail.

Stagonolepis is an extinct genus of stagonolepidid aetosaur known from the Late Triassic (Carnian stage) Hassberge Formation of Germany, the Drawno Beds of Poland, and the Lossiemouth Sandstone of Scotland. Supposed fossils from North and South America have been placed into their own genera, Calyptosuchus and Aetosauroides, respectively.

Platygonus ("flat head" in reference to the straight shape of the forehead) is an extinct genus of herbivorous peccaries of the family Tayassuidae, endemic to North and South America from the Miocene through Pleistocene epochs (10.3 million to 11,000 years ago), existing for about . P. compressus stood tall.

Shastasauridae is an extinct family of ichthyosaurs from the Late Triassic with a possible Early Jurassic record. The family contains the largest known species of ichthyosaurs, which include some of and possibly the largest known marine reptiles.

Anchitherium (meaning near beast) is a genus of extinct equid with a three-toed hoof. thumb|left|Mandibles Anchitherium was a browsing (leaf eating) horse that originated in the early Miocene of North America, being found as far south as Panama, and subsequently dispersed to Europe and Asia, where it gave rise to the larger bodied genus Sinohippus. It was around high at the shoulder, and probably represented a side-branch of horse evolution that left no modern descendants.

Desmostylus is an extinct genus of herbivorous mammal of the family Desmostylidae living from the Chattian stage of the Late Oligocene subepoch through the Late Miocene subepoch (28.4 mya–7.250 Mya) and in existence for approximately .

Omphalosaurus (from the Greek root "Button Lizard", for their button-like teeth) is an extinct genus of marine reptile from the Early Triassic to Middle Triassic, thought to be in the order of Ichthyosauria. Most of what is known about Omphalosaurus is based on multiple jaw fragments, ribs, and vertebrae. Specimens of Omphalosaurus have been described from the western United States, Poland, Austria and the island of Spitsbergen off the northern coast of Norway.

Paleoparadoxia ("ancient paradox") is a genus of large, herbivorous aquatic mammals that inhabited the northern Pacific coastal region during the Miocene epoch (). It ranged from the waters of Japan (Tsuyama and Yanagawa), to Alaska in the north, and down to Baja California, Mexico.

Glyptotherium (from Ancient Greek for 'grooved or carved beast') is a genus of glyptodont (an extinct group of large, herbivorous armadillos) in the family Chlamyphoridae that lived from the Early Pliocene, about 3.9 million years ago, to the Late Pleistocene, around 15,000 years ago. It was widely distributed, living in the United States, Mexico, Guatemala, Costa Rica, Honduras, El Salvador, Panama, Venezuela, Colombia, and Brazil. Fossils that had been found in the Pliocene Blancan Beds in Llano Estacado, Texas were named Glyptotherium texanum by American paleontologist Henry Fairfield Osbor

Enchodus (from , 'spear' and 'tooth') is an extinct genus of aulopiform ray-finned fish related to lancetfish and lizardfish. Species of Enchodus flourished during the Late Cretaceous, where they were a widespread component of marine ecosystems worldwide, and there is some evidence that they may have survived to the Paleocene or Eocene; however, this may just represent reworked Cretaceous material.

Favosites is an extinct genus of tabulate coral characterized by polygonal closely packed corallites (giving it the common name "honeycomb coral"). The walls between corallites are pierced by pores known as mural pores which allowed transfer of nutrients between polyps. Favosites, like many corals, thrived in warm sunlit seas, feeding by filtering microscopic plankton with their stinging tentacles and often forming part of reef complexes. The genus had a worldwide distribution from the Late Ordovician to Late Permian. ==Distribution== Favosites had a vast distribution, and its fossils can be

Dinohippus (from Ancient Greek δεινός (deinós), meaning "terrible", and ἵππος (híppos), meaning "horse") is an extinct equid which was endemic to North America from the late Hemphillian stage of the Miocene through the Zanclean stage of the Pliocene (10.3—3.6 mya) and in existence for approximately . Fossils are widespread throughout North America, being found at more than 30 sites from Florida to Alberta and from Mexico all the way down to Panama (Alajuela Formation). The majority of fossils of Dinohippus have been unearthed in the Western United States in Nevada, New Mexico, Utah, and Califo

Ceratodus (from and ) is an extinct genus of freshwater lungfish that was found worldwide during the Mesozoic Era. It has been described as a "catch all", and a "form genus" used to refer to the remains (typically toothplates) of a variety of lungfish belonging to the extinct family Ceratodontidae. Fossil evidence dates back to the Early Triassic. A wide range of fossil species from different time periods have been found around the world in places such as the United States, Argentina, Greenland, England, Germany, Egypt, Madagascar, China, and Australia. Ceratodus is believed to have become ext

Captorhinus (from , 'to gulp down' and , 'nose') is an extinct genus of captorhinid reptiles that lived during the Permian period. Its remains are known from North America (Oklahoma, Texas) and possibly South America.

Mesenosaurus is an extinct genus of synapsid belonging to the family Varanopidae. This genus includes two species: the type species Mesenosaurus romeri from the middle Permian (upper Kazanian) Mezen River Basin of northern Russia, and Mesenosaurus efremovi from the early Permian (Artinskian) Richards Spur locality (Oklahoma, United States). M. romeri’s stratigraphic range is the middle to late Guadalupian while M. efremovi’s stratigraphic range is the Cisuralian.

Carpolestes (from Ancient Greek καρπός (karpós), meaning "fruit", and λῃστής (lēistḗs), meaning "robber", and thus, "fruit robber") is a genus of extinct primate-like mammals from the late Paleocene of North America. It first existed around 58 million years ago. The three species of Carpolestes appear to form a lineage, with the earliest occurring species, C. dubius, ancestral to the type species, C. nigridens, which, in turn, was ancestral to the most recently occurring species, C. simpsoni.

Cimoliasaurus was a plesiosaur that lived during the Late Cretaceous (Maastrichtian) of the eastern United States, with fossils known from New Jersey, North Carolina, and Maryland.

Allodesmus is an extinct genus of pinniped from the middle to late Miocene of California and Japan that belongs to the extinct pinniped family Desmatophocidae.

thumb|right|Thin-section view of Halysites corallum

Diacodexis is an extinct genus of small herbivorous mammals belonging to the family Diacodexeidae that lived in North America and Europe from 55.4 mya to 46.2 mya, existing for approximately .

Diplomystus is an extinct genus of freshwater and marine clupeomorph fish distantly related to modern-day extant herrings, anchovies, and sardines. It is known from the United States, Canada, China, Uzbekistan and Lebanon from the Late Cretaceous to the middle Eocene. Many other clupeomorph species from around the world were also formerly placed in the genus, due to it being a former wastebasket taxon. It was among the last surviving members of the formerly-diverse order Ellimmichthyiformes, with only its close relative Guiclupea living for longer.

species of plant

Cimolichthys (Greek for "chalk fish") is an extinct genus of large predatory marine aulopiform ray-finned fish known worldwide from the Late Cretaceous. It is the only member of the family Cimolichthyidae.

Olenellus is an extinct genus of redlichiid trilobites, with species of average size (about long). It lived during the Botomian and Toyonian stages of the Lower Cambrian (Olenellus-zone), , in what is currently North America, part of the palaeocontinent Laurentia.

Gillicus was a relatively small (about long) marine ichthyodectiform ray-finned fish that lived in central North America (Western Interior Seaway), Europe and East Asia, from the late Albian to the early Maastrichtian.

Tatenectes is a genus of cryptoclidid plesiosaur known from the Upper Jurassic of Wyoming. Its remains were recovered from the Redwater Shale Member of the Sundance Formation, and initially described as a new species of Cimoliosaurus by Wilbur Clinton Knight in 1900. It was reassigned to Tricleidus by Maurice G. Mehl in 1912 before being given its own genus by O'Keefe and Wahl in 2003. Tatenectes laramiensis is the type and only species of Tatenectes. While the original specimen was lost, subsequent discoveries have revealed that Tatenectes was a very unusual plesiosaur. Its torso had a flatte

Toretocnemus (meaning 'perforated tibia') is an extinct genus of ichthyosaurs that lived during the Carnian stage of the Upper Triassic in what is now North America. Two species are known, T. californicus and T. zitelli, first described in 1903 by John Campbell Merriam from fossils discovered in the Hosselkus Limestone, Shasta County. The second species was first seen by Merriam as belonging to a distinct genus, but in 1999 it was reclassified into the original taxon. Toretocnemus fossils are primarily known from California, although some specimens are also reported from Alaska and Mexico. Wit

Atrypa is a genus of brachiopod with round to short egg-shaped shells covered with many fine radial ridges (or costae). Growth lines form perpendicular to the costae and are spaced approximately 2 to 3 times further apart than the costae.. The pedunculate valve is slightly convex, but oftentimes levels out or becomes slightly concave toward the anterior margin (opposite the hinge and pedicle). The brachial valve is highly convex. Neither valve contains an interarea (a flat area bordering the hinge line, approximately perpendicular with the rest of the valve). Atrypa had a large geographic rang

species of mammal (fossil)

Bananogmius is an extinct genus of marine ray-finned fish that was found in what is now North America and Europe during the Late Cretaceous, from the Cenomanian to the Santonian. It lived in the Western Interior Seaway, which split North America in two during the Late Cretaceous, as well as the proto-North Sea of Europe.

Hemiauchenia is an extinct genus of lamine camelids that evolved in North America in the Miocene epoch about 10 million years ago. This genus diversified and entered South America in the Late Pliocene about three to two million years ago, as part of the Great American Biotic Interchange. The genus became extinct at the end of the Pleistocene. The monophyly of the genus has been considered questionable, with phylogenetic analyses finding the genus to paraphyletic or polyphyletic, with some species suggested to be more closely related to living lamines (llamas and relatives) than to other Hemiau

Cretalamna is a genus of extinct otodontid shark that lived from the latest Early Cretaceous to Eocene epoch (about 103 to 46 million years ago). 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.

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thumb|right|250px|Elrathia kingii growth series with holaspids ranging from 16.2 mm to 39.8 mm in length

Escavadodon ("tooth from Escavada") is an extinct genus of pangolin-like myrmecophagous placental mammals of extinct monotypic family Escavadodontidae within extinct order Palaeanodonta, that lived in North America during the middle Paleocene. It contains a single species, Escavadodon zygus, recovered from the Nacimiento Formation of New Mexico.

Bohaskaia is an extinct genus of beluga-like odontocete cetacean known from the Early Pliocene of Virginia and North Carolina, United States. It was first named by Jorge Vélez-Juarbe and Nicholas D. Pyenson in 2012 and the type species is Bohaskaia monodontoides.

Pahasapasaurus is an extinct genus of polycotylid plesiosaurs from Late Cretaceous rocks of the United States. Distinctive features of the taxon include elongate epipodial bones (radius/ulna - tibia/fibula) and the nature of the palate bones (roof of the mouth). The genus contains two species; type species, Pahasapasaurus haasi, was named in 2007 based on remains from the late Cenomanian-aged Greenhorn Limestone of South Dakota, In 2025, a second species was named, Pahasapasaurus gillettei, based on a complete skull and partial skeleton from the early Turonian-aged Tropic Shale of Utah.

Belantsea (named after a legendary ancestor of the Crow Tribe) is a genus of extinct petalodontiform cartilaginous fish that lived during the Early Carboniferous. Fossils of Belantsea montana have been found in the Bear Gulch Limestone lagerstätte, and are preserved in exceptional detail. Its body was tall and compressed, with large pectoral fins and a small tail fin. This body plan suggests a lifestyle similar to modern reef fish, and it is thought that Belantsea was adapted for life in reefs of sponges. Its few, large, triangular teeth suggest a diet of hard-shelled marine invertebrates. The

Gagadon ("Gaga tooth") is an extinct genus of even-toed ungulate that lived in the early Eocene of North America. The type and only known species, Gagadon minimonstrum, was described in 2014 based on lower teeth and jaw fragments found in the Wasatch Formation of Bitter Creek, Wyoming. The genus is named in honor of the singer Lady Gaga, while the species name minimonstrum ("mini monster") refers simultaneously to the small size and presence of unusual cusps on the teeth and to Gaga's name for her fans, the "little monsters".

Prolimnocyon ("before Limnocyon") is an extinct paraphyletic genus of limnocyonin hyaenodonts that lived in Asia and North America during the Late Paleocene to Middle Eocene. Prolimnocyon chowi is one of the earliest known member of the order Hyaenodonta and clade Limnocyoninae.

Platystrophia is an extinct genus of brachiopods that lived from the Ordovician to the Silurian in Asia, Europe, North America, and South America. It has a prominent sulcus and fold. It usually lived in marine lime mud and sands.

Eusthenodon (Greek for "strong-tooth" – eusthenes- meaning "strong", -odon meaning "tooth") is an extinct genus of marine tristichopterid tetrapodomorphs from the Late Devonian period, ranging between 365 and 359 million years ago (Late Famennian). They are well known for being a cosmopolitan genus with remains being recovered from East Greenland, Australia, Central Russia, USA (Pennsylvania), and Belgium. Compared to the other closely related genera of the Tristichopteridae clade, Eusthenodon was one of the largest lobe-finned fishes (approximately 2.5 meters in length) and among the most der

Bonnerichthys is a genus of fossil fishes within the family Pachycormidae that lived during the Coniacian to Maastrichtian stage of the Late Cretaceous. Fossil remains of this taxon were first described from the Smoky Hill Member of the Niobrara Chalk Formation of Kansas (Late Coniacian-Early Campanian), and additional material was later reported from the Pierre Shale, Mooreville Chalk, Demopolis Chalk, Wenonah Formation, and Moreno Formation, among other localities. It has also been reported in European Russia, specifically from the Rybushka Formation of the Saratov Region. It grew to at leas

Caturus (from , 'down' and 'tail') is an extinct genus of predatory marine fishes in the family Caturidae in the order Amiiformes, related to modern bowfin. It has been suggested that the genus is non-monophyletic with respect to other caturid genera.

alt=Coniophis sp. snake vertebra|thumb|Coniophis sp. vertebra Coniophis is an extinct genus of snakes from the late Cretaceous period. The type species, Coniophis precedes, was about 7 cm long and had snake-like teeth and body form, with a skull and a largely lizard-like bone structure. It probably ate small vertebrates, such as lizards and salamanders. The fossil remains of Coniophis were first discovered at the end of the 19th century in the Lance Formation of the US state of Wyoming, and were described in 1892 by Othniel Charles Marsh. For the genus Coniophis, a number of other species