Meniscoessus is a genus of extinct mammal from the Upper Cretaceous Period of what is now North America. It was a member of the extinct order Multituberculata, lying within the suborder Cimolodonta and family Cimolomyidae.
Cimolomys is a mammal genus from the Upper Cretaceous of North America. It was a member of the extinct order Multituberculata within the suborder Cimolodonta and family Cimolomyidae.
The Hell Creek Formation is an intensively studied division of mostly Upper Cretaceous and some lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana. The formation stretches over portions of Montana, North Dakota, South Dakota, and Wyoming. In Montana, the Hell Creek Formation overlies the Fox Hills Formation. The site of Pompeys Pillar National Monument is a small isolated section of the Hell Creek Formation. In 1966, the Hell Creek Fossil Area was designated as a National Natural Landmark by the National Park Service.
Denversaurus is a genus of panoplosaurin nodosaurid dinosaur from the late Maastrichtian of Late Cretaceous Western North America. Although at one point treated as a junior synonym of Edmontonia by some taxonomists, current research indicates that it is its own distinct nodosaurid genus.
Symmoriiformes is an extinct order of stem-group holocephalians. Originally named Symmoriida by Zangerl (1981), it has subsequently been known by several other names. Lund (1986) synonymized the group with Cladodontida, while Maisey (2008) corrected the name to Symmoriiformes in order to prevent it from being mistaken for a family. The symmoriiform fossils record begins during the late Devonian. Most of them died out at the start of the Permian, but Dwykaselachus is known from the Artinskian-Kungurian of South Africa. Teeth described from the Valanginian of France and Austria indicate that members of the family Falcatidae might have survived until the Early Cretaceous; however, these teeth were also argued to be more likely neoselachian teeth.
The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from Pembina Valley in Canada to New Mexico.
Jeletzkytes is an extinct genus of scaphatoid ammonite from the Upper Cretaceous (Maastrichtian) of North America named and described by Riccardi, 1983. In overall form Jeletzkytes closely resembles the genus Scaphites.
Cylindracanthus is an extinct genus of Cretaceous to Eocene aged ray-finned fish. It is almost exclusively known from bony rostrum fragments as well as some associated teeth, with the rest of the skeleton being cartilaginous. While originally considered to be closely related to billfish, the structure of its rostrum is dissimilar, and is unlikely to be closely related, some later studies suggested closer affinities to the Acipenseriformes. However, this was later rejected due to the lack of osteocytes in histologically examined specimens, which resembles the condition of derived teleosts. A close relation to Blochius has been suggested.
Gamerabaena is an extinct genus of baenid turtle which existed in North Dakota during the late Cretaceous Period. It is known from a single fragmentary skull that was found in the Maastrichtian-age Hell Creek Formation. It contains the species Gamerabaena sonsalla. Gamerabaena is similar to the genus Palatobaena, but it differs in its lack of a posterior expansion of the triturating surface, a somewhat rectangular skull, and a wide angle between the maxillae. Gamerabaena also has a lingual ridge on the inner side of the jaw that is not seen in Palatobaena.
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.
Paleontology in Arkansas refers to paleontological research occurring within or conducted by people from the U.S. state of Arkansas. The fossil record of Arkansas spans from the Ordovician to the Eocene. Nearly all of the state's fossils have come from ancient invertebrate life. During the early Paleozoic, much of Arkansas was covered by seawater. This sea would come to be home to creatures including Archimedes, brachiopods, and conodonts. This sea would begin its withdrawal during the Carboniferous, and by the Permian the entire state was dry land. Terrestrial conditions continued into the Triassic, but during the Jurassic, another sea encroached into the state's southern half. During the Cretaceous the state was still covered by seawater and home to marine invertebrates such as Belemnitella. On land the state was home to long necked sauropod dinosaurs, who left behind footprints and ostrich dinosaurs such as Arkansaurus.
This list of fossil fish species is a list of taxa of fish that have been described during the year 2012. The list only includes taxa at the level of genus or species.
The Arkadelphia Marl, also called the Arkadelphia Formation, is a geologic formation in Arkansas in Clark, Nevada, and Hempstead counties. It preserves fossils dating back to the Cretaceous period.
The Ferron Sandstone Member of the Mancos Shale is a geologic unit in Utah. It preserves fossils dating back to the Cretaceous period; and more specifically the middle Turonian.
Eorhincodon is an invalid genus of requiem shark from the Late Eocene of Xinjiang, China, originally described as a whale shark. It is currently considered a junior synonym of Rhizoprionodon. The genus was originally erected by Li (1997) to include the species Eorhincodon tianshanensis, but Nessov (1999) used the preoccupied genus in a different paleontological context to include an unrelated species, E. casei, from Late Cretaceous Russian marine strata. A new genus, Pseudomegachasma, was erected in 2015 for E. casei to be transferred into.
Synechodontiformes is an extinct order of prehistoric sharks, known from the Permian to the Paleogene. They are considered to be members of Neoselachii, the group that contains modern sharks and rays. Their placement in the group is uncertain, some authors have considered them to be galeomorph crown-group sharks, while others have considered them to represent a stem-group to modern sharks. They have sometimes been considered a paraphyletic grouping, but Klug (2010) recovered the group as monophyletic. Members of the clade are united by two synapomorphies, "pseudopolyaulacorhize tooth root pattern present; labial root depression in basal view present". The oldest possible member of the clade are teeth from the early Permian (Cisuralian) of the Ural Mountains.
Galagadon is an extinct genus of small carpet shark that lived during the Late Cretaceous period. It contains one species, G.nordquistae. It was named after the video game Galaga due to a resemblance between its teeth and the spaceships in the game, and Field Museum volunteer Karen Nordquist.
Angolabatis is an extinct genus of skate from the Late Cretaceous of the Cretaceous. It is represented by a single described species, A. benguelaensis. It was described from isolated teeth found in the late Campanian to early Maastrichtian rocks of Quimbala, a site in the Benguela Basin of Angola. These teeth were originally placed under the genus Angolaia; however, this name was preoccupied by a living genus of leafhopper. Teeth attributed to this genus have been described from the contemporary Allen Formation of the Cerro Tortuga locality in the Santa Rosa Basin of the Río Negro province, Argentina. The Argentinian specimens likely represent a new species, but the fragmentary nature of the finds precludes a formal description of a new taxon. While A. benguelaensis was found in marine deposits, the Argentinian species was found among freshwater fish.
Ctenacanthiformes is an extinct order of elasmobranch fish. They possessed ornamented fin spines at the front of their dorsal fins and cladodont-type dentition, that is typically of a grasping morphology, though some taxa developed cutting and gouging tooth morphologies. Some ctenacanths are thought to have reached sizes comparable to the great white shark, with body lengths of up to 7 metres (23 ft) and weights of 1,500–2,500 kilograms (3,300–5,500 lb). Ctenacanths are typically thought to have existed from the Devonian to the Late Permian, becoming extinct in the Permian-Triassic extinction event. Members of the family Ctenacanthidae may have survived into the Cretaceous based on teeth found in deep water deposits of Valanginian age in France and Austria, however, other authors contend that the similarity of these teeth to Paleozoic ctenacanths is only superficial, and they likely belong to neoselachians instead. The monophyly of the group has been questioned, with some studies recovering the group as a whole as paraphyletic or polyphyletic.
