Archaeornithomimus is a genus of ornithomimosaurian theropod dinosaur that lived in Asia during the Late Cretaceous period, around 96 million years ago in the Iren Dabasu Formation.
The Bayan Shireh Formation is a geological formation in Mongolia, that dates to the Cretaceous period. It was first described and established by Vasiliev et al. 1959.
Selmasaurus is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Plioplatecarpinae subfamily alongside genera like Angolasaurus and Platecarpus. Two species are known, S. russelli and S. johnsoni; both are exclusively known from Santonian deposits in the United States.
"Coelosaurus" antiquus is a dubious species of theropod dinosaurs. It was named by Joseph Leidy in 1865 for two tibiae found in the Navesink Formation of New Jersey.
Eonatator is an extinct genus of marine lizard belonging to the mosasaur family. It is a close relative of Halisaurus, and part of the same subfamily, the Halisaurinae. It is known from the Late Cretaceous of North America, Colombia and Sweden. Originally, this taxon was included within Halisaurus, but was placed in its own genus, which also led to the subfamily Halisaurinae being created for the two genera.
Protosphyraena is a fossil genus of swordfish-like marine fish, that thrived worldwide during the Upper Cretaceous Period (Coniacian-Maastrichtian). Though fossil remains of this taxon have been found in both Europe and Asia, it is perhaps best known from the Smoky Hill Member of the Niobrara Chalk Formation of Kansas. Protosphyraena was a large fish, averaging 2–3 metres in length. Protosphyraena shared the Cretaceous oceans with aquatic reptiles, such as mosasaurs and plesiosaurs, as well as with many other species of extinct predatory fish. The name Protosphyraena is a combination of the Greek word protos ("early") plus Sphyraena, the genus name for barracuda, as paleontologists initially mistook Protosphyraena for an ancestral barracuda. Recent research shows that the genus Protosphyraena is not at all related to the true swordfish-family Xiphiidae, but belongs to the extinct family Pachycormidae.
Apateodus is a genus of prehistoric marine ray-finned fish which was described by Woodward in 1901. It was a relative of modern lizardfish and lancetfish in the order Aulopiformes, and one of a number of prominent nektonic aulopiforms of Cretaceous marine ecosystems.
The Mooreville Chalk is a geological formation in North America, within the U.S. states of Alabama and Mississippi, which were part of the subcontinent of Appalachia. The strata date back to the early Santonian to the early Campanian stage of the Late Cretaceous. The chalk was formed by pelagic sediments deposited along the eastern edge of the Mississippi embayment. It is a unit of the Selma Group and consists of the upper Arcola Limestone Member and an unnamed lower member. Dinosaur, mosasaur, and primitive bird remains are among the fossils that have been recovered from the Mooreville Chalk Formation.
The Demopolis Chalk is a geological formation in North America, within the U.S. states of Alabama, Mississippi, and Tennessee. The chalk was formed by pelagic sediments deposited along the eastern edge of the Mississippi embayment during the middle Campanian age of the Late Cretaceous. It is a unit of the Selma Group and consists of the upper Bluffport Marl Member and a lower unnamed member. Dinosaur and mosasaur remains are among the fossils that have been recovered from the Demopolis Chalk.
The Cerro del Pueblo Formation is a geological formation in Coahuila, Mexico whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation. The formation is believed to correlate with the Baculites reesidesi and Baculites jenseni ammonite zones, which dates it to 73.63-72.74 Ma.
The Yezo Group is a stratigraphic group in Hokkaido, Japan and Sakhalin, Russia which is primarily Late Cretaceous in age. It is exposed as roughly north–south trending belt extending 1,500 kilometres through central Hokkaido from Urakawa to Cape Sōya and Sakhalin from the south coast to Alexandrovsk-Sakhalinsky District. It consists of marine forearc basin sediments, typically turbiditic and bioturbated mudstones and sandstones with subordinate conglomerate primarily deposited on the continental shelf and slope of the ancient Yezo subduction margin. It forms a continuous depositional sequence with the Sorachi Group, which overlies the Horokanai Ophiolite. The sequence gradually shallows upwards with the terminal Hakobuchi Formation representing a fluvial-inner shelf environment.
The Selma Group is a geological formation in North America, within the U.S. states of Alabama, Mississippi, and Tennessee. The strata date from the Santonian to the Maastrichtian stages of the Late Cretaceous. The group is composed of, in ascending order, the Mooreville Chalk Formation, Demopolis Chalk Formation, Ripley Formation, and Prairie Bluff Chalk Formation. Dinosaur and mosasaur remains are among the fossils that have been recovered from the Selma Group.
The Ripley Formation is a geological formation in North America found in the U.S. states of Alabama, Georgia, Mississippi, Missouri, and Tennessee. The lithology is consistent throughout the layer. It consists mainly of glauconitic sandstone. It was formed by sediments deposited during the Maastrichtian stage of the Late Cretaceous. It is a unit of the Selma Group and consists of the Cusseta Sand Member, McNairy Sand Member and an unnamed lower member. It has not been extensively studied by vertebrate paleontologists, due to a lack of accessible exposures. However, fossils have been unearthed including crocodile, hadrosaur, nodosaur, tyrannosaur, ornithomimid, dromaeosaur, and mosasaur remains have been recovered from the Ripley Formation.
The Navesink Formation is a 66 to 70 mya greensand glauconitic marl and sand geological formation in New Jersey. It is known for its Cretaceous period fossil shell beds and dinosaur bones.
During the time of the deposition of the Niobrara Chalk, much life inhabited the seas of the Western Interior Seaway. By this time in the Late Cretaceous many new lifeforms appeared such as mosasaurs, which were to be some of the last of the aquatic lifeforms to evolve before the end of the Mesozoic. Life of the Niobrara Chalk is comparable to that of the Dakota Formation, although the Dakota Formation, which was deposited during the Cenomanian, predates the chalk by about 10 million years.
The Tamayama Formation is a Coniacian-Santonian geologic formation in Japan. Dinosaur remains not referrable to the genus level are among the fossils that have been recovered from the formation. The lower and middle part of the formation consists of braided river sandstone, while the upper portion consists of upper shoreface to inner shelf sandstone. Vertebrate taxa from the formation include Futabasaurus and Cretalamna, along with titanosauriform teeth and neosuchian remains. Seeds of the nymphaeales plant Symphaenale futabensis are also known from this formation.
During most of the Late Cretaceous the eastern half of North America formed Appalachia, an island land mass separated from Laramidia to the west by the Western Interior Seaway. This seaway had split North America into two massive landmasses due to a multitude of factors such as tectonism and sea-level fluctuations for nearly 40 million years. The seaway eventually expanded, divided across the Dakotas, and by the end of the Cretaceous, it retreated towards the Gulf of Mexico and the Hudson Bay. This left the island masses joined in the continent of North America as the Rocky Mountains rose. From the Cenomanian to the end of the Campanian ages of the Late Cretaceous, Appalachia was separated from the rest of North America. As the Western Interior Seaway retreated in the Maastrichtian, Laramidia and Appalachia eventually connected. Because of this, its fauna was isolated, and developed very differently from the tyrannosaur, ceratopsian, hadrosaurid, pachycephalosaur and ankylosaurid dominated fauna of the western part of North America, known as "Laramidia".
The Snow Hill Island Formation is an Early Maastrichtian geologic formation found on James Ross Island, James Ross Island group, Antarctica. Remains of a paravian theropod Imperobator antarcticus have been recovered from it, as well as the elasmarian ornithopods Trinisaura santamartaensis, Biscoveosaurus and Morrosaurus antarcticus, the ankylosaurian Antarctopelta oliveroi, and the shark Notidanodon sp. Alongside these described genera are also the remains of indeterminate elasmosaurids, lithostrotian titanosaurs and an indeterminate pterosaur.
Eotrachodon orientalis is a species of hadrosaurid that was described in 2016. The holotype was found in the Mooreville Chalk Formation in Alabama in 2007 and includes a well-preserved skull and partial skeleton, making it a rare find among dinosaurs of Appalachia. Another primitive hadrosaur, Lophorhothon, is also known from the same formation, although Eotrachodon lived a few million years prior. A phylogenetic study has found Eotrachodon to be the sister taxon to the hadrosaurid subfamilies Lambeosaurinae and Saurolophinae. This, along with the other Appalachian hadrosaur Hadrosaurus and possibly Lophorhothon, Claosaurus and both species of Hypsibema, suggests that Appalachia was the ancestral area of Hadrosauridae.
