The Cretaceous is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin creta, "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation Kreide.
Ginkgoales are a gymnosperm order containing only one extant species: Ginkgo biloba, the ginkgo tree. It is monotypic, within the class Ginkgoopsida, which itself is monotypic within the division Ginkgophyta. The order includes five families, of which only Ginkgoaceae remains extant.
Orthoceras is a genus of extinct nautiloid cephalopod restricted to Middle Ordovician-aged marine limestones of the Baltic States and Sweden. This genus is sometimes called Orthoceratites. Note it is sometimes misspelled as Orthocera, Orthocerus or Orthoceros.
Allodaposuchus is an extinct genus of crocodyliforms that includes four species that lived in what is now southern Europe during the Campanian and Maastrichtian stages of the Late Cretaceous. Although generally classified as a non-crocodylian crocodylomorph, it is sometimes placed as one of the earliest true crocodylians. Allodaposuchus is one of the most common Late Cretaceous crocodylomorphs from Europe, with fossils known from Romania, Spain, and France.
Axestemys is an extinct genus of softshell turtle that lived from the Late Cretaceous to the Eocene in western North America and Europe.
Ichthyornithes is an extinct group of toothed avialans very closely related to the common ancestor of all modern birds. They are known from fossil remains found throughout the late Cretaceous period of North America, though only one species, Ichthyornis dispar, is represented by complete enough fossils to have been named. Ichthyornitheans became extinct at the Cretaceous–Paleogene boundary, along with enantiornitheans, all other non-avian dinosaurs, and many other animal and plant groups.
Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction.
Carcharias is a genus of sand tiger 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.
Ctenochelys is an extinct genus of marine turtle, which existed during the Cretaceous period, and lived in the shallow waters of the Western Interior Seaway. Its fossils have been found in the Ripley Formation and Mooreville Chalk of central Alabama, United States. It was first named by C.H. Sternberg in 1904, and contains two species, C. stenoporus and C. acris.
Mesodermochelys is an extinct genus of sea turtle known from the Campanian to the Maastrichtian of what today is Japan. One species is known, the type species M. undulatus; it was given its binomial name by Ren Hirayama and Tsutomu Chitoku in 1996. Studies of its skull indicate that it was a primitive member of the Dermochelyidae that was closely related to the Protostegidae. It has been described as the best representative of Mesozoic dermochelyids.
Eoconfuciusornis a genus of extinct avialan that lived 131 Ma ago, in the Early Cretaceous of China.
Tadzhikosuchus is an extinct genus of neosuchian crocodyliform from the Late Cretaceous of Tajikistan. Three species have been named: the type species T. macrodentis, described by Efimov in 1982 from the lower Santonian-age Upper Cretaceous Ialovachsk Formation of Kansai, Tajikistan, in the Fergana Basin of Tajikistan; T. neutralis from the same location, by Efimov in 1988; and T. kizylkumensis from Turonian-age rocks of the Upper Cretaceous Bissekty Formation of Dzharakhuduk, Uzbekistan, by Nesov and colleagues in 1989. However, a 2000 review by Glenn Storrs and Mikhail Efimov could not differentiate between the species based on their type material, and recommended grouping the specimens of all three species under T. macrodentis. They also could not determine how Tadzhikosuchus and the contemporaneous Zhyrasuchus were related, or even if they were synonyms, due to the poor fossils available. The name of the Tadzhikosuchus is derived from the Russian spelling of the name of the former Soviet republic of Tajikistan.
Keuppia is an extinct genus of octopus.
Ovoo gurvel is an extinct monitor lizard from the Late Cretaceous of Mongolia. It is one of the smallest and earliest monitor lizards. It was described in 2008. Ovoo possesses a pair of two small bones in its skull that are not seen in any other lizard.
Cherminotus is an extinct genus of monitor lizard from the Late Cretaceous of Mongolia. The type and only species, Cherminotus longifrons, was named in 1984.
Telmasaurus is an extinct genus of varanoid lizard from the Late Cretaceous of Mongolia. Fossils have been found from the Djadokha and Barun Goyot Formations that date between the early and middle Campanian stage from approximately 80 to 75 million years ago. The type species Telmasaurus grangeri was named in 1943.
Albicoccus is an extinct genus of scale insect in the extinct monotypic family Albicoccidae, containing a single species, Albicoccus dimai. The genus is solely known from the Albian - Cenomanian Burmese amber deposits.
Priscagama is an extinct genus of iguanian lizard from the Late Cretaceous of Mongolia and China. It belongs to an extinct family of iguanians called Priscagamidae. Several incomplete skulls have been found in the Barun Goyot and Djadochta formations, and were originally referred to the genus Mimeosaurus; the type species Priscagama gobiensis was named in 1984 when it was recognized that these skulls belonged to a distinct species. Priscagama differs from most other priscagamids in having a more elongate, lightly built skull. It is very similar in appearance to another priscagamid called Pleurodontagama, as the two can only be distinguished by the shape of their teeth.
Makhaira rossica is an extinct genus and species of a marine reptile belonging to the family Pliosauridae. It lived during the early Cretaceous period, and its fossils have been found in Russia.
Nanhsiungchelyidae is an extinct family of land turtles known from Cretaceous deposits in Asia and North America. Nanhsiungchelyids were more terrestrial than many of their contemporaries, and may have gone extinct at the end of the Cretaceous as a result.
