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.
The Mesozoic Era, also called the Age of Reptiles and the Age of Conifers, is the second-to-last era of Earth's geological history, lasting from about 252 to 66 million years ago and comprising the Triassic, Jurassic and Cretaceous Periods. It is characterized by the dominance of archosaurian reptiles, like the dinosaurs; an abundance of conifers and ferns; a hot greenhouse climate; and the tectonic break-up of Pangaea. The Mesozoic is the middle of three eras since complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic.
Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids than they are to shelled nautiloids such as the living Nautilus species. The earliest ammonites appeared during the Devonian, and the last species either vanished in the Cretaceous–Paleogene extinction event, or shortly after during the Danian epoch of the Paleocene.
Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs". Plagiaulacids, an informal suborder, are the most basal of this order, and ranged from the Middle Jurassic Period to the Lower Cretaceous Period of the northern hemisphere.
Morrisonodon brentbaatar is an extinct multituberculate mammal from the Upper Jurassic Morrison Formation of North America.
Liopleurodon is a genus of large, carnivorous marine reptile belonging to the Pliosauroidea, a clade of short-necked plesiosaurs. The two species of Liopleurodon lived from the Callovian Stage of the Middle Jurassic to the Kimmeridgian stage of the Late Jurassic Period. It was the apex predator of the Middle to Late Jurassic seas that covered Europe. The largest species, L. ferox, is estimated to have grown up to 6.4 metres (21 ft) in length.
Snakeflies are a group of predatory insects comprising the order Raphidioptera with two extant families: Raphidiidae and Inocelliidae, consisting of roughly 260 species. In the past, the group had a much wider distribution than it does now; snakeflies are found in temperate regions worldwide but are absent from the tropics and the southern hemisphere. They are a relict group and have been considered living fossils, as species from the early Jurassic period closely resemble modern-day species.
The Brachiosauridae are a family or clade of herbivorous, quadrupedal sauropod dinosaurs. Brachiosaurids had long necks that enabled them to access the leaves of tall trees that other sauropods would have been unable to reach. In addition, they possessed thick spoon-shaped teeth which helped them to consume tough plants more efficiently than other sauropods. They have also been characterized by a few unique traits or synapomorphies; dorsal vertebrae with 'rod-like' transverse processes and an ischium with an abbreviated pubic peduncle.
Lisboasaurus is a small genus of Mesozoic crocodylomorph that lived in fresh water. It is known from fossilized tooth and jaw fragments of Late Jurassic and Early Cretaceous age. Two species have been described. In the past Lisboasaurus has been interpreted as an avialan, troodontid, or an anguimorph lizard. Both species are currently assigned to Crocodylomorpha, one is reassigned to the genus Lusitanisuchus.
Ceratosauridae is an extinct family of theropod dinosaurs belonging to the infraorder Ceratosauria. The family's type genus, Ceratosaurus, was first found in Jurassic rocks from North America. Ceratosauridae is made up of the genera Ceratosaurus, found in North America, Tanzania, and Portugal, and Genyodectes, from the Early Cretaceous of Argentina. Unnamed probable ceratosaurids are known from limited material in the Middle Jurassic of Madagascar, the Late Jurassic of Switzerland, the Late Jurassic of Tanzania, and the Late Jurassic or possibly Early Cretaceous of Uruguay.
Paracryptodira are an extinct clade of turtles in the order Testudines, known from the Jurassic to Paleogene of North America and Europe. Initially treated as a suborder sister to the Cryptodira, they were then thought to be a very primitive lineage inside the Cryptodira according to the most common use of the latter taxon. They are now considered to be a third fundamental division of the Testudines, alongside Cryptodira and Pleurodira. The paracryptodirian turtles are said to have phylogenic relationships, noted as primary subclades, within the Baenidae and Pleurosternidae. Within each subclade, lies many biodiverse turtles that are continuously being investigated and added to the fossil record. Paracryptodires are divided into 3 main groups, Compsemydidae, known from the Late Jurassic to Paleocene of North America and Europe, Pleurosternidae, known from the Late Jurassic to Early Cretaceous of North America and Europe, and Baenidae, known from the Early Cretaceous to Eocene of North America. The latter two groups are more closely related to each other than to Compsemys, forming the clade Baenoidea.
Lusitanisuchus is an extinct genus of mesoeucrocodylian crocodylomorph. Mostly fragmentary fossils have been found from several localities in Portugal and are Late Jurassic and Early Cretaceous in age.
Amblotherium is an extinct genus of Late Jurassic and Early Cretaceous mammal. The type species Amblotherium pusillum is from the Lulworth Formation of southern England, while the referred species Amblotherium gracile is from stratigraphic zones 2, 3 and 5 of the Morrison Formation of the US.
Paramacellodus is an extinct genus of scincomorph lizards from the Early Cretaceous of England and France, and the Late Jurassic of Portugal and the western United States. The type species, Paramacellodus oweni, was named in 1967 from the earliest Cretaceous (Berriasian) Purbeck Group in Dorset, England. Additional material referable to a species of Paramacellodus, possibly P. oweni, has been described from the Morrison Formation, specifically in Como Bluff, Wyoming, and Dinosaur National Monument, Utah. An indeterminate species is known from the Berriasian aged Angeac-Charente bonebed in France. Paramacellodus belongs to an extinct family of scincomorphs called Paramacellodidae, which spanned most of Laurasia during the Late Jurassic and Early Cretaceous and represented one of the earliest evolutionary radiations of lizards.
The Ommatidae are a family of beetles in the suborder Archostemata. The Ommatidae are considered the extant beetle family that has most ancestral characteristics. Extant species of this group only occur in Australia and South America, but the geographical distribution was much wider during the Mesozoic spanning across Eurasia and Australia, suggesting that they were widespread on Pangea. So far, 28 extinct genera containing over 100 species of these beetles have been described. Three extant genera have been assigned to this family: Omma,Tetraphalerus and Beutelius. The family is considered to be a subfamily of Cupedidae by some authors, but have been found to be more closely related to Micromalthidae in molecular phylogenies. A close relationship with Micromalthidae is supported by several morphological characters, including those of the mandibles and male genitalia. Due to their rarity, their ecology is obscure, it is likely that their larvae feed on deadwood.
Compsemys is an extinct genus of prehistoric turtles from the Late Cretaceous and Paleocene of North America and possibly Europe. The type species C. victa, first described by Joseph Leidy from the Hell Creek Formation in Montana in 1856., and another probable species C. Russelli, described in 2012, from Paleocene deposits in France. Its affinites have long been uncertain, but it has recently been considered to be the most basal member of Paracryptodira, despite the clade first appearing in the Late Jurassic, and is sometimes included in its own family, Compsemydidae. A revision in 2020 found Compsemydidae to be more expansive, also containing Riodevemys and Selenemys from the Late Jurassic of Europe, and Peltochelys from the Early Cretaceous of Europe.
Pleurosternon is an extinct genus of freshwater pleurosternid turtle from the late Jurassic period to the early Cretaceous period of Europe. Its type species, P. bullocki was described by the paleontologist Richard Owen in 1853. Since then, and throughout the late 19th century, many fossil turtles were incorrectly assigned to this genus, though only two are currently considered valid.
Montirictus is an extinct genus of tritylodonts known from the Early Cretaceous Kuwajima Formation of Japan. It is currently the latest surviving tritylodontid species, and is closely related to the earlier Xenocretosuchus from mainland Asia, and the Jurassic Stereognathus from the UK. It may be a species of the genus Stereognathus, but resolution of its affinities conditions upon the discovery of additional material.
Jurassic World Camp Cretaceous is an American animated science fiction action-adventure streaming television series developed by Zack Stentz. A part of the Jurassic Park franchise, it features the voices of Paul-Mikél Williams, Sean Giambrone, Kausar Mohammed, Jenna Ortega, Ryan Potter, and Raini Rodriguez as a group of teenage campers who become stranded on Isla Nublar after multiple dinosaurs escape their habitats. Jameela Jamil, Glen Powell, Stephanie Beatriz, Bradley Whitford, Angus Sampson, Greg Chun, Kirby Howell-Baptiste, and Haley Joel Osment also star in recurring roles.
