Portal:Cretaceous

Topics Culture Geography Health History Mathematics Nature People Philosophy Religion Society Technology The Cretaceous Portal Mounted skeletons at the AMNH. The Cretaceous /krɪˈteɪʃəs/, derived from the Latin "creta" (chalk), usually abbreviated K for its German translation Kreide (chalk), is a geologic period and system from circa 145 ± 4 to 66 ± 0.3 million years (Ma) ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the Cenozoic era. It is the youngest period of the Mesozoic era, and at 80 million years long, the longest period of the Phanerozoic Eon. The end of the Cretaceous defines the boundary between the Mesozoic and Cenozoic eras. In many languages this period is known as "chalk period". The Cretaceous was a period with a relatively warm climate and high eustatic sea level. The oceans and seas were populated with now extinct marine reptiles, ammonites and rudists; and the land by dinosaurs. At the same time, new groups of mammals and birds as well as flowering plants appeared. The Cretaceous ended with one of the largest mass extinctions in Earth history, the K–T extinction, when many species, including non-avian dinosaurs, pterosaurs, and large marine reptiles, disappeared. (see more...) Artist's restoration of Gorgosaurus libratus. Gorgosaurus is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period, between about 76.6 and 75.1 million years ago. Fossil remains have been found in the Canadian province of Alberta and possibly the U.S. state of Montana. Paleontologists recognize only the type species, G. libratus, although other species have been erroneously referred to the genus. Like most known tyrannosaurids, Gorgosaurus was a bipedal predator weighing more than two metric tons as an adult; dozens of large, sharp teeth lined its jaws, while its two-fingered forelimbs were comparatively small. Gorgosaurus was most closely related to Albertosaurus, and more distantly related to the larger Tyrannosaurus. Some experts consider G. libratus to be a species of Albertosaurus; this would make Gorgosaurus a junior synonym of that genus. Gorgosaurus lived in a lush floodplain environment along the edge of an inland sea. It was an apex predator (meaning that it was at the top of its food chain), preying upon abundant ceratopsids and hadrosaurs. In some areas, Gorgosaurus coexisted with another tyrannosaurid, Daspletosaurus. Although these animals were roughly the same size, there is some evidence of niche differentiation between the two. Gorgosaurus is the best-represented tyrannosaurid in the fossil record, known from dozens of specimens. These plentiful remains have allowed scientists to investigate its ontogeny, life history and other aspects of its biology. (see more...) Bone Sharps, Cowboys, and Thunder Lizards: A Tale of Edward Drinker Cope, Othniel Charles Marsh, and the Gilded Age of Paleontology (2005) is a graphic novel written by Jim Ottaviani and illustrated by the company Big Time Attic. The book tells a slightly fictionalized account of the Bone Wars, a period of intense excavation, speculation, and rivalry which led to a greater understanding of dinosaurs in the western United States. This novel is the first semi-fictional work written by Ottaviani; previously, he had taken no creative license with the characters he depicted, portraying them strictly according to historical sources. Bone Sharps follows the two scientists Edward Drinker Cope and Othniel Marsh as they engage in an intense rivalry for prestige. Ottaviani has Cope and Marsh interact and meet many important figures of the Gilded Age, from P. T. Barnum to U.S. Grant, as the two scientists pursue their hotheaded and sometimes illegal acquisitions of fossils. Unlike in his previous books, "the scientists are the bad guys this time". Upon release, the novel received praise from critics for its exceptional historical content, although some reviewers wished more fiction had been woven into the story. (see more...) Fossil of the Late Cretaceous ammonoid Bostrychoceras polyplocum A fossil shell of the nostoceratid ammonoid Bostrychoceras polyplocum. The shell dates back to the Campanian age (72.1 to 83.6 million years ago) of the Late Cretaceous epoch and is about 20 cm long. It was collected near Haldem, Germany and is exhibited in the Museum für Naturkunde in Berlin. Photo credit: H. Zell File:Araripesuchus.jpg ... that the Cretaceous terrestrial crocodilian Araripesuchus is known from five distinct species, two from Africa and the other three from South America? ... that the cretaceous subfamily Sphecomyrminae has not been included in several recent phylogenetic studies of the ant family? ... that the extinct snakefly Alavaraphidia is known from a single female trapped in amber (pictured)? ... that Alanqa is a newly described pterosaur from Morocco which had a wingspan of up to six metres? ... that Ororaphidia and Styporaphidia are the oldest snakeflies known from China, dating from the Middle Jurassic? Template:/box-header Epochs - Early Cretaceous - Late Cretaceous Stages - Berriasian - Valanginian - Hauterivian - Barremian - Aptian - Albian - Cenomanian - Turonian - Coniacian - Santonian - Campanian - Maastrichtian Events - Cambrian–Ordovician extinction event - Great Ordovician Biodiversification Event - Taconic orogeny - Late Ordovician glaciation - Alice Springs Orogeny - Ordovician–Silurian extinction event Landmasses - Baltica - Gondwana - Laurentia - Siberia Bodies of water - Iapetus Ocean - Khanty Ocean - Proto-Tethys Ocean - Rheic Ocean - Tornquist Sea - Ural Ocean Animals - Articulate brachiopods - Bryozoans - Cornulitids - Crinoids - Cystoids - Gastropods - Graptolites - Jawed fishes - Nautiloids - Ostracoderms - Rugose corals - Star fishes - Tabulate corals - Tentaculitids - Trilobites Trace fossils - Petroxestes - Trypanites Plants - Marchantiophyta Fossil sites - Beecher's Trilobite Bed - Walcott–Rust quarry Stratigraphic units - Chazy Formation - Fezouata formation - Holston Formation - Kope Formation - Potsdam Sandstone - St. Peter Sandstone Researchers - Charles Emerson Beecher - Charles Lapworth - Charles Doolittle Walcott Culture - Animal Armageddon - List of creatures in the Walking with... series - Sea Monsters Template:/box-footer Template:/box-header Featured Cretaceous articles - Bone Sharps, Cowboys, and Thunder Lizards - Bone Wars - Edward Drinker Cope - Geology of the Capitol Reef area - Geology of the Death Valley area -Geology of the Grand Canyon area - Geology of the Zion and Kolob canyons area Good Cretaceous articles - Chitinozoan - Coal ball - Dimetrodon - History of paleontology - Evolutionary history of life - Ornatifilum - Opabinia - Paleontology- Schinderhannes - Small shelly fauna - Temnospondyli - Tiktaalik - Waptia Template:/box-footer ▼ Cretaceous ► Cretaceous life Here are some tasks awaiting attention: Stubs : Cretaceous stubs Current Cretaceous FACs - none currently Template:/box-footer Time Earth sciences Paleontology Extinct and Endangered Species Paleozoic Triassic Jurassic Cretaceous Cenozoic What are portals? 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