User:Abyssal/Portal:Mosasaurs

The Mosasaurs Portal Introduction Selected article related to mosasaurs An asteroid impacting on Earth. The Cretaceous–Paleogene extinction event, often referred to as the Cretaceous–Tertiary extinction event, was the large-scale mass extinction of animal and plant species in a geologically short period of time, approximately 66 million years ago (mya). The K–Pg extinction event is associated with a geological signature, usually a thin band dated to that time and found in various parts of the world, known as the K–Pg boundary. K is the traditional abbreviation for the Cretaceous Period, and Pg is the abbreviation for the Paleogene Period. The event marks the end of the Mesozoic Era, and the beginning of the Cenozoic Era. Non-avian dinosaur fossils are only found below the K–Pg boundary and became extinct immediately before or during the event. A very small number of dinosaur fossils have been found above the K-Pg boundary, but they have been explained as reworked, that is, fossils that have been eroded from their original locations then preserved in later sedimentary layers. Mosasaurs, plesiosaurs, pterosaurs and many species of plants and invertebrates also became extinct. Mammalian and bird clades passed through the boundary with few extinctions, and radiation from those Maastrichtian clades occurred well past the boundary. Rates of extinction and radiation varied across different clades of organisms. Many scientists theorize that the Cretaceous–Paleogene extinctions were caused by one or more catastrophic geological events such as massive asteroid impacts or increased volcanic activity. Several impact craters and massive volcanic activity in the Deccan traps have been dated to the approximate time of the extinction event. These geological events may have reduced sunlight and hindered photosynthesis, leading to a massive disruption in Earth's ecology. Other researchers believe the extinction was more gradual, resulting from slower changes in sea level or climate. (see more...) Selected image A mounted skeleton of a Late Cretaceous mosasaurid species belonging to the genus Plioplatecarpus, probably P. ictericus. In life the animal would have been about 5.5 m in length. The mounted skeleton is actually a composite of two individuals collected from the Niobrara Formation, of Kansas, USA and is exhibited in the Museum für Naturkunde in Karlsruhe, Germany. Photo credit: H. Zell Did you know? Artist's restoration of Kaganaias ...that the extinct marine reptile Kaganaias is the only ancient aquatic scaled reptile to be found in Asia? Need help? Do you have a question about Abyssal/Portal:Mosasaurs that you can't find the answer to? Consider asking it at the Wikipedia reference desk. Subcategories Mosasaurs Mosasaurs by continent Mosasaurids Related content Paleontology Extinct and Endangered Species Mesozoic Ichthyosauromorphs Sauropterygians Dinosaurs Ammonoids Belemnoids Associated Wikimedia The following Wikimedia Foundation sister projects provide more on this subject: Commons Free media repository Wikibooks Free textbooks and manuals Wikidata Free knowledge base Wikinews Free-content news Wikiquote Collection of quotations Wikisource Free-content library Wikiversity Free learning tools Wiktionary Dictionary and thesaurus Category:Mosasaurs portal