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Archelon
''Archelon'' is an extinct marine turtle from the Late Cretaceous, and is the largest turtle ever to have been documented, with the biggest specimen measuring from head to tail and in body mass. It is known only from the Pierre Shale and has one species, ''A. ischyros''. In the past, the genus also contained ''A. marshii'' and ''A. copei'', though these have been reassigned to ''Protostega'' and ''Kansastega'', respectively. The genus was named in 1896 by American paleontologist George Reber Wieland based on a skeleton from South Dakota, who placed it into the extinct family (biology), family Protostegidae. The leatherback sea turtle (''Dermochelys coriacea'') was once thought to be its closest living relative, but now, Protostegidae is thought to be a completely separate lineage from any living sea turtle. ''Archelon'' had a leathery carapace instead of the hard shell seen in most sea turtles. The carapace may have featured a row of small ridges, each peaking at in heigh ...
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Protostegidae
Protostegidae is a family of extinct sea turtle, marine turtles that lived during the Cretaceous period. The family includes some of the largest sea turtles that ever existed. The largest ''Archelon'' had a head long. Like most sea turtles, they had flattened bodies and flipper (anatomy), flippers for front appendages; protostegids had minimal carapace, shells like Dermochelyidae, leatherback turtles of modern times. Anatomy As some of the first sea turtle, marine turtles, the protostegids set the general body plan for future species of sea turtles. They had a generally depressed turtle body plan, complete with four limbs, a short tail, and a large head at the end of a relatively short neck. Like other sea turtles, they possessed oar-like front appendages especially evolved for swimming in the open ocean. Similar to the still-extant taxon, extant, possibly closely related Dermochelyidae, protostegids possessed extremely reduced carapaces. Some specimens had skeletal protrusions ...
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Pierre Shale
The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from Pembina Valley in Canada to New Mexico. The Pierre Shale was described by Fielding Bradford Meek, Meek and Ferdinand Vandeveer Hayden, Hayden in 1862 in the Proceedings of the Academy of Sciences (Philadelphia). They described it as a dark-gray shale, fossiliferous, with veins and seams of gypsum, and concretions of iron oxide. The Pierre Shale is about 3,138 feet (956m) thick at the type locality. It overlies the Niobrara Chalk, Niobrara division and underlies the Fox Hills beds. It was named for an occurrence near Fort Pierre, South Dakota, Fort Pierre on the Missouri River in South Dakota. The Pierre Shale is of marine origin and was deposited in the Western Interior Seaway. It is correlative with other marine shales that occur farther west, such as the Bearpaw Shale Formation, Bearpaw Shale, Mancos Shale and the Lewis Shale. It corre ...
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Protostega
''Protostega'' ('first roof') is an extinct genus of sea turtle containing a single species, ''Protostega gigas''. Its fossil remains have been found in the Smoky Hill Chalk formation of western Kansas (''Hesperornis'' zone, dated to 83.5 million years agoCarpenter, K. (2003). "Vertebrate Biostratigraphy of the Smoky Hill Chalk (Niobrara Formation) and the Sharon Springs Member (Pierre Shale)." ''High-Resolution Approaches in Stratigraphic Paleontology'', 21: 421-437. ), time-equivalent beds of the Mooreville Chalk Formation of Alabama and Campanian beds of the Rybushka Formation (Saratov Oblast, Russia). Fossil specimens of this species were first collected in 1871, and named by Edward Drinker Cope in 1872. With a total length of , it is the second-largest sea turtle that ever lived, second only to the giant ''Archelon'', and one of the three largest turtles of all time alongside ''Archelon'' and '' Gigantatypus''. Discovery and history The first known ''Protostega'' specim ...
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Kansastega
''Kansastega'' is an extinct genus of protostegid sea turtles that lived during the Late Cretaceous. It contains one valid species, ''K. copei'', which has been found in the Niobrara Formation of Kansas. It was originally named as a species of ''Protostega'', then was moved to its own genus ''Microstega''. However, that genus name was preoccupied by the moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ... '' Microstega''. As a result, ''Kansastega'' was proposed as a replacement name. References {{Taxonbar, from=Q123125186 Protostegidae Prehistoric turtle genera Fossil taxa described in 2023 ...
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Sea Turtle
Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerhead, Kemp's ridley, and olive ridley. Six of the seven sea turtle species, all but the flatback, are present in U.S. waters, and are listed as endangered and/or threatened under the Endangered Species Act. They are listed as threatened with extinction globally on the IUCN Red List of Threatened Species. The flatback turtle is found only in the waters of Australia, Papua New Guinea, and Indonesia. Sea turtles can be categorized as hard-shelled ( cheloniid) or leathery-shelled ( dermochelyid).Wyneken, J. 2001. The Anatomy of Sea Turtles. U.S Department of Commerce NOAA Technical Memorandum NMFS-SEFSC-470, 1-172 pp. The only dermochelyid species of sea turtle is the leatherback. Description For each of the seven species of sea turtles, ...
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Peabody Museum Of Natural History
The Peabody Museum of Natural History at Yale University (also known as the Yale Peabody Museum of Natural History or the Yale Peabody Museum) is one of the oldest, largest, and most prolific university natural history museums in the world. It was founded by the philanthropist George Peabody in 1866 at the behest of his nephew Othniel Charles Marsh, an early paleontologist. The museum is best known for the Great Hall of Dinosaurs, which includes a mounted juvenile ''Brontosaurus'' and the mural '' The Age of Reptiles''. The museum also has permanent exhibits dedicated to human and mammal evolution; wildlife dioramas; Egyptian artifacts; local birds and minerals; and Native Americans of Connecticut. In 2020, the Peabody Museum closed for its "first comprehensive renovation in 90 years." It reopened, with more than twice the exhibition space, on March 26, 2024. Description The Peabody Museum is located at 170 Whitney Avenue in New Haven, Connecticut and is staffed by nearl ...
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Hesperornithiform
Hesperornithes is an extinct and highly specialized group of aquatic avialans closely related to the ancestors of modern birds. They inhabited both marine and freshwater habitats in the Northern Hemisphere, and include genera such as ''Hesperornis'', '' Parahesperornis'', '' Baptornis'', '' Enaliornis'', and '' Potamornis'', all strong-swimming, predatory divers. Many of the species most specialized for swimming were completely flightless. The largest known hesperornithean, '' Canadaga arctica'', may have reached a maximum adult length of . Hesperornitheans were the only Mesozoic avialans known to colonize the oceans. They were wiped out in the Cretaceous–Paleogene extinction event, along with enantiornitheans and all other non-avian dinosaurs. Anatomy and ecology Most of what is known about this group rests on analyses of single species, as few provide sufficiently complete fossils for analysis. Although some of the smaller and more basal species, like those belonging to the ...
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Mosasaur
Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Ancient Greek, Greek ' meaning 'lizard') are an extinct group of large aquatic reptiles within the family Mosasauridae that lived during the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. They belong to the order Squamata, which includes lizards and snakes. During the last 20 million years of the Cretaceous period (Turonian–Maastrichtian ages), with the extinction of the ichthyosaurs and Pliosauridae, pliosaurs, mosasaurids became the dominant marine predators. They themselves became extinct as a result of the Cretaceous–Paleogene extinction event, K-Pg event at the end of the Cretaceous period, about 66 million years ago. Description Mosasaurs breathed air, were powerful swimmers, and were well-adapted to living in the warm, shallow Inland sea (geology), inland seas prevalent during the Late Cretaceous period. Mosasaurs were so well adapted to thi ...
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Holotype Specimen
A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was Species description, formally described. It is either the single such physical example (or illustration) or one of several examples, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature (ICZN), a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae, fungi, and plants (ICN) and ICZN, the definitions of types are similar in intent but not identical in terminology or underlying concept. For example, the holotype for the butterfly ''Plebejus idas, Plebejus idas longinus'' is a preserved specimen of that subspecies, held by the Museum of Comparative Zoology at Harvard University. In botany and mycology, an isotype is a duplicate of the holotype, generally pieces from the same individual plant or samples from the same genetic individual. A ...
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South Dakota
South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux tribe, which comprises a large portion of the population—with nine Indian reservation, reservations in the state—and has historically dominated the territory. South Dakota is the List of U.S. states and territories by area, 17th-largest by area, the List of U.S. states and territories by population, fifth-least populous, and the List of U.S. states and territories by population density, fifth-least densely populated of the List of U.S. states, 50 United States. Pierre, South Dakota, Pierre is the List of capitals in the United States, state capital, and Sioux Falls, South Dakota, Sioux Falls, with a population of about 213,900, is South Dakota's List of cities in South Dakota, most populous city. The state is bisected by the Missouri Ri ...
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