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Cryptoclidia
Cryptoclidia is a clade of plesiosaurs. Cryptoclidia was named and defined as a node clade in 2010 by Hilary Ketchum and Roger Benson: the group consisting of the last common ancestor of ''Cryptoclidus eurymerus'' and ''Polycotylus latipinnis''; and all its descendants. The following cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ... follows an analysis by Benson & Druckenmiller (2014). References Plesiosaurs {{plesiosaur-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microcleididae
Microcleididae is an extinct family of basal plesiosauroid plesiosaurs from the Early Jurassic (middle Sinemurian to late Toarcian stages) of France, Germany, Portugal and the United Kingdom. Currently, the oldest and the most known microcleidid is ''Eretmosaurus'' from the middle Sinemurian of the United Kingdom. Microcleididae was formally named and described by Roger B. J. Benson, Mark Evans and Patrick S. Druckenmiller in 2012. History and Phylogeny Großman (2007) referred informally to "microcleidid elasmosaurs", a clade comprising the three taxa referred to the Microcleididae by Benson ''et al.'' (2012). Ketchum and Benson (2010) found the traditional "microcleidid" genera to nest within a monophyletic Plesiosauridae, in a close position to ''Plesiosaurus''. However, Ketchum and Benson (2011) performed a phylogenetic analysis which found a monospecific Plesiosauridae, and a monophyletic Microcleididae. Smith ''et al.'' (in press) described a new "microcleidid" '' Lusonec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiosaur
The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period, possibly in the Rhaetian stage, about 203 million years ago. They became especially common during the Jurassic Period, thriving until their disappearance due to the Cretaceous–Paleogene extinction event at the end of the Cretaceous Period, about 66 million years ago. They had a worldwide oceanic distribution, and some species at least partly inhabited freshwater environments. Plesiosaurs were among the first fossil reptiles discovered. In the beginning of the nineteenth century, scientists realised how distinctive their build was and they were named as a separate order in 1835. The first plesiosaurian genus, the eponymous ''Plesiosaurus'', was named in 1821. Since then, more than a hundred valid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations containing land animal fossils include the Forest Marble Formation in England, the Kilmaluag Formation in Scotland,British Geological Survey. 2011Stratigraphic framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf: research report RR/11/06 British Geological Survey, Keyworth, Nottingham. the Daohugou Beds in China, the Itat Formation in Russia, and the Isalo III Formation of western Madagascar. Paleogeography During the Middle Jurassic Epoch, Pangaea began to separate into Laurasia and Gondwana, and the Atlantic Ocean formed. Eastern Laurasia was tectonically active as the Cimmerian plate continued to collide with Laurasia's southern coast, completely closing the Paleo-Tethys Ocean. A subduction zone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptoclidus
''Cryptoclidus'' ( ) is a genus of plesiosaur reptile from the Middle Jurassic Period (geology), period of England, France, and Cuba. Discovery ''Cryptoclidus'' was a plesiosaur whose specimens include adult and juvenile skeletons, and remains which have been found in various degrees of preservation in England, Northern France, Russia, and South America. Its name, meaning "hidden clavicles", refer to its small, practically invisible clavicles buried in its front limb girdle. The type species was initially described as ''Plesiosaurus eurymerus'' by Phillips (1871). The specific name "wide femur" refers to the forelimb, which was mistaken for a hindlimb at the time. Fossils of ''Cryptoclidus'' have been found in the Oxford Clay of Cambridgeshire, England. The dubious species ''Cryptoclidus beaugrandi'' is known from Kimmeridgian-age deposits in Boulogne-sur-Mer, France. ''Cryptoclidus vignalensis'', which is now considered undiagnostic, hails from the Jagua Formation of western ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leptocleididae
Leptocleididae is a family of small-sized plesiosaurs that lived during the Early Cretaceous period (early Berriasian to early Albian stage). They had small bodies with small heads and short necks. ''Leptocleidus'' and '' Umoonasaurus'' had round bodies and triangle-shaped heads. Leptocleidids have been found in what were shallow nearshore, freshwater and brackish habitats. Hilary F. Ketchum and Roger B. J. Benson (2010), transferred ''Brancasaurus'', ''Kaiwhekea'', '' Nichollssaura'' and ''Thililua ''Thililua'' is a genus of polycotylid plesiosaur, containing one species, ''T. longicollis''. Discovery The name ''Thililua'' is derived from that of an ancient aquatic god from local Berber mythology; ''longicollis'' refers to the animal's ...'' to this family. However, Ketchum and Benson (2011) reassigned ''Kaiwhekea'' and ''Thililua'' to their original positions, as an elasmosaurid and a polycotylid, respectively. Phylogeny Cladogram based on Ketchum and Benson (2011): ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiopterys
''Plesiopterys'' is an extinct genus of plesiosaur native to Germany. It was a small plesiosaur with the type specimen measuring about long. See also * List of plesiosaur genera * Timeline of plesiosaur research This timeline of plesiosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, taxonomic revisions, and cultural portrayals of plesiosaurs, an order of marine reptiles that flourished duri ... References Jurassic plesiosaurs Fossils of Germany Cryptoclidids Early Jurassic plesiosaurs of Europe Fossil taxa described in 2004 Sauropterygian genera {{paleo-reptile-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Westphaliasaurus
''Westphaliasaurus'' is an extinct genus of plesiosaur from Lower Jurassic (Pliensbachian stage) deposits of Westphalia, northwestern Germany. It is known from a nearly complete and articulated skeleton missing the skull and about 38% of the upper neck vertebrae. It was found by Sönke Simonsen, an amateur paleontologist, in 2007 from the Höxter district near Bielefeld, in the east of North Rhine-Westphalia, Germany. It was first named by Leonie Schwermann and Martin Sander in 2011 and the type species is ''Westphaliasaurus simonsensii''. The generic name is derived from the latinized name for Westfalen, ''Westphalia'' and lizard, ''saurus''. The specific name honors Sönke Simonsen. Estimates suggest that it was about long and weighed . See also * List of plesiosaur genera * Timeline of plesiosaur research This timeline of plesiosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, taxonomic revisions, and cultur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eretmosaurus
''Eretmosaurus'' is an extinct genus of plesiosaur. Taxonomic history ''Eretmosaurus'' was coined by Harry Govier Seeley for ''Plesiosaurus rugosus'' Owen, 1840. Richard Owen had coined the name ''P. rugosus'' for numerous vertebrae from the Early Jurassic Blue Lias of Gloucestershire and other unspecified locations in the UK. Later, Owen described a headless skeleton (NHMUK 14435) that he assigned to ''P. rugosus'',R. Owen. 1865. A monograph of the fossil Reptilia of the Liassic formations. Part I, Sauropterygia. Palaeontographical Society Monographs 17(75):1-40 and Seeley used NHMUK 14435 as the basis for coining a new genus for this species. See also * List of plesiosaur genera * Timeline of plesiosaur research * * List of plesiosaurs This list of plesiosaurs is a comprehensive listing of all genera that have ever been included in the order Plesiosauria, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiosaurus
''Plesiosaurus'' (Greek: ' ('), near to + ' ('), lizard) is a genus of extinct, large marine sauropterygian reptile that lived during the Early Jurassic. It is known by nearly complete skeletons from the Lias Group, Lias of England. It is distinguishable by its small head, long and slender neck, broad turtle-like body, a short tail, and two pairs of large, elongated paddles. It lends its name to the order Plesiosauria, of which it is an early, but fairly typical member. It contains only one species, the type species, type, ''Plesiosaurus dolichodeirus''. Other species once assigned to this genus, including ''P. brachypterygius'', ''P. guilielmiimperatoris'', and ''P. tournemirensis'' have been reassigned to new genera, such as ''Hydrorion'', ''Seeleyosaurus'' and ''Occitanosaurus''. Discovery The first complete skeleton of ''Plesiosaurus'' was discovered by early paleontologist and fossil hunter Mary Anning in Sinemurian (Early Jurassic)-age rocks of the lower Lias Group in Dec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiosauroidea
Plesiosauroidea (; Greek: 'near, close to' and 'lizard') is an extinct clade of carnivorous marine reptiles. They have the snake-like longest neck to body ratio of any reptile. Plesiosauroids are known from the Jurassic and Cretaceous periods. After their discovery, some plesiosauroids were said to have resembled "a snake threaded through the shell of a turtle", although they had no shell. Plesiosauroidea appeared at the Early Jurassic Period (late Sinemurian stage) and thrived until the K-Pg extinction, at the end of the Cretaceous Period. The oldest confirmed plesiosauroid is ''Plesiosaurus'' itself, as all younger taxa were recently found to be pliosauroids. While they were Mesozoic diapsid reptiles that lived at the same time as dinosaurs, they did not belong to the latter. Gastroliths are frequently found associated with plesiosaurs. History of discovery The first complete plesiosauroid skeletons were found in England by Mary Anning, in the early 19th century, and wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other evolutionary narratives about ance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycotylus
''Polycotylus'' is a genus of plesiosaur within the family Polycotylidae. The type species is ''P. latippinis'' and was named by American paleontologist Edward Drinker Cope in 1869. Eleven other species have been identified. The name means 'much-cupped vertebrae', referring to the shape of the vertebrae. It lived in the Western Interior Seaway of North America toward the end of the Cretaceous. One fossil preserves an adult with a single large fetus inside of it, indicating that ''Polycotylus'' gave live birth, an unusual adaptation among reptiles. History Edward Drinker Cope named ''Polycotylus'' from the Niobrara Formation in Kansas in 1869. The holotype bones from which he based his description were fragmentary, representing only a small portion of the skeleton. A more complete skeleton was later found in Kansas and was described in 1906. A nearly complete skeleton was found in 1949 from the Mooreville Chalk Formation in Alabama, but was not described until 2002. A new species, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
